mirror of
https://github.com/torvalds/linux
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7989 lines
224 KiB
C
7989 lines
224 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* kernel/workqueue.c - generic async execution with shared worker pool
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*
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* Copyright (C) 2002 Ingo Molnar
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*
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* Derived from the taskqueue/keventd code by:
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* David Woodhouse <dwmw2@infradead.org>
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* Andrew Morton
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* Kai Petzke <wpp@marie.physik.tu-berlin.de>
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* Theodore Ts'o <tytso@mit.edu>
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*
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* Made to use alloc_percpu by Christoph Lameter.
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*
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* Copyright (C) 2010 SUSE Linux Products GmbH
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* Copyright (C) 2010 Tejun Heo <tj@kernel.org>
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*
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* This is the generic async execution mechanism. Work items as are
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* executed in process context. The worker pool is shared and
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* automatically managed. There are two worker pools for each CPU (one for
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* normal work items and the other for high priority ones) and some extra
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* pools for workqueues which are not bound to any specific CPU - the
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* number of these backing pools is dynamic.
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*
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* Please read Documentation/core-api/workqueue.rst for details.
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*/
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#include <linux/export.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/signal.h>
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#include <linux/completion.h>
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#include <linux/workqueue.h>
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#include <linux/slab.h>
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#include <linux/cpu.h>
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#include <linux/notifier.h>
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#include <linux/kthread.h>
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#include <linux/hardirq.h>
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#include <linux/mempolicy.h>
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#include <linux/freezer.h>
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#include <linux/debug_locks.h>
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#include <linux/lockdep.h>
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#include <linux/idr.h>
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#include <linux/jhash.h>
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#include <linux/hashtable.h>
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#include <linux/rculist.h>
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#include <linux/nodemask.h>
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#include <linux/moduleparam.h>
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#include <linux/uaccess.h>
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#include <linux/sched/isolation.h>
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#include <linux/sched/debug.h>
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#include <linux/nmi.h>
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#include <linux/kvm_para.h>
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#include <linux/delay.h>
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#include <linux/irq_work.h>
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#include "workqueue_internal.h"
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enum worker_pool_flags {
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/*
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* worker_pool flags
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*
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* A bound pool is either associated or disassociated with its CPU.
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* While associated (!DISASSOCIATED), all workers are bound to the
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* CPU and none has %WORKER_UNBOUND set and concurrency management
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* is in effect.
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*
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* While DISASSOCIATED, the cpu may be offline and all workers have
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* %WORKER_UNBOUND set and concurrency management disabled, and may
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* be executing on any CPU. The pool behaves as an unbound one.
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*
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* Note that DISASSOCIATED should be flipped only while holding
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* wq_pool_attach_mutex to avoid changing binding state while
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* worker_attach_to_pool() is in progress.
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*
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* As there can only be one concurrent BH execution context per CPU, a
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* BH pool is per-CPU and always DISASSOCIATED.
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*/
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POOL_BH = 1 << 0, /* is a BH pool */
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POOL_MANAGER_ACTIVE = 1 << 1, /* being managed */
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POOL_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */
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POOL_BH_DRAINING = 1 << 3, /* draining after CPU offline */
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};
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enum worker_flags {
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/* worker flags */
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WORKER_DIE = 1 << 1, /* die die die */
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WORKER_IDLE = 1 << 2, /* is idle */
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WORKER_PREP = 1 << 3, /* preparing to run works */
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WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */
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WORKER_UNBOUND = 1 << 7, /* worker is unbound */
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WORKER_REBOUND = 1 << 8, /* worker was rebound */
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WORKER_NOT_RUNNING = WORKER_PREP | WORKER_CPU_INTENSIVE |
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WORKER_UNBOUND | WORKER_REBOUND,
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};
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enum work_cancel_flags {
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WORK_CANCEL_DELAYED = 1 << 0, /* canceling a delayed_work */
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WORK_CANCEL_DISABLE = 1 << 1, /* canceling to disable */
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};
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enum wq_internal_consts {
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NR_STD_WORKER_POOLS = 2, /* # standard pools per cpu */
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UNBOUND_POOL_HASH_ORDER = 6, /* hashed by pool->attrs */
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BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */
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MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */
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IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */
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MAYDAY_INITIAL_TIMEOUT = HZ / 100 >= 2 ? HZ / 100 : 2,
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/* call for help after 10ms
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(min two ticks) */
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MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */
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CREATE_COOLDOWN = HZ, /* time to breath after fail */
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/*
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* Rescue workers are used only on emergencies and shared by
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* all cpus. Give MIN_NICE.
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*/
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RESCUER_NICE_LEVEL = MIN_NICE,
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HIGHPRI_NICE_LEVEL = MIN_NICE,
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WQ_NAME_LEN = 32,
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};
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/*
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* We don't want to trap softirq for too long. See MAX_SOFTIRQ_TIME and
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* MAX_SOFTIRQ_RESTART in kernel/softirq.c. These are macros because
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* msecs_to_jiffies() can't be an initializer.
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*/
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#define BH_WORKER_JIFFIES msecs_to_jiffies(2)
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#define BH_WORKER_RESTARTS 10
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/*
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* Structure fields follow one of the following exclusion rules.
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*
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* I: Modifiable by initialization/destruction paths and read-only for
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* everyone else.
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*
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* P: Preemption protected. Disabling preemption is enough and should
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* only be modified and accessed from the local cpu.
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*
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* L: pool->lock protected. Access with pool->lock held.
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*
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* LN: pool->lock and wq_node_nr_active->lock protected for writes. Either for
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* reads.
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*
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* K: Only modified by worker while holding pool->lock. Can be safely read by
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* self, while holding pool->lock or from IRQ context if %current is the
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* kworker.
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*
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* S: Only modified by worker self.
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*
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* A: wq_pool_attach_mutex protected.
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*
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* PL: wq_pool_mutex protected.
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*
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* PR: wq_pool_mutex protected for writes. RCU protected for reads.
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*
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* PW: wq_pool_mutex and wq->mutex protected for writes. Either for reads.
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*
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* PWR: wq_pool_mutex and wq->mutex protected for writes. Either or
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* RCU for reads.
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*
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* WQ: wq->mutex protected.
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*
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* WR: wq->mutex protected for writes. RCU protected for reads.
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*
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* WO: wq->mutex protected for writes. Updated with WRITE_ONCE() and can be read
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* with READ_ONCE() without locking.
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*
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* MD: wq_mayday_lock protected.
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*
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* WD: Used internally by the watchdog.
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*/
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/* struct worker is defined in workqueue_internal.h */
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struct worker_pool {
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raw_spinlock_t lock; /* the pool lock */
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int cpu; /* I: the associated cpu */
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int node; /* I: the associated node ID */
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int id; /* I: pool ID */
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unsigned int flags; /* L: flags */
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unsigned long watchdog_ts; /* L: watchdog timestamp */
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bool cpu_stall; /* WD: stalled cpu bound pool */
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/*
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* The counter is incremented in a process context on the associated CPU
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* w/ preemption disabled, and decremented or reset in the same context
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* but w/ pool->lock held. The readers grab pool->lock and are
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* guaranteed to see if the counter reached zero.
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*/
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int nr_running;
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struct list_head worklist; /* L: list of pending works */
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int nr_workers; /* L: total number of workers */
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int nr_idle; /* L: currently idle workers */
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struct list_head idle_list; /* L: list of idle workers */
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struct timer_list idle_timer; /* L: worker idle timeout */
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struct work_struct idle_cull_work; /* L: worker idle cleanup */
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struct timer_list mayday_timer; /* L: SOS timer for workers */
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/* a workers is either on busy_hash or idle_list, or the manager */
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DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER);
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/* L: hash of busy workers */
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struct worker *manager; /* L: purely informational */
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struct list_head workers; /* A: attached workers */
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struct list_head dying_workers; /* A: workers about to die */
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struct completion *detach_completion; /* all workers detached */
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struct ida worker_ida; /* worker IDs for task name */
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struct workqueue_attrs *attrs; /* I: worker attributes */
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struct hlist_node hash_node; /* PL: unbound_pool_hash node */
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int refcnt; /* PL: refcnt for unbound pools */
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/*
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* Destruction of pool is RCU protected to allow dereferences
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* from get_work_pool().
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*/
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struct rcu_head rcu;
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};
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/*
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* Per-pool_workqueue statistics. These can be monitored using
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* tools/workqueue/wq_monitor.py.
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*/
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enum pool_workqueue_stats {
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PWQ_STAT_STARTED, /* work items started execution */
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PWQ_STAT_COMPLETED, /* work items completed execution */
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PWQ_STAT_CPU_TIME, /* total CPU time consumed */
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PWQ_STAT_CPU_INTENSIVE, /* wq_cpu_intensive_thresh_us violations */
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PWQ_STAT_CM_WAKEUP, /* concurrency-management worker wakeups */
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PWQ_STAT_REPATRIATED, /* unbound workers brought back into scope */
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PWQ_STAT_MAYDAY, /* maydays to rescuer */
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PWQ_STAT_RESCUED, /* linked work items executed by rescuer */
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PWQ_NR_STATS,
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};
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/*
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* The per-pool workqueue. While queued, bits below WORK_PWQ_SHIFT
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* of work_struct->data are used for flags and the remaining high bits
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* point to the pwq; thus, pwqs need to be aligned at two's power of the
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* number of flag bits.
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*/
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struct pool_workqueue {
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struct worker_pool *pool; /* I: the associated pool */
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struct workqueue_struct *wq; /* I: the owning workqueue */
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int work_color; /* L: current color */
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int flush_color; /* L: flushing color */
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int refcnt; /* L: reference count */
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int nr_in_flight[WORK_NR_COLORS];
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/* L: nr of in_flight works */
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bool plugged; /* L: execution suspended */
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/*
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* nr_active management and WORK_STRUCT_INACTIVE:
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*
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* When pwq->nr_active >= max_active, new work item is queued to
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* pwq->inactive_works instead of pool->worklist and marked with
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* WORK_STRUCT_INACTIVE.
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*
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* All work items marked with WORK_STRUCT_INACTIVE do not participate in
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* nr_active and all work items in pwq->inactive_works are marked with
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* WORK_STRUCT_INACTIVE. But not all WORK_STRUCT_INACTIVE work items are
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* in pwq->inactive_works. Some of them are ready to run in
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* pool->worklist or worker->scheduled. Those work itmes are only struct
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* wq_barrier which is used for flush_work() and should not participate
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* in nr_active. For non-barrier work item, it is marked with
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* WORK_STRUCT_INACTIVE iff it is in pwq->inactive_works.
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*/
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int nr_active; /* L: nr of active works */
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struct list_head inactive_works; /* L: inactive works */
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struct list_head pending_node; /* LN: node on wq_node_nr_active->pending_pwqs */
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struct list_head pwqs_node; /* WR: node on wq->pwqs */
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struct list_head mayday_node; /* MD: node on wq->maydays */
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u64 stats[PWQ_NR_STATS];
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/*
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* Release of unbound pwq is punted to a kthread_worker. See put_pwq()
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* and pwq_release_workfn() for details. pool_workqueue itself is also
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* RCU protected so that the first pwq can be determined without
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* grabbing wq->mutex.
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*/
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struct kthread_work release_work;
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struct rcu_head rcu;
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} __aligned(1 << WORK_STRUCT_PWQ_SHIFT);
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/*
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* Structure used to wait for workqueue flush.
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*/
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struct wq_flusher {
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struct list_head list; /* WQ: list of flushers */
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int flush_color; /* WQ: flush color waiting for */
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struct completion done; /* flush completion */
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};
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struct wq_device;
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/*
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* Unlike in a per-cpu workqueue where max_active limits its concurrency level
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* on each CPU, in an unbound workqueue, max_active applies to the whole system.
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* As sharing a single nr_active across multiple sockets can be very expensive,
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* the counting and enforcement is per NUMA node.
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*
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* The following struct is used to enforce per-node max_active. When a pwq wants
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* to start executing a work item, it should increment ->nr using
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* tryinc_node_nr_active(). If acquisition fails due to ->nr already being over
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* ->max, the pwq is queued on ->pending_pwqs. As in-flight work items finish
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* and decrement ->nr, node_activate_pending_pwq() activates the pending pwqs in
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* round-robin order.
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*/
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struct wq_node_nr_active {
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int max; /* per-node max_active */
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atomic_t nr; /* per-node nr_active */
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raw_spinlock_t lock; /* nests inside pool locks */
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struct list_head pending_pwqs; /* LN: pwqs with inactive works */
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};
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/*
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* The externally visible workqueue. It relays the issued work items to
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* the appropriate worker_pool through its pool_workqueues.
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*/
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struct workqueue_struct {
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struct list_head pwqs; /* WR: all pwqs of this wq */
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struct list_head list; /* PR: list of all workqueues */
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struct mutex mutex; /* protects this wq */
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int work_color; /* WQ: current work color */
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int flush_color; /* WQ: current flush color */
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atomic_t nr_pwqs_to_flush; /* flush in progress */
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struct wq_flusher *first_flusher; /* WQ: first flusher */
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struct list_head flusher_queue; /* WQ: flush waiters */
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struct list_head flusher_overflow; /* WQ: flush overflow list */
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struct list_head maydays; /* MD: pwqs requesting rescue */
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struct worker *rescuer; /* MD: rescue worker */
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int nr_drainers; /* WQ: drain in progress */
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/* See alloc_workqueue() function comment for info on min/max_active */
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int max_active; /* WO: max active works */
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int min_active; /* WO: min active works */
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int saved_max_active; /* WQ: saved max_active */
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int saved_min_active; /* WQ: saved min_active */
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struct workqueue_attrs *unbound_attrs; /* PW: only for unbound wqs */
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struct pool_workqueue __rcu *dfl_pwq; /* PW: only for unbound wqs */
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#ifdef CONFIG_SYSFS
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struct wq_device *wq_dev; /* I: for sysfs interface */
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#endif
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#ifdef CONFIG_LOCKDEP
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char *lock_name;
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struct lock_class_key key;
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struct lockdep_map lockdep_map;
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#endif
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char name[WQ_NAME_LEN]; /* I: workqueue name */
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/*
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* Destruction of workqueue_struct is RCU protected to allow walking
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* the workqueues list without grabbing wq_pool_mutex.
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* This is used to dump all workqueues from sysrq.
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*/
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struct rcu_head rcu;
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/* hot fields used during command issue, aligned to cacheline */
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unsigned int flags ____cacheline_aligned; /* WQ: WQ_* flags */
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struct pool_workqueue __percpu __rcu **cpu_pwq; /* I: per-cpu pwqs */
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struct wq_node_nr_active *node_nr_active[]; /* I: per-node nr_active */
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};
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/*
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* Each pod type describes how CPUs should be grouped for unbound workqueues.
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* See the comment above workqueue_attrs->affn_scope.
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*/
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struct wq_pod_type {
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int nr_pods; /* number of pods */
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cpumask_var_t *pod_cpus; /* pod -> cpus */
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int *pod_node; /* pod -> node */
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int *cpu_pod; /* cpu -> pod */
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};
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struct work_offq_data {
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u32 pool_id;
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u32 disable;
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u32 flags;
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};
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static const char *wq_affn_names[WQ_AFFN_NR_TYPES] = {
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[WQ_AFFN_DFL] = "default",
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[WQ_AFFN_CPU] = "cpu",
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[WQ_AFFN_SMT] = "smt",
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[WQ_AFFN_CACHE] = "cache",
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[WQ_AFFN_NUMA] = "numa",
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[WQ_AFFN_SYSTEM] = "system",
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};
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/*
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* Per-cpu work items which run for longer than the following threshold are
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* automatically considered CPU intensive and excluded from concurrency
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* management to prevent them from noticeably delaying other per-cpu work items.
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* ULONG_MAX indicates that the user hasn't overridden it with a boot parameter.
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* The actual value is initialized in wq_cpu_intensive_thresh_init().
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*/
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static unsigned long wq_cpu_intensive_thresh_us = ULONG_MAX;
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module_param_named(cpu_intensive_thresh_us, wq_cpu_intensive_thresh_us, ulong, 0644);
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#ifdef CONFIG_WQ_CPU_INTENSIVE_REPORT
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static unsigned int wq_cpu_intensive_warning_thresh = 4;
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module_param_named(cpu_intensive_warning_thresh, wq_cpu_intensive_warning_thresh, uint, 0644);
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#endif
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/* see the comment above the definition of WQ_POWER_EFFICIENT */
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static bool wq_power_efficient = IS_ENABLED(CONFIG_WQ_POWER_EFFICIENT_DEFAULT);
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module_param_named(power_efficient, wq_power_efficient, bool, 0444);
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static bool wq_online; /* can kworkers be created yet? */
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static bool wq_topo_initialized __read_mostly = false;
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static struct kmem_cache *pwq_cache;
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static struct wq_pod_type wq_pod_types[WQ_AFFN_NR_TYPES];
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static enum wq_affn_scope wq_affn_dfl = WQ_AFFN_CACHE;
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/* buf for wq_update_unbound_pod_attrs(), protected by CPU hotplug exclusion */
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static struct workqueue_attrs *wq_update_pod_attrs_buf;
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static DEFINE_MUTEX(wq_pool_mutex); /* protects pools and workqueues list */
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static DEFINE_MUTEX(wq_pool_attach_mutex); /* protects worker attach/detach */
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static DEFINE_RAW_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */
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/* wait for manager to go away */
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static struct rcuwait manager_wait = __RCUWAIT_INITIALIZER(manager_wait);
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static LIST_HEAD(workqueues); /* PR: list of all workqueues */
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static bool workqueue_freezing; /* PL: have wqs started freezing? */
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|
|
/* PL&A: allowable cpus for unbound wqs and work items */
|
|
static cpumask_var_t wq_unbound_cpumask;
|
|
|
|
/* PL: user requested unbound cpumask via sysfs */
|
|
static cpumask_var_t wq_requested_unbound_cpumask;
|
|
|
|
/* PL: isolated cpumask to be excluded from unbound cpumask */
|
|
static cpumask_var_t wq_isolated_cpumask;
|
|
|
|
/* for further constrain wq_unbound_cpumask by cmdline parameter*/
|
|
static struct cpumask wq_cmdline_cpumask __initdata;
|
|
|
|
/* CPU where unbound work was last round robin scheduled from this CPU */
|
|
static DEFINE_PER_CPU(int, wq_rr_cpu_last);
|
|
|
|
/*
|
|
* Local execution of unbound work items is no longer guaranteed. The
|
|
* following always forces round-robin CPU selection on unbound work items
|
|
* to uncover usages which depend on it.
|
|
*/
|
|
#ifdef CONFIG_DEBUG_WQ_FORCE_RR_CPU
|
|
static bool wq_debug_force_rr_cpu = true;
|
|
#else
|
|
static bool wq_debug_force_rr_cpu = false;
|
|
#endif
|
|
module_param_named(debug_force_rr_cpu, wq_debug_force_rr_cpu, bool, 0644);
|
|
|
|
/* to raise softirq for the BH worker pools on other CPUs */
|
|
static DEFINE_PER_CPU_SHARED_ALIGNED(struct irq_work [NR_STD_WORKER_POOLS],
|
|
bh_pool_irq_works);
|
|
|
|
/* the BH worker pools */
|
|
static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS],
|
|
bh_worker_pools);
|
|
|
|
/* the per-cpu worker pools */
|
|
static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS],
|
|
cpu_worker_pools);
|
|
|
|
static DEFINE_IDR(worker_pool_idr); /* PR: idr of all pools */
|
|
|
|
/* PL: hash of all unbound pools keyed by pool->attrs */
|
|
static DEFINE_HASHTABLE(unbound_pool_hash, UNBOUND_POOL_HASH_ORDER);
|
|
|
|
/* I: attributes used when instantiating standard unbound pools on demand */
|
|
static struct workqueue_attrs *unbound_std_wq_attrs[NR_STD_WORKER_POOLS];
|
|
|
|
/* I: attributes used when instantiating ordered pools on demand */
|
|
static struct workqueue_attrs *ordered_wq_attrs[NR_STD_WORKER_POOLS];
|
|
|
|
/*
|
|
* I: kthread_worker to release pwq's. pwq release needs to be bounced to a
|
|
* process context while holding a pool lock. Bounce to a dedicated kthread
|
|
* worker to avoid A-A deadlocks.
|
|
*/
|
|
static struct kthread_worker *pwq_release_worker __ro_after_init;
|
|
|
|
struct workqueue_struct *system_wq __ro_after_init;
|
|
EXPORT_SYMBOL(system_wq);
|
|
struct workqueue_struct *system_highpri_wq __ro_after_init;
|
|
EXPORT_SYMBOL_GPL(system_highpri_wq);
|
|
struct workqueue_struct *system_long_wq __ro_after_init;
|
|
EXPORT_SYMBOL_GPL(system_long_wq);
|
|
struct workqueue_struct *system_unbound_wq __ro_after_init;
|
|
EXPORT_SYMBOL_GPL(system_unbound_wq);
|
|
struct workqueue_struct *system_freezable_wq __ro_after_init;
|
|
EXPORT_SYMBOL_GPL(system_freezable_wq);
|
|
struct workqueue_struct *system_power_efficient_wq __ro_after_init;
|
|
EXPORT_SYMBOL_GPL(system_power_efficient_wq);
|
|
struct workqueue_struct *system_freezable_power_efficient_wq __ro_after_init;
|
|
EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq);
|
|
struct workqueue_struct *system_bh_wq;
|
|
EXPORT_SYMBOL_GPL(system_bh_wq);
|
|
struct workqueue_struct *system_bh_highpri_wq;
|
|
EXPORT_SYMBOL_GPL(system_bh_highpri_wq);
|
|
|
|
static int worker_thread(void *__worker);
|
|
static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
|
|
static void show_pwq(struct pool_workqueue *pwq);
|
|
static void show_one_worker_pool(struct worker_pool *pool);
|
|
|
|
#define CREATE_TRACE_POINTS
|
|
#include <trace/events/workqueue.h>
|
|
|
|
#define assert_rcu_or_pool_mutex() \
|
|
RCU_LOCKDEP_WARN(!rcu_read_lock_any_held() && \
|
|
!lockdep_is_held(&wq_pool_mutex), \
|
|
"RCU or wq_pool_mutex should be held")
|
|
|
|
#define assert_rcu_or_wq_mutex_or_pool_mutex(wq) \
|
|
RCU_LOCKDEP_WARN(!rcu_read_lock_any_held() && \
|
|
!lockdep_is_held(&wq->mutex) && \
|
|
!lockdep_is_held(&wq_pool_mutex), \
|
|
"RCU, wq->mutex or wq_pool_mutex should be held")
|
|
|
|
#define for_each_bh_worker_pool(pool, cpu) \
|
|
for ((pool) = &per_cpu(bh_worker_pools, cpu)[0]; \
|
|
(pool) < &per_cpu(bh_worker_pools, cpu)[NR_STD_WORKER_POOLS]; \
|
|
(pool)++)
|
|
|
|
#define for_each_cpu_worker_pool(pool, cpu) \
|
|
for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0]; \
|
|
(pool) < &per_cpu(cpu_worker_pools, cpu)[NR_STD_WORKER_POOLS]; \
|
|
(pool)++)
|
|
|
|
/**
|
|
* for_each_pool - iterate through all worker_pools in the system
|
|
* @pool: iteration cursor
|
|
* @pi: integer used for iteration
|
|
*
|
|
* This must be called either with wq_pool_mutex held or RCU read
|
|
* locked. If the pool needs to be used beyond the locking in effect, the
|
|
* caller is responsible for guaranteeing that the pool stays online.
|
|
*
|
|
* The if/else clause exists only for the lockdep assertion and can be
|
|
* ignored.
|
|
*/
|
|
#define for_each_pool(pool, pi) \
|
|
idr_for_each_entry(&worker_pool_idr, pool, pi) \
|
|
if (({ assert_rcu_or_pool_mutex(); false; })) { } \
|
|
else
|
|
|
|
/**
|
|
* for_each_pool_worker - iterate through all workers of a worker_pool
|
|
* @worker: iteration cursor
|
|
* @pool: worker_pool to iterate workers of
|
|
*
|
|
* This must be called with wq_pool_attach_mutex.
|
|
*
|
|
* The if/else clause exists only for the lockdep assertion and can be
|
|
* ignored.
|
|
*/
|
|
#define for_each_pool_worker(worker, pool) \
|
|
list_for_each_entry((worker), &(pool)->workers, node) \
|
|
if (({ lockdep_assert_held(&wq_pool_attach_mutex); false; })) { } \
|
|
else
|
|
|
|
/**
|
|
* for_each_pwq - iterate through all pool_workqueues of the specified workqueue
|
|
* @pwq: iteration cursor
|
|
* @wq: the target workqueue
|
|
*
|
|
* This must be called either with wq->mutex held or RCU read locked.
|
|
* If the pwq needs to be used beyond the locking in effect, the caller is
|
|
* responsible for guaranteeing that the pwq stays online.
|
|
*
|
|
* The if/else clause exists only for the lockdep assertion and can be
|
|
* ignored.
|
|
*/
|
|
#define for_each_pwq(pwq, wq) \
|
|
list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node, \
|
|
lockdep_is_held(&(wq->mutex)))
|
|
|
|
#ifdef CONFIG_DEBUG_OBJECTS_WORK
|
|
|
|
static const struct debug_obj_descr work_debug_descr;
|
|
|
|
static void *work_debug_hint(void *addr)
|
|
{
|
|
return ((struct work_struct *) addr)->func;
|
|
}
|
|
|
|
static bool work_is_static_object(void *addr)
|
|
{
|
|
struct work_struct *work = addr;
|
|
|
|
return test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work));
|
|
}
|
|
|
|
/*
|
|
* fixup_init is called when:
|
|
* - an active object is initialized
|
|
*/
|
|
static bool work_fixup_init(void *addr, enum debug_obj_state state)
|
|
{
|
|
struct work_struct *work = addr;
|
|
|
|
switch (state) {
|
|
case ODEBUG_STATE_ACTIVE:
|
|
cancel_work_sync(work);
|
|
debug_object_init(work, &work_debug_descr);
|
|
return true;
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* fixup_free is called when:
|
|
* - an active object is freed
|
|
*/
|
|
static bool work_fixup_free(void *addr, enum debug_obj_state state)
|
|
{
|
|
struct work_struct *work = addr;
|
|
|
|
switch (state) {
|
|
case ODEBUG_STATE_ACTIVE:
|
|
cancel_work_sync(work);
|
|
debug_object_free(work, &work_debug_descr);
|
|
return true;
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
static const struct debug_obj_descr work_debug_descr = {
|
|
.name = "work_struct",
|
|
.debug_hint = work_debug_hint,
|
|
.is_static_object = work_is_static_object,
|
|
.fixup_init = work_fixup_init,
|
|
.fixup_free = work_fixup_free,
|
|
};
|
|
|
|
static inline void debug_work_activate(struct work_struct *work)
|
|
{
|
|
debug_object_activate(work, &work_debug_descr);
|
|
}
|
|
|
|
static inline void debug_work_deactivate(struct work_struct *work)
|
|
{
|
|
debug_object_deactivate(work, &work_debug_descr);
|
|
}
|
|
|
|
void __init_work(struct work_struct *work, int onstack)
|
|
{
|
|
if (onstack)
|
|
debug_object_init_on_stack(work, &work_debug_descr);
|
|
else
|
|
debug_object_init(work, &work_debug_descr);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__init_work);
|
|
|
|
void destroy_work_on_stack(struct work_struct *work)
|
|
{
|
|
debug_object_free(work, &work_debug_descr);
|
|
}
|
|
EXPORT_SYMBOL_GPL(destroy_work_on_stack);
|
|
|
|
void destroy_delayed_work_on_stack(struct delayed_work *work)
|
|
{
|
|
destroy_timer_on_stack(&work->timer);
|
|
debug_object_free(&work->work, &work_debug_descr);
|
|
}
|
|
EXPORT_SYMBOL_GPL(destroy_delayed_work_on_stack);
|
|
|
|
#else
|
|
static inline void debug_work_activate(struct work_struct *work) { }
|
|
static inline void debug_work_deactivate(struct work_struct *work) { }
|
|
#endif
|
|
|
|
/**
|
|
* worker_pool_assign_id - allocate ID and assign it to @pool
|
|
* @pool: the pool pointer of interest
|
|
*
|
|
* Returns 0 if ID in [0, WORK_OFFQ_POOL_NONE) is allocated and assigned
|
|
* successfully, -errno on failure.
|
|
*/
|
|
static int worker_pool_assign_id(struct worker_pool *pool)
|
|
{
|
|
int ret;
|
|
|
|
lockdep_assert_held(&wq_pool_mutex);
|
|
|
|
ret = idr_alloc(&worker_pool_idr, pool, 0, WORK_OFFQ_POOL_NONE,
|
|
GFP_KERNEL);
|
|
if (ret >= 0) {
|
|
pool->id = ret;
|
|
return 0;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static struct pool_workqueue __rcu **
|
|
unbound_pwq_slot(struct workqueue_struct *wq, int cpu)
|
|
{
|
|
if (cpu >= 0)
|
|
return per_cpu_ptr(wq->cpu_pwq, cpu);
|
|
else
|
|
return &wq->dfl_pwq;
|
|
}
|
|
|
|
/* @cpu < 0 for dfl_pwq */
|
|
static struct pool_workqueue *unbound_pwq(struct workqueue_struct *wq, int cpu)
|
|
{
|
|
return rcu_dereference_check(*unbound_pwq_slot(wq, cpu),
|
|
lockdep_is_held(&wq_pool_mutex) ||
|
|
lockdep_is_held(&wq->mutex));
|
|
}
|
|
|
|
/**
|
|
* unbound_effective_cpumask - effective cpumask of an unbound workqueue
|
|
* @wq: workqueue of interest
|
|
*
|
|
* @wq->unbound_attrs->cpumask contains the cpumask requested by the user which
|
|
* is masked with wq_unbound_cpumask to determine the effective cpumask. The
|
|
* default pwq is always mapped to the pool with the current effective cpumask.
|
|
*/
|
|
static struct cpumask *unbound_effective_cpumask(struct workqueue_struct *wq)
|
|
{
|
|
return unbound_pwq(wq, -1)->pool->attrs->__pod_cpumask;
|
|
}
|
|
|
|
static unsigned int work_color_to_flags(int color)
|
|
{
|
|
return color << WORK_STRUCT_COLOR_SHIFT;
|
|
}
|
|
|
|
static int get_work_color(unsigned long work_data)
|
|
{
|
|
return (work_data >> WORK_STRUCT_COLOR_SHIFT) &
|
|
((1 << WORK_STRUCT_COLOR_BITS) - 1);
|
|
}
|
|
|
|
static int work_next_color(int color)
|
|
{
|
|
return (color + 1) % WORK_NR_COLORS;
|
|
}
|
|
|
|
static unsigned long pool_offq_flags(struct worker_pool *pool)
|
|
{
|
|
return (pool->flags & POOL_BH) ? WORK_OFFQ_BH : 0;
|
|
}
|
|
|
|
/*
|
|
* While queued, %WORK_STRUCT_PWQ is set and non flag bits of a work's data
|
|
* contain the pointer to the queued pwq. Once execution starts, the flag
|
|
* is cleared and the high bits contain OFFQ flags and pool ID.
|
|
*
|
|
* set_work_pwq(), set_work_pool_and_clear_pending() and mark_work_canceling()
|
|
* can be used to set the pwq, pool or clear work->data. These functions should
|
|
* only be called while the work is owned - ie. while the PENDING bit is set.
|
|
*
|
|
* get_work_pool() and get_work_pwq() can be used to obtain the pool or pwq
|
|
* corresponding to a work. Pool is available once the work has been
|
|
* queued anywhere after initialization until it is sync canceled. pwq is
|
|
* available only while the work item is queued.
|
|
*/
|
|
static inline void set_work_data(struct work_struct *work, unsigned long data)
|
|
{
|
|
WARN_ON_ONCE(!work_pending(work));
|
|
atomic_long_set(&work->data, data | work_static(work));
|
|
}
|
|
|
|
static void set_work_pwq(struct work_struct *work, struct pool_workqueue *pwq,
|
|
unsigned long flags)
|
|
{
|
|
set_work_data(work, (unsigned long)pwq | WORK_STRUCT_PENDING |
|
|
WORK_STRUCT_PWQ | flags);
|
|
}
|
|
|
|
static void set_work_pool_and_keep_pending(struct work_struct *work,
|
|
int pool_id, unsigned long flags)
|
|
{
|
|
set_work_data(work, ((unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT) |
|
|
WORK_STRUCT_PENDING | flags);
|
|
}
|
|
|
|
static void set_work_pool_and_clear_pending(struct work_struct *work,
|
|
int pool_id, unsigned long flags)
|
|
{
|
|
/*
|
|
* The following wmb is paired with the implied mb in
|
|
* test_and_set_bit(PENDING) and ensures all updates to @work made
|
|
* here are visible to and precede any updates by the next PENDING
|
|
* owner.
|
|
*/
|
|
smp_wmb();
|
|
set_work_data(work, ((unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT) |
|
|
flags);
|
|
/*
|
|
* The following mb guarantees that previous clear of a PENDING bit
|
|
* will not be reordered with any speculative LOADS or STORES from
|
|
* work->current_func, which is executed afterwards. This possible
|
|
* reordering can lead to a missed execution on attempt to queue
|
|
* the same @work. E.g. consider this case:
|
|
*
|
|
* CPU#0 CPU#1
|
|
* ---------------------------- --------------------------------
|
|
*
|
|
* 1 STORE event_indicated
|
|
* 2 queue_work_on() {
|
|
* 3 test_and_set_bit(PENDING)
|
|
* 4 } set_..._and_clear_pending() {
|
|
* 5 set_work_data() # clear bit
|
|
* 6 smp_mb()
|
|
* 7 work->current_func() {
|
|
* 8 LOAD event_indicated
|
|
* }
|
|
*
|
|
* Without an explicit full barrier speculative LOAD on line 8 can
|
|
* be executed before CPU#0 does STORE on line 1. If that happens,
|
|
* CPU#0 observes the PENDING bit is still set and new execution of
|
|
* a @work is not queued in a hope, that CPU#1 will eventually
|
|
* finish the queued @work. Meanwhile CPU#1 does not see
|
|
* event_indicated is set, because speculative LOAD was executed
|
|
* before actual STORE.
|
|
*/
|
|
smp_mb();
|
|
}
|
|
|
|
static inline struct pool_workqueue *work_struct_pwq(unsigned long data)
|
|
{
|
|
return (struct pool_workqueue *)(data & WORK_STRUCT_PWQ_MASK);
|
|
}
|
|
|
|
static struct pool_workqueue *get_work_pwq(struct work_struct *work)
|
|
{
|
|
unsigned long data = atomic_long_read(&work->data);
|
|
|
|
if (data & WORK_STRUCT_PWQ)
|
|
return work_struct_pwq(data);
|
|
else
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* get_work_pool - return the worker_pool a given work was associated with
|
|
* @work: the work item of interest
|
|
*
|
|
* Pools are created and destroyed under wq_pool_mutex, and allows read
|
|
* access under RCU read lock. As such, this function should be
|
|
* called under wq_pool_mutex or inside of a rcu_read_lock() region.
|
|
*
|
|
* All fields of the returned pool are accessible as long as the above
|
|
* mentioned locking is in effect. If the returned pool needs to be used
|
|
* beyond the critical section, the caller is responsible for ensuring the
|
|
* returned pool is and stays online.
|
|
*
|
|
* Return: The worker_pool @work was last associated with. %NULL if none.
|
|
*/
|
|
static struct worker_pool *get_work_pool(struct work_struct *work)
|
|
{
|
|
unsigned long data = atomic_long_read(&work->data);
|
|
int pool_id;
|
|
|
|
assert_rcu_or_pool_mutex();
|
|
|
|
if (data & WORK_STRUCT_PWQ)
|
|
return work_struct_pwq(data)->pool;
|
|
|
|
pool_id = data >> WORK_OFFQ_POOL_SHIFT;
|
|
if (pool_id == WORK_OFFQ_POOL_NONE)
|
|
return NULL;
|
|
|
|
return idr_find(&worker_pool_idr, pool_id);
|
|
}
|
|
|
|
static unsigned long shift_and_mask(unsigned long v, u32 shift, u32 bits)
|
|
{
|
|
return (v >> shift) & ((1 << bits) - 1);
|
|
}
|
|
|
|
static void work_offqd_unpack(struct work_offq_data *offqd, unsigned long data)
|
|
{
|
|
WARN_ON_ONCE(data & WORK_STRUCT_PWQ);
|
|
|
|
offqd->pool_id = shift_and_mask(data, WORK_OFFQ_POOL_SHIFT,
|
|
WORK_OFFQ_POOL_BITS);
|
|
offqd->disable = shift_and_mask(data, WORK_OFFQ_DISABLE_SHIFT,
|
|
WORK_OFFQ_DISABLE_BITS);
|
|
offqd->flags = data & WORK_OFFQ_FLAG_MASK;
|
|
}
|
|
|
|
static unsigned long work_offqd_pack_flags(struct work_offq_data *offqd)
|
|
{
|
|
return ((unsigned long)offqd->disable << WORK_OFFQ_DISABLE_SHIFT) |
|
|
((unsigned long)offqd->flags);
|
|
}
|
|
|
|
/*
|
|
* Policy functions. These define the policies on how the global worker
|
|
* pools are managed. Unless noted otherwise, these functions assume that
|
|
* they're being called with pool->lock held.
|
|
*/
|
|
|
|
/*
|
|
* Need to wake up a worker? Called from anything but currently
|
|
* running workers.
|
|
*
|
|
* Note that, because unbound workers never contribute to nr_running, this
|
|
* function will always return %true for unbound pools as long as the
|
|
* worklist isn't empty.
|
|
*/
|
|
static bool need_more_worker(struct worker_pool *pool)
|
|
{
|
|
return !list_empty(&pool->worklist) && !pool->nr_running;
|
|
}
|
|
|
|
/* Can I start working? Called from busy but !running workers. */
|
|
static bool may_start_working(struct worker_pool *pool)
|
|
{
|
|
return pool->nr_idle;
|
|
}
|
|
|
|
/* Do I need to keep working? Called from currently running workers. */
|
|
static bool keep_working(struct worker_pool *pool)
|
|
{
|
|
return !list_empty(&pool->worklist) && (pool->nr_running <= 1);
|
|
}
|
|
|
|
/* Do we need a new worker? Called from manager. */
|
|
static bool need_to_create_worker(struct worker_pool *pool)
|
|
{
|
|
return need_more_worker(pool) && !may_start_working(pool);
|
|
}
|
|
|
|
/* Do we have too many workers and should some go away? */
|
|
static bool too_many_workers(struct worker_pool *pool)
|
|
{
|
|
bool managing = pool->flags & POOL_MANAGER_ACTIVE;
|
|
int nr_idle = pool->nr_idle + managing; /* manager is considered idle */
|
|
int nr_busy = pool->nr_workers - nr_idle;
|
|
|
|
return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy;
|
|
}
|
|
|
|
/**
|
|
* worker_set_flags - set worker flags and adjust nr_running accordingly
|
|
* @worker: self
|
|
* @flags: flags to set
|
|
*
|
|
* Set @flags in @worker->flags and adjust nr_running accordingly.
|
|
*/
|
|
static inline void worker_set_flags(struct worker *worker, unsigned int flags)
|
|
{
|
|
struct worker_pool *pool = worker->pool;
|
|
|
|
lockdep_assert_held(&pool->lock);
|
|
|
|
/* If transitioning into NOT_RUNNING, adjust nr_running. */
|
|
if ((flags & WORKER_NOT_RUNNING) &&
|
|
!(worker->flags & WORKER_NOT_RUNNING)) {
|
|
pool->nr_running--;
|
|
}
|
|
|
|
worker->flags |= flags;
|
|
}
|
|
|
|
/**
|
|
* worker_clr_flags - clear worker flags and adjust nr_running accordingly
|
|
* @worker: self
|
|
* @flags: flags to clear
|
|
*
|
|
* Clear @flags in @worker->flags and adjust nr_running accordingly.
|
|
*/
|
|
static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
|
|
{
|
|
struct worker_pool *pool = worker->pool;
|
|
unsigned int oflags = worker->flags;
|
|
|
|
lockdep_assert_held(&pool->lock);
|
|
|
|
worker->flags &= ~flags;
|
|
|
|
/*
|
|
* If transitioning out of NOT_RUNNING, increment nr_running. Note
|
|
* that the nested NOT_RUNNING is not a noop. NOT_RUNNING is mask
|
|
* of multiple flags, not a single flag.
|
|
*/
|
|
if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING))
|
|
if (!(worker->flags & WORKER_NOT_RUNNING))
|
|
pool->nr_running++;
|
|
}
|
|
|
|
/* Return the first idle worker. Called with pool->lock held. */
|
|
static struct worker *first_idle_worker(struct worker_pool *pool)
|
|
{
|
|
if (unlikely(list_empty(&pool->idle_list)))
|
|
return NULL;
|
|
|
|
return list_first_entry(&pool->idle_list, struct worker, entry);
|
|
}
|
|
|
|
/**
|
|
* worker_enter_idle - enter idle state
|
|
* @worker: worker which is entering idle state
|
|
*
|
|
* @worker is entering idle state. Update stats and idle timer if
|
|
* necessary.
|
|
*
|
|
* LOCKING:
|
|
* raw_spin_lock_irq(pool->lock).
|
|
*/
|
|
static void worker_enter_idle(struct worker *worker)
|
|
{
|
|
struct worker_pool *pool = worker->pool;
|
|
|
|
if (WARN_ON_ONCE(worker->flags & WORKER_IDLE) ||
|
|
WARN_ON_ONCE(!list_empty(&worker->entry) &&
|
|
(worker->hentry.next || worker->hentry.pprev)))
|
|
return;
|
|
|
|
/* can't use worker_set_flags(), also called from create_worker() */
|
|
worker->flags |= WORKER_IDLE;
|
|
pool->nr_idle++;
|
|
worker->last_active = jiffies;
|
|
|
|
/* idle_list is LIFO */
|
|
list_add(&worker->entry, &pool->idle_list);
|
|
|
|
if (too_many_workers(pool) && !timer_pending(&pool->idle_timer))
|
|
mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT);
|
|
|
|
/* Sanity check nr_running. */
|
|
WARN_ON_ONCE(pool->nr_workers == pool->nr_idle && pool->nr_running);
|
|
}
|
|
|
|
/**
|
|
* worker_leave_idle - leave idle state
|
|
* @worker: worker which is leaving idle state
|
|
*
|
|
* @worker is leaving idle state. Update stats.
|
|
*
|
|
* LOCKING:
|
|
* raw_spin_lock_irq(pool->lock).
|
|
*/
|
|
static void worker_leave_idle(struct worker *worker)
|
|
{
|
|
struct worker_pool *pool = worker->pool;
|
|
|
|
if (WARN_ON_ONCE(!(worker->flags & WORKER_IDLE)))
|
|
return;
|
|
worker_clr_flags(worker, WORKER_IDLE);
|
|
pool->nr_idle--;
|
|
list_del_init(&worker->entry);
|
|
}
|
|
|
|
/**
|
|
* find_worker_executing_work - find worker which is executing a work
|
|
* @pool: pool of interest
|
|
* @work: work to find worker for
|
|
*
|
|
* Find a worker which is executing @work on @pool by searching
|
|
* @pool->busy_hash which is keyed by the address of @work. For a worker
|
|
* to match, its current execution should match the address of @work and
|
|
* its work function. This is to avoid unwanted dependency between
|
|
* unrelated work executions through a work item being recycled while still
|
|
* being executed.
|
|
*
|
|
* This is a bit tricky. A work item may be freed once its execution
|
|
* starts and nothing prevents the freed area from being recycled for
|
|
* another work item. If the same work item address ends up being reused
|
|
* before the original execution finishes, workqueue will identify the
|
|
* recycled work item as currently executing and make it wait until the
|
|
* current execution finishes, introducing an unwanted dependency.
|
|
*
|
|
* This function checks the work item address and work function to avoid
|
|
* false positives. Note that this isn't complete as one may construct a
|
|
* work function which can introduce dependency onto itself through a
|
|
* recycled work item. Well, if somebody wants to shoot oneself in the
|
|
* foot that badly, there's only so much we can do, and if such deadlock
|
|
* actually occurs, it should be easy to locate the culprit work function.
|
|
*
|
|
* CONTEXT:
|
|
* raw_spin_lock_irq(pool->lock).
|
|
*
|
|
* Return:
|
|
* Pointer to worker which is executing @work if found, %NULL
|
|
* otherwise.
|
|
*/
|
|
static struct worker *find_worker_executing_work(struct worker_pool *pool,
|
|
struct work_struct *work)
|
|
{
|
|
struct worker *worker;
|
|
|
|
hash_for_each_possible(pool->busy_hash, worker, hentry,
|
|
(unsigned long)work)
|
|
if (worker->current_work == work &&
|
|
worker->current_func == work->func)
|
|
return worker;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* move_linked_works - move linked works to a list
|
|
* @work: start of series of works to be scheduled
|
|
* @head: target list to append @work to
|
|
* @nextp: out parameter for nested worklist walking
|
|
*
|
|
* Schedule linked works starting from @work to @head. Work series to be
|
|
* scheduled starts at @work and includes any consecutive work with
|
|
* WORK_STRUCT_LINKED set in its predecessor. See assign_work() for details on
|
|
* @nextp.
|
|
*
|
|
* CONTEXT:
|
|
* raw_spin_lock_irq(pool->lock).
|
|
*/
|
|
static void move_linked_works(struct work_struct *work, struct list_head *head,
|
|
struct work_struct **nextp)
|
|
{
|
|
struct work_struct *n;
|
|
|
|
/*
|
|
* Linked worklist will always end before the end of the list,
|
|
* use NULL for list head.
|
|
*/
|
|
list_for_each_entry_safe_from(work, n, NULL, entry) {
|
|
list_move_tail(&work->entry, head);
|
|
if (!(*work_data_bits(work) & WORK_STRUCT_LINKED))
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* If we're already inside safe list traversal and have moved
|
|
* multiple works to the scheduled queue, the next position
|
|
* needs to be updated.
|
|
*/
|
|
if (nextp)
|
|
*nextp = n;
|
|
}
|
|
|
|
/**
|
|
* assign_work - assign a work item and its linked work items to a worker
|
|
* @work: work to assign
|
|
* @worker: worker to assign to
|
|
* @nextp: out parameter for nested worklist walking
|
|
*
|
|
* Assign @work and its linked work items to @worker. If @work is already being
|
|
* executed by another worker in the same pool, it'll be punted there.
|
|
*
|
|
* If @nextp is not NULL, it's updated to point to the next work of the last
|
|
* scheduled work. This allows assign_work() to be nested inside
|
|
* list_for_each_entry_safe().
|
|
*
|
|
* Returns %true if @work was successfully assigned to @worker. %false if @work
|
|
* was punted to another worker already executing it.
|
|
*/
|
|
static bool assign_work(struct work_struct *work, struct worker *worker,
|
|
struct work_struct **nextp)
|
|
{
|
|
struct worker_pool *pool = worker->pool;
|
|
struct worker *collision;
|
|
|
|
lockdep_assert_held(&pool->lock);
|
|
|
|
/*
|
|
* A single work shouldn't be executed concurrently by multiple workers.
|
|
* __queue_work() ensures that @work doesn't jump to a different pool
|
|
* while still running in the previous pool. Here, we should ensure that
|
|
* @work is not executed concurrently by multiple workers from the same
|
|
* pool. Check whether anyone is already processing the work. If so,
|
|
* defer the work to the currently executing one.
|
|
*/
|
|
collision = find_worker_executing_work(pool, work);
|
|
if (unlikely(collision)) {
|
|
move_linked_works(work, &collision->scheduled, nextp);
|
|
return false;
|
|
}
|
|
|
|
move_linked_works(work, &worker->scheduled, nextp);
|
|
return true;
|
|
}
|
|
|
|
static struct irq_work *bh_pool_irq_work(struct worker_pool *pool)
|
|
{
|
|
int high = pool->attrs->nice == HIGHPRI_NICE_LEVEL ? 1 : 0;
|
|
|
|
return &per_cpu(bh_pool_irq_works, pool->cpu)[high];
|
|
}
|
|
|
|
static void kick_bh_pool(struct worker_pool *pool)
|
|
{
|
|
#ifdef CONFIG_SMP
|
|
/* see drain_dead_softirq_workfn() for BH_DRAINING */
|
|
if (unlikely(pool->cpu != smp_processor_id() &&
|
|
!(pool->flags & POOL_BH_DRAINING))) {
|
|
irq_work_queue_on(bh_pool_irq_work(pool), pool->cpu);
|
|
return;
|
|
}
|
|
#endif
|
|
if (pool->attrs->nice == HIGHPRI_NICE_LEVEL)
|
|
raise_softirq_irqoff(HI_SOFTIRQ);
|
|
else
|
|
raise_softirq_irqoff(TASKLET_SOFTIRQ);
|
|
}
|
|
|
|
/**
|
|
* kick_pool - wake up an idle worker if necessary
|
|
* @pool: pool to kick
|
|
*
|
|
* @pool may have pending work items. Wake up worker if necessary. Returns
|
|
* whether a worker was woken up.
|
|
*/
|
|
static bool kick_pool(struct worker_pool *pool)
|
|
{
|
|
struct worker *worker = first_idle_worker(pool);
|
|
struct task_struct *p;
|
|
|
|
lockdep_assert_held(&pool->lock);
|
|
|
|
if (!need_more_worker(pool) || !worker)
|
|
return false;
|
|
|
|
if (pool->flags & POOL_BH) {
|
|
kick_bh_pool(pool);
|
|
return true;
|
|
}
|
|
|
|
p = worker->task;
|
|
|
|
#ifdef CONFIG_SMP
|
|
/*
|
|
* Idle @worker is about to execute @work and waking up provides an
|
|
* opportunity to migrate @worker at a lower cost by setting the task's
|
|
* wake_cpu field. Let's see if we want to move @worker to improve
|
|
* execution locality.
|
|
*
|
|
* We're waking the worker that went idle the latest and there's some
|
|
* chance that @worker is marked idle but hasn't gone off CPU yet. If
|
|
* so, setting the wake_cpu won't do anything. As this is a best-effort
|
|
* optimization and the race window is narrow, let's leave as-is for
|
|
* now. If this becomes pronounced, we can skip over workers which are
|
|
* still on cpu when picking an idle worker.
|
|
*
|
|
* If @pool has non-strict affinity, @worker might have ended up outside
|
|
* its affinity scope. Repatriate.
|
|
*/
|
|
if (!pool->attrs->affn_strict &&
|
|
!cpumask_test_cpu(p->wake_cpu, pool->attrs->__pod_cpumask)) {
|
|
struct work_struct *work = list_first_entry(&pool->worklist,
|
|
struct work_struct, entry);
|
|
int wake_cpu = cpumask_any_and_distribute(pool->attrs->__pod_cpumask,
|
|
cpu_online_mask);
|
|
if (wake_cpu < nr_cpu_ids) {
|
|
p->wake_cpu = wake_cpu;
|
|
get_work_pwq(work)->stats[PWQ_STAT_REPATRIATED]++;
|
|
}
|
|
}
|
|
#endif
|
|
wake_up_process(p);
|
|
return true;
|
|
}
|
|
|
|
#ifdef CONFIG_WQ_CPU_INTENSIVE_REPORT
|
|
|
|
/*
|
|
* Concurrency-managed per-cpu work items that hog CPU for longer than
|
|
* wq_cpu_intensive_thresh_us trigger the automatic CPU_INTENSIVE mechanism,
|
|
* which prevents them from stalling other concurrency-managed work items. If a
|
|
* work function keeps triggering this mechanism, it's likely that the work item
|
|
* should be using an unbound workqueue instead.
|
|
*
|
|
* wq_cpu_intensive_report() tracks work functions which trigger such conditions
|
|
* and report them so that they can be examined and converted to use unbound
|
|
* workqueues as appropriate. To avoid flooding the console, each violating work
|
|
* function is tracked and reported with exponential backoff.
|
|
*/
|
|
#define WCI_MAX_ENTS 128
|
|
|
|
struct wci_ent {
|
|
work_func_t func;
|
|
atomic64_t cnt;
|
|
struct hlist_node hash_node;
|
|
};
|
|
|
|
static struct wci_ent wci_ents[WCI_MAX_ENTS];
|
|
static int wci_nr_ents;
|
|
static DEFINE_RAW_SPINLOCK(wci_lock);
|
|
static DEFINE_HASHTABLE(wci_hash, ilog2(WCI_MAX_ENTS));
|
|
|
|
static struct wci_ent *wci_find_ent(work_func_t func)
|
|
{
|
|
struct wci_ent *ent;
|
|
|
|
hash_for_each_possible_rcu(wci_hash, ent, hash_node,
|
|
(unsigned long)func) {
|
|
if (ent->func == func)
|
|
return ent;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static void wq_cpu_intensive_report(work_func_t func)
|
|
{
|
|
struct wci_ent *ent;
|
|
|
|
restart:
|
|
ent = wci_find_ent(func);
|
|
if (ent) {
|
|
u64 cnt;
|
|
|
|
/*
|
|
* Start reporting from the warning_thresh and back off
|
|
* exponentially.
|
|
*/
|
|
cnt = atomic64_inc_return_relaxed(&ent->cnt);
|
|
if (wq_cpu_intensive_warning_thresh &&
|
|
cnt >= wq_cpu_intensive_warning_thresh &&
|
|
is_power_of_2(cnt + 1 - wq_cpu_intensive_warning_thresh))
|
|
printk_deferred(KERN_WARNING "workqueue: %ps hogged CPU for >%luus %llu times, consider switching to WQ_UNBOUND\n",
|
|
ent->func, wq_cpu_intensive_thresh_us,
|
|
atomic64_read(&ent->cnt));
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* @func is a new violation. Allocate a new entry for it. If wcn_ents[]
|
|
* is exhausted, something went really wrong and we probably made enough
|
|
* noise already.
|
|
*/
|
|
if (wci_nr_ents >= WCI_MAX_ENTS)
|
|
return;
|
|
|
|
raw_spin_lock(&wci_lock);
|
|
|
|
if (wci_nr_ents >= WCI_MAX_ENTS) {
|
|
raw_spin_unlock(&wci_lock);
|
|
return;
|
|
}
|
|
|
|
if (wci_find_ent(func)) {
|
|
raw_spin_unlock(&wci_lock);
|
|
goto restart;
|
|
}
|
|
|
|
ent = &wci_ents[wci_nr_ents++];
|
|
ent->func = func;
|
|
atomic64_set(&ent->cnt, 0);
|
|
hash_add_rcu(wci_hash, &ent->hash_node, (unsigned long)func);
|
|
|
|
raw_spin_unlock(&wci_lock);
|
|
|
|
goto restart;
|
|
}
|
|
|
|
#else /* CONFIG_WQ_CPU_INTENSIVE_REPORT */
|
|
static void wq_cpu_intensive_report(work_func_t func) {}
|
|
#endif /* CONFIG_WQ_CPU_INTENSIVE_REPORT */
|
|
|
|
/**
|
|
* wq_worker_running - a worker is running again
|
|
* @task: task waking up
|
|
*
|
|
* This function is called when a worker returns from schedule()
|
|
*/
|
|
void wq_worker_running(struct task_struct *task)
|
|
{
|
|
struct worker *worker = kthread_data(task);
|
|
|
|
if (!READ_ONCE(worker->sleeping))
|
|
return;
|
|
|
|
/*
|
|
* If preempted by unbind_workers() between the WORKER_NOT_RUNNING check
|
|
* and the nr_running increment below, we may ruin the nr_running reset
|
|
* and leave with an unexpected pool->nr_running == 1 on the newly unbound
|
|
* pool. Protect against such race.
|
|
*/
|
|
preempt_disable();
|
|
if (!(worker->flags & WORKER_NOT_RUNNING))
|
|
worker->pool->nr_running++;
|
|
preempt_enable();
|
|
|
|
/*
|
|
* CPU intensive auto-detection cares about how long a work item hogged
|
|
* CPU without sleeping. Reset the starting timestamp on wakeup.
|
|
*/
|
|
worker->current_at = worker->task->se.sum_exec_runtime;
|
|
|
|
WRITE_ONCE(worker->sleeping, 0);
|
|
}
|
|
|
|
/**
|
|
* wq_worker_sleeping - a worker is going to sleep
|
|
* @task: task going to sleep
|
|
*
|
|
* This function is called from schedule() when a busy worker is
|
|
* going to sleep.
|
|
*/
|
|
void wq_worker_sleeping(struct task_struct *task)
|
|
{
|
|
struct worker *worker = kthread_data(task);
|
|
struct worker_pool *pool;
|
|
|
|
/*
|
|
* Rescuers, which may not have all the fields set up like normal
|
|
* workers, also reach here, let's not access anything before
|
|
* checking NOT_RUNNING.
|
|
*/
|
|
if (worker->flags & WORKER_NOT_RUNNING)
|
|
return;
|
|
|
|
pool = worker->pool;
|
|
|
|
/* Return if preempted before wq_worker_running() was reached */
|
|
if (READ_ONCE(worker->sleeping))
|
|
return;
|
|
|
|
WRITE_ONCE(worker->sleeping, 1);
|
|
raw_spin_lock_irq(&pool->lock);
|
|
|
|
/*
|
|
* Recheck in case unbind_workers() preempted us. We don't
|
|
* want to decrement nr_running after the worker is unbound
|
|
* and nr_running has been reset.
|
|
*/
|
|
if (worker->flags & WORKER_NOT_RUNNING) {
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
return;
|
|
}
|
|
|
|
pool->nr_running--;
|
|
if (kick_pool(pool))
|
|
worker->current_pwq->stats[PWQ_STAT_CM_WAKEUP]++;
|
|
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
}
|
|
|
|
/**
|
|
* wq_worker_tick - a scheduler tick occurred while a kworker is running
|
|
* @task: task currently running
|
|
*
|
|
* Called from sched_tick(). We're in the IRQ context and the current
|
|
* worker's fields which follow the 'K' locking rule can be accessed safely.
|
|
*/
|
|
void wq_worker_tick(struct task_struct *task)
|
|
{
|
|
struct worker *worker = kthread_data(task);
|
|
struct pool_workqueue *pwq = worker->current_pwq;
|
|
struct worker_pool *pool = worker->pool;
|
|
|
|
if (!pwq)
|
|
return;
|
|
|
|
pwq->stats[PWQ_STAT_CPU_TIME] += TICK_USEC;
|
|
|
|
if (!wq_cpu_intensive_thresh_us)
|
|
return;
|
|
|
|
/*
|
|
* If the current worker is concurrency managed and hogged the CPU for
|
|
* longer than wq_cpu_intensive_thresh_us, it's automatically marked
|
|
* CPU_INTENSIVE to avoid stalling other concurrency-managed work items.
|
|
*
|
|
* Set @worker->sleeping means that @worker is in the process of
|
|
* switching out voluntarily and won't be contributing to
|
|
* @pool->nr_running until it wakes up. As wq_worker_sleeping() also
|
|
* decrements ->nr_running, setting CPU_INTENSIVE here can lead to
|
|
* double decrements. The task is releasing the CPU anyway. Let's skip.
|
|
* We probably want to make this prettier in the future.
|
|
*/
|
|
if ((worker->flags & WORKER_NOT_RUNNING) || READ_ONCE(worker->sleeping) ||
|
|
worker->task->se.sum_exec_runtime - worker->current_at <
|
|
wq_cpu_intensive_thresh_us * NSEC_PER_USEC)
|
|
return;
|
|
|
|
raw_spin_lock(&pool->lock);
|
|
|
|
worker_set_flags(worker, WORKER_CPU_INTENSIVE);
|
|
wq_cpu_intensive_report(worker->current_func);
|
|
pwq->stats[PWQ_STAT_CPU_INTENSIVE]++;
|
|
|
|
if (kick_pool(pool))
|
|
pwq->stats[PWQ_STAT_CM_WAKEUP]++;
|
|
|
|
raw_spin_unlock(&pool->lock);
|
|
}
|
|
|
|
/**
|
|
* wq_worker_last_func - retrieve worker's last work function
|
|
* @task: Task to retrieve last work function of.
|
|
*
|
|
* Determine the last function a worker executed. This is called from
|
|
* the scheduler to get a worker's last known identity.
|
|
*
|
|
* CONTEXT:
|
|
* raw_spin_lock_irq(rq->lock)
|
|
*
|
|
* This function is called during schedule() when a kworker is going
|
|
* to sleep. It's used by psi to identify aggregation workers during
|
|
* dequeuing, to allow periodic aggregation to shut-off when that
|
|
* worker is the last task in the system or cgroup to go to sleep.
|
|
*
|
|
* As this function doesn't involve any workqueue-related locking, it
|
|
* only returns stable values when called from inside the scheduler's
|
|
* queuing and dequeuing paths, when @task, which must be a kworker,
|
|
* is guaranteed to not be processing any works.
|
|
*
|
|
* Return:
|
|
* The last work function %current executed as a worker, NULL if it
|
|
* hasn't executed any work yet.
|
|
*/
|
|
work_func_t wq_worker_last_func(struct task_struct *task)
|
|
{
|
|
struct worker *worker = kthread_data(task);
|
|
|
|
return worker->last_func;
|
|
}
|
|
|
|
/**
|
|
* wq_node_nr_active - Determine wq_node_nr_active to use
|
|
* @wq: workqueue of interest
|
|
* @node: NUMA node, can be %NUMA_NO_NODE
|
|
*
|
|
* Determine wq_node_nr_active to use for @wq on @node. Returns:
|
|
*
|
|
* - %NULL for per-cpu workqueues as they don't need to use shared nr_active.
|
|
*
|
|
* - node_nr_active[nr_node_ids] if @node is %NUMA_NO_NODE.
|
|
*
|
|
* - Otherwise, node_nr_active[@node].
|
|
*/
|
|
static struct wq_node_nr_active *wq_node_nr_active(struct workqueue_struct *wq,
|
|
int node)
|
|
{
|
|
if (!(wq->flags & WQ_UNBOUND))
|
|
return NULL;
|
|
|
|
if (node == NUMA_NO_NODE)
|
|
node = nr_node_ids;
|
|
|
|
return wq->node_nr_active[node];
|
|
}
|
|
|
|
/**
|
|
* wq_update_node_max_active - Update per-node max_actives to use
|
|
* @wq: workqueue to update
|
|
* @off_cpu: CPU that's going down, -1 if a CPU is not going down
|
|
*
|
|
* Update @wq->node_nr_active[]->max. @wq must be unbound. max_active is
|
|
* distributed among nodes according to the proportions of numbers of online
|
|
* cpus. The result is always between @wq->min_active and max_active.
|
|
*/
|
|
static void wq_update_node_max_active(struct workqueue_struct *wq, int off_cpu)
|
|
{
|
|
struct cpumask *effective = unbound_effective_cpumask(wq);
|
|
int min_active = READ_ONCE(wq->min_active);
|
|
int max_active = READ_ONCE(wq->max_active);
|
|
int total_cpus, node;
|
|
|
|
lockdep_assert_held(&wq->mutex);
|
|
|
|
if (!wq_topo_initialized)
|
|
return;
|
|
|
|
if (off_cpu >= 0 && !cpumask_test_cpu(off_cpu, effective))
|
|
off_cpu = -1;
|
|
|
|
total_cpus = cpumask_weight_and(effective, cpu_online_mask);
|
|
if (off_cpu >= 0)
|
|
total_cpus--;
|
|
|
|
/* If all CPUs of the wq get offline, use the default values */
|
|
if (unlikely(!total_cpus)) {
|
|
for_each_node(node)
|
|
wq_node_nr_active(wq, node)->max = min_active;
|
|
|
|
wq_node_nr_active(wq, NUMA_NO_NODE)->max = max_active;
|
|
return;
|
|
}
|
|
|
|
for_each_node(node) {
|
|
int node_cpus;
|
|
|
|
node_cpus = cpumask_weight_and(effective, cpumask_of_node(node));
|
|
if (off_cpu >= 0 && cpu_to_node(off_cpu) == node)
|
|
node_cpus--;
|
|
|
|
wq_node_nr_active(wq, node)->max =
|
|
clamp(DIV_ROUND_UP(max_active * node_cpus, total_cpus),
|
|
min_active, max_active);
|
|
}
|
|
|
|
wq_node_nr_active(wq, NUMA_NO_NODE)->max = max_active;
|
|
}
|
|
|
|
/**
|
|
* get_pwq - get an extra reference on the specified pool_workqueue
|
|
* @pwq: pool_workqueue to get
|
|
*
|
|
* Obtain an extra reference on @pwq. The caller should guarantee that
|
|
* @pwq has positive refcnt and be holding the matching pool->lock.
|
|
*/
|
|
static void get_pwq(struct pool_workqueue *pwq)
|
|
{
|
|
lockdep_assert_held(&pwq->pool->lock);
|
|
WARN_ON_ONCE(pwq->refcnt <= 0);
|
|
pwq->refcnt++;
|
|
}
|
|
|
|
/**
|
|
* put_pwq - put a pool_workqueue reference
|
|
* @pwq: pool_workqueue to put
|
|
*
|
|
* Drop a reference of @pwq. If its refcnt reaches zero, schedule its
|
|
* destruction. The caller should be holding the matching pool->lock.
|
|
*/
|
|
static void put_pwq(struct pool_workqueue *pwq)
|
|
{
|
|
lockdep_assert_held(&pwq->pool->lock);
|
|
if (likely(--pwq->refcnt))
|
|
return;
|
|
/*
|
|
* @pwq can't be released under pool->lock, bounce to a dedicated
|
|
* kthread_worker to avoid A-A deadlocks.
|
|
*/
|
|
kthread_queue_work(pwq_release_worker, &pwq->release_work);
|
|
}
|
|
|
|
/**
|
|
* put_pwq_unlocked - put_pwq() with surrounding pool lock/unlock
|
|
* @pwq: pool_workqueue to put (can be %NULL)
|
|
*
|
|
* put_pwq() with locking. This function also allows %NULL @pwq.
|
|
*/
|
|
static void put_pwq_unlocked(struct pool_workqueue *pwq)
|
|
{
|
|
if (pwq) {
|
|
/*
|
|
* As both pwqs and pools are RCU protected, the
|
|
* following lock operations are safe.
|
|
*/
|
|
raw_spin_lock_irq(&pwq->pool->lock);
|
|
put_pwq(pwq);
|
|
raw_spin_unlock_irq(&pwq->pool->lock);
|
|
}
|
|
}
|
|
|
|
static bool pwq_is_empty(struct pool_workqueue *pwq)
|
|
{
|
|
return !pwq->nr_active && list_empty(&pwq->inactive_works);
|
|
}
|
|
|
|
static void __pwq_activate_work(struct pool_workqueue *pwq,
|
|
struct work_struct *work)
|
|
{
|
|
unsigned long *wdb = work_data_bits(work);
|
|
|
|
WARN_ON_ONCE(!(*wdb & WORK_STRUCT_INACTIVE));
|
|
trace_workqueue_activate_work(work);
|
|
if (list_empty(&pwq->pool->worklist))
|
|
pwq->pool->watchdog_ts = jiffies;
|
|
move_linked_works(work, &pwq->pool->worklist, NULL);
|
|
__clear_bit(WORK_STRUCT_INACTIVE_BIT, wdb);
|
|
}
|
|
|
|
/**
|
|
* pwq_activate_work - Activate a work item if inactive
|
|
* @pwq: pool_workqueue @work belongs to
|
|
* @work: work item to activate
|
|
*
|
|
* Returns %true if activated. %false if already active.
|
|
*/
|
|
static bool pwq_activate_work(struct pool_workqueue *pwq,
|
|
struct work_struct *work)
|
|
{
|
|
struct worker_pool *pool = pwq->pool;
|
|
struct wq_node_nr_active *nna;
|
|
|
|
lockdep_assert_held(&pool->lock);
|
|
|
|
if (!(*work_data_bits(work) & WORK_STRUCT_INACTIVE))
|
|
return false;
|
|
|
|
nna = wq_node_nr_active(pwq->wq, pool->node);
|
|
if (nna)
|
|
atomic_inc(&nna->nr);
|
|
|
|
pwq->nr_active++;
|
|
__pwq_activate_work(pwq, work);
|
|
return true;
|
|
}
|
|
|
|
static bool tryinc_node_nr_active(struct wq_node_nr_active *nna)
|
|
{
|
|
int max = READ_ONCE(nna->max);
|
|
|
|
while (true) {
|
|
int old, tmp;
|
|
|
|
old = atomic_read(&nna->nr);
|
|
if (old >= max)
|
|
return false;
|
|
tmp = atomic_cmpxchg_relaxed(&nna->nr, old, old + 1);
|
|
if (tmp == old)
|
|
return true;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* pwq_tryinc_nr_active - Try to increment nr_active for a pwq
|
|
* @pwq: pool_workqueue of interest
|
|
* @fill: max_active may have increased, try to increase concurrency level
|
|
*
|
|
* Try to increment nr_active for @pwq. Returns %true if an nr_active count is
|
|
* successfully obtained. %false otherwise.
|
|
*/
|
|
static bool pwq_tryinc_nr_active(struct pool_workqueue *pwq, bool fill)
|
|
{
|
|
struct workqueue_struct *wq = pwq->wq;
|
|
struct worker_pool *pool = pwq->pool;
|
|
struct wq_node_nr_active *nna = wq_node_nr_active(wq, pool->node);
|
|
bool obtained = false;
|
|
|
|
lockdep_assert_held(&pool->lock);
|
|
|
|
if (!nna) {
|
|
/* BH or per-cpu workqueue, pwq->nr_active is sufficient */
|
|
obtained = pwq->nr_active < READ_ONCE(wq->max_active);
|
|
goto out;
|
|
}
|
|
|
|
if (unlikely(pwq->plugged))
|
|
return false;
|
|
|
|
/*
|
|
* Unbound workqueue uses per-node shared nr_active $nna. If @pwq is
|
|
* already waiting on $nna, pwq_dec_nr_active() will maintain the
|
|
* concurrency level. Don't jump the line.
|
|
*
|
|
* We need to ignore the pending test after max_active has increased as
|
|
* pwq_dec_nr_active() can only maintain the concurrency level but not
|
|
* increase it. This is indicated by @fill.
|
|
*/
|
|
if (!list_empty(&pwq->pending_node) && likely(!fill))
|
|
goto out;
|
|
|
|
obtained = tryinc_node_nr_active(nna);
|
|
if (obtained)
|
|
goto out;
|
|
|
|
/*
|
|
* Lockless acquisition failed. Lock, add ourself to $nna->pending_pwqs
|
|
* and try again. The smp_mb() is paired with the implied memory barrier
|
|
* of atomic_dec_return() in pwq_dec_nr_active() to ensure that either
|
|
* we see the decremented $nna->nr or they see non-empty
|
|
* $nna->pending_pwqs.
|
|
*/
|
|
raw_spin_lock(&nna->lock);
|
|
|
|
if (list_empty(&pwq->pending_node))
|
|
list_add_tail(&pwq->pending_node, &nna->pending_pwqs);
|
|
else if (likely(!fill))
|
|
goto out_unlock;
|
|
|
|
smp_mb();
|
|
|
|
obtained = tryinc_node_nr_active(nna);
|
|
|
|
/*
|
|
* If @fill, @pwq might have already been pending. Being spuriously
|
|
* pending in cold paths doesn't affect anything. Let's leave it be.
|
|
*/
|
|
if (obtained && likely(!fill))
|
|
list_del_init(&pwq->pending_node);
|
|
|
|
out_unlock:
|
|
raw_spin_unlock(&nna->lock);
|
|
out:
|
|
if (obtained)
|
|
pwq->nr_active++;
|
|
return obtained;
|
|
}
|
|
|
|
/**
|
|
* pwq_activate_first_inactive - Activate the first inactive work item on a pwq
|
|
* @pwq: pool_workqueue of interest
|
|
* @fill: max_active may have increased, try to increase concurrency level
|
|
*
|
|
* Activate the first inactive work item of @pwq if available and allowed by
|
|
* max_active limit.
|
|
*
|
|
* Returns %true if an inactive work item has been activated. %false if no
|
|
* inactive work item is found or max_active limit is reached.
|
|
*/
|
|
static bool pwq_activate_first_inactive(struct pool_workqueue *pwq, bool fill)
|
|
{
|
|
struct work_struct *work =
|
|
list_first_entry_or_null(&pwq->inactive_works,
|
|
struct work_struct, entry);
|
|
|
|
if (work && pwq_tryinc_nr_active(pwq, fill)) {
|
|
__pwq_activate_work(pwq, work);
|
|
return true;
|
|
} else {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* unplug_oldest_pwq - unplug the oldest pool_workqueue
|
|
* @wq: workqueue_struct where its oldest pwq is to be unplugged
|
|
*
|
|
* This function should only be called for ordered workqueues where only the
|
|
* oldest pwq is unplugged, the others are plugged to suspend execution to
|
|
* ensure proper work item ordering::
|
|
*
|
|
* dfl_pwq --------------+ [P] - plugged
|
|
* |
|
|
* v
|
|
* pwqs -> A -> B [P] -> C [P] (newest)
|
|
* | | |
|
|
* 1 3 5
|
|
* | | |
|
|
* 2 4 6
|
|
*
|
|
* When the oldest pwq is drained and removed, this function should be called
|
|
* to unplug the next oldest one to start its work item execution. Note that
|
|
* pwq's are linked into wq->pwqs with the oldest first, so the first one in
|
|
* the list is the oldest.
|
|
*/
|
|
static void unplug_oldest_pwq(struct workqueue_struct *wq)
|
|
{
|
|
struct pool_workqueue *pwq;
|
|
|
|
lockdep_assert_held(&wq->mutex);
|
|
|
|
/* Caller should make sure that pwqs isn't empty before calling */
|
|
pwq = list_first_entry_or_null(&wq->pwqs, struct pool_workqueue,
|
|
pwqs_node);
|
|
raw_spin_lock_irq(&pwq->pool->lock);
|
|
if (pwq->plugged) {
|
|
pwq->plugged = false;
|
|
if (pwq_activate_first_inactive(pwq, true))
|
|
kick_pool(pwq->pool);
|
|
}
|
|
raw_spin_unlock_irq(&pwq->pool->lock);
|
|
}
|
|
|
|
/**
|
|
* node_activate_pending_pwq - Activate a pending pwq on a wq_node_nr_active
|
|
* @nna: wq_node_nr_active to activate a pending pwq for
|
|
* @caller_pool: worker_pool the caller is locking
|
|
*
|
|
* Activate a pwq in @nna->pending_pwqs. Called with @caller_pool locked.
|
|
* @caller_pool may be unlocked and relocked to lock other worker_pools.
|
|
*/
|
|
static void node_activate_pending_pwq(struct wq_node_nr_active *nna,
|
|
struct worker_pool *caller_pool)
|
|
{
|
|
struct worker_pool *locked_pool = caller_pool;
|
|
struct pool_workqueue *pwq;
|
|
struct work_struct *work;
|
|
|
|
lockdep_assert_held(&caller_pool->lock);
|
|
|
|
raw_spin_lock(&nna->lock);
|
|
retry:
|
|
pwq = list_first_entry_or_null(&nna->pending_pwqs,
|
|
struct pool_workqueue, pending_node);
|
|
if (!pwq)
|
|
goto out_unlock;
|
|
|
|
/*
|
|
* If @pwq is for a different pool than @locked_pool, we need to lock
|
|
* @pwq->pool->lock. Let's trylock first. If unsuccessful, do the unlock
|
|
* / lock dance. For that, we also need to release @nna->lock as it's
|
|
* nested inside pool locks.
|
|
*/
|
|
if (pwq->pool != locked_pool) {
|
|
raw_spin_unlock(&locked_pool->lock);
|
|
locked_pool = pwq->pool;
|
|
if (!raw_spin_trylock(&locked_pool->lock)) {
|
|
raw_spin_unlock(&nna->lock);
|
|
raw_spin_lock(&locked_pool->lock);
|
|
raw_spin_lock(&nna->lock);
|
|
goto retry;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* $pwq may not have any inactive work items due to e.g. cancellations.
|
|
* Drop it from pending_pwqs and see if there's another one.
|
|
*/
|
|
work = list_first_entry_or_null(&pwq->inactive_works,
|
|
struct work_struct, entry);
|
|
if (!work) {
|
|
list_del_init(&pwq->pending_node);
|
|
goto retry;
|
|
}
|
|
|
|
/*
|
|
* Acquire an nr_active count and activate the inactive work item. If
|
|
* $pwq still has inactive work items, rotate it to the end of the
|
|
* pending_pwqs so that we round-robin through them. This means that
|
|
* inactive work items are not activated in queueing order which is fine
|
|
* given that there has never been any ordering across different pwqs.
|
|
*/
|
|
if (likely(tryinc_node_nr_active(nna))) {
|
|
pwq->nr_active++;
|
|
__pwq_activate_work(pwq, work);
|
|
|
|
if (list_empty(&pwq->inactive_works))
|
|
list_del_init(&pwq->pending_node);
|
|
else
|
|
list_move_tail(&pwq->pending_node, &nna->pending_pwqs);
|
|
|
|
/* if activating a foreign pool, make sure it's running */
|
|
if (pwq->pool != caller_pool)
|
|
kick_pool(pwq->pool);
|
|
}
|
|
|
|
out_unlock:
|
|
raw_spin_unlock(&nna->lock);
|
|
if (locked_pool != caller_pool) {
|
|
raw_spin_unlock(&locked_pool->lock);
|
|
raw_spin_lock(&caller_pool->lock);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* pwq_dec_nr_active - Retire an active count
|
|
* @pwq: pool_workqueue of interest
|
|
*
|
|
* Decrement @pwq's nr_active and try to activate the first inactive work item.
|
|
* For unbound workqueues, this function may temporarily drop @pwq->pool->lock.
|
|
*/
|
|
static void pwq_dec_nr_active(struct pool_workqueue *pwq)
|
|
{
|
|
struct worker_pool *pool = pwq->pool;
|
|
struct wq_node_nr_active *nna = wq_node_nr_active(pwq->wq, pool->node);
|
|
|
|
lockdep_assert_held(&pool->lock);
|
|
|
|
/*
|
|
* @pwq->nr_active should be decremented for both percpu and unbound
|
|
* workqueues.
|
|
*/
|
|
pwq->nr_active--;
|
|
|
|
/*
|
|
* For a percpu workqueue, it's simple. Just need to kick the first
|
|
* inactive work item on @pwq itself.
|
|
*/
|
|
if (!nna) {
|
|
pwq_activate_first_inactive(pwq, false);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* If @pwq is for an unbound workqueue, it's more complicated because
|
|
* multiple pwqs and pools may be sharing the nr_active count. When a
|
|
* pwq needs to wait for an nr_active count, it puts itself on
|
|
* $nna->pending_pwqs. The following atomic_dec_return()'s implied
|
|
* memory barrier is paired with smp_mb() in pwq_tryinc_nr_active() to
|
|
* guarantee that either we see non-empty pending_pwqs or they see
|
|
* decremented $nna->nr.
|
|
*
|
|
* $nna->max may change as CPUs come online/offline and @pwq->wq's
|
|
* max_active gets updated. However, it is guaranteed to be equal to or
|
|
* larger than @pwq->wq->min_active which is above zero unless freezing.
|
|
* This maintains the forward progress guarantee.
|
|
*/
|
|
if (atomic_dec_return(&nna->nr) >= READ_ONCE(nna->max))
|
|
return;
|
|
|
|
if (!list_empty(&nna->pending_pwqs))
|
|
node_activate_pending_pwq(nna, pool);
|
|
}
|
|
|
|
/**
|
|
* pwq_dec_nr_in_flight - decrement pwq's nr_in_flight
|
|
* @pwq: pwq of interest
|
|
* @work_data: work_data of work which left the queue
|
|
*
|
|
* A work either has completed or is removed from pending queue,
|
|
* decrement nr_in_flight of its pwq and handle workqueue flushing.
|
|
*
|
|
* NOTE:
|
|
* For unbound workqueues, this function may temporarily drop @pwq->pool->lock
|
|
* and thus should be called after all other state updates for the in-flight
|
|
* work item is complete.
|
|
*
|
|
* CONTEXT:
|
|
* raw_spin_lock_irq(pool->lock).
|
|
*/
|
|
static void pwq_dec_nr_in_flight(struct pool_workqueue *pwq, unsigned long work_data)
|
|
{
|
|
int color = get_work_color(work_data);
|
|
|
|
if (!(work_data & WORK_STRUCT_INACTIVE))
|
|
pwq_dec_nr_active(pwq);
|
|
|
|
pwq->nr_in_flight[color]--;
|
|
|
|
/* is flush in progress and are we at the flushing tip? */
|
|
if (likely(pwq->flush_color != color))
|
|
goto out_put;
|
|
|
|
/* are there still in-flight works? */
|
|
if (pwq->nr_in_flight[color])
|
|
goto out_put;
|
|
|
|
/* this pwq is done, clear flush_color */
|
|
pwq->flush_color = -1;
|
|
|
|
/*
|
|
* If this was the last pwq, wake up the first flusher. It
|
|
* will handle the rest.
|
|
*/
|
|
if (atomic_dec_and_test(&pwq->wq->nr_pwqs_to_flush))
|
|
complete(&pwq->wq->first_flusher->done);
|
|
out_put:
|
|
put_pwq(pwq);
|
|
}
|
|
|
|
/**
|
|
* try_to_grab_pending - steal work item from worklist and disable irq
|
|
* @work: work item to steal
|
|
* @cflags: %WORK_CANCEL_ flags
|
|
* @irq_flags: place to store irq state
|
|
*
|
|
* Try to grab PENDING bit of @work. This function can handle @work in any
|
|
* stable state - idle, on timer or on worklist.
|
|
*
|
|
* Return:
|
|
*
|
|
* ======== ================================================================
|
|
* 1 if @work was pending and we successfully stole PENDING
|
|
* 0 if @work was idle and we claimed PENDING
|
|
* -EAGAIN if PENDING couldn't be grabbed at the moment, safe to busy-retry
|
|
* ======== ================================================================
|
|
*
|
|
* Note:
|
|
* On >= 0 return, the caller owns @work's PENDING bit. To avoid getting
|
|
* interrupted while holding PENDING and @work off queue, irq must be
|
|
* disabled on entry. This, combined with delayed_work->timer being
|
|
* irqsafe, ensures that we return -EAGAIN for finite short period of time.
|
|
*
|
|
* On successful return, >= 0, irq is disabled and the caller is
|
|
* responsible for releasing it using local_irq_restore(*@irq_flags).
|
|
*
|
|
* This function is safe to call from any context including IRQ handler.
|
|
*/
|
|
static int try_to_grab_pending(struct work_struct *work, u32 cflags,
|
|
unsigned long *irq_flags)
|
|
{
|
|
struct worker_pool *pool;
|
|
struct pool_workqueue *pwq;
|
|
|
|
local_irq_save(*irq_flags);
|
|
|
|
/* try to steal the timer if it exists */
|
|
if (cflags & WORK_CANCEL_DELAYED) {
|
|
struct delayed_work *dwork = to_delayed_work(work);
|
|
|
|
/*
|
|
* dwork->timer is irqsafe. If del_timer() fails, it's
|
|
* guaranteed that the timer is not queued anywhere and not
|
|
* running on the local CPU.
|
|
*/
|
|
if (likely(del_timer(&dwork->timer)))
|
|
return 1;
|
|
}
|
|
|
|
/* try to claim PENDING the normal way */
|
|
if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
|
|
return 0;
|
|
|
|
rcu_read_lock();
|
|
/*
|
|
* The queueing is in progress, or it is already queued. Try to
|
|
* steal it from ->worklist without clearing WORK_STRUCT_PENDING.
|
|
*/
|
|
pool = get_work_pool(work);
|
|
if (!pool)
|
|
goto fail;
|
|
|
|
raw_spin_lock(&pool->lock);
|
|
/*
|
|
* work->data is guaranteed to point to pwq only while the work
|
|
* item is queued on pwq->wq, and both updating work->data to point
|
|
* to pwq on queueing and to pool on dequeueing are done under
|
|
* pwq->pool->lock. This in turn guarantees that, if work->data
|
|
* points to pwq which is associated with a locked pool, the work
|
|
* item is currently queued on that pool.
|
|
*/
|
|
pwq = get_work_pwq(work);
|
|
if (pwq && pwq->pool == pool) {
|
|
unsigned long work_data;
|
|
|
|
debug_work_deactivate(work);
|
|
|
|
/*
|
|
* A cancelable inactive work item must be in the
|
|
* pwq->inactive_works since a queued barrier can't be
|
|
* canceled (see the comments in insert_wq_barrier()).
|
|
*
|
|
* An inactive work item cannot be grabbed directly because
|
|
* it might have linked barrier work items which, if left
|
|
* on the inactive_works list, will confuse pwq->nr_active
|
|
* management later on and cause stall. Make sure the work
|
|
* item is activated before grabbing.
|
|
*/
|
|
pwq_activate_work(pwq, work);
|
|
|
|
list_del_init(&work->entry);
|
|
|
|
/*
|
|
* work->data points to pwq iff queued. Let's point to pool. As
|
|
* this destroys work->data needed by the next step, stash it.
|
|
*/
|
|
work_data = *work_data_bits(work);
|
|
set_work_pool_and_keep_pending(work, pool->id,
|
|
pool_offq_flags(pool));
|
|
|
|
/* must be the last step, see the function comment */
|
|
pwq_dec_nr_in_flight(pwq, work_data);
|
|
|
|
raw_spin_unlock(&pool->lock);
|
|
rcu_read_unlock();
|
|
return 1;
|
|
}
|
|
raw_spin_unlock(&pool->lock);
|
|
fail:
|
|
rcu_read_unlock();
|
|
local_irq_restore(*irq_flags);
|
|
return -EAGAIN;
|
|
}
|
|
|
|
/**
|
|
* work_grab_pending - steal work item from worklist and disable irq
|
|
* @work: work item to steal
|
|
* @cflags: %WORK_CANCEL_ flags
|
|
* @irq_flags: place to store IRQ state
|
|
*
|
|
* Grab PENDING bit of @work. @work can be in any stable state - idle, on timer
|
|
* or on worklist.
|
|
*
|
|
* Can be called from any context. IRQ is disabled on return with IRQ state
|
|
* stored in *@irq_flags. The caller is responsible for re-enabling it using
|
|
* local_irq_restore().
|
|
*
|
|
* Returns %true if @work was pending. %false if idle.
|
|
*/
|
|
static bool work_grab_pending(struct work_struct *work, u32 cflags,
|
|
unsigned long *irq_flags)
|
|
{
|
|
int ret;
|
|
|
|
while (true) {
|
|
ret = try_to_grab_pending(work, cflags, irq_flags);
|
|
if (ret >= 0)
|
|
return ret;
|
|
cpu_relax();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* insert_work - insert a work into a pool
|
|
* @pwq: pwq @work belongs to
|
|
* @work: work to insert
|
|
* @head: insertion point
|
|
* @extra_flags: extra WORK_STRUCT_* flags to set
|
|
*
|
|
* Insert @work which belongs to @pwq after @head. @extra_flags is or'd to
|
|
* work_struct flags.
|
|
*
|
|
* CONTEXT:
|
|
* raw_spin_lock_irq(pool->lock).
|
|
*/
|
|
static void insert_work(struct pool_workqueue *pwq, struct work_struct *work,
|
|
struct list_head *head, unsigned int extra_flags)
|
|
{
|
|
debug_work_activate(work);
|
|
|
|
/* record the work call stack in order to print it in KASAN reports */
|
|
kasan_record_aux_stack_noalloc(work);
|
|
|
|
/* we own @work, set data and link */
|
|
set_work_pwq(work, pwq, extra_flags);
|
|
list_add_tail(&work->entry, head);
|
|
get_pwq(pwq);
|
|
}
|
|
|
|
/*
|
|
* Test whether @work is being queued from another work executing on the
|
|
* same workqueue.
|
|
*/
|
|
static bool is_chained_work(struct workqueue_struct *wq)
|
|
{
|
|
struct worker *worker;
|
|
|
|
worker = current_wq_worker();
|
|
/*
|
|
* Return %true iff I'm a worker executing a work item on @wq. If
|
|
* I'm @worker, it's safe to dereference it without locking.
|
|
*/
|
|
return worker && worker->current_pwq->wq == wq;
|
|
}
|
|
|
|
/*
|
|
* When queueing an unbound work item to a wq, prefer local CPU if allowed
|
|
* by wq_unbound_cpumask. Otherwise, round robin among the allowed ones to
|
|
* avoid perturbing sensitive tasks.
|
|
*/
|
|
static int wq_select_unbound_cpu(int cpu)
|
|
{
|
|
int new_cpu;
|
|
|
|
if (likely(!wq_debug_force_rr_cpu)) {
|
|
if (cpumask_test_cpu(cpu, wq_unbound_cpumask))
|
|
return cpu;
|
|
} else {
|
|
pr_warn_once("workqueue: round-robin CPU selection forced, expect performance impact\n");
|
|
}
|
|
|
|
new_cpu = __this_cpu_read(wq_rr_cpu_last);
|
|
new_cpu = cpumask_next_and(new_cpu, wq_unbound_cpumask, cpu_online_mask);
|
|
if (unlikely(new_cpu >= nr_cpu_ids)) {
|
|
new_cpu = cpumask_first_and(wq_unbound_cpumask, cpu_online_mask);
|
|
if (unlikely(new_cpu >= nr_cpu_ids))
|
|
return cpu;
|
|
}
|
|
__this_cpu_write(wq_rr_cpu_last, new_cpu);
|
|
|
|
return new_cpu;
|
|
}
|
|
|
|
static void __queue_work(int cpu, struct workqueue_struct *wq,
|
|
struct work_struct *work)
|
|
{
|
|
struct pool_workqueue *pwq;
|
|
struct worker_pool *last_pool, *pool;
|
|
unsigned int work_flags;
|
|
unsigned int req_cpu = cpu;
|
|
|
|
/*
|
|
* While a work item is PENDING && off queue, a task trying to
|
|
* steal the PENDING will busy-loop waiting for it to either get
|
|
* queued or lose PENDING. Grabbing PENDING and queueing should
|
|
* happen with IRQ disabled.
|
|
*/
|
|
lockdep_assert_irqs_disabled();
|
|
|
|
/*
|
|
* For a draining wq, only works from the same workqueue are
|
|
* allowed. The __WQ_DESTROYING helps to spot the issue that
|
|
* queues a new work item to a wq after destroy_workqueue(wq).
|
|
*/
|
|
if (unlikely(wq->flags & (__WQ_DESTROYING | __WQ_DRAINING) &&
|
|
WARN_ON_ONCE(!is_chained_work(wq))))
|
|
return;
|
|
rcu_read_lock();
|
|
retry:
|
|
/* pwq which will be used unless @work is executing elsewhere */
|
|
if (req_cpu == WORK_CPU_UNBOUND) {
|
|
if (wq->flags & WQ_UNBOUND)
|
|
cpu = wq_select_unbound_cpu(raw_smp_processor_id());
|
|
else
|
|
cpu = raw_smp_processor_id();
|
|
}
|
|
|
|
pwq = rcu_dereference(*per_cpu_ptr(wq->cpu_pwq, cpu));
|
|
pool = pwq->pool;
|
|
|
|
/*
|
|
* If @work was previously on a different pool, it might still be
|
|
* running there, in which case the work needs to be queued on that
|
|
* pool to guarantee non-reentrancy.
|
|
*/
|
|
last_pool = get_work_pool(work);
|
|
if (last_pool && last_pool != pool) {
|
|
struct worker *worker;
|
|
|
|
raw_spin_lock(&last_pool->lock);
|
|
|
|
worker = find_worker_executing_work(last_pool, work);
|
|
|
|
if (worker && worker->current_pwq->wq == wq) {
|
|
pwq = worker->current_pwq;
|
|
pool = pwq->pool;
|
|
WARN_ON_ONCE(pool != last_pool);
|
|
} else {
|
|
/* meh... not running there, queue here */
|
|
raw_spin_unlock(&last_pool->lock);
|
|
raw_spin_lock(&pool->lock);
|
|
}
|
|
} else {
|
|
raw_spin_lock(&pool->lock);
|
|
}
|
|
|
|
/*
|
|
* pwq is determined and locked. For unbound pools, we could have raced
|
|
* with pwq release and it could already be dead. If its refcnt is zero,
|
|
* repeat pwq selection. Note that unbound pwqs never die without
|
|
* another pwq replacing it in cpu_pwq or while work items are executing
|
|
* on it, so the retrying is guaranteed to make forward-progress.
|
|
*/
|
|
if (unlikely(!pwq->refcnt)) {
|
|
if (wq->flags & WQ_UNBOUND) {
|
|
raw_spin_unlock(&pool->lock);
|
|
cpu_relax();
|
|
goto retry;
|
|
}
|
|
/* oops */
|
|
WARN_ONCE(true, "workqueue: per-cpu pwq for %s on cpu%d has 0 refcnt",
|
|
wq->name, cpu);
|
|
}
|
|
|
|
/* pwq determined, queue */
|
|
trace_workqueue_queue_work(req_cpu, pwq, work);
|
|
|
|
if (WARN_ON(!list_empty(&work->entry)))
|
|
goto out;
|
|
|
|
pwq->nr_in_flight[pwq->work_color]++;
|
|
work_flags = work_color_to_flags(pwq->work_color);
|
|
|
|
/*
|
|
* Limit the number of concurrently active work items to max_active.
|
|
* @work must also queue behind existing inactive work items to maintain
|
|
* ordering when max_active changes. See wq_adjust_max_active().
|
|
*/
|
|
if (list_empty(&pwq->inactive_works) && pwq_tryinc_nr_active(pwq, false)) {
|
|
if (list_empty(&pool->worklist))
|
|
pool->watchdog_ts = jiffies;
|
|
|
|
trace_workqueue_activate_work(work);
|
|
insert_work(pwq, work, &pool->worklist, work_flags);
|
|
kick_pool(pool);
|
|
} else {
|
|
work_flags |= WORK_STRUCT_INACTIVE;
|
|
insert_work(pwq, work, &pwq->inactive_works, work_flags);
|
|
}
|
|
|
|
out:
|
|
raw_spin_unlock(&pool->lock);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static bool clear_pending_if_disabled(struct work_struct *work)
|
|
{
|
|
unsigned long data = *work_data_bits(work);
|
|
struct work_offq_data offqd;
|
|
|
|
if (likely((data & WORK_STRUCT_PWQ) ||
|
|
!(data & WORK_OFFQ_DISABLE_MASK)))
|
|
return false;
|
|
|
|
work_offqd_unpack(&offqd, data);
|
|
set_work_pool_and_clear_pending(work, offqd.pool_id,
|
|
work_offqd_pack_flags(&offqd));
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* queue_work_on - queue work on specific cpu
|
|
* @cpu: CPU number to execute work on
|
|
* @wq: workqueue to use
|
|
* @work: work to queue
|
|
*
|
|
* We queue the work to a specific CPU, the caller must ensure it
|
|
* can't go away. Callers that fail to ensure that the specified
|
|
* CPU cannot go away will execute on a randomly chosen CPU.
|
|
* But note well that callers specifying a CPU that never has been
|
|
* online will get a splat.
|
|
*
|
|
* Return: %false if @work was already on a queue, %true otherwise.
|
|
*/
|
|
bool queue_work_on(int cpu, struct workqueue_struct *wq,
|
|
struct work_struct *work)
|
|
{
|
|
bool ret = false;
|
|
unsigned long irq_flags;
|
|
|
|
local_irq_save(irq_flags);
|
|
|
|
if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)) &&
|
|
!clear_pending_if_disabled(work)) {
|
|
__queue_work(cpu, wq, work);
|
|
ret = true;
|
|
}
|
|
|
|
local_irq_restore(irq_flags);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(queue_work_on);
|
|
|
|
/**
|
|
* select_numa_node_cpu - Select a CPU based on NUMA node
|
|
* @node: NUMA node ID that we want to select a CPU from
|
|
*
|
|
* This function will attempt to find a "random" cpu available on a given
|
|
* node. If there are no CPUs available on the given node it will return
|
|
* WORK_CPU_UNBOUND indicating that we should just schedule to any
|
|
* available CPU if we need to schedule this work.
|
|
*/
|
|
static int select_numa_node_cpu(int node)
|
|
{
|
|
int cpu;
|
|
|
|
/* Delay binding to CPU if node is not valid or online */
|
|
if (node < 0 || node >= MAX_NUMNODES || !node_online(node))
|
|
return WORK_CPU_UNBOUND;
|
|
|
|
/* Use local node/cpu if we are already there */
|
|
cpu = raw_smp_processor_id();
|
|
if (node == cpu_to_node(cpu))
|
|
return cpu;
|
|
|
|
/* Use "random" otherwise know as "first" online CPU of node */
|
|
cpu = cpumask_any_and(cpumask_of_node(node), cpu_online_mask);
|
|
|
|
/* If CPU is valid return that, otherwise just defer */
|
|
return cpu < nr_cpu_ids ? cpu : WORK_CPU_UNBOUND;
|
|
}
|
|
|
|
/**
|
|
* queue_work_node - queue work on a "random" cpu for a given NUMA node
|
|
* @node: NUMA node that we are targeting the work for
|
|
* @wq: workqueue to use
|
|
* @work: work to queue
|
|
*
|
|
* We queue the work to a "random" CPU within a given NUMA node. The basic
|
|
* idea here is to provide a way to somehow associate work with a given
|
|
* NUMA node.
|
|
*
|
|
* This function will only make a best effort attempt at getting this onto
|
|
* the right NUMA node. If no node is requested or the requested node is
|
|
* offline then we just fall back to standard queue_work behavior.
|
|
*
|
|
* Currently the "random" CPU ends up being the first available CPU in the
|
|
* intersection of cpu_online_mask and the cpumask of the node, unless we
|
|
* are running on the node. In that case we just use the current CPU.
|
|
*
|
|
* Return: %false if @work was already on a queue, %true otherwise.
|
|
*/
|
|
bool queue_work_node(int node, struct workqueue_struct *wq,
|
|
struct work_struct *work)
|
|
{
|
|
unsigned long irq_flags;
|
|
bool ret = false;
|
|
|
|
/*
|
|
* This current implementation is specific to unbound workqueues.
|
|
* Specifically we only return the first available CPU for a given
|
|
* node instead of cycling through individual CPUs within the node.
|
|
*
|
|
* If this is used with a per-cpu workqueue then the logic in
|
|
* workqueue_select_cpu_near would need to be updated to allow for
|
|
* some round robin type logic.
|
|
*/
|
|
WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND));
|
|
|
|
local_irq_save(irq_flags);
|
|
|
|
if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)) &&
|
|
!clear_pending_if_disabled(work)) {
|
|
int cpu = select_numa_node_cpu(node);
|
|
|
|
__queue_work(cpu, wq, work);
|
|
ret = true;
|
|
}
|
|
|
|
local_irq_restore(irq_flags);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(queue_work_node);
|
|
|
|
void delayed_work_timer_fn(struct timer_list *t)
|
|
{
|
|
struct delayed_work *dwork = from_timer(dwork, t, timer);
|
|
|
|
/* should have been called from irqsafe timer with irq already off */
|
|
__queue_work(dwork->cpu, dwork->wq, &dwork->work);
|
|
}
|
|
EXPORT_SYMBOL(delayed_work_timer_fn);
|
|
|
|
static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
|
|
struct delayed_work *dwork, unsigned long delay)
|
|
{
|
|
struct timer_list *timer = &dwork->timer;
|
|
struct work_struct *work = &dwork->work;
|
|
|
|
WARN_ON_ONCE(!wq);
|
|
WARN_ON_ONCE(timer->function != delayed_work_timer_fn);
|
|
WARN_ON_ONCE(timer_pending(timer));
|
|
WARN_ON_ONCE(!list_empty(&work->entry));
|
|
|
|
/*
|
|
* If @delay is 0, queue @dwork->work immediately. This is for
|
|
* both optimization and correctness. The earliest @timer can
|
|
* expire is on the closest next tick and delayed_work users depend
|
|
* on that there's no such delay when @delay is 0.
|
|
*/
|
|
if (!delay) {
|
|
__queue_work(cpu, wq, &dwork->work);
|
|
return;
|
|
}
|
|
|
|
dwork->wq = wq;
|
|
dwork->cpu = cpu;
|
|
timer->expires = jiffies + delay;
|
|
|
|
if (housekeeping_enabled(HK_TYPE_TIMER)) {
|
|
/* If the current cpu is a housekeeping cpu, use it. */
|
|
cpu = smp_processor_id();
|
|
if (!housekeeping_test_cpu(cpu, HK_TYPE_TIMER))
|
|
cpu = housekeeping_any_cpu(HK_TYPE_TIMER);
|
|
add_timer_on(timer, cpu);
|
|
} else {
|
|
if (likely(cpu == WORK_CPU_UNBOUND))
|
|
add_timer_global(timer);
|
|
else
|
|
add_timer_on(timer, cpu);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* queue_delayed_work_on - queue work on specific CPU after delay
|
|
* @cpu: CPU number to execute work on
|
|
* @wq: workqueue to use
|
|
* @dwork: work to queue
|
|
* @delay: number of jiffies to wait before queueing
|
|
*
|
|
* Return: %false if @work was already on a queue, %true otherwise. If
|
|
* @delay is zero and @dwork is idle, it will be scheduled for immediate
|
|
* execution.
|
|
*/
|
|
bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
|
|
struct delayed_work *dwork, unsigned long delay)
|
|
{
|
|
struct work_struct *work = &dwork->work;
|
|
bool ret = false;
|
|
unsigned long irq_flags;
|
|
|
|
/* read the comment in __queue_work() */
|
|
local_irq_save(irq_flags);
|
|
|
|
if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)) &&
|
|
!clear_pending_if_disabled(work)) {
|
|
__queue_delayed_work(cpu, wq, dwork, delay);
|
|
ret = true;
|
|
}
|
|
|
|
local_irq_restore(irq_flags);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(queue_delayed_work_on);
|
|
|
|
/**
|
|
* mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU
|
|
* @cpu: CPU number to execute work on
|
|
* @wq: workqueue to use
|
|
* @dwork: work to queue
|
|
* @delay: number of jiffies to wait before queueing
|
|
*
|
|
* If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise,
|
|
* modify @dwork's timer so that it expires after @delay. If @delay is
|
|
* zero, @work is guaranteed to be scheduled immediately regardless of its
|
|
* current state.
|
|
*
|
|
* Return: %false if @dwork was idle and queued, %true if @dwork was
|
|
* pending and its timer was modified.
|
|
*
|
|
* This function is safe to call from any context including IRQ handler.
|
|
* See try_to_grab_pending() for details.
|
|
*/
|
|
bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
|
|
struct delayed_work *dwork, unsigned long delay)
|
|
{
|
|
unsigned long irq_flags;
|
|
bool ret;
|
|
|
|
ret = work_grab_pending(&dwork->work, WORK_CANCEL_DELAYED, &irq_flags);
|
|
|
|
if (!clear_pending_if_disabled(&dwork->work))
|
|
__queue_delayed_work(cpu, wq, dwork, delay);
|
|
|
|
local_irq_restore(irq_flags);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(mod_delayed_work_on);
|
|
|
|
static void rcu_work_rcufn(struct rcu_head *rcu)
|
|
{
|
|
struct rcu_work *rwork = container_of(rcu, struct rcu_work, rcu);
|
|
|
|
/* read the comment in __queue_work() */
|
|
local_irq_disable();
|
|
__queue_work(WORK_CPU_UNBOUND, rwork->wq, &rwork->work);
|
|
local_irq_enable();
|
|
}
|
|
|
|
/**
|
|
* queue_rcu_work - queue work after a RCU grace period
|
|
* @wq: workqueue to use
|
|
* @rwork: work to queue
|
|
*
|
|
* Return: %false if @rwork was already pending, %true otherwise. Note
|
|
* that a full RCU grace period is guaranteed only after a %true return.
|
|
* While @rwork is guaranteed to be executed after a %false return, the
|
|
* execution may happen before a full RCU grace period has passed.
|
|
*/
|
|
bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork)
|
|
{
|
|
struct work_struct *work = &rwork->work;
|
|
|
|
/*
|
|
* rcu_work can't be canceled or disabled. Warn if the user reached
|
|
* inside @rwork and disabled the inner work.
|
|
*/
|
|
if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)) &&
|
|
!WARN_ON_ONCE(clear_pending_if_disabled(work))) {
|
|
rwork->wq = wq;
|
|
call_rcu_hurry(&rwork->rcu, rcu_work_rcufn);
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL(queue_rcu_work);
|
|
|
|
static struct worker *alloc_worker(int node)
|
|
{
|
|
struct worker *worker;
|
|
|
|
worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, node);
|
|
if (worker) {
|
|
INIT_LIST_HEAD(&worker->entry);
|
|
INIT_LIST_HEAD(&worker->scheduled);
|
|
INIT_LIST_HEAD(&worker->node);
|
|
/* on creation a worker is in !idle && prep state */
|
|
worker->flags = WORKER_PREP;
|
|
}
|
|
return worker;
|
|
}
|
|
|
|
static cpumask_t *pool_allowed_cpus(struct worker_pool *pool)
|
|
{
|
|
if (pool->cpu < 0 && pool->attrs->affn_strict)
|
|
return pool->attrs->__pod_cpumask;
|
|
else
|
|
return pool->attrs->cpumask;
|
|
}
|
|
|
|
/**
|
|
* worker_attach_to_pool() - attach a worker to a pool
|
|
* @worker: worker to be attached
|
|
* @pool: the target pool
|
|
*
|
|
* Attach @worker to @pool. Once attached, the %WORKER_UNBOUND flag and
|
|
* cpu-binding of @worker are kept coordinated with the pool across
|
|
* cpu-[un]hotplugs.
|
|
*/
|
|
static void worker_attach_to_pool(struct worker *worker,
|
|
struct worker_pool *pool)
|
|
{
|
|
mutex_lock(&wq_pool_attach_mutex);
|
|
|
|
/*
|
|
* The wq_pool_attach_mutex ensures %POOL_DISASSOCIATED remains stable
|
|
* across this function. See the comments above the flag definition for
|
|
* details. BH workers are, while per-CPU, always DISASSOCIATED.
|
|
*/
|
|
if (pool->flags & POOL_DISASSOCIATED) {
|
|
worker->flags |= WORKER_UNBOUND;
|
|
} else {
|
|
WARN_ON_ONCE(pool->flags & POOL_BH);
|
|
kthread_set_per_cpu(worker->task, pool->cpu);
|
|
}
|
|
|
|
if (worker->rescue_wq)
|
|
set_cpus_allowed_ptr(worker->task, pool_allowed_cpus(pool));
|
|
|
|
list_add_tail(&worker->node, &pool->workers);
|
|
worker->pool = pool;
|
|
|
|
mutex_unlock(&wq_pool_attach_mutex);
|
|
}
|
|
|
|
/**
|
|
* worker_detach_from_pool() - detach a worker from its pool
|
|
* @worker: worker which is attached to its pool
|
|
*
|
|
* Undo the attaching which had been done in worker_attach_to_pool(). The
|
|
* caller worker shouldn't access to the pool after detached except it has
|
|
* other reference to the pool.
|
|
*/
|
|
static void worker_detach_from_pool(struct worker *worker)
|
|
{
|
|
struct worker_pool *pool = worker->pool;
|
|
struct completion *detach_completion = NULL;
|
|
|
|
/* there is one permanent BH worker per CPU which should never detach */
|
|
WARN_ON_ONCE(pool->flags & POOL_BH);
|
|
|
|
mutex_lock(&wq_pool_attach_mutex);
|
|
|
|
kthread_set_per_cpu(worker->task, -1);
|
|
list_del(&worker->node);
|
|
worker->pool = NULL;
|
|
|
|
if (list_empty(&pool->workers) && list_empty(&pool->dying_workers))
|
|
detach_completion = pool->detach_completion;
|
|
mutex_unlock(&wq_pool_attach_mutex);
|
|
|
|
/* clear leftover flags without pool->lock after it is detached */
|
|
worker->flags &= ~(WORKER_UNBOUND | WORKER_REBOUND);
|
|
|
|
if (detach_completion)
|
|
complete(detach_completion);
|
|
}
|
|
|
|
/**
|
|
* create_worker - create a new workqueue worker
|
|
* @pool: pool the new worker will belong to
|
|
*
|
|
* Create and start a new worker which is attached to @pool.
|
|
*
|
|
* CONTEXT:
|
|
* Might sleep. Does GFP_KERNEL allocations.
|
|
*
|
|
* Return:
|
|
* Pointer to the newly created worker.
|
|
*/
|
|
static struct worker *create_worker(struct worker_pool *pool)
|
|
{
|
|
struct worker *worker;
|
|
int id;
|
|
char id_buf[23];
|
|
|
|
/* ID is needed to determine kthread name */
|
|
id = ida_alloc(&pool->worker_ida, GFP_KERNEL);
|
|
if (id < 0) {
|
|
pr_err_once("workqueue: Failed to allocate a worker ID: %pe\n",
|
|
ERR_PTR(id));
|
|
return NULL;
|
|
}
|
|
|
|
worker = alloc_worker(pool->node);
|
|
if (!worker) {
|
|
pr_err_once("workqueue: Failed to allocate a worker\n");
|
|
goto fail;
|
|
}
|
|
|
|
worker->id = id;
|
|
|
|
if (!(pool->flags & POOL_BH)) {
|
|
if (pool->cpu >= 0)
|
|
snprintf(id_buf, sizeof(id_buf), "%d:%d%s", pool->cpu, id,
|
|
pool->attrs->nice < 0 ? "H" : "");
|
|
else
|
|
snprintf(id_buf, sizeof(id_buf), "u%d:%d", pool->id, id);
|
|
|
|
worker->task = kthread_create_on_node(worker_thread, worker,
|
|
pool->node, "kworker/%s", id_buf);
|
|
if (IS_ERR(worker->task)) {
|
|
if (PTR_ERR(worker->task) == -EINTR) {
|
|
pr_err("workqueue: Interrupted when creating a worker thread \"kworker/%s\"\n",
|
|
id_buf);
|
|
} else {
|
|
pr_err_once("workqueue: Failed to create a worker thread: %pe",
|
|
worker->task);
|
|
}
|
|
goto fail;
|
|
}
|
|
|
|
set_user_nice(worker->task, pool->attrs->nice);
|
|
kthread_bind_mask(worker->task, pool_allowed_cpus(pool));
|
|
}
|
|
|
|
/* successful, attach the worker to the pool */
|
|
worker_attach_to_pool(worker, pool);
|
|
|
|
/* start the newly created worker */
|
|
raw_spin_lock_irq(&pool->lock);
|
|
|
|
worker->pool->nr_workers++;
|
|
worker_enter_idle(worker);
|
|
|
|
/*
|
|
* @worker is waiting on a completion in kthread() and will trigger hung
|
|
* check if not woken up soon. As kick_pool() is noop if @pool is empty,
|
|
* wake it up explicitly.
|
|
*/
|
|
if (worker->task)
|
|
wake_up_process(worker->task);
|
|
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
|
|
return worker;
|
|
|
|
fail:
|
|
ida_free(&pool->worker_ida, id);
|
|
kfree(worker);
|
|
return NULL;
|
|
}
|
|
|
|
static void unbind_worker(struct worker *worker)
|
|
{
|
|
lockdep_assert_held(&wq_pool_attach_mutex);
|
|
|
|
kthread_set_per_cpu(worker->task, -1);
|
|
if (cpumask_intersects(wq_unbound_cpumask, cpu_active_mask))
|
|
WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, wq_unbound_cpumask) < 0);
|
|
else
|
|
WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, cpu_possible_mask) < 0);
|
|
}
|
|
|
|
static void wake_dying_workers(struct list_head *cull_list)
|
|
{
|
|
struct worker *worker, *tmp;
|
|
|
|
list_for_each_entry_safe(worker, tmp, cull_list, entry) {
|
|
list_del_init(&worker->entry);
|
|
unbind_worker(worker);
|
|
/*
|
|
* If the worker was somehow already running, then it had to be
|
|
* in pool->idle_list when set_worker_dying() happened or we
|
|
* wouldn't have gotten here.
|
|
*
|
|
* Thus, the worker must either have observed the WORKER_DIE
|
|
* flag, or have set its state to TASK_IDLE. Either way, the
|
|
* below will be observed by the worker and is safe to do
|
|
* outside of pool->lock.
|
|
*/
|
|
wake_up_process(worker->task);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* set_worker_dying - Tag a worker for destruction
|
|
* @worker: worker to be destroyed
|
|
* @list: transfer worker away from its pool->idle_list and into list
|
|
*
|
|
* Tag @worker for destruction and adjust @pool stats accordingly. The worker
|
|
* should be idle.
|
|
*
|
|
* CONTEXT:
|
|
* raw_spin_lock_irq(pool->lock).
|
|
*/
|
|
static void set_worker_dying(struct worker *worker, struct list_head *list)
|
|
{
|
|
struct worker_pool *pool = worker->pool;
|
|
|
|
lockdep_assert_held(&pool->lock);
|
|
lockdep_assert_held(&wq_pool_attach_mutex);
|
|
|
|
/* sanity check frenzy */
|
|
if (WARN_ON(worker->current_work) ||
|
|
WARN_ON(!list_empty(&worker->scheduled)) ||
|
|
WARN_ON(!(worker->flags & WORKER_IDLE)))
|
|
return;
|
|
|
|
pool->nr_workers--;
|
|
pool->nr_idle--;
|
|
|
|
worker->flags |= WORKER_DIE;
|
|
|
|
list_move(&worker->entry, list);
|
|
list_move(&worker->node, &pool->dying_workers);
|
|
}
|
|
|
|
/**
|
|
* idle_worker_timeout - check if some idle workers can now be deleted.
|
|
* @t: The pool's idle_timer that just expired
|
|
*
|
|
* The timer is armed in worker_enter_idle(). Note that it isn't disarmed in
|
|
* worker_leave_idle(), as a worker flicking between idle and active while its
|
|
* pool is at the too_many_workers() tipping point would cause too much timer
|
|
* housekeeping overhead. Since IDLE_WORKER_TIMEOUT is long enough, we just let
|
|
* it expire and re-evaluate things from there.
|
|
*/
|
|
static void idle_worker_timeout(struct timer_list *t)
|
|
{
|
|
struct worker_pool *pool = from_timer(pool, t, idle_timer);
|
|
bool do_cull = false;
|
|
|
|
if (work_pending(&pool->idle_cull_work))
|
|
return;
|
|
|
|
raw_spin_lock_irq(&pool->lock);
|
|
|
|
if (too_many_workers(pool)) {
|
|
struct worker *worker;
|
|
unsigned long expires;
|
|
|
|
/* idle_list is kept in LIFO order, check the last one */
|
|
worker = list_last_entry(&pool->idle_list, struct worker, entry);
|
|
expires = worker->last_active + IDLE_WORKER_TIMEOUT;
|
|
do_cull = !time_before(jiffies, expires);
|
|
|
|
if (!do_cull)
|
|
mod_timer(&pool->idle_timer, expires);
|
|
}
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
|
|
if (do_cull)
|
|
queue_work(system_unbound_wq, &pool->idle_cull_work);
|
|
}
|
|
|
|
/**
|
|
* idle_cull_fn - cull workers that have been idle for too long.
|
|
* @work: the pool's work for handling these idle workers
|
|
*
|
|
* This goes through a pool's idle workers and gets rid of those that have been
|
|
* idle for at least IDLE_WORKER_TIMEOUT seconds.
|
|
*
|
|
* We don't want to disturb isolated CPUs because of a pcpu kworker being
|
|
* culled, so this also resets worker affinity. This requires a sleepable
|
|
* context, hence the split between timer callback and work item.
|
|
*/
|
|
static void idle_cull_fn(struct work_struct *work)
|
|
{
|
|
struct worker_pool *pool = container_of(work, struct worker_pool, idle_cull_work);
|
|
LIST_HEAD(cull_list);
|
|
|
|
/*
|
|
* Grabbing wq_pool_attach_mutex here ensures an already-running worker
|
|
* cannot proceed beyong worker_detach_from_pool() in its self-destruct
|
|
* path. This is required as a previously-preempted worker could run after
|
|
* set_worker_dying() has happened but before wake_dying_workers() did.
|
|
*/
|
|
mutex_lock(&wq_pool_attach_mutex);
|
|
raw_spin_lock_irq(&pool->lock);
|
|
|
|
while (too_many_workers(pool)) {
|
|
struct worker *worker;
|
|
unsigned long expires;
|
|
|
|
worker = list_last_entry(&pool->idle_list, struct worker, entry);
|
|
expires = worker->last_active + IDLE_WORKER_TIMEOUT;
|
|
|
|
if (time_before(jiffies, expires)) {
|
|
mod_timer(&pool->idle_timer, expires);
|
|
break;
|
|
}
|
|
|
|
set_worker_dying(worker, &cull_list);
|
|
}
|
|
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
wake_dying_workers(&cull_list);
|
|
mutex_unlock(&wq_pool_attach_mutex);
|
|
}
|
|
|
|
static void send_mayday(struct work_struct *work)
|
|
{
|
|
struct pool_workqueue *pwq = get_work_pwq(work);
|
|
struct workqueue_struct *wq = pwq->wq;
|
|
|
|
lockdep_assert_held(&wq_mayday_lock);
|
|
|
|
if (!wq->rescuer)
|
|
return;
|
|
|
|
/* mayday mayday mayday */
|
|
if (list_empty(&pwq->mayday_node)) {
|
|
/*
|
|
* If @pwq is for an unbound wq, its base ref may be put at
|
|
* any time due to an attribute change. Pin @pwq until the
|
|
* rescuer is done with it.
|
|
*/
|
|
get_pwq(pwq);
|
|
list_add_tail(&pwq->mayday_node, &wq->maydays);
|
|
wake_up_process(wq->rescuer->task);
|
|
pwq->stats[PWQ_STAT_MAYDAY]++;
|
|
}
|
|
}
|
|
|
|
static void pool_mayday_timeout(struct timer_list *t)
|
|
{
|
|
struct worker_pool *pool = from_timer(pool, t, mayday_timer);
|
|
struct work_struct *work;
|
|
|
|
raw_spin_lock_irq(&pool->lock);
|
|
raw_spin_lock(&wq_mayday_lock); /* for wq->maydays */
|
|
|
|
if (need_to_create_worker(pool)) {
|
|
/*
|
|
* We've been trying to create a new worker but
|
|
* haven't been successful. We might be hitting an
|
|
* allocation deadlock. Send distress signals to
|
|
* rescuers.
|
|
*/
|
|
list_for_each_entry(work, &pool->worklist, entry)
|
|
send_mayday(work);
|
|
}
|
|
|
|
raw_spin_unlock(&wq_mayday_lock);
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
|
|
mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL);
|
|
}
|
|
|
|
/**
|
|
* maybe_create_worker - create a new worker if necessary
|
|
* @pool: pool to create a new worker for
|
|
*
|
|
* Create a new worker for @pool if necessary. @pool is guaranteed to
|
|
* have at least one idle worker on return from this function. If
|
|
* creating a new worker takes longer than MAYDAY_INTERVAL, mayday is
|
|
* sent to all rescuers with works scheduled on @pool to resolve
|
|
* possible allocation deadlock.
|
|
*
|
|
* On return, need_to_create_worker() is guaranteed to be %false and
|
|
* may_start_working() %true.
|
|
*
|
|
* LOCKING:
|
|
* raw_spin_lock_irq(pool->lock) which may be released and regrabbed
|
|
* multiple times. Does GFP_KERNEL allocations. Called only from
|
|
* manager.
|
|
*/
|
|
static void maybe_create_worker(struct worker_pool *pool)
|
|
__releases(&pool->lock)
|
|
__acquires(&pool->lock)
|
|
{
|
|
restart:
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
|
|
/* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */
|
|
mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT);
|
|
|
|
while (true) {
|
|
if (create_worker(pool) || !need_to_create_worker(pool))
|
|
break;
|
|
|
|
schedule_timeout_interruptible(CREATE_COOLDOWN);
|
|
|
|
if (!need_to_create_worker(pool))
|
|
break;
|
|
}
|
|
|
|
del_timer_sync(&pool->mayday_timer);
|
|
raw_spin_lock_irq(&pool->lock);
|
|
/*
|
|
* This is necessary even after a new worker was just successfully
|
|
* created as @pool->lock was dropped and the new worker might have
|
|
* already become busy.
|
|
*/
|
|
if (need_to_create_worker(pool))
|
|
goto restart;
|
|
}
|
|
|
|
/**
|
|
* manage_workers - manage worker pool
|
|
* @worker: self
|
|
*
|
|
* Assume the manager role and manage the worker pool @worker belongs
|
|
* to. At any given time, there can be only zero or one manager per
|
|
* pool. The exclusion is handled automatically by this function.
|
|
*
|
|
* The caller can safely start processing works on false return. On
|
|
* true return, it's guaranteed that need_to_create_worker() is false
|
|
* and may_start_working() is true.
|
|
*
|
|
* CONTEXT:
|
|
* raw_spin_lock_irq(pool->lock) which may be released and regrabbed
|
|
* multiple times. Does GFP_KERNEL allocations.
|
|
*
|
|
* Return:
|
|
* %false if the pool doesn't need management and the caller can safely
|
|
* start processing works, %true if management function was performed and
|
|
* the conditions that the caller verified before calling the function may
|
|
* no longer be true.
|
|
*/
|
|
static bool manage_workers(struct worker *worker)
|
|
{
|
|
struct worker_pool *pool = worker->pool;
|
|
|
|
if (pool->flags & POOL_MANAGER_ACTIVE)
|
|
return false;
|
|
|
|
pool->flags |= POOL_MANAGER_ACTIVE;
|
|
pool->manager = worker;
|
|
|
|
maybe_create_worker(pool);
|
|
|
|
pool->manager = NULL;
|
|
pool->flags &= ~POOL_MANAGER_ACTIVE;
|
|
rcuwait_wake_up(&manager_wait);
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* process_one_work - process single work
|
|
* @worker: self
|
|
* @work: work to process
|
|
*
|
|
* Process @work. This function contains all the logics necessary to
|
|
* process a single work including synchronization against and
|
|
* interaction with other workers on the same cpu, queueing and
|
|
* flushing. As long as context requirement is met, any worker can
|
|
* call this function to process a work.
|
|
*
|
|
* CONTEXT:
|
|
* raw_spin_lock_irq(pool->lock) which is released and regrabbed.
|
|
*/
|
|
static void process_one_work(struct worker *worker, struct work_struct *work)
|
|
__releases(&pool->lock)
|
|
__acquires(&pool->lock)
|
|
{
|
|
struct pool_workqueue *pwq = get_work_pwq(work);
|
|
struct worker_pool *pool = worker->pool;
|
|
unsigned long work_data;
|
|
int lockdep_start_depth, rcu_start_depth;
|
|
bool bh_draining = pool->flags & POOL_BH_DRAINING;
|
|
#ifdef CONFIG_LOCKDEP
|
|
/*
|
|
* It is permissible to free the struct work_struct from
|
|
* inside the function that is called from it, this we need to
|
|
* take into account for lockdep too. To avoid bogus "held
|
|
* lock freed" warnings as well as problems when looking into
|
|
* work->lockdep_map, make a copy and use that here.
|
|
*/
|
|
struct lockdep_map lockdep_map;
|
|
|
|
lockdep_copy_map(&lockdep_map, &work->lockdep_map);
|
|
#endif
|
|
/* ensure we're on the correct CPU */
|
|
WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) &&
|
|
raw_smp_processor_id() != pool->cpu);
|
|
|
|
/* claim and dequeue */
|
|
debug_work_deactivate(work);
|
|
hash_add(pool->busy_hash, &worker->hentry, (unsigned long)work);
|
|
worker->current_work = work;
|
|
worker->current_func = work->func;
|
|
worker->current_pwq = pwq;
|
|
if (worker->task)
|
|
worker->current_at = worker->task->se.sum_exec_runtime;
|
|
work_data = *work_data_bits(work);
|
|
worker->current_color = get_work_color(work_data);
|
|
|
|
/*
|
|
* Record wq name for cmdline and debug reporting, may get
|
|
* overridden through set_worker_desc().
|
|
*/
|
|
strscpy(worker->desc, pwq->wq->name, WORKER_DESC_LEN);
|
|
|
|
list_del_init(&work->entry);
|
|
|
|
/*
|
|
* CPU intensive works don't participate in concurrency management.
|
|
* They're the scheduler's responsibility. This takes @worker out
|
|
* of concurrency management and the next code block will chain
|
|
* execution of the pending work items.
|
|
*/
|
|
if (unlikely(pwq->wq->flags & WQ_CPU_INTENSIVE))
|
|
worker_set_flags(worker, WORKER_CPU_INTENSIVE);
|
|
|
|
/*
|
|
* Kick @pool if necessary. It's always noop for per-cpu worker pools
|
|
* since nr_running would always be >= 1 at this point. This is used to
|
|
* chain execution of the pending work items for WORKER_NOT_RUNNING
|
|
* workers such as the UNBOUND and CPU_INTENSIVE ones.
|
|
*/
|
|
kick_pool(pool);
|
|
|
|
/*
|
|
* Record the last pool and clear PENDING which should be the last
|
|
* update to @work. Also, do this inside @pool->lock so that
|
|
* PENDING and queued state changes happen together while IRQ is
|
|
* disabled.
|
|
*/
|
|
set_work_pool_and_clear_pending(work, pool->id, pool_offq_flags(pool));
|
|
|
|
pwq->stats[PWQ_STAT_STARTED]++;
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
|
|
rcu_start_depth = rcu_preempt_depth();
|
|
lockdep_start_depth = lockdep_depth(current);
|
|
/* see drain_dead_softirq_workfn() */
|
|
if (!bh_draining)
|
|
lock_map_acquire(&pwq->wq->lockdep_map);
|
|
lock_map_acquire(&lockdep_map);
|
|
/*
|
|
* Strictly speaking we should mark the invariant state without holding
|
|
* any locks, that is, before these two lock_map_acquire()'s.
|
|
*
|
|
* However, that would result in:
|
|
*
|
|
* A(W1)
|
|
* WFC(C)
|
|
* A(W1)
|
|
* C(C)
|
|
*
|
|
* Which would create W1->C->W1 dependencies, even though there is no
|
|
* actual deadlock possible. There are two solutions, using a
|
|
* read-recursive acquire on the work(queue) 'locks', but this will then
|
|
* hit the lockdep limitation on recursive locks, or simply discard
|
|
* these locks.
|
|
*
|
|
* AFAICT there is no possible deadlock scenario between the
|
|
* flush_work() and complete() primitives (except for single-threaded
|
|
* workqueues), so hiding them isn't a problem.
|
|
*/
|
|
lockdep_invariant_state(true);
|
|
trace_workqueue_execute_start(work);
|
|
worker->current_func(work);
|
|
/*
|
|
* While we must be careful to not use "work" after this, the trace
|
|
* point will only record its address.
|
|
*/
|
|
trace_workqueue_execute_end(work, worker->current_func);
|
|
pwq->stats[PWQ_STAT_COMPLETED]++;
|
|
lock_map_release(&lockdep_map);
|
|
if (!bh_draining)
|
|
lock_map_release(&pwq->wq->lockdep_map);
|
|
|
|
if (unlikely((worker->task && in_atomic()) ||
|
|
lockdep_depth(current) != lockdep_start_depth ||
|
|
rcu_preempt_depth() != rcu_start_depth)) {
|
|
pr_err("BUG: workqueue leaked atomic, lock or RCU: %s[%d]\n"
|
|
" preempt=0x%08x lock=%d->%d RCU=%d->%d workfn=%ps\n",
|
|
current->comm, task_pid_nr(current), preempt_count(),
|
|
lockdep_start_depth, lockdep_depth(current),
|
|
rcu_start_depth, rcu_preempt_depth(),
|
|
worker->current_func);
|
|
debug_show_held_locks(current);
|
|
dump_stack();
|
|
}
|
|
|
|
/*
|
|
* The following prevents a kworker from hogging CPU on !PREEMPTION
|
|
* kernels, where a requeueing work item waiting for something to
|
|
* happen could deadlock with stop_machine as such work item could
|
|
* indefinitely requeue itself while all other CPUs are trapped in
|
|
* stop_machine. At the same time, report a quiescent RCU state so
|
|
* the same condition doesn't freeze RCU.
|
|
*/
|
|
if (worker->task)
|
|
cond_resched();
|
|
|
|
raw_spin_lock_irq(&pool->lock);
|
|
|
|
/*
|
|
* In addition to %WQ_CPU_INTENSIVE, @worker may also have been marked
|
|
* CPU intensive by wq_worker_tick() if @work hogged CPU longer than
|
|
* wq_cpu_intensive_thresh_us. Clear it.
|
|
*/
|
|
worker_clr_flags(worker, WORKER_CPU_INTENSIVE);
|
|
|
|
/* tag the worker for identification in schedule() */
|
|
worker->last_func = worker->current_func;
|
|
|
|
/* we're done with it, release */
|
|
hash_del(&worker->hentry);
|
|
worker->current_work = NULL;
|
|
worker->current_func = NULL;
|
|
worker->current_pwq = NULL;
|
|
worker->current_color = INT_MAX;
|
|
|
|
/* must be the last step, see the function comment */
|
|
pwq_dec_nr_in_flight(pwq, work_data);
|
|
}
|
|
|
|
/**
|
|
* process_scheduled_works - process scheduled works
|
|
* @worker: self
|
|
*
|
|
* Process all scheduled works. Please note that the scheduled list
|
|
* may change while processing a work, so this function repeatedly
|
|
* fetches a work from the top and executes it.
|
|
*
|
|
* CONTEXT:
|
|
* raw_spin_lock_irq(pool->lock) which may be released and regrabbed
|
|
* multiple times.
|
|
*/
|
|
static void process_scheduled_works(struct worker *worker)
|
|
{
|
|
struct work_struct *work;
|
|
bool first = true;
|
|
|
|
while ((work = list_first_entry_or_null(&worker->scheduled,
|
|
struct work_struct, entry))) {
|
|
if (first) {
|
|
worker->pool->watchdog_ts = jiffies;
|
|
first = false;
|
|
}
|
|
process_one_work(worker, work);
|
|
}
|
|
}
|
|
|
|
static void set_pf_worker(bool val)
|
|
{
|
|
mutex_lock(&wq_pool_attach_mutex);
|
|
if (val)
|
|
current->flags |= PF_WQ_WORKER;
|
|
else
|
|
current->flags &= ~PF_WQ_WORKER;
|
|
mutex_unlock(&wq_pool_attach_mutex);
|
|
}
|
|
|
|
/**
|
|
* worker_thread - the worker thread function
|
|
* @__worker: self
|
|
*
|
|
* The worker thread function. All workers belong to a worker_pool -
|
|
* either a per-cpu one or dynamic unbound one. These workers process all
|
|
* work items regardless of their specific target workqueue. The only
|
|
* exception is work items which belong to workqueues with a rescuer which
|
|
* will be explained in rescuer_thread().
|
|
*
|
|
* Return: 0
|
|
*/
|
|
static int worker_thread(void *__worker)
|
|
{
|
|
struct worker *worker = __worker;
|
|
struct worker_pool *pool = worker->pool;
|
|
|
|
/* tell the scheduler that this is a workqueue worker */
|
|
set_pf_worker(true);
|
|
woke_up:
|
|
raw_spin_lock_irq(&pool->lock);
|
|
|
|
/* am I supposed to die? */
|
|
if (unlikely(worker->flags & WORKER_DIE)) {
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
set_pf_worker(false);
|
|
|
|
set_task_comm(worker->task, "kworker/dying");
|
|
ida_free(&pool->worker_ida, worker->id);
|
|
worker_detach_from_pool(worker);
|
|
WARN_ON_ONCE(!list_empty(&worker->entry));
|
|
kfree(worker);
|
|
return 0;
|
|
}
|
|
|
|
worker_leave_idle(worker);
|
|
recheck:
|
|
/* no more worker necessary? */
|
|
if (!need_more_worker(pool))
|
|
goto sleep;
|
|
|
|
/* do we need to manage? */
|
|
if (unlikely(!may_start_working(pool)) && manage_workers(worker))
|
|
goto recheck;
|
|
|
|
/*
|
|
* ->scheduled list can only be filled while a worker is
|
|
* preparing to process a work or actually processing it.
|
|
* Make sure nobody diddled with it while I was sleeping.
|
|
*/
|
|
WARN_ON_ONCE(!list_empty(&worker->scheduled));
|
|
|
|
/*
|
|
* Finish PREP stage. We're guaranteed to have at least one idle
|
|
* worker or that someone else has already assumed the manager
|
|
* role. This is where @worker starts participating in concurrency
|
|
* management if applicable and concurrency management is restored
|
|
* after being rebound. See rebind_workers() for details.
|
|
*/
|
|
worker_clr_flags(worker, WORKER_PREP | WORKER_REBOUND);
|
|
|
|
do {
|
|
struct work_struct *work =
|
|
list_first_entry(&pool->worklist,
|
|
struct work_struct, entry);
|
|
|
|
if (assign_work(work, worker, NULL))
|
|
process_scheduled_works(worker);
|
|
} while (keep_working(pool));
|
|
|
|
worker_set_flags(worker, WORKER_PREP);
|
|
sleep:
|
|
/*
|
|
* pool->lock is held and there's no work to process and no need to
|
|
* manage, sleep. Workers are woken up only while holding
|
|
* pool->lock or from local cpu, so setting the current state
|
|
* before releasing pool->lock is enough to prevent losing any
|
|
* event.
|
|
*/
|
|
worker_enter_idle(worker);
|
|
__set_current_state(TASK_IDLE);
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
schedule();
|
|
goto woke_up;
|
|
}
|
|
|
|
/**
|
|
* rescuer_thread - the rescuer thread function
|
|
* @__rescuer: self
|
|
*
|
|
* Workqueue rescuer thread function. There's one rescuer for each
|
|
* workqueue which has WQ_MEM_RECLAIM set.
|
|
*
|
|
* Regular work processing on a pool may block trying to create a new
|
|
* worker which uses GFP_KERNEL allocation which has slight chance of
|
|
* developing into deadlock if some works currently on the same queue
|
|
* need to be processed to satisfy the GFP_KERNEL allocation. This is
|
|
* the problem rescuer solves.
|
|
*
|
|
* When such condition is possible, the pool summons rescuers of all
|
|
* workqueues which have works queued on the pool and let them process
|
|
* those works so that forward progress can be guaranteed.
|
|
*
|
|
* This should happen rarely.
|
|
*
|
|
* Return: 0
|
|
*/
|
|
static int rescuer_thread(void *__rescuer)
|
|
{
|
|
struct worker *rescuer = __rescuer;
|
|
struct workqueue_struct *wq = rescuer->rescue_wq;
|
|
bool should_stop;
|
|
|
|
set_user_nice(current, RESCUER_NICE_LEVEL);
|
|
|
|
/*
|
|
* Mark rescuer as worker too. As WORKER_PREP is never cleared, it
|
|
* doesn't participate in concurrency management.
|
|
*/
|
|
set_pf_worker(true);
|
|
repeat:
|
|
set_current_state(TASK_IDLE);
|
|
|
|
/*
|
|
* By the time the rescuer is requested to stop, the workqueue
|
|
* shouldn't have any work pending, but @wq->maydays may still have
|
|
* pwq(s) queued. This can happen by non-rescuer workers consuming
|
|
* all the work items before the rescuer got to them. Go through
|
|
* @wq->maydays processing before acting on should_stop so that the
|
|
* list is always empty on exit.
|
|
*/
|
|
should_stop = kthread_should_stop();
|
|
|
|
/* see whether any pwq is asking for help */
|
|
raw_spin_lock_irq(&wq_mayday_lock);
|
|
|
|
while (!list_empty(&wq->maydays)) {
|
|
struct pool_workqueue *pwq = list_first_entry(&wq->maydays,
|
|
struct pool_workqueue, mayday_node);
|
|
struct worker_pool *pool = pwq->pool;
|
|
struct work_struct *work, *n;
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
list_del_init(&pwq->mayday_node);
|
|
|
|
raw_spin_unlock_irq(&wq_mayday_lock);
|
|
|
|
worker_attach_to_pool(rescuer, pool);
|
|
|
|
raw_spin_lock_irq(&pool->lock);
|
|
|
|
/*
|
|
* Slurp in all works issued via this workqueue and
|
|
* process'em.
|
|
*/
|
|
WARN_ON_ONCE(!list_empty(&rescuer->scheduled));
|
|
list_for_each_entry_safe(work, n, &pool->worklist, entry) {
|
|
if (get_work_pwq(work) == pwq &&
|
|
assign_work(work, rescuer, &n))
|
|
pwq->stats[PWQ_STAT_RESCUED]++;
|
|
}
|
|
|
|
if (!list_empty(&rescuer->scheduled)) {
|
|
process_scheduled_works(rescuer);
|
|
|
|
/*
|
|
* The above execution of rescued work items could
|
|
* have created more to rescue through
|
|
* pwq_activate_first_inactive() or chained
|
|
* queueing. Let's put @pwq back on mayday list so
|
|
* that such back-to-back work items, which may be
|
|
* being used to relieve memory pressure, don't
|
|
* incur MAYDAY_INTERVAL delay inbetween.
|
|
*/
|
|
if (pwq->nr_active && need_to_create_worker(pool)) {
|
|
raw_spin_lock(&wq_mayday_lock);
|
|
/*
|
|
* Queue iff we aren't racing destruction
|
|
* and somebody else hasn't queued it already.
|
|
*/
|
|
if (wq->rescuer && list_empty(&pwq->mayday_node)) {
|
|
get_pwq(pwq);
|
|
list_add_tail(&pwq->mayday_node, &wq->maydays);
|
|
}
|
|
raw_spin_unlock(&wq_mayday_lock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Put the reference grabbed by send_mayday(). @pool won't
|
|
* go away while we're still attached to it.
|
|
*/
|
|
put_pwq(pwq);
|
|
|
|
/*
|
|
* Leave this pool. Notify regular workers; otherwise, we end up
|
|
* with 0 concurrency and stalling the execution.
|
|
*/
|
|
kick_pool(pool);
|
|
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
|
|
worker_detach_from_pool(rescuer);
|
|
|
|
raw_spin_lock_irq(&wq_mayday_lock);
|
|
}
|
|
|
|
raw_spin_unlock_irq(&wq_mayday_lock);
|
|
|
|
if (should_stop) {
|
|
__set_current_state(TASK_RUNNING);
|
|
set_pf_worker(false);
|
|
return 0;
|
|
}
|
|
|
|
/* rescuers should never participate in concurrency management */
|
|
WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING));
|
|
schedule();
|
|
goto repeat;
|
|
}
|
|
|
|
static void bh_worker(struct worker *worker)
|
|
{
|
|
struct worker_pool *pool = worker->pool;
|
|
int nr_restarts = BH_WORKER_RESTARTS;
|
|
unsigned long end = jiffies + BH_WORKER_JIFFIES;
|
|
|
|
raw_spin_lock_irq(&pool->lock);
|
|
worker_leave_idle(worker);
|
|
|
|
/*
|
|
* This function follows the structure of worker_thread(). See there for
|
|
* explanations on each step.
|
|
*/
|
|
if (!need_more_worker(pool))
|
|
goto done;
|
|
|
|
WARN_ON_ONCE(!list_empty(&worker->scheduled));
|
|
worker_clr_flags(worker, WORKER_PREP | WORKER_REBOUND);
|
|
|
|
do {
|
|
struct work_struct *work =
|
|
list_first_entry(&pool->worklist,
|
|
struct work_struct, entry);
|
|
|
|
if (assign_work(work, worker, NULL))
|
|
process_scheduled_works(worker);
|
|
} while (keep_working(pool) &&
|
|
--nr_restarts && time_before(jiffies, end));
|
|
|
|
worker_set_flags(worker, WORKER_PREP);
|
|
done:
|
|
worker_enter_idle(worker);
|
|
kick_pool(pool);
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
}
|
|
|
|
/*
|
|
* TODO: Convert all tasklet users to workqueue and use softirq directly.
|
|
*
|
|
* This is currently called from tasklet[_hi]action() and thus is also called
|
|
* whenever there are tasklets to run. Let's do an early exit if there's nothing
|
|
* queued. Once conversion from tasklet is complete, the need_more_worker() test
|
|
* can be dropped.
|
|
*
|
|
* After full conversion, we'll add worker->softirq_action, directly use the
|
|
* softirq action and obtain the worker pointer from the softirq_action pointer.
|
|
*/
|
|
void workqueue_softirq_action(bool highpri)
|
|
{
|
|
struct worker_pool *pool =
|
|
&per_cpu(bh_worker_pools, smp_processor_id())[highpri];
|
|
if (need_more_worker(pool))
|
|
bh_worker(list_first_entry(&pool->workers, struct worker, node));
|
|
}
|
|
|
|
struct wq_drain_dead_softirq_work {
|
|
struct work_struct work;
|
|
struct worker_pool *pool;
|
|
struct completion done;
|
|
};
|
|
|
|
static void drain_dead_softirq_workfn(struct work_struct *work)
|
|
{
|
|
struct wq_drain_dead_softirq_work *dead_work =
|
|
container_of(work, struct wq_drain_dead_softirq_work, work);
|
|
struct worker_pool *pool = dead_work->pool;
|
|
bool repeat;
|
|
|
|
/*
|
|
* @pool's CPU is dead and we want to execute its still pending work
|
|
* items from this BH work item which is running on a different CPU. As
|
|
* its CPU is dead, @pool can't be kicked and, as work execution path
|
|
* will be nested, a lockdep annotation needs to be suppressed. Mark
|
|
* @pool with %POOL_BH_DRAINING for the special treatments.
|
|
*/
|
|
raw_spin_lock_irq(&pool->lock);
|
|
pool->flags |= POOL_BH_DRAINING;
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
|
|
bh_worker(list_first_entry(&pool->workers, struct worker, node));
|
|
|
|
raw_spin_lock_irq(&pool->lock);
|
|
pool->flags &= ~POOL_BH_DRAINING;
|
|
repeat = need_more_worker(pool);
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
|
|
/*
|
|
* bh_worker() might hit consecutive execution limit and bail. If there
|
|
* still are pending work items, reschedule self and return so that we
|
|
* don't hog this CPU's BH.
|
|
*/
|
|
if (repeat) {
|
|
if (pool->attrs->nice == HIGHPRI_NICE_LEVEL)
|
|
queue_work(system_bh_highpri_wq, work);
|
|
else
|
|
queue_work(system_bh_wq, work);
|
|
} else {
|
|
complete(&dead_work->done);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* @cpu is dead. Drain the remaining BH work items on the current CPU. It's
|
|
* possible to allocate dead_work per CPU and avoid flushing. However, then we
|
|
* have to worry about draining overlapping with CPU coming back online or
|
|
* nesting (one CPU's dead_work queued on another CPU which is also dead and so
|
|
* on). Let's keep it simple and drain them synchronously. These are BH work
|
|
* items which shouldn't be requeued on the same pool. Shouldn't take long.
|
|
*/
|
|
void workqueue_softirq_dead(unsigned int cpu)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < NR_STD_WORKER_POOLS; i++) {
|
|
struct worker_pool *pool = &per_cpu(bh_worker_pools, cpu)[i];
|
|
struct wq_drain_dead_softirq_work dead_work;
|
|
|
|
if (!need_more_worker(pool))
|
|
continue;
|
|
|
|
INIT_WORK_ONSTACK(&dead_work.work, drain_dead_softirq_workfn);
|
|
dead_work.pool = pool;
|
|
init_completion(&dead_work.done);
|
|
|
|
if (pool->attrs->nice == HIGHPRI_NICE_LEVEL)
|
|
queue_work(system_bh_highpri_wq, &dead_work.work);
|
|
else
|
|
queue_work(system_bh_wq, &dead_work.work);
|
|
|
|
wait_for_completion(&dead_work.done);
|
|
destroy_work_on_stack(&dead_work.work);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* check_flush_dependency - check for flush dependency sanity
|
|
* @target_wq: workqueue being flushed
|
|
* @target_work: work item being flushed (NULL for workqueue flushes)
|
|
*
|
|
* %current is trying to flush the whole @target_wq or @target_work on it.
|
|
* If @target_wq doesn't have %WQ_MEM_RECLAIM, verify that %current is not
|
|
* reclaiming memory or running on a workqueue which doesn't have
|
|
* %WQ_MEM_RECLAIM as that can break forward-progress guarantee leading to
|
|
* a deadlock.
|
|
*/
|
|
static void check_flush_dependency(struct workqueue_struct *target_wq,
|
|
struct work_struct *target_work)
|
|
{
|
|
work_func_t target_func = target_work ? target_work->func : NULL;
|
|
struct worker *worker;
|
|
|
|
if (target_wq->flags & WQ_MEM_RECLAIM)
|
|
return;
|
|
|
|
worker = current_wq_worker();
|
|
|
|
WARN_ONCE(current->flags & PF_MEMALLOC,
|
|
"workqueue: PF_MEMALLOC task %d(%s) is flushing !WQ_MEM_RECLAIM %s:%ps",
|
|
current->pid, current->comm, target_wq->name, target_func);
|
|
WARN_ONCE(worker && ((worker->current_pwq->wq->flags &
|
|
(WQ_MEM_RECLAIM | __WQ_LEGACY)) == WQ_MEM_RECLAIM),
|
|
"workqueue: WQ_MEM_RECLAIM %s:%ps is flushing !WQ_MEM_RECLAIM %s:%ps",
|
|
worker->current_pwq->wq->name, worker->current_func,
|
|
target_wq->name, target_func);
|
|
}
|
|
|
|
struct wq_barrier {
|
|
struct work_struct work;
|
|
struct completion done;
|
|
struct task_struct *task; /* purely informational */
|
|
};
|
|
|
|
static void wq_barrier_func(struct work_struct *work)
|
|
{
|
|
struct wq_barrier *barr = container_of(work, struct wq_barrier, work);
|
|
complete(&barr->done);
|
|
}
|
|
|
|
/**
|
|
* insert_wq_barrier - insert a barrier work
|
|
* @pwq: pwq to insert barrier into
|
|
* @barr: wq_barrier to insert
|
|
* @target: target work to attach @barr to
|
|
* @worker: worker currently executing @target, NULL if @target is not executing
|
|
*
|
|
* @barr is linked to @target such that @barr is completed only after
|
|
* @target finishes execution. Please note that the ordering
|
|
* guarantee is observed only with respect to @target and on the local
|
|
* cpu.
|
|
*
|
|
* Currently, a queued barrier can't be canceled. This is because
|
|
* try_to_grab_pending() can't determine whether the work to be
|
|
* grabbed is at the head of the queue and thus can't clear LINKED
|
|
* flag of the previous work while there must be a valid next work
|
|
* after a work with LINKED flag set.
|
|
*
|
|
* Note that when @worker is non-NULL, @target may be modified
|
|
* underneath us, so we can't reliably determine pwq from @target.
|
|
*
|
|
* CONTEXT:
|
|
* raw_spin_lock_irq(pool->lock).
|
|
*/
|
|
static void insert_wq_barrier(struct pool_workqueue *pwq,
|
|
struct wq_barrier *barr,
|
|
struct work_struct *target, struct worker *worker)
|
|
{
|
|
static __maybe_unused struct lock_class_key bh_key, thr_key;
|
|
unsigned int work_flags = 0;
|
|
unsigned int work_color;
|
|
struct list_head *head;
|
|
|
|
/*
|
|
* debugobject calls are safe here even with pool->lock locked
|
|
* as we know for sure that this will not trigger any of the
|
|
* checks and call back into the fixup functions where we
|
|
* might deadlock.
|
|
*
|
|
* BH and threaded workqueues need separate lockdep keys to avoid
|
|
* spuriously triggering "inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W}
|
|
* usage".
|
|
*/
|
|
INIT_WORK_ONSTACK_KEY(&barr->work, wq_barrier_func,
|
|
(pwq->wq->flags & WQ_BH) ? &bh_key : &thr_key);
|
|
__set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work));
|
|
|
|
init_completion_map(&barr->done, &target->lockdep_map);
|
|
|
|
barr->task = current;
|
|
|
|
/* The barrier work item does not participate in nr_active. */
|
|
work_flags |= WORK_STRUCT_INACTIVE;
|
|
|
|
/*
|
|
* If @target is currently being executed, schedule the
|
|
* barrier to the worker; otherwise, put it after @target.
|
|
*/
|
|
if (worker) {
|
|
head = worker->scheduled.next;
|
|
work_color = worker->current_color;
|
|
} else {
|
|
unsigned long *bits = work_data_bits(target);
|
|
|
|
head = target->entry.next;
|
|
/* there can already be other linked works, inherit and set */
|
|
work_flags |= *bits & WORK_STRUCT_LINKED;
|
|
work_color = get_work_color(*bits);
|
|
__set_bit(WORK_STRUCT_LINKED_BIT, bits);
|
|
}
|
|
|
|
pwq->nr_in_flight[work_color]++;
|
|
work_flags |= work_color_to_flags(work_color);
|
|
|
|
insert_work(pwq, &barr->work, head, work_flags);
|
|
}
|
|
|
|
/**
|
|
* flush_workqueue_prep_pwqs - prepare pwqs for workqueue flushing
|
|
* @wq: workqueue being flushed
|
|
* @flush_color: new flush color, < 0 for no-op
|
|
* @work_color: new work color, < 0 for no-op
|
|
*
|
|
* Prepare pwqs for workqueue flushing.
|
|
*
|
|
* If @flush_color is non-negative, flush_color on all pwqs should be
|
|
* -1. If no pwq has in-flight commands at the specified color, all
|
|
* pwq->flush_color's stay at -1 and %false is returned. If any pwq
|
|
* has in flight commands, its pwq->flush_color is set to
|
|
* @flush_color, @wq->nr_pwqs_to_flush is updated accordingly, pwq
|
|
* wakeup logic is armed and %true is returned.
|
|
*
|
|
* The caller should have initialized @wq->first_flusher prior to
|
|
* calling this function with non-negative @flush_color. If
|
|
* @flush_color is negative, no flush color update is done and %false
|
|
* is returned.
|
|
*
|
|
* If @work_color is non-negative, all pwqs should have the same
|
|
* work_color which is previous to @work_color and all will be
|
|
* advanced to @work_color.
|
|
*
|
|
* CONTEXT:
|
|
* mutex_lock(wq->mutex).
|
|
*
|
|
* Return:
|
|
* %true if @flush_color >= 0 and there's something to flush. %false
|
|
* otherwise.
|
|
*/
|
|
static bool flush_workqueue_prep_pwqs(struct workqueue_struct *wq,
|
|
int flush_color, int work_color)
|
|
{
|
|
bool wait = false;
|
|
struct pool_workqueue *pwq;
|
|
|
|
if (flush_color >= 0) {
|
|
WARN_ON_ONCE(atomic_read(&wq->nr_pwqs_to_flush));
|
|
atomic_set(&wq->nr_pwqs_to_flush, 1);
|
|
}
|
|
|
|
for_each_pwq(pwq, wq) {
|
|
struct worker_pool *pool = pwq->pool;
|
|
|
|
raw_spin_lock_irq(&pool->lock);
|
|
|
|
if (flush_color >= 0) {
|
|
WARN_ON_ONCE(pwq->flush_color != -1);
|
|
|
|
if (pwq->nr_in_flight[flush_color]) {
|
|
pwq->flush_color = flush_color;
|
|
atomic_inc(&wq->nr_pwqs_to_flush);
|
|
wait = true;
|
|
}
|
|
}
|
|
|
|
if (work_color >= 0) {
|
|
WARN_ON_ONCE(work_color != work_next_color(pwq->work_color));
|
|
pwq->work_color = work_color;
|
|
}
|
|
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
}
|
|
|
|
if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_pwqs_to_flush))
|
|
complete(&wq->first_flusher->done);
|
|
|
|
return wait;
|
|
}
|
|
|
|
static void touch_wq_lockdep_map(struct workqueue_struct *wq)
|
|
{
|
|
#ifdef CONFIG_LOCKDEP
|
|
if (wq->flags & WQ_BH)
|
|
local_bh_disable();
|
|
|
|
lock_map_acquire(&wq->lockdep_map);
|
|
lock_map_release(&wq->lockdep_map);
|
|
|
|
if (wq->flags & WQ_BH)
|
|
local_bh_enable();
|
|
#endif
|
|
}
|
|
|
|
static void touch_work_lockdep_map(struct work_struct *work,
|
|
struct workqueue_struct *wq)
|
|
{
|
|
#ifdef CONFIG_LOCKDEP
|
|
if (wq->flags & WQ_BH)
|
|
local_bh_disable();
|
|
|
|
lock_map_acquire(&work->lockdep_map);
|
|
lock_map_release(&work->lockdep_map);
|
|
|
|
if (wq->flags & WQ_BH)
|
|
local_bh_enable();
|
|
#endif
|
|
}
|
|
|
|
/**
|
|
* __flush_workqueue - ensure that any scheduled work has run to completion.
|
|
* @wq: workqueue to flush
|
|
*
|
|
* This function sleeps until all work items which were queued on entry
|
|
* have finished execution, but it is not livelocked by new incoming ones.
|
|
*/
|
|
void __flush_workqueue(struct workqueue_struct *wq)
|
|
{
|
|
struct wq_flusher this_flusher = {
|
|
.list = LIST_HEAD_INIT(this_flusher.list),
|
|
.flush_color = -1,
|
|
.done = COMPLETION_INITIALIZER_ONSTACK_MAP(this_flusher.done, wq->lockdep_map),
|
|
};
|
|
int next_color;
|
|
|
|
if (WARN_ON(!wq_online))
|
|
return;
|
|
|
|
touch_wq_lockdep_map(wq);
|
|
|
|
mutex_lock(&wq->mutex);
|
|
|
|
/*
|
|
* Start-to-wait phase
|
|
*/
|
|
next_color = work_next_color(wq->work_color);
|
|
|
|
if (next_color != wq->flush_color) {
|
|
/*
|
|
* Color space is not full. The current work_color
|
|
* becomes our flush_color and work_color is advanced
|
|
* by one.
|
|
*/
|
|
WARN_ON_ONCE(!list_empty(&wq->flusher_overflow));
|
|
this_flusher.flush_color = wq->work_color;
|
|
wq->work_color = next_color;
|
|
|
|
if (!wq->first_flusher) {
|
|
/* no flush in progress, become the first flusher */
|
|
WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color);
|
|
|
|
wq->first_flusher = &this_flusher;
|
|
|
|
if (!flush_workqueue_prep_pwqs(wq, wq->flush_color,
|
|
wq->work_color)) {
|
|
/* nothing to flush, done */
|
|
wq->flush_color = next_color;
|
|
wq->first_flusher = NULL;
|
|
goto out_unlock;
|
|
}
|
|
} else {
|
|
/* wait in queue */
|
|
WARN_ON_ONCE(wq->flush_color == this_flusher.flush_color);
|
|
list_add_tail(&this_flusher.list, &wq->flusher_queue);
|
|
flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
|
|
}
|
|
} else {
|
|
/*
|
|
* Oops, color space is full, wait on overflow queue.
|
|
* The next flush completion will assign us
|
|
* flush_color and transfer to flusher_queue.
|
|
*/
|
|
list_add_tail(&this_flusher.list, &wq->flusher_overflow);
|
|
}
|
|
|
|
check_flush_dependency(wq, NULL);
|
|
|
|
mutex_unlock(&wq->mutex);
|
|
|
|
wait_for_completion(&this_flusher.done);
|
|
|
|
/*
|
|
* Wake-up-and-cascade phase
|
|
*
|
|
* First flushers are responsible for cascading flushes and
|
|
* handling overflow. Non-first flushers can simply return.
|
|
*/
|
|
if (READ_ONCE(wq->first_flusher) != &this_flusher)
|
|
return;
|
|
|
|
mutex_lock(&wq->mutex);
|
|
|
|
/* we might have raced, check again with mutex held */
|
|
if (wq->first_flusher != &this_flusher)
|
|
goto out_unlock;
|
|
|
|
WRITE_ONCE(wq->first_flusher, NULL);
|
|
|
|
WARN_ON_ONCE(!list_empty(&this_flusher.list));
|
|
WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color);
|
|
|
|
while (true) {
|
|
struct wq_flusher *next, *tmp;
|
|
|
|
/* complete all the flushers sharing the current flush color */
|
|
list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) {
|
|
if (next->flush_color != wq->flush_color)
|
|
break;
|
|
list_del_init(&next->list);
|
|
complete(&next->done);
|
|
}
|
|
|
|
WARN_ON_ONCE(!list_empty(&wq->flusher_overflow) &&
|
|
wq->flush_color != work_next_color(wq->work_color));
|
|
|
|
/* this flush_color is finished, advance by one */
|
|
wq->flush_color = work_next_color(wq->flush_color);
|
|
|
|
/* one color has been freed, handle overflow queue */
|
|
if (!list_empty(&wq->flusher_overflow)) {
|
|
/*
|
|
* Assign the same color to all overflowed
|
|
* flushers, advance work_color and append to
|
|
* flusher_queue. This is the start-to-wait
|
|
* phase for these overflowed flushers.
|
|
*/
|
|
list_for_each_entry(tmp, &wq->flusher_overflow, list)
|
|
tmp->flush_color = wq->work_color;
|
|
|
|
wq->work_color = work_next_color(wq->work_color);
|
|
|
|
list_splice_tail_init(&wq->flusher_overflow,
|
|
&wq->flusher_queue);
|
|
flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
|
|
}
|
|
|
|
if (list_empty(&wq->flusher_queue)) {
|
|
WARN_ON_ONCE(wq->flush_color != wq->work_color);
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Need to flush more colors. Make the next flusher
|
|
* the new first flusher and arm pwqs.
|
|
*/
|
|
WARN_ON_ONCE(wq->flush_color == wq->work_color);
|
|
WARN_ON_ONCE(wq->flush_color != next->flush_color);
|
|
|
|
list_del_init(&next->list);
|
|
wq->first_flusher = next;
|
|
|
|
if (flush_workqueue_prep_pwqs(wq, wq->flush_color, -1))
|
|
break;
|
|
|
|
/*
|
|
* Meh... this color is already done, clear first
|
|
* flusher and repeat cascading.
|
|
*/
|
|
wq->first_flusher = NULL;
|
|
}
|
|
|
|
out_unlock:
|
|
mutex_unlock(&wq->mutex);
|
|
}
|
|
EXPORT_SYMBOL(__flush_workqueue);
|
|
|
|
/**
|
|
* drain_workqueue - drain a workqueue
|
|
* @wq: workqueue to drain
|
|
*
|
|
* Wait until the workqueue becomes empty. While draining is in progress,
|
|
* only chain queueing is allowed. IOW, only currently pending or running
|
|
* work items on @wq can queue further work items on it. @wq is flushed
|
|
* repeatedly until it becomes empty. The number of flushing is determined
|
|
* by the depth of chaining and should be relatively short. Whine if it
|
|
* takes too long.
|
|
*/
|
|
void drain_workqueue(struct workqueue_struct *wq)
|
|
{
|
|
unsigned int flush_cnt = 0;
|
|
struct pool_workqueue *pwq;
|
|
|
|
/*
|
|
* __queue_work() needs to test whether there are drainers, is much
|
|
* hotter than drain_workqueue() and already looks at @wq->flags.
|
|
* Use __WQ_DRAINING so that queue doesn't have to check nr_drainers.
|
|
*/
|
|
mutex_lock(&wq->mutex);
|
|
if (!wq->nr_drainers++)
|
|
wq->flags |= __WQ_DRAINING;
|
|
mutex_unlock(&wq->mutex);
|
|
reflush:
|
|
__flush_workqueue(wq);
|
|
|
|
mutex_lock(&wq->mutex);
|
|
|
|
for_each_pwq(pwq, wq) {
|
|
bool drained;
|
|
|
|
raw_spin_lock_irq(&pwq->pool->lock);
|
|
drained = pwq_is_empty(pwq);
|
|
raw_spin_unlock_irq(&pwq->pool->lock);
|
|
|
|
if (drained)
|
|
continue;
|
|
|
|
if (++flush_cnt == 10 ||
|
|
(flush_cnt % 100 == 0 && flush_cnt <= 1000))
|
|
pr_warn("workqueue %s: %s() isn't complete after %u tries\n",
|
|
wq->name, __func__, flush_cnt);
|
|
|
|
mutex_unlock(&wq->mutex);
|
|
goto reflush;
|
|
}
|
|
|
|
if (!--wq->nr_drainers)
|
|
wq->flags &= ~__WQ_DRAINING;
|
|
mutex_unlock(&wq->mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(drain_workqueue);
|
|
|
|
static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr,
|
|
bool from_cancel)
|
|
{
|
|
struct worker *worker = NULL;
|
|
struct worker_pool *pool;
|
|
struct pool_workqueue *pwq;
|
|
struct workqueue_struct *wq;
|
|
|
|
rcu_read_lock();
|
|
pool = get_work_pool(work);
|
|
if (!pool) {
|
|
rcu_read_unlock();
|
|
return false;
|
|
}
|
|
|
|
raw_spin_lock_irq(&pool->lock);
|
|
/* see the comment in try_to_grab_pending() with the same code */
|
|
pwq = get_work_pwq(work);
|
|
if (pwq) {
|
|
if (unlikely(pwq->pool != pool))
|
|
goto already_gone;
|
|
} else {
|
|
worker = find_worker_executing_work(pool, work);
|
|
if (!worker)
|
|
goto already_gone;
|
|
pwq = worker->current_pwq;
|
|
}
|
|
|
|
wq = pwq->wq;
|
|
check_flush_dependency(wq, work);
|
|
|
|
insert_wq_barrier(pwq, barr, work, worker);
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
|
|
touch_work_lockdep_map(work, wq);
|
|
|
|
/*
|
|
* Force a lock recursion deadlock when using flush_work() inside a
|
|
* single-threaded or rescuer equipped workqueue.
|
|
*
|
|
* For single threaded workqueues the deadlock happens when the work
|
|
* is after the work issuing the flush_work(). For rescuer equipped
|
|
* workqueues the deadlock happens when the rescuer stalls, blocking
|
|
* forward progress.
|
|
*/
|
|
if (!from_cancel && (wq->saved_max_active == 1 || wq->rescuer))
|
|
touch_wq_lockdep_map(wq);
|
|
|
|
rcu_read_unlock();
|
|
return true;
|
|
already_gone:
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
rcu_read_unlock();
|
|
return false;
|
|
}
|
|
|
|
static bool __flush_work(struct work_struct *work, bool from_cancel)
|
|
{
|
|
struct wq_barrier barr;
|
|
unsigned long data;
|
|
|
|
if (WARN_ON(!wq_online))
|
|
return false;
|
|
|
|
if (WARN_ON(!work->func))
|
|
return false;
|
|
|
|
if (!start_flush_work(work, &barr, from_cancel))
|
|
return false;
|
|
|
|
/*
|
|
* start_flush_work() returned %true. If @from_cancel is set, we know
|
|
* that @work must have been executing during start_flush_work() and
|
|
* can't currently be queued. Its data must contain OFFQ bits. If @work
|
|
* was queued on a BH workqueue, we also know that it was running in the
|
|
* BH context and thus can be busy-waited.
|
|
*/
|
|
data = *work_data_bits(work);
|
|
if (from_cancel &&
|
|
!WARN_ON_ONCE(data & WORK_STRUCT_PWQ) && (data & WORK_OFFQ_BH)) {
|
|
/*
|
|
* On RT, prevent a live lock when %current preempted soft
|
|
* interrupt processing or prevents ksoftirqd from running by
|
|
* keeping flipping BH. If the BH work item runs on a different
|
|
* CPU then this has no effect other than doing the BH
|
|
* disable/enable dance for nothing. This is copied from
|
|
* kernel/softirq.c::tasklet_unlock_spin_wait().
|
|
*/
|
|
while (!try_wait_for_completion(&barr.done)) {
|
|
if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
|
|
local_bh_disable();
|
|
local_bh_enable();
|
|
} else {
|
|
cpu_relax();
|
|
}
|
|
}
|
|
} else {
|
|
wait_for_completion(&barr.done);
|
|
}
|
|
|
|
destroy_work_on_stack(&barr.work);
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* flush_work - wait for a work to finish executing the last queueing instance
|
|
* @work: the work to flush
|
|
*
|
|
* Wait until @work has finished execution. @work is guaranteed to be idle
|
|
* on return if it hasn't been requeued since flush started.
|
|
*
|
|
* Return:
|
|
* %true if flush_work() waited for the work to finish execution,
|
|
* %false if it was already idle.
|
|
*/
|
|
bool flush_work(struct work_struct *work)
|
|
{
|
|
might_sleep();
|
|
return __flush_work(work, false);
|
|
}
|
|
EXPORT_SYMBOL_GPL(flush_work);
|
|
|
|
/**
|
|
* flush_delayed_work - wait for a dwork to finish executing the last queueing
|
|
* @dwork: the delayed work to flush
|
|
*
|
|
* Delayed timer is cancelled and the pending work is queued for
|
|
* immediate execution. Like flush_work(), this function only
|
|
* considers the last queueing instance of @dwork.
|
|
*
|
|
* Return:
|
|
* %true if flush_work() waited for the work to finish execution,
|
|
* %false if it was already idle.
|
|
*/
|
|
bool flush_delayed_work(struct delayed_work *dwork)
|
|
{
|
|
local_irq_disable();
|
|
if (del_timer_sync(&dwork->timer))
|
|
__queue_work(dwork->cpu, dwork->wq, &dwork->work);
|
|
local_irq_enable();
|
|
return flush_work(&dwork->work);
|
|
}
|
|
EXPORT_SYMBOL(flush_delayed_work);
|
|
|
|
/**
|
|
* flush_rcu_work - wait for a rwork to finish executing the last queueing
|
|
* @rwork: the rcu work to flush
|
|
*
|
|
* Return:
|
|
* %true if flush_rcu_work() waited for the work to finish execution,
|
|
* %false if it was already idle.
|
|
*/
|
|
bool flush_rcu_work(struct rcu_work *rwork)
|
|
{
|
|
if (test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&rwork->work))) {
|
|
rcu_barrier();
|
|
flush_work(&rwork->work);
|
|
return true;
|
|
} else {
|
|
return flush_work(&rwork->work);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(flush_rcu_work);
|
|
|
|
static void work_offqd_disable(struct work_offq_data *offqd)
|
|
{
|
|
const unsigned long max = (1lu << WORK_OFFQ_DISABLE_BITS) - 1;
|
|
|
|
if (likely(offqd->disable < max))
|
|
offqd->disable++;
|
|
else
|
|
WARN_ONCE(true, "workqueue: work disable count overflowed\n");
|
|
}
|
|
|
|
static void work_offqd_enable(struct work_offq_data *offqd)
|
|
{
|
|
if (likely(offqd->disable > 0))
|
|
offqd->disable--;
|
|
else
|
|
WARN_ONCE(true, "workqueue: work disable count underflowed\n");
|
|
}
|
|
|
|
static bool __cancel_work(struct work_struct *work, u32 cflags)
|
|
{
|
|
struct work_offq_data offqd;
|
|
unsigned long irq_flags;
|
|
int ret;
|
|
|
|
ret = work_grab_pending(work, cflags, &irq_flags);
|
|
|
|
work_offqd_unpack(&offqd, *work_data_bits(work));
|
|
|
|
if (cflags & WORK_CANCEL_DISABLE)
|
|
work_offqd_disable(&offqd);
|
|
|
|
set_work_pool_and_clear_pending(work, offqd.pool_id,
|
|
work_offqd_pack_flags(&offqd));
|
|
local_irq_restore(irq_flags);
|
|
return ret;
|
|
}
|
|
|
|
static bool __cancel_work_sync(struct work_struct *work, u32 cflags)
|
|
{
|
|
bool ret;
|
|
|
|
ret = __cancel_work(work, cflags | WORK_CANCEL_DISABLE);
|
|
|
|
if (*work_data_bits(work) & WORK_OFFQ_BH)
|
|
WARN_ON_ONCE(in_hardirq());
|
|
else
|
|
might_sleep();
|
|
|
|
/*
|
|
* Skip __flush_work() during early boot when we know that @work isn't
|
|
* executing. This allows canceling during early boot.
|
|
*/
|
|
if (wq_online)
|
|
__flush_work(work, true);
|
|
|
|
if (!(cflags & WORK_CANCEL_DISABLE))
|
|
enable_work(work);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* See cancel_delayed_work()
|
|
*/
|
|
bool cancel_work(struct work_struct *work)
|
|
{
|
|
return __cancel_work(work, 0);
|
|
}
|
|
EXPORT_SYMBOL(cancel_work);
|
|
|
|
/**
|
|
* cancel_work_sync - cancel a work and wait for it to finish
|
|
* @work: the work to cancel
|
|
*
|
|
* Cancel @work and wait for its execution to finish. This function can be used
|
|
* even if the work re-queues itself or migrates to another workqueue. On return
|
|
* from this function, @work is guaranteed to be not pending or executing on any
|
|
* CPU as long as there aren't racing enqueues.
|
|
*
|
|
* cancel_work_sync(&delayed_work->work) must not be used for delayed_work's.
|
|
* Use cancel_delayed_work_sync() instead.
|
|
*
|
|
* Must be called from a sleepable context if @work was last queued on a non-BH
|
|
* workqueue. Can also be called from non-hardirq atomic contexts including BH
|
|
* if @work was last queued on a BH workqueue.
|
|
*
|
|
* Returns %true if @work was pending, %false otherwise.
|
|
*/
|
|
bool cancel_work_sync(struct work_struct *work)
|
|
{
|
|
return __cancel_work_sync(work, 0);
|
|
}
|
|
EXPORT_SYMBOL_GPL(cancel_work_sync);
|
|
|
|
/**
|
|
* cancel_delayed_work - cancel a delayed work
|
|
* @dwork: delayed_work to cancel
|
|
*
|
|
* Kill off a pending delayed_work.
|
|
*
|
|
* Return: %true if @dwork was pending and canceled; %false if it wasn't
|
|
* pending.
|
|
*
|
|
* Note:
|
|
* The work callback function may still be running on return, unless
|
|
* it returns %true and the work doesn't re-arm itself. Explicitly flush or
|
|
* use cancel_delayed_work_sync() to wait on it.
|
|
*
|
|
* This function is safe to call from any context including IRQ handler.
|
|
*/
|
|
bool cancel_delayed_work(struct delayed_work *dwork)
|
|
{
|
|
return __cancel_work(&dwork->work, WORK_CANCEL_DELAYED);
|
|
}
|
|
EXPORT_SYMBOL(cancel_delayed_work);
|
|
|
|
/**
|
|
* cancel_delayed_work_sync - cancel a delayed work and wait for it to finish
|
|
* @dwork: the delayed work cancel
|
|
*
|
|
* This is cancel_work_sync() for delayed works.
|
|
*
|
|
* Return:
|
|
* %true if @dwork was pending, %false otherwise.
|
|
*/
|
|
bool cancel_delayed_work_sync(struct delayed_work *dwork)
|
|
{
|
|
return __cancel_work_sync(&dwork->work, WORK_CANCEL_DELAYED);
|
|
}
|
|
EXPORT_SYMBOL(cancel_delayed_work_sync);
|
|
|
|
/**
|
|
* disable_work - Disable and cancel a work item
|
|
* @work: work item to disable
|
|
*
|
|
* Disable @work by incrementing its disable count and cancel it if currently
|
|
* pending. As long as the disable count is non-zero, any attempt to queue @work
|
|
* will fail and return %false. The maximum supported disable depth is 2 to the
|
|
* power of %WORK_OFFQ_DISABLE_BITS, currently 65536.
|
|
*
|
|
* Can be called from any context. Returns %true if @work was pending, %false
|
|
* otherwise.
|
|
*/
|
|
bool disable_work(struct work_struct *work)
|
|
{
|
|
return __cancel_work(work, WORK_CANCEL_DISABLE);
|
|
}
|
|
EXPORT_SYMBOL_GPL(disable_work);
|
|
|
|
/**
|
|
* disable_work_sync - Disable, cancel and drain a work item
|
|
* @work: work item to disable
|
|
*
|
|
* Similar to disable_work() but also wait for @work to finish if currently
|
|
* executing.
|
|
*
|
|
* Must be called from a sleepable context if @work was last queued on a non-BH
|
|
* workqueue. Can also be called from non-hardirq atomic contexts including BH
|
|
* if @work was last queued on a BH workqueue.
|
|
*
|
|
* Returns %true if @work was pending, %false otherwise.
|
|
*/
|
|
bool disable_work_sync(struct work_struct *work)
|
|
{
|
|
return __cancel_work_sync(work, WORK_CANCEL_DISABLE);
|
|
}
|
|
EXPORT_SYMBOL_GPL(disable_work_sync);
|
|
|
|
/**
|
|
* enable_work - Enable a work item
|
|
* @work: work item to enable
|
|
*
|
|
* Undo disable_work[_sync]() by decrementing @work's disable count. @work can
|
|
* only be queued if its disable count is 0.
|
|
*
|
|
* Can be called from any context. Returns %true if the disable count reached 0.
|
|
* Otherwise, %false.
|
|
*/
|
|
bool enable_work(struct work_struct *work)
|
|
{
|
|
struct work_offq_data offqd;
|
|
unsigned long irq_flags;
|
|
|
|
work_grab_pending(work, 0, &irq_flags);
|
|
|
|
work_offqd_unpack(&offqd, *work_data_bits(work));
|
|
work_offqd_enable(&offqd);
|
|
set_work_pool_and_clear_pending(work, offqd.pool_id,
|
|
work_offqd_pack_flags(&offqd));
|
|
local_irq_restore(irq_flags);
|
|
|
|
return !offqd.disable;
|
|
}
|
|
EXPORT_SYMBOL_GPL(enable_work);
|
|
|
|
/**
|
|
* disable_delayed_work - Disable and cancel a delayed work item
|
|
* @dwork: delayed work item to disable
|
|
*
|
|
* disable_work() for delayed work items.
|
|
*/
|
|
bool disable_delayed_work(struct delayed_work *dwork)
|
|
{
|
|
return __cancel_work(&dwork->work,
|
|
WORK_CANCEL_DELAYED | WORK_CANCEL_DISABLE);
|
|
}
|
|
EXPORT_SYMBOL_GPL(disable_delayed_work);
|
|
|
|
/**
|
|
* disable_delayed_work_sync - Disable, cancel and drain a delayed work item
|
|
* @dwork: delayed work item to disable
|
|
*
|
|
* disable_work_sync() for delayed work items.
|
|
*/
|
|
bool disable_delayed_work_sync(struct delayed_work *dwork)
|
|
{
|
|
return __cancel_work_sync(&dwork->work,
|
|
WORK_CANCEL_DELAYED | WORK_CANCEL_DISABLE);
|
|
}
|
|
EXPORT_SYMBOL_GPL(disable_delayed_work_sync);
|
|
|
|
/**
|
|
* enable_delayed_work - Enable a delayed work item
|
|
* @dwork: delayed work item to enable
|
|
*
|
|
* enable_work() for delayed work items.
|
|
*/
|
|
bool enable_delayed_work(struct delayed_work *dwork)
|
|
{
|
|
return enable_work(&dwork->work);
|
|
}
|
|
EXPORT_SYMBOL_GPL(enable_delayed_work);
|
|
|
|
/**
|
|
* schedule_on_each_cpu - execute a function synchronously on each online CPU
|
|
* @func: the function to call
|
|
*
|
|
* schedule_on_each_cpu() executes @func on each online CPU using the
|
|
* system workqueue and blocks until all CPUs have completed.
|
|
* schedule_on_each_cpu() is very slow.
|
|
*
|
|
* Return:
|
|
* 0 on success, -errno on failure.
|
|
*/
|
|
int schedule_on_each_cpu(work_func_t func)
|
|
{
|
|
int cpu;
|
|
struct work_struct __percpu *works;
|
|
|
|
works = alloc_percpu(struct work_struct);
|
|
if (!works)
|
|
return -ENOMEM;
|
|
|
|
cpus_read_lock();
|
|
|
|
for_each_online_cpu(cpu) {
|
|
struct work_struct *work = per_cpu_ptr(works, cpu);
|
|
|
|
INIT_WORK(work, func);
|
|
schedule_work_on(cpu, work);
|
|
}
|
|
|
|
for_each_online_cpu(cpu)
|
|
flush_work(per_cpu_ptr(works, cpu));
|
|
|
|
cpus_read_unlock();
|
|
free_percpu(works);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* execute_in_process_context - reliably execute the routine with user context
|
|
* @fn: the function to execute
|
|
* @ew: guaranteed storage for the execute work structure (must
|
|
* be available when the work executes)
|
|
*
|
|
* Executes the function immediately if process context is available,
|
|
* otherwise schedules the function for delayed execution.
|
|
*
|
|
* Return: 0 - function was executed
|
|
* 1 - function was scheduled for execution
|
|
*/
|
|
int execute_in_process_context(work_func_t fn, struct execute_work *ew)
|
|
{
|
|
if (!in_interrupt()) {
|
|
fn(&ew->work);
|
|
return 0;
|
|
}
|
|
|
|
INIT_WORK(&ew->work, fn);
|
|
schedule_work(&ew->work);
|
|
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL_GPL(execute_in_process_context);
|
|
|
|
/**
|
|
* free_workqueue_attrs - free a workqueue_attrs
|
|
* @attrs: workqueue_attrs to free
|
|
*
|
|
* Undo alloc_workqueue_attrs().
|
|
*/
|
|
void free_workqueue_attrs(struct workqueue_attrs *attrs)
|
|
{
|
|
if (attrs) {
|
|
free_cpumask_var(attrs->cpumask);
|
|
free_cpumask_var(attrs->__pod_cpumask);
|
|
kfree(attrs);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* alloc_workqueue_attrs - allocate a workqueue_attrs
|
|
*
|
|
* Allocate a new workqueue_attrs, initialize with default settings and
|
|
* return it.
|
|
*
|
|
* Return: The allocated new workqueue_attr on success. %NULL on failure.
|
|
*/
|
|
struct workqueue_attrs *alloc_workqueue_attrs(void)
|
|
{
|
|
struct workqueue_attrs *attrs;
|
|
|
|
attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
|
|
if (!attrs)
|
|
goto fail;
|
|
if (!alloc_cpumask_var(&attrs->cpumask, GFP_KERNEL))
|
|
goto fail;
|
|
if (!alloc_cpumask_var(&attrs->__pod_cpumask, GFP_KERNEL))
|
|
goto fail;
|
|
|
|
cpumask_copy(attrs->cpumask, cpu_possible_mask);
|
|
attrs->affn_scope = WQ_AFFN_DFL;
|
|
return attrs;
|
|
fail:
|
|
free_workqueue_attrs(attrs);
|
|
return NULL;
|
|
}
|
|
|
|
static void copy_workqueue_attrs(struct workqueue_attrs *to,
|
|
const struct workqueue_attrs *from)
|
|
{
|
|
to->nice = from->nice;
|
|
cpumask_copy(to->cpumask, from->cpumask);
|
|
cpumask_copy(to->__pod_cpumask, from->__pod_cpumask);
|
|
to->affn_strict = from->affn_strict;
|
|
|
|
/*
|
|
* Unlike hash and equality test, copying shouldn't ignore wq-only
|
|
* fields as copying is used for both pool and wq attrs. Instead,
|
|
* get_unbound_pool() explicitly clears the fields.
|
|
*/
|
|
to->affn_scope = from->affn_scope;
|
|
to->ordered = from->ordered;
|
|
}
|
|
|
|
/*
|
|
* Some attrs fields are workqueue-only. Clear them for worker_pool's. See the
|
|
* comments in 'struct workqueue_attrs' definition.
|
|
*/
|
|
static void wqattrs_clear_for_pool(struct workqueue_attrs *attrs)
|
|
{
|
|
attrs->affn_scope = WQ_AFFN_NR_TYPES;
|
|
attrs->ordered = false;
|
|
if (attrs->affn_strict)
|
|
cpumask_copy(attrs->cpumask, cpu_possible_mask);
|
|
}
|
|
|
|
/* hash value of the content of @attr */
|
|
static u32 wqattrs_hash(const struct workqueue_attrs *attrs)
|
|
{
|
|
u32 hash = 0;
|
|
|
|
hash = jhash_1word(attrs->nice, hash);
|
|
hash = jhash_1word(attrs->affn_strict, hash);
|
|
hash = jhash(cpumask_bits(attrs->__pod_cpumask),
|
|
BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long), hash);
|
|
if (!attrs->affn_strict)
|
|
hash = jhash(cpumask_bits(attrs->cpumask),
|
|
BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long), hash);
|
|
return hash;
|
|
}
|
|
|
|
/* content equality test */
|
|
static bool wqattrs_equal(const struct workqueue_attrs *a,
|
|
const struct workqueue_attrs *b)
|
|
{
|
|
if (a->nice != b->nice)
|
|
return false;
|
|
if (a->affn_strict != b->affn_strict)
|
|
return false;
|
|
if (!cpumask_equal(a->__pod_cpumask, b->__pod_cpumask))
|
|
return false;
|
|
if (!a->affn_strict && !cpumask_equal(a->cpumask, b->cpumask))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
/* Update @attrs with actually available CPUs */
|
|
static void wqattrs_actualize_cpumask(struct workqueue_attrs *attrs,
|
|
const cpumask_t *unbound_cpumask)
|
|
{
|
|
/*
|
|
* Calculate the effective CPU mask of @attrs given @unbound_cpumask. If
|
|
* @attrs->cpumask doesn't overlap with @unbound_cpumask, we fallback to
|
|
* @unbound_cpumask.
|
|
*/
|
|
cpumask_and(attrs->cpumask, attrs->cpumask, unbound_cpumask);
|
|
if (unlikely(cpumask_empty(attrs->cpumask)))
|
|
cpumask_copy(attrs->cpumask, unbound_cpumask);
|
|
}
|
|
|
|
/* find wq_pod_type to use for @attrs */
|
|
static const struct wq_pod_type *
|
|
wqattrs_pod_type(const struct workqueue_attrs *attrs)
|
|
{
|
|
enum wq_affn_scope scope;
|
|
struct wq_pod_type *pt;
|
|
|
|
/* to synchronize access to wq_affn_dfl */
|
|
lockdep_assert_held(&wq_pool_mutex);
|
|
|
|
if (attrs->affn_scope == WQ_AFFN_DFL)
|
|
scope = wq_affn_dfl;
|
|
else
|
|
scope = attrs->affn_scope;
|
|
|
|
pt = &wq_pod_types[scope];
|
|
|
|
if (!WARN_ON_ONCE(attrs->affn_scope == WQ_AFFN_NR_TYPES) &&
|
|
likely(pt->nr_pods))
|
|
return pt;
|
|
|
|
/*
|
|
* Before workqueue_init_topology(), only SYSTEM is available which is
|
|
* initialized in workqueue_init_early().
|
|
*/
|
|
pt = &wq_pod_types[WQ_AFFN_SYSTEM];
|
|
BUG_ON(!pt->nr_pods);
|
|
return pt;
|
|
}
|
|
|
|
/**
|
|
* init_worker_pool - initialize a newly zalloc'd worker_pool
|
|
* @pool: worker_pool to initialize
|
|
*
|
|
* Initialize a newly zalloc'd @pool. It also allocates @pool->attrs.
|
|
*
|
|
* Return: 0 on success, -errno on failure. Even on failure, all fields
|
|
* inside @pool proper are initialized and put_unbound_pool() can be called
|
|
* on @pool safely to release it.
|
|
*/
|
|
static int init_worker_pool(struct worker_pool *pool)
|
|
{
|
|
raw_spin_lock_init(&pool->lock);
|
|
pool->id = -1;
|
|
pool->cpu = -1;
|
|
pool->node = NUMA_NO_NODE;
|
|
pool->flags |= POOL_DISASSOCIATED;
|
|
pool->watchdog_ts = jiffies;
|
|
INIT_LIST_HEAD(&pool->worklist);
|
|
INIT_LIST_HEAD(&pool->idle_list);
|
|
hash_init(pool->busy_hash);
|
|
|
|
timer_setup(&pool->idle_timer, idle_worker_timeout, TIMER_DEFERRABLE);
|
|
INIT_WORK(&pool->idle_cull_work, idle_cull_fn);
|
|
|
|
timer_setup(&pool->mayday_timer, pool_mayday_timeout, 0);
|
|
|
|
INIT_LIST_HEAD(&pool->workers);
|
|
INIT_LIST_HEAD(&pool->dying_workers);
|
|
|
|
ida_init(&pool->worker_ida);
|
|
INIT_HLIST_NODE(&pool->hash_node);
|
|
pool->refcnt = 1;
|
|
|
|
/* shouldn't fail above this point */
|
|
pool->attrs = alloc_workqueue_attrs();
|
|
if (!pool->attrs)
|
|
return -ENOMEM;
|
|
|
|
wqattrs_clear_for_pool(pool->attrs);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_LOCKDEP
|
|
static void wq_init_lockdep(struct workqueue_struct *wq)
|
|
{
|
|
char *lock_name;
|
|
|
|
lockdep_register_key(&wq->key);
|
|
lock_name = kasprintf(GFP_KERNEL, "%s%s", "(wq_completion)", wq->name);
|
|
if (!lock_name)
|
|
lock_name = wq->name;
|
|
|
|
wq->lock_name = lock_name;
|
|
lockdep_init_map(&wq->lockdep_map, lock_name, &wq->key, 0);
|
|
}
|
|
|
|
static void wq_unregister_lockdep(struct workqueue_struct *wq)
|
|
{
|
|
lockdep_unregister_key(&wq->key);
|
|
}
|
|
|
|
static void wq_free_lockdep(struct workqueue_struct *wq)
|
|
{
|
|
if (wq->lock_name != wq->name)
|
|
kfree(wq->lock_name);
|
|
}
|
|
#else
|
|
static void wq_init_lockdep(struct workqueue_struct *wq)
|
|
{
|
|
}
|
|
|
|
static void wq_unregister_lockdep(struct workqueue_struct *wq)
|
|
{
|
|
}
|
|
|
|
static void wq_free_lockdep(struct workqueue_struct *wq)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
static void free_node_nr_active(struct wq_node_nr_active **nna_ar)
|
|
{
|
|
int node;
|
|
|
|
for_each_node(node) {
|
|
kfree(nna_ar[node]);
|
|
nna_ar[node] = NULL;
|
|
}
|
|
|
|
kfree(nna_ar[nr_node_ids]);
|
|
nna_ar[nr_node_ids] = NULL;
|
|
}
|
|
|
|
static void init_node_nr_active(struct wq_node_nr_active *nna)
|
|
{
|
|
nna->max = WQ_DFL_MIN_ACTIVE;
|
|
atomic_set(&nna->nr, 0);
|
|
raw_spin_lock_init(&nna->lock);
|
|
INIT_LIST_HEAD(&nna->pending_pwqs);
|
|
}
|
|
|
|
/*
|
|
* Each node's nr_active counter will be accessed mostly from its own node and
|
|
* should be allocated in the node.
|
|
*/
|
|
static int alloc_node_nr_active(struct wq_node_nr_active **nna_ar)
|
|
{
|
|
struct wq_node_nr_active *nna;
|
|
int node;
|
|
|
|
for_each_node(node) {
|
|
nna = kzalloc_node(sizeof(*nna), GFP_KERNEL, node);
|
|
if (!nna)
|
|
goto err_free;
|
|
init_node_nr_active(nna);
|
|
nna_ar[node] = nna;
|
|
}
|
|
|
|
/* [nr_node_ids] is used as the fallback */
|
|
nna = kzalloc_node(sizeof(*nna), GFP_KERNEL, NUMA_NO_NODE);
|
|
if (!nna)
|
|
goto err_free;
|
|
init_node_nr_active(nna);
|
|
nna_ar[nr_node_ids] = nna;
|
|
|
|
return 0;
|
|
|
|
err_free:
|
|
free_node_nr_active(nna_ar);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static void rcu_free_wq(struct rcu_head *rcu)
|
|
{
|
|
struct workqueue_struct *wq =
|
|
container_of(rcu, struct workqueue_struct, rcu);
|
|
|
|
if (wq->flags & WQ_UNBOUND)
|
|
free_node_nr_active(wq->node_nr_active);
|
|
|
|
wq_free_lockdep(wq);
|
|
free_percpu(wq->cpu_pwq);
|
|
free_workqueue_attrs(wq->unbound_attrs);
|
|
kfree(wq);
|
|
}
|
|
|
|
static void rcu_free_pool(struct rcu_head *rcu)
|
|
{
|
|
struct worker_pool *pool = container_of(rcu, struct worker_pool, rcu);
|
|
|
|
ida_destroy(&pool->worker_ida);
|
|
free_workqueue_attrs(pool->attrs);
|
|
kfree(pool);
|
|
}
|
|
|
|
/**
|
|
* put_unbound_pool - put a worker_pool
|
|
* @pool: worker_pool to put
|
|
*
|
|
* Put @pool. If its refcnt reaches zero, it gets destroyed in RCU
|
|
* safe manner. get_unbound_pool() calls this function on its failure path
|
|
* and this function should be able to release pools which went through,
|
|
* successfully or not, init_worker_pool().
|
|
*
|
|
* Should be called with wq_pool_mutex held.
|
|
*/
|
|
static void put_unbound_pool(struct worker_pool *pool)
|
|
{
|
|
DECLARE_COMPLETION_ONSTACK(detach_completion);
|
|
struct worker *worker;
|
|
LIST_HEAD(cull_list);
|
|
|
|
lockdep_assert_held(&wq_pool_mutex);
|
|
|
|
if (--pool->refcnt)
|
|
return;
|
|
|
|
/* sanity checks */
|
|
if (WARN_ON(!(pool->cpu < 0)) ||
|
|
WARN_ON(!list_empty(&pool->worklist)))
|
|
return;
|
|
|
|
/* release id and unhash */
|
|
if (pool->id >= 0)
|
|
idr_remove(&worker_pool_idr, pool->id);
|
|
hash_del(&pool->hash_node);
|
|
|
|
/*
|
|
* Become the manager and destroy all workers. This prevents
|
|
* @pool's workers from blocking on attach_mutex. We're the last
|
|
* manager and @pool gets freed with the flag set.
|
|
*
|
|
* Having a concurrent manager is quite unlikely to happen as we can
|
|
* only get here with
|
|
* pwq->refcnt == pool->refcnt == 0
|
|
* which implies no work queued to the pool, which implies no worker can
|
|
* become the manager. However a worker could have taken the role of
|
|
* manager before the refcnts dropped to 0, since maybe_create_worker()
|
|
* drops pool->lock
|
|
*/
|
|
while (true) {
|
|
rcuwait_wait_event(&manager_wait,
|
|
!(pool->flags & POOL_MANAGER_ACTIVE),
|
|
TASK_UNINTERRUPTIBLE);
|
|
|
|
mutex_lock(&wq_pool_attach_mutex);
|
|
raw_spin_lock_irq(&pool->lock);
|
|
if (!(pool->flags & POOL_MANAGER_ACTIVE)) {
|
|
pool->flags |= POOL_MANAGER_ACTIVE;
|
|
break;
|
|
}
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
mutex_unlock(&wq_pool_attach_mutex);
|
|
}
|
|
|
|
while ((worker = first_idle_worker(pool)))
|
|
set_worker_dying(worker, &cull_list);
|
|
WARN_ON(pool->nr_workers || pool->nr_idle);
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
|
|
wake_dying_workers(&cull_list);
|
|
|
|
if (!list_empty(&pool->workers) || !list_empty(&pool->dying_workers))
|
|
pool->detach_completion = &detach_completion;
|
|
mutex_unlock(&wq_pool_attach_mutex);
|
|
|
|
if (pool->detach_completion)
|
|
wait_for_completion(pool->detach_completion);
|
|
|
|
/* shut down the timers */
|
|
del_timer_sync(&pool->idle_timer);
|
|
cancel_work_sync(&pool->idle_cull_work);
|
|
del_timer_sync(&pool->mayday_timer);
|
|
|
|
/* RCU protected to allow dereferences from get_work_pool() */
|
|
call_rcu(&pool->rcu, rcu_free_pool);
|
|
}
|
|
|
|
/**
|
|
* get_unbound_pool - get a worker_pool with the specified attributes
|
|
* @attrs: the attributes of the worker_pool to get
|
|
*
|
|
* Obtain a worker_pool which has the same attributes as @attrs, bump the
|
|
* reference count and return it. If there already is a matching
|
|
* worker_pool, it will be used; otherwise, this function attempts to
|
|
* create a new one.
|
|
*
|
|
* Should be called with wq_pool_mutex held.
|
|
*
|
|
* Return: On success, a worker_pool with the same attributes as @attrs.
|
|
* On failure, %NULL.
|
|
*/
|
|
static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
|
|
{
|
|
struct wq_pod_type *pt = &wq_pod_types[WQ_AFFN_NUMA];
|
|
u32 hash = wqattrs_hash(attrs);
|
|
struct worker_pool *pool;
|
|
int pod, node = NUMA_NO_NODE;
|
|
|
|
lockdep_assert_held(&wq_pool_mutex);
|
|
|
|
/* do we already have a matching pool? */
|
|
hash_for_each_possible(unbound_pool_hash, pool, hash_node, hash) {
|
|
if (wqattrs_equal(pool->attrs, attrs)) {
|
|
pool->refcnt++;
|
|
return pool;
|
|
}
|
|
}
|
|
|
|
/* If __pod_cpumask is contained inside a NUMA pod, that's our node */
|
|
for (pod = 0; pod < pt->nr_pods; pod++) {
|
|
if (cpumask_subset(attrs->__pod_cpumask, pt->pod_cpus[pod])) {
|
|
node = pt->pod_node[pod];
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* nope, create a new one */
|
|
pool = kzalloc_node(sizeof(*pool), GFP_KERNEL, node);
|
|
if (!pool || init_worker_pool(pool) < 0)
|
|
goto fail;
|
|
|
|
pool->node = node;
|
|
copy_workqueue_attrs(pool->attrs, attrs);
|
|
wqattrs_clear_for_pool(pool->attrs);
|
|
|
|
if (worker_pool_assign_id(pool) < 0)
|
|
goto fail;
|
|
|
|
/* create and start the initial worker */
|
|
if (wq_online && !create_worker(pool))
|
|
goto fail;
|
|
|
|
/* install */
|
|
hash_add(unbound_pool_hash, &pool->hash_node, hash);
|
|
|
|
return pool;
|
|
fail:
|
|
if (pool)
|
|
put_unbound_pool(pool);
|
|
return NULL;
|
|
}
|
|
|
|
static void rcu_free_pwq(struct rcu_head *rcu)
|
|
{
|
|
kmem_cache_free(pwq_cache,
|
|
container_of(rcu, struct pool_workqueue, rcu));
|
|
}
|
|
|
|
/*
|
|
* Scheduled on pwq_release_worker by put_pwq() when an unbound pwq hits zero
|
|
* refcnt and needs to be destroyed.
|
|
*/
|
|
static void pwq_release_workfn(struct kthread_work *work)
|
|
{
|
|
struct pool_workqueue *pwq = container_of(work, struct pool_workqueue,
|
|
release_work);
|
|
struct workqueue_struct *wq = pwq->wq;
|
|
struct worker_pool *pool = pwq->pool;
|
|
bool is_last = false;
|
|
|
|
/*
|
|
* When @pwq is not linked, it doesn't hold any reference to the
|
|
* @wq, and @wq is invalid to access.
|
|
*/
|
|
if (!list_empty(&pwq->pwqs_node)) {
|
|
mutex_lock(&wq->mutex);
|
|
list_del_rcu(&pwq->pwqs_node);
|
|
is_last = list_empty(&wq->pwqs);
|
|
|
|
/*
|
|
* For ordered workqueue with a plugged dfl_pwq, restart it now.
|
|
*/
|
|
if (!is_last && (wq->flags & __WQ_ORDERED))
|
|
unplug_oldest_pwq(wq);
|
|
|
|
mutex_unlock(&wq->mutex);
|
|
}
|
|
|
|
if (wq->flags & WQ_UNBOUND) {
|
|
mutex_lock(&wq_pool_mutex);
|
|
put_unbound_pool(pool);
|
|
mutex_unlock(&wq_pool_mutex);
|
|
}
|
|
|
|
if (!list_empty(&pwq->pending_node)) {
|
|
struct wq_node_nr_active *nna =
|
|
wq_node_nr_active(pwq->wq, pwq->pool->node);
|
|
|
|
raw_spin_lock_irq(&nna->lock);
|
|
list_del_init(&pwq->pending_node);
|
|
raw_spin_unlock_irq(&nna->lock);
|
|
}
|
|
|
|
call_rcu(&pwq->rcu, rcu_free_pwq);
|
|
|
|
/*
|
|
* If we're the last pwq going away, @wq is already dead and no one
|
|
* is gonna access it anymore. Schedule RCU free.
|
|
*/
|
|
if (is_last) {
|
|
wq_unregister_lockdep(wq);
|
|
call_rcu(&wq->rcu, rcu_free_wq);
|
|
}
|
|
}
|
|
|
|
/* initialize newly allocated @pwq which is associated with @wq and @pool */
|
|
static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq,
|
|
struct worker_pool *pool)
|
|
{
|
|
BUG_ON((unsigned long)pwq & ~WORK_STRUCT_PWQ_MASK);
|
|
|
|
memset(pwq, 0, sizeof(*pwq));
|
|
|
|
pwq->pool = pool;
|
|
pwq->wq = wq;
|
|
pwq->flush_color = -1;
|
|
pwq->refcnt = 1;
|
|
INIT_LIST_HEAD(&pwq->inactive_works);
|
|
INIT_LIST_HEAD(&pwq->pending_node);
|
|
INIT_LIST_HEAD(&pwq->pwqs_node);
|
|
INIT_LIST_HEAD(&pwq->mayday_node);
|
|
kthread_init_work(&pwq->release_work, pwq_release_workfn);
|
|
}
|
|
|
|
/* sync @pwq with the current state of its associated wq and link it */
|
|
static void link_pwq(struct pool_workqueue *pwq)
|
|
{
|
|
struct workqueue_struct *wq = pwq->wq;
|
|
|
|
lockdep_assert_held(&wq->mutex);
|
|
|
|
/* may be called multiple times, ignore if already linked */
|
|
if (!list_empty(&pwq->pwqs_node))
|
|
return;
|
|
|
|
/* set the matching work_color */
|
|
pwq->work_color = wq->work_color;
|
|
|
|
/* link in @pwq */
|
|
list_add_tail_rcu(&pwq->pwqs_node, &wq->pwqs);
|
|
}
|
|
|
|
/* obtain a pool matching @attr and create a pwq associating the pool and @wq */
|
|
static struct pool_workqueue *alloc_unbound_pwq(struct workqueue_struct *wq,
|
|
const struct workqueue_attrs *attrs)
|
|
{
|
|
struct worker_pool *pool;
|
|
struct pool_workqueue *pwq;
|
|
|
|
lockdep_assert_held(&wq_pool_mutex);
|
|
|
|
pool = get_unbound_pool(attrs);
|
|
if (!pool)
|
|
return NULL;
|
|
|
|
pwq = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, pool->node);
|
|
if (!pwq) {
|
|
put_unbound_pool(pool);
|
|
return NULL;
|
|
}
|
|
|
|
init_pwq(pwq, wq, pool);
|
|
return pwq;
|
|
}
|
|
|
|
/**
|
|
* wq_calc_pod_cpumask - calculate a wq_attrs' cpumask for a pod
|
|
* @attrs: the wq_attrs of the default pwq of the target workqueue
|
|
* @cpu: the target CPU
|
|
* @cpu_going_down: if >= 0, the CPU to consider as offline
|
|
*
|
|
* Calculate the cpumask a workqueue with @attrs should use on @pod. If
|
|
* @cpu_going_down is >= 0, that cpu is considered offline during calculation.
|
|
* The result is stored in @attrs->__pod_cpumask.
|
|
*
|
|
* If pod affinity is not enabled, @attrs->cpumask is always used. If enabled
|
|
* and @pod has online CPUs requested by @attrs, the returned cpumask is the
|
|
* intersection of the possible CPUs of @pod and @attrs->cpumask.
|
|
*
|
|
* The caller is responsible for ensuring that the cpumask of @pod stays stable.
|
|
*/
|
|
static void wq_calc_pod_cpumask(struct workqueue_attrs *attrs, int cpu,
|
|
int cpu_going_down)
|
|
{
|
|
const struct wq_pod_type *pt = wqattrs_pod_type(attrs);
|
|
int pod = pt->cpu_pod[cpu];
|
|
|
|
/* does @pod have any online CPUs @attrs wants? */
|
|
cpumask_and(attrs->__pod_cpumask, pt->pod_cpus[pod], attrs->cpumask);
|
|
cpumask_and(attrs->__pod_cpumask, attrs->__pod_cpumask, cpu_online_mask);
|
|
if (cpu_going_down >= 0)
|
|
cpumask_clear_cpu(cpu_going_down, attrs->__pod_cpumask);
|
|
|
|
if (cpumask_empty(attrs->__pod_cpumask)) {
|
|
cpumask_copy(attrs->__pod_cpumask, attrs->cpumask);
|
|
return;
|
|
}
|
|
|
|
/* yeap, return possible CPUs in @pod that @attrs wants */
|
|
cpumask_and(attrs->__pod_cpumask, attrs->cpumask, pt->pod_cpus[pod]);
|
|
|
|
if (cpumask_empty(attrs->__pod_cpumask))
|
|
pr_warn_once("WARNING: workqueue cpumask: online intersect > "
|
|
"possible intersect\n");
|
|
}
|
|
|
|
/* install @pwq into @wq and return the old pwq, @cpu < 0 for dfl_pwq */
|
|
static struct pool_workqueue *install_unbound_pwq(struct workqueue_struct *wq,
|
|
int cpu, struct pool_workqueue *pwq)
|
|
{
|
|
struct pool_workqueue __rcu **slot = unbound_pwq_slot(wq, cpu);
|
|
struct pool_workqueue *old_pwq;
|
|
|
|
lockdep_assert_held(&wq_pool_mutex);
|
|
lockdep_assert_held(&wq->mutex);
|
|
|
|
/* link_pwq() can handle duplicate calls */
|
|
link_pwq(pwq);
|
|
|
|
old_pwq = rcu_access_pointer(*slot);
|
|
rcu_assign_pointer(*slot, pwq);
|
|
return old_pwq;
|
|
}
|
|
|
|
/* context to store the prepared attrs & pwqs before applying */
|
|
struct apply_wqattrs_ctx {
|
|
struct workqueue_struct *wq; /* target workqueue */
|
|
struct workqueue_attrs *attrs; /* attrs to apply */
|
|
struct list_head list; /* queued for batching commit */
|
|
struct pool_workqueue *dfl_pwq;
|
|
struct pool_workqueue *pwq_tbl[];
|
|
};
|
|
|
|
/* free the resources after success or abort */
|
|
static void apply_wqattrs_cleanup(struct apply_wqattrs_ctx *ctx)
|
|
{
|
|
if (ctx) {
|
|
int cpu;
|
|
|
|
for_each_possible_cpu(cpu)
|
|
put_pwq_unlocked(ctx->pwq_tbl[cpu]);
|
|
put_pwq_unlocked(ctx->dfl_pwq);
|
|
|
|
free_workqueue_attrs(ctx->attrs);
|
|
|
|
kfree(ctx);
|
|
}
|
|
}
|
|
|
|
/* allocate the attrs and pwqs for later installation */
|
|
static struct apply_wqattrs_ctx *
|
|
apply_wqattrs_prepare(struct workqueue_struct *wq,
|
|
const struct workqueue_attrs *attrs,
|
|
const cpumask_var_t unbound_cpumask)
|
|
{
|
|
struct apply_wqattrs_ctx *ctx;
|
|
struct workqueue_attrs *new_attrs;
|
|
int cpu;
|
|
|
|
lockdep_assert_held(&wq_pool_mutex);
|
|
|
|
if (WARN_ON(attrs->affn_scope < 0 ||
|
|
attrs->affn_scope >= WQ_AFFN_NR_TYPES))
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
ctx = kzalloc(struct_size(ctx, pwq_tbl, nr_cpu_ids), GFP_KERNEL);
|
|
|
|
new_attrs = alloc_workqueue_attrs();
|
|
if (!ctx || !new_attrs)
|
|
goto out_free;
|
|
|
|
/*
|
|
* If something goes wrong during CPU up/down, we'll fall back to
|
|
* the default pwq covering whole @attrs->cpumask. Always create
|
|
* it even if we don't use it immediately.
|
|
*/
|
|
copy_workqueue_attrs(new_attrs, attrs);
|
|
wqattrs_actualize_cpumask(new_attrs, unbound_cpumask);
|
|
cpumask_copy(new_attrs->__pod_cpumask, new_attrs->cpumask);
|
|
ctx->dfl_pwq = alloc_unbound_pwq(wq, new_attrs);
|
|
if (!ctx->dfl_pwq)
|
|
goto out_free;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
if (new_attrs->ordered) {
|
|
ctx->dfl_pwq->refcnt++;
|
|
ctx->pwq_tbl[cpu] = ctx->dfl_pwq;
|
|
} else {
|
|
wq_calc_pod_cpumask(new_attrs, cpu, -1);
|
|
ctx->pwq_tbl[cpu] = alloc_unbound_pwq(wq, new_attrs);
|
|
if (!ctx->pwq_tbl[cpu])
|
|
goto out_free;
|
|
}
|
|
}
|
|
|
|
/* save the user configured attrs and sanitize it. */
|
|
copy_workqueue_attrs(new_attrs, attrs);
|
|
cpumask_and(new_attrs->cpumask, new_attrs->cpumask, cpu_possible_mask);
|
|
cpumask_copy(new_attrs->__pod_cpumask, new_attrs->cpumask);
|
|
ctx->attrs = new_attrs;
|
|
|
|
/*
|
|
* For initialized ordered workqueues, there should only be one pwq
|
|
* (dfl_pwq). Set the plugged flag of ctx->dfl_pwq to suspend execution
|
|
* of newly queued work items until execution of older work items in
|
|
* the old pwq's have completed.
|
|
*/
|
|
if ((wq->flags & __WQ_ORDERED) && !list_empty(&wq->pwqs))
|
|
ctx->dfl_pwq->plugged = true;
|
|
|
|
ctx->wq = wq;
|
|
return ctx;
|
|
|
|
out_free:
|
|
free_workqueue_attrs(new_attrs);
|
|
apply_wqattrs_cleanup(ctx);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
/* set attrs and install prepared pwqs, @ctx points to old pwqs on return */
|
|
static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx)
|
|
{
|
|
int cpu;
|
|
|
|
/* all pwqs have been created successfully, let's install'em */
|
|
mutex_lock(&ctx->wq->mutex);
|
|
|
|
copy_workqueue_attrs(ctx->wq->unbound_attrs, ctx->attrs);
|
|
|
|
/* save the previous pwqs and install the new ones */
|
|
for_each_possible_cpu(cpu)
|
|
ctx->pwq_tbl[cpu] = install_unbound_pwq(ctx->wq, cpu,
|
|
ctx->pwq_tbl[cpu]);
|
|
ctx->dfl_pwq = install_unbound_pwq(ctx->wq, -1, ctx->dfl_pwq);
|
|
|
|
/* update node_nr_active->max */
|
|
wq_update_node_max_active(ctx->wq, -1);
|
|
|
|
/* rescuer needs to respect wq cpumask changes */
|
|
if (ctx->wq->rescuer)
|
|
set_cpus_allowed_ptr(ctx->wq->rescuer->task,
|
|
unbound_effective_cpumask(ctx->wq));
|
|
|
|
mutex_unlock(&ctx->wq->mutex);
|
|
}
|
|
|
|
static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
|
|
const struct workqueue_attrs *attrs)
|
|
{
|
|
struct apply_wqattrs_ctx *ctx;
|
|
|
|
/* only unbound workqueues can change attributes */
|
|
if (WARN_ON(!(wq->flags & WQ_UNBOUND)))
|
|
return -EINVAL;
|
|
|
|
ctx = apply_wqattrs_prepare(wq, attrs, wq_unbound_cpumask);
|
|
if (IS_ERR(ctx))
|
|
return PTR_ERR(ctx);
|
|
|
|
/* the ctx has been prepared successfully, let's commit it */
|
|
apply_wqattrs_commit(ctx);
|
|
apply_wqattrs_cleanup(ctx);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue
|
|
* @wq: the target workqueue
|
|
* @attrs: the workqueue_attrs to apply, allocated with alloc_workqueue_attrs()
|
|
*
|
|
* Apply @attrs to an unbound workqueue @wq. Unless disabled, this function maps
|
|
* a separate pwq to each CPU pod with possibles CPUs in @attrs->cpumask so that
|
|
* work items are affine to the pod it was issued on. Older pwqs are released as
|
|
* in-flight work items finish. Note that a work item which repeatedly requeues
|
|
* itself back-to-back will stay on its current pwq.
|
|
*
|
|
* Performs GFP_KERNEL allocations.
|
|
*
|
|
* Assumes caller has CPU hotplug read exclusion, i.e. cpus_read_lock().
|
|
*
|
|
* Return: 0 on success and -errno on failure.
|
|
*/
|
|
int apply_workqueue_attrs(struct workqueue_struct *wq,
|
|
const struct workqueue_attrs *attrs)
|
|
{
|
|
int ret;
|
|
|
|
lockdep_assert_cpus_held();
|
|
|
|
mutex_lock(&wq_pool_mutex);
|
|
ret = apply_workqueue_attrs_locked(wq, attrs);
|
|
mutex_unlock(&wq_pool_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* wq_update_pod - update pod affinity of a wq for CPU hot[un]plug
|
|
* @wq: the target workqueue
|
|
* @cpu: the CPU to update pool association for
|
|
* @hotplug_cpu: the CPU coming up or going down
|
|
* @online: whether @cpu is coming up or going down
|
|
*
|
|
* This function is to be called from %CPU_DOWN_PREPARE, %CPU_ONLINE and
|
|
* %CPU_DOWN_FAILED. @cpu is being hot[un]plugged, update pod affinity of
|
|
* @wq accordingly.
|
|
*
|
|
*
|
|
* If pod affinity can't be adjusted due to memory allocation failure, it falls
|
|
* back to @wq->dfl_pwq which may not be optimal but is always correct.
|
|
*
|
|
* Note that when the last allowed CPU of a pod goes offline for a workqueue
|
|
* with a cpumask spanning multiple pods, the workers which were already
|
|
* executing the work items for the workqueue will lose their CPU affinity and
|
|
* may execute on any CPU. This is similar to how per-cpu workqueues behave on
|
|
* CPU_DOWN. If a workqueue user wants strict affinity, it's the user's
|
|
* responsibility to flush the work item from CPU_DOWN_PREPARE.
|
|
*/
|
|
static void wq_update_pod(struct workqueue_struct *wq, int cpu,
|
|
int hotplug_cpu, bool online)
|
|
{
|
|
int off_cpu = online ? -1 : hotplug_cpu;
|
|
struct pool_workqueue *old_pwq = NULL, *pwq;
|
|
struct workqueue_attrs *target_attrs;
|
|
|
|
lockdep_assert_held(&wq_pool_mutex);
|
|
|
|
if (!(wq->flags & WQ_UNBOUND) || wq->unbound_attrs->ordered)
|
|
return;
|
|
|
|
/*
|
|
* We don't wanna alloc/free wq_attrs for each wq for each CPU.
|
|
* Let's use a preallocated one. The following buf is protected by
|
|
* CPU hotplug exclusion.
|
|
*/
|
|
target_attrs = wq_update_pod_attrs_buf;
|
|
|
|
copy_workqueue_attrs(target_attrs, wq->unbound_attrs);
|
|
wqattrs_actualize_cpumask(target_attrs, wq_unbound_cpumask);
|
|
|
|
/* nothing to do if the target cpumask matches the current pwq */
|
|
wq_calc_pod_cpumask(target_attrs, cpu, off_cpu);
|
|
if (wqattrs_equal(target_attrs, unbound_pwq(wq, cpu)->pool->attrs))
|
|
return;
|
|
|
|
/* create a new pwq */
|
|
pwq = alloc_unbound_pwq(wq, target_attrs);
|
|
if (!pwq) {
|
|
pr_warn("workqueue: allocation failed while updating CPU pod affinity of \"%s\"\n",
|
|
wq->name);
|
|
goto use_dfl_pwq;
|
|
}
|
|
|
|
/* Install the new pwq. */
|
|
mutex_lock(&wq->mutex);
|
|
old_pwq = install_unbound_pwq(wq, cpu, pwq);
|
|
goto out_unlock;
|
|
|
|
use_dfl_pwq:
|
|
mutex_lock(&wq->mutex);
|
|
pwq = unbound_pwq(wq, -1);
|
|
raw_spin_lock_irq(&pwq->pool->lock);
|
|
get_pwq(pwq);
|
|
raw_spin_unlock_irq(&pwq->pool->lock);
|
|
old_pwq = install_unbound_pwq(wq, cpu, pwq);
|
|
out_unlock:
|
|
mutex_unlock(&wq->mutex);
|
|
put_pwq_unlocked(old_pwq);
|
|
}
|
|
|
|
static int alloc_and_link_pwqs(struct workqueue_struct *wq)
|
|
{
|
|
bool highpri = wq->flags & WQ_HIGHPRI;
|
|
int cpu, ret;
|
|
|
|
wq->cpu_pwq = alloc_percpu(struct pool_workqueue *);
|
|
if (!wq->cpu_pwq)
|
|
goto enomem;
|
|
|
|
if (!(wq->flags & WQ_UNBOUND)) {
|
|
for_each_possible_cpu(cpu) {
|
|
struct pool_workqueue **pwq_p;
|
|
struct worker_pool __percpu *pools;
|
|
struct worker_pool *pool;
|
|
|
|
if (wq->flags & WQ_BH)
|
|
pools = bh_worker_pools;
|
|
else
|
|
pools = cpu_worker_pools;
|
|
|
|
pool = &(per_cpu_ptr(pools, cpu)[highpri]);
|
|
pwq_p = per_cpu_ptr(wq->cpu_pwq, cpu);
|
|
|
|
*pwq_p = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL,
|
|
pool->node);
|
|
if (!*pwq_p)
|
|
goto enomem;
|
|
|
|
init_pwq(*pwq_p, wq, pool);
|
|
|
|
mutex_lock(&wq->mutex);
|
|
link_pwq(*pwq_p);
|
|
mutex_unlock(&wq->mutex);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
cpus_read_lock();
|
|
if (wq->flags & __WQ_ORDERED) {
|
|
struct pool_workqueue *dfl_pwq;
|
|
|
|
ret = apply_workqueue_attrs(wq, ordered_wq_attrs[highpri]);
|
|
/* there should only be single pwq for ordering guarantee */
|
|
dfl_pwq = rcu_access_pointer(wq->dfl_pwq);
|
|
WARN(!ret && (wq->pwqs.next != &dfl_pwq->pwqs_node ||
|
|
wq->pwqs.prev != &dfl_pwq->pwqs_node),
|
|
"ordering guarantee broken for workqueue %s\n", wq->name);
|
|
} else {
|
|
ret = apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]);
|
|
}
|
|
cpus_read_unlock();
|
|
|
|
/* for unbound pwq, flush the pwq_release_worker ensures that the
|
|
* pwq_release_workfn() completes before calling kfree(wq).
|
|
*/
|
|
if (ret)
|
|
kthread_flush_worker(pwq_release_worker);
|
|
|
|
return ret;
|
|
|
|
enomem:
|
|
if (wq->cpu_pwq) {
|
|
for_each_possible_cpu(cpu) {
|
|
struct pool_workqueue *pwq = *per_cpu_ptr(wq->cpu_pwq, cpu);
|
|
|
|
if (pwq)
|
|
kmem_cache_free(pwq_cache, pwq);
|
|
}
|
|
free_percpu(wq->cpu_pwq);
|
|
wq->cpu_pwq = NULL;
|
|
}
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static int wq_clamp_max_active(int max_active, unsigned int flags,
|
|
const char *name)
|
|
{
|
|
if (max_active < 1 || max_active > WQ_MAX_ACTIVE)
|
|
pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n",
|
|
max_active, name, 1, WQ_MAX_ACTIVE);
|
|
|
|
return clamp_val(max_active, 1, WQ_MAX_ACTIVE);
|
|
}
|
|
|
|
/*
|
|
* Workqueues which may be used during memory reclaim should have a rescuer
|
|
* to guarantee forward progress.
|
|
*/
|
|
static int init_rescuer(struct workqueue_struct *wq)
|
|
{
|
|
struct worker *rescuer;
|
|
int ret;
|
|
|
|
if (!(wq->flags & WQ_MEM_RECLAIM))
|
|
return 0;
|
|
|
|
rescuer = alloc_worker(NUMA_NO_NODE);
|
|
if (!rescuer) {
|
|
pr_err("workqueue: Failed to allocate a rescuer for wq \"%s\"\n",
|
|
wq->name);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
rescuer->rescue_wq = wq;
|
|
rescuer->task = kthread_create(rescuer_thread, rescuer, "kworker/R-%s", wq->name);
|
|
if (IS_ERR(rescuer->task)) {
|
|
ret = PTR_ERR(rescuer->task);
|
|
pr_err("workqueue: Failed to create a rescuer kthread for wq \"%s\": %pe",
|
|
wq->name, ERR_PTR(ret));
|
|
kfree(rescuer);
|
|
return ret;
|
|
}
|
|
|
|
wq->rescuer = rescuer;
|
|
if (wq->flags & WQ_UNBOUND)
|
|
kthread_bind_mask(rescuer->task, wq_unbound_cpumask);
|
|
else
|
|
kthread_bind_mask(rescuer->task, cpu_possible_mask);
|
|
wake_up_process(rescuer->task);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* wq_adjust_max_active - update a wq's max_active to the current setting
|
|
* @wq: target workqueue
|
|
*
|
|
* If @wq isn't freezing, set @wq->max_active to the saved_max_active and
|
|
* activate inactive work items accordingly. If @wq is freezing, clear
|
|
* @wq->max_active to zero.
|
|
*/
|
|
static void wq_adjust_max_active(struct workqueue_struct *wq)
|
|
{
|
|
bool activated;
|
|
int new_max, new_min;
|
|
|
|
lockdep_assert_held(&wq->mutex);
|
|
|
|
if ((wq->flags & WQ_FREEZABLE) && workqueue_freezing) {
|
|
new_max = 0;
|
|
new_min = 0;
|
|
} else {
|
|
new_max = wq->saved_max_active;
|
|
new_min = wq->saved_min_active;
|
|
}
|
|
|
|
if (wq->max_active == new_max && wq->min_active == new_min)
|
|
return;
|
|
|
|
/*
|
|
* Update @wq->max/min_active and then kick inactive work items if more
|
|
* active work items are allowed. This doesn't break work item ordering
|
|
* because new work items are always queued behind existing inactive
|
|
* work items if there are any.
|
|
*/
|
|
WRITE_ONCE(wq->max_active, new_max);
|
|
WRITE_ONCE(wq->min_active, new_min);
|
|
|
|
if (wq->flags & WQ_UNBOUND)
|
|
wq_update_node_max_active(wq, -1);
|
|
|
|
if (new_max == 0)
|
|
return;
|
|
|
|
/*
|
|
* Round-robin through pwq's activating the first inactive work item
|
|
* until max_active is filled.
|
|
*/
|
|
do {
|
|
struct pool_workqueue *pwq;
|
|
|
|
activated = false;
|
|
for_each_pwq(pwq, wq) {
|
|
unsigned long irq_flags;
|
|
|
|
/* can be called during early boot w/ irq disabled */
|
|
raw_spin_lock_irqsave(&pwq->pool->lock, irq_flags);
|
|
if (pwq_activate_first_inactive(pwq, true)) {
|
|
activated = true;
|
|
kick_pool(pwq->pool);
|
|
}
|
|
raw_spin_unlock_irqrestore(&pwq->pool->lock, irq_flags);
|
|
}
|
|
} while (activated);
|
|
}
|
|
|
|
__printf(1, 4)
|
|
struct workqueue_struct *alloc_workqueue(const char *fmt,
|
|
unsigned int flags,
|
|
int max_active, ...)
|
|
{
|
|
va_list args;
|
|
struct workqueue_struct *wq;
|
|
size_t wq_size;
|
|
int name_len;
|
|
|
|
if (flags & WQ_BH) {
|
|
if (WARN_ON_ONCE(flags & ~__WQ_BH_ALLOWS))
|
|
return NULL;
|
|
if (WARN_ON_ONCE(max_active))
|
|
return NULL;
|
|
}
|
|
|
|
/* see the comment above the definition of WQ_POWER_EFFICIENT */
|
|
if ((flags & WQ_POWER_EFFICIENT) && wq_power_efficient)
|
|
flags |= WQ_UNBOUND;
|
|
|
|
/* allocate wq and format name */
|
|
if (flags & WQ_UNBOUND)
|
|
wq_size = struct_size(wq, node_nr_active, nr_node_ids + 1);
|
|
else
|
|
wq_size = sizeof(*wq);
|
|
|
|
wq = kzalloc(wq_size, GFP_KERNEL);
|
|
if (!wq)
|
|
return NULL;
|
|
|
|
if (flags & WQ_UNBOUND) {
|
|
wq->unbound_attrs = alloc_workqueue_attrs();
|
|
if (!wq->unbound_attrs)
|
|
goto err_free_wq;
|
|
}
|
|
|
|
va_start(args, max_active);
|
|
name_len = vsnprintf(wq->name, sizeof(wq->name), fmt, args);
|
|
va_end(args);
|
|
|
|
if (name_len >= WQ_NAME_LEN)
|
|
pr_warn_once("workqueue: name exceeds WQ_NAME_LEN. Truncating to: %s\n",
|
|
wq->name);
|
|
|
|
if (flags & WQ_BH) {
|
|
/*
|
|
* BH workqueues always share a single execution context per CPU
|
|
* and don't impose any max_active limit.
|
|
*/
|
|
max_active = INT_MAX;
|
|
} else {
|
|
max_active = max_active ?: WQ_DFL_ACTIVE;
|
|
max_active = wq_clamp_max_active(max_active, flags, wq->name);
|
|
}
|
|
|
|
/* init wq */
|
|
wq->flags = flags;
|
|
wq->max_active = max_active;
|
|
wq->min_active = min(max_active, WQ_DFL_MIN_ACTIVE);
|
|
wq->saved_max_active = wq->max_active;
|
|
wq->saved_min_active = wq->min_active;
|
|
mutex_init(&wq->mutex);
|
|
atomic_set(&wq->nr_pwqs_to_flush, 0);
|
|
INIT_LIST_HEAD(&wq->pwqs);
|
|
INIT_LIST_HEAD(&wq->flusher_queue);
|
|
INIT_LIST_HEAD(&wq->flusher_overflow);
|
|
INIT_LIST_HEAD(&wq->maydays);
|
|
|
|
wq_init_lockdep(wq);
|
|
INIT_LIST_HEAD(&wq->list);
|
|
|
|
if (flags & WQ_UNBOUND) {
|
|
if (alloc_node_nr_active(wq->node_nr_active) < 0)
|
|
goto err_unreg_lockdep;
|
|
}
|
|
|
|
if (alloc_and_link_pwqs(wq) < 0)
|
|
goto err_free_node_nr_active;
|
|
|
|
if (wq_online && init_rescuer(wq) < 0)
|
|
goto err_destroy;
|
|
|
|
if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq))
|
|
goto err_destroy;
|
|
|
|
/*
|
|
* wq_pool_mutex protects global freeze state and workqueues list.
|
|
* Grab it, adjust max_active and add the new @wq to workqueues
|
|
* list.
|
|
*/
|
|
mutex_lock(&wq_pool_mutex);
|
|
|
|
mutex_lock(&wq->mutex);
|
|
wq_adjust_max_active(wq);
|
|
mutex_unlock(&wq->mutex);
|
|
|
|
list_add_tail_rcu(&wq->list, &workqueues);
|
|
|
|
mutex_unlock(&wq_pool_mutex);
|
|
|
|
return wq;
|
|
|
|
err_free_node_nr_active:
|
|
if (wq->flags & WQ_UNBOUND)
|
|
free_node_nr_active(wq->node_nr_active);
|
|
err_unreg_lockdep:
|
|
wq_unregister_lockdep(wq);
|
|
wq_free_lockdep(wq);
|
|
err_free_wq:
|
|
free_workqueue_attrs(wq->unbound_attrs);
|
|
kfree(wq);
|
|
return NULL;
|
|
err_destroy:
|
|
destroy_workqueue(wq);
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(alloc_workqueue);
|
|
|
|
static bool pwq_busy(struct pool_workqueue *pwq)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < WORK_NR_COLORS; i++)
|
|
if (pwq->nr_in_flight[i])
|
|
return true;
|
|
|
|
if ((pwq != rcu_access_pointer(pwq->wq->dfl_pwq)) && (pwq->refcnt > 1))
|
|
return true;
|
|
if (!pwq_is_empty(pwq))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* destroy_workqueue - safely terminate a workqueue
|
|
* @wq: target workqueue
|
|
*
|
|
* Safely destroy a workqueue. All work currently pending will be done first.
|
|
*/
|
|
void destroy_workqueue(struct workqueue_struct *wq)
|
|
{
|
|
struct pool_workqueue *pwq;
|
|
int cpu;
|
|
|
|
/*
|
|
* Remove it from sysfs first so that sanity check failure doesn't
|
|
* lead to sysfs name conflicts.
|
|
*/
|
|
workqueue_sysfs_unregister(wq);
|
|
|
|
/* mark the workqueue destruction is in progress */
|
|
mutex_lock(&wq->mutex);
|
|
wq->flags |= __WQ_DESTROYING;
|
|
mutex_unlock(&wq->mutex);
|
|
|
|
/* drain it before proceeding with destruction */
|
|
drain_workqueue(wq);
|
|
|
|
/* kill rescuer, if sanity checks fail, leave it w/o rescuer */
|
|
if (wq->rescuer) {
|
|
struct worker *rescuer = wq->rescuer;
|
|
|
|
/* this prevents new queueing */
|
|
raw_spin_lock_irq(&wq_mayday_lock);
|
|
wq->rescuer = NULL;
|
|
raw_spin_unlock_irq(&wq_mayday_lock);
|
|
|
|
/* rescuer will empty maydays list before exiting */
|
|
kthread_stop(rescuer->task);
|
|
kfree(rescuer);
|
|
}
|
|
|
|
/*
|
|
* Sanity checks - grab all the locks so that we wait for all
|
|
* in-flight operations which may do put_pwq().
|
|
*/
|
|
mutex_lock(&wq_pool_mutex);
|
|
mutex_lock(&wq->mutex);
|
|
for_each_pwq(pwq, wq) {
|
|
raw_spin_lock_irq(&pwq->pool->lock);
|
|
if (WARN_ON(pwq_busy(pwq))) {
|
|
pr_warn("%s: %s has the following busy pwq\n",
|
|
__func__, wq->name);
|
|
show_pwq(pwq);
|
|
raw_spin_unlock_irq(&pwq->pool->lock);
|
|
mutex_unlock(&wq->mutex);
|
|
mutex_unlock(&wq_pool_mutex);
|
|
show_one_workqueue(wq);
|
|
return;
|
|
}
|
|
raw_spin_unlock_irq(&pwq->pool->lock);
|
|
}
|
|
mutex_unlock(&wq->mutex);
|
|
|
|
/*
|
|
* wq list is used to freeze wq, remove from list after
|
|
* flushing is complete in case freeze races us.
|
|
*/
|
|
list_del_rcu(&wq->list);
|
|
mutex_unlock(&wq_pool_mutex);
|
|
|
|
/*
|
|
* We're the sole accessor of @wq. Directly access cpu_pwq and dfl_pwq
|
|
* to put the base refs. @wq will be auto-destroyed from the last
|
|
* pwq_put. RCU read lock prevents @wq from going away from under us.
|
|
*/
|
|
rcu_read_lock();
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
put_pwq_unlocked(unbound_pwq(wq, cpu));
|
|
RCU_INIT_POINTER(*unbound_pwq_slot(wq, cpu), NULL);
|
|
}
|
|
|
|
put_pwq_unlocked(unbound_pwq(wq, -1));
|
|
RCU_INIT_POINTER(*unbound_pwq_slot(wq, -1), NULL);
|
|
|
|
rcu_read_unlock();
|
|
}
|
|
EXPORT_SYMBOL_GPL(destroy_workqueue);
|
|
|
|
/**
|
|
* workqueue_set_max_active - adjust max_active of a workqueue
|
|
* @wq: target workqueue
|
|
* @max_active: new max_active value.
|
|
*
|
|
* Set max_active of @wq to @max_active. See the alloc_workqueue() function
|
|
* comment.
|
|
*
|
|
* CONTEXT:
|
|
* Don't call from IRQ context.
|
|
*/
|
|
void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
|
|
{
|
|
/* max_active doesn't mean anything for BH workqueues */
|
|
if (WARN_ON(wq->flags & WQ_BH))
|
|
return;
|
|
/* disallow meddling with max_active for ordered workqueues */
|
|
if (WARN_ON(wq->flags & __WQ_ORDERED))
|
|
return;
|
|
|
|
max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);
|
|
|
|
mutex_lock(&wq->mutex);
|
|
|
|
wq->saved_max_active = max_active;
|
|
if (wq->flags & WQ_UNBOUND)
|
|
wq->saved_min_active = min(wq->saved_min_active, max_active);
|
|
|
|
wq_adjust_max_active(wq);
|
|
|
|
mutex_unlock(&wq->mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(workqueue_set_max_active);
|
|
|
|
/**
|
|
* workqueue_set_min_active - adjust min_active of an unbound workqueue
|
|
* @wq: target unbound workqueue
|
|
* @min_active: new min_active value
|
|
*
|
|
* Set min_active of an unbound workqueue. Unlike other types of workqueues, an
|
|
* unbound workqueue is not guaranteed to be able to process max_active
|
|
* interdependent work items. Instead, an unbound workqueue is guaranteed to be
|
|
* able to process min_active number of interdependent work items which is
|
|
* %WQ_DFL_MIN_ACTIVE by default.
|
|
*
|
|
* Use this function to adjust the min_active value between 0 and the current
|
|
* max_active.
|
|
*/
|
|
void workqueue_set_min_active(struct workqueue_struct *wq, int min_active)
|
|
{
|
|
/* min_active is only meaningful for non-ordered unbound workqueues */
|
|
if (WARN_ON((wq->flags & (WQ_BH | WQ_UNBOUND | __WQ_ORDERED)) !=
|
|
WQ_UNBOUND))
|
|
return;
|
|
|
|
mutex_lock(&wq->mutex);
|
|
wq->saved_min_active = clamp(min_active, 0, wq->saved_max_active);
|
|
wq_adjust_max_active(wq);
|
|
mutex_unlock(&wq->mutex);
|
|
}
|
|
|
|
/**
|
|
* current_work - retrieve %current task's work struct
|
|
*
|
|
* Determine if %current task is a workqueue worker and what it's working on.
|
|
* Useful to find out the context that the %current task is running in.
|
|
*
|
|
* Return: work struct if %current task is a workqueue worker, %NULL otherwise.
|
|
*/
|
|
struct work_struct *current_work(void)
|
|
{
|
|
struct worker *worker = current_wq_worker();
|
|
|
|
return worker ? worker->current_work : NULL;
|
|
}
|
|
EXPORT_SYMBOL(current_work);
|
|
|
|
/**
|
|
* current_is_workqueue_rescuer - is %current workqueue rescuer?
|
|
*
|
|
* Determine whether %current is a workqueue rescuer. Can be used from
|
|
* work functions to determine whether it's being run off the rescuer task.
|
|
*
|
|
* Return: %true if %current is a workqueue rescuer. %false otherwise.
|
|
*/
|
|
bool current_is_workqueue_rescuer(void)
|
|
{
|
|
struct worker *worker = current_wq_worker();
|
|
|
|
return worker && worker->rescue_wq;
|
|
}
|
|
|
|
/**
|
|
* workqueue_congested - test whether a workqueue is congested
|
|
* @cpu: CPU in question
|
|
* @wq: target workqueue
|
|
*
|
|
* Test whether @wq's cpu workqueue for @cpu is congested. There is
|
|
* no synchronization around this function and the test result is
|
|
* unreliable and only useful as advisory hints or for debugging.
|
|
*
|
|
* If @cpu is WORK_CPU_UNBOUND, the test is performed on the local CPU.
|
|
*
|
|
* With the exception of ordered workqueues, all workqueues have per-cpu
|
|
* pool_workqueues, each with its own congested state. A workqueue being
|
|
* congested on one CPU doesn't mean that the workqueue is contested on any
|
|
* other CPUs.
|
|
*
|
|
* Return:
|
|
* %true if congested, %false otherwise.
|
|
*/
|
|
bool workqueue_congested(int cpu, struct workqueue_struct *wq)
|
|
{
|
|
struct pool_workqueue *pwq;
|
|
bool ret;
|
|
|
|
rcu_read_lock();
|
|
preempt_disable();
|
|
|
|
if (cpu == WORK_CPU_UNBOUND)
|
|
cpu = smp_processor_id();
|
|
|
|
pwq = *per_cpu_ptr(wq->cpu_pwq, cpu);
|
|
ret = !list_empty(&pwq->inactive_works);
|
|
|
|
preempt_enable();
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(workqueue_congested);
|
|
|
|
/**
|
|
* work_busy - test whether a work is currently pending or running
|
|
* @work: the work to be tested
|
|
*
|
|
* Test whether @work is currently pending or running. There is no
|
|
* synchronization around this function and the test result is
|
|
* unreliable and only useful as advisory hints or for debugging.
|
|
*
|
|
* Return:
|
|
* OR'd bitmask of WORK_BUSY_* bits.
|
|
*/
|
|
unsigned int work_busy(struct work_struct *work)
|
|
{
|
|
struct worker_pool *pool;
|
|
unsigned long irq_flags;
|
|
unsigned int ret = 0;
|
|
|
|
if (work_pending(work))
|
|
ret |= WORK_BUSY_PENDING;
|
|
|
|
rcu_read_lock();
|
|
pool = get_work_pool(work);
|
|
if (pool) {
|
|
raw_spin_lock_irqsave(&pool->lock, irq_flags);
|
|
if (find_worker_executing_work(pool, work))
|
|
ret |= WORK_BUSY_RUNNING;
|
|
raw_spin_unlock_irqrestore(&pool->lock, irq_flags);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(work_busy);
|
|
|
|
/**
|
|
* set_worker_desc - set description for the current work item
|
|
* @fmt: printf-style format string
|
|
* @...: arguments for the format string
|
|
*
|
|
* This function can be called by a running work function to describe what
|
|
* the work item is about. If the worker task gets dumped, this
|
|
* information will be printed out together to help debugging. The
|
|
* description can be at most WORKER_DESC_LEN including the trailing '\0'.
|
|
*/
|
|
void set_worker_desc(const char *fmt, ...)
|
|
{
|
|
struct worker *worker = current_wq_worker();
|
|
va_list args;
|
|
|
|
if (worker) {
|
|
va_start(args, fmt);
|
|
vsnprintf(worker->desc, sizeof(worker->desc), fmt, args);
|
|
va_end(args);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(set_worker_desc);
|
|
|
|
/**
|
|
* print_worker_info - print out worker information and description
|
|
* @log_lvl: the log level to use when printing
|
|
* @task: target task
|
|
*
|
|
* If @task is a worker and currently executing a work item, print out the
|
|
* name of the workqueue being serviced and worker description set with
|
|
* set_worker_desc() by the currently executing work item.
|
|
*
|
|
* This function can be safely called on any task as long as the
|
|
* task_struct itself is accessible. While safe, this function isn't
|
|
* synchronized and may print out mixups or garbages of limited length.
|
|
*/
|
|
void print_worker_info(const char *log_lvl, struct task_struct *task)
|
|
{
|
|
work_func_t *fn = NULL;
|
|
char name[WQ_NAME_LEN] = { };
|
|
char desc[WORKER_DESC_LEN] = { };
|
|
struct pool_workqueue *pwq = NULL;
|
|
struct workqueue_struct *wq = NULL;
|
|
struct worker *worker;
|
|
|
|
if (!(task->flags & PF_WQ_WORKER))
|
|
return;
|
|
|
|
/*
|
|
* This function is called without any synchronization and @task
|
|
* could be in any state. Be careful with dereferences.
|
|
*/
|
|
worker = kthread_probe_data(task);
|
|
|
|
/*
|
|
* Carefully copy the associated workqueue's workfn, name and desc.
|
|
* Keep the original last '\0' in case the original is garbage.
|
|
*/
|
|
copy_from_kernel_nofault(&fn, &worker->current_func, sizeof(fn));
|
|
copy_from_kernel_nofault(&pwq, &worker->current_pwq, sizeof(pwq));
|
|
copy_from_kernel_nofault(&wq, &pwq->wq, sizeof(wq));
|
|
copy_from_kernel_nofault(name, wq->name, sizeof(name) - 1);
|
|
copy_from_kernel_nofault(desc, worker->desc, sizeof(desc) - 1);
|
|
|
|
if (fn || name[0] || desc[0]) {
|
|
printk("%sWorkqueue: %s %ps", log_lvl, name, fn);
|
|
if (strcmp(name, desc))
|
|
pr_cont(" (%s)", desc);
|
|
pr_cont("\n");
|
|
}
|
|
}
|
|
|
|
static void pr_cont_pool_info(struct worker_pool *pool)
|
|
{
|
|
pr_cont(" cpus=%*pbl", nr_cpumask_bits, pool->attrs->cpumask);
|
|
if (pool->node != NUMA_NO_NODE)
|
|
pr_cont(" node=%d", pool->node);
|
|
pr_cont(" flags=0x%x", pool->flags);
|
|
if (pool->flags & POOL_BH)
|
|
pr_cont(" bh%s",
|
|
pool->attrs->nice == HIGHPRI_NICE_LEVEL ? "-hi" : "");
|
|
else
|
|
pr_cont(" nice=%d", pool->attrs->nice);
|
|
}
|
|
|
|
static void pr_cont_worker_id(struct worker *worker)
|
|
{
|
|
struct worker_pool *pool = worker->pool;
|
|
|
|
if (pool->flags & WQ_BH)
|
|
pr_cont("bh%s",
|
|
pool->attrs->nice == HIGHPRI_NICE_LEVEL ? "-hi" : "");
|
|
else
|
|
pr_cont("%d%s", task_pid_nr(worker->task),
|
|
worker->rescue_wq ? "(RESCUER)" : "");
|
|
}
|
|
|
|
struct pr_cont_work_struct {
|
|
bool comma;
|
|
work_func_t func;
|
|
long ctr;
|
|
};
|
|
|
|
static void pr_cont_work_flush(bool comma, work_func_t func, struct pr_cont_work_struct *pcwsp)
|
|
{
|
|
if (!pcwsp->ctr)
|
|
goto out_record;
|
|
if (func == pcwsp->func) {
|
|
pcwsp->ctr++;
|
|
return;
|
|
}
|
|
if (pcwsp->ctr == 1)
|
|
pr_cont("%s %ps", pcwsp->comma ? "," : "", pcwsp->func);
|
|
else
|
|
pr_cont("%s %ld*%ps", pcwsp->comma ? "," : "", pcwsp->ctr, pcwsp->func);
|
|
pcwsp->ctr = 0;
|
|
out_record:
|
|
if ((long)func == -1L)
|
|
return;
|
|
pcwsp->comma = comma;
|
|
pcwsp->func = func;
|
|
pcwsp->ctr = 1;
|
|
}
|
|
|
|
static void pr_cont_work(bool comma, struct work_struct *work, struct pr_cont_work_struct *pcwsp)
|
|
{
|
|
if (work->func == wq_barrier_func) {
|
|
struct wq_barrier *barr;
|
|
|
|
barr = container_of(work, struct wq_barrier, work);
|
|
|
|
pr_cont_work_flush(comma, (work_func_t)-1, pcwsp);
|
|
pr_cont("%s BAR(%d)", comma ? "," : "",
|
|
task_pid_nr(barr->task));
|
|
} else {
|
|
if (!comma)
|
|
pr_cont_work_flush(comma, (work_func_t)-1, pcwsp);
|
|
pr_cont_work_flush(comma, work->func, pcwsp);
|
|
}
|
|
}
|
|
|
|
static void show_pwq(struct pool_workqueue *pwq)
|
|
{
|
|
struct pr_cont_work_struct pcws = { .ctr = 0, };
|
|
struct worker_pool *pool = pwq->pool;
|
|
struct work_struct *work;
|
|
struct worker *worker;
|
|
bool has_in_flight = false, has_pending = false;
|
|
int bkt;
|
|
|
|
pr_info(" pwq %d:", pool->id);
|
|
pr_cont_pool_info(pool);
|
|
|
|
pr_cont(" active=%d refcnt=%d%s\n",
|
|
pwq->nr_active, pwq->refcnt,
|
|
!list_empty(&pwq->mayday_node) ? " MAYDAY" : "");
|
|
|
|
hash_for_each(pool->busy_hash, bkt, worker, hentry) {
|
|
if (worker->current_pwq == pwq) {
|
|
has_in_flight = true;
|
|
break;
|
|
}
|
|
}
|
|
if (has_in_flight) {
|
|
bool comma = false;
|
|
|
|
pr_info(" in-flight:");
|
|
hash_for_each(pool->busy_hash, bkt, worker, hentry) {
|
|
if (worker->current_pwq != pwq)
|
|
continue;
|
|
|
|
pr_cont(" %s", comma ? "," : "");
|
|
pr_cont_worker_id(worker);
|
|
pr_cont(":%ps", worker->current_func);
|
|
list_for_each_entry(work, &worker->scheduled, entry)
|
|
pr_cont_work(false, work, &pcws);
|
|
pr_cont_work_flush(comma, (work_func_t)-1L, &pcws);
|
|
comma = true;
|
|
}
|
|
pr_cont("\n");
|
|
}
|
|
|
|
list_for_each_entry(work, &pool->worklist, entry) {
|
|
if (get_work_pwq(work) == pwq) {
|
|
has_pending = true;
|
|
break;
|
|
}
|
|
}
|
|
if (has_pending) {
|
|
bool comma = false;
|
|
|
|
pr_info(" pending:");
|
|
list_for_each_entry(work, &pool->worklist, entry) {
|
|
if (get_work_pwq(work) != pwq)
|
|
continue;
|
|
|
|
pr_cont_work(comma, work, &pcws);
|
|
comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED);
|
|
}
|
|
pr_cont_work_flush(comma, (work_func_t)-1L, &pcws);
|
|
pr_cont("\n");
|
|
}
|
|
|
|
if (!list_empty(&pwq->inactive_works)) {
|
|
bool comma = false;
|
|
|
|
pr_info(" inactive:");
|
|
list_for_each_entry(work, &pwq->inactive_works, entry) {
|
|
pr_cont_work(comma, work, &pcws);
|
|
comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED);
|
|
}
|
|
pr_cont_work_flush(comma, (work_func_t)-1L, &pcws);
|
|
pr_cont("\n");
|
|
}
|
|
}
|
|
|
|
/**
|
|
* show_one_workqueue - dump state of specified workqueue
|
|
* @wq: workqueue whose state will be printed
|
|
*/
|
|
void show_one_workqueue(struct workqueue_struct *wq)
|
|
{
|
|
struct pool_workqueue *pwq;
|
|
bool idle = true;
|
|
unsigned long irq_flags;
|
|
|
|
for_each_pwq(pwq, wq) {
|
|
if (!pwq_is_empty(pwq)) {
|
|
idle = false;
|
|
break;
|
|
}
|
|
}
|
|
if (idle) /* Nothing to print for idle workqueue */
|
|
return;
|
|
|
|
pr_info("workqueue %s: flags=0x%x\n", wq->name, wq->flags);
|
|
|
|
for_each_pwq(pwq, wq) {
|
|
raw_spin_lock_irqsave(&pwq->pool->lock, irq_flags);
|
|
if (!pwq_is_empty(pwq)) {
|
|
/*
|
|
* Defer printing to avoid deadlocks in console
|
|
* drivers that queue work while holding locks
|
|
* also taken in their write paths.
|
|
*/
|
|
printk_deferred_enter();
|
|
show_pwq(pwq);
|
|
printk_deferred_exit();
|
|
}
|
|
raw_spin_unlock_irqrestore(&pwq->pool->lock, irq_flags);
|
|
/*
|
|
* We could be printing a lot from atomic context, e.g.
|
|
* sysrq-t -> show_all_workqueues(). Avoid triggering
|
|
* hard lockup.
|
|
*/
|
|
touch_nmi_watchdog();
|
|
}
|
|
|
|
}
|
|
|
|
/**
|
|
* show_one_worker_pool - dump state of specified worker pool
|
|
* @pool: worker pool whose state will be printed
|
|
*/
|
|
static void show_one_worker_pool(struct worker_pool *pool)
|
|
{
|
|
struct worker *worker;
|
|
bool first = true;
|
|
unsigned long irq_flags;
|
|
unsigned long hung = 0;
|
|
|
|
raw_spin_lock_irqsave(&pool->lock, irq_flags);
|
|
if (pool->nr_workers == pool->nr_idle)
|
|
goto next_pool;
|
|
|
|
/* How long the first pending work is waiting for a worker. */
|
|
if (!list_empty(&pool->worklist))
|
|
hung = jiffies_to_msecs(jiffies - pool->watchdog_ts) / 1000;
|
|
|
|
/*
|
|
* Defer printing to avoid deadlocks in console drivers that
|
|
* queue work while holding locks also taken in their write
|
|
* paths.
|
|
*/
|
|
printk_deferred_enter();
|
|
pr_info("pool %d:", pool->id);
|
|
pr_cont_pool_info(pool);
|
|
pr_cont(" hung=%lus workers=%d", hung, pool->nr_workers);
|
|
if (pool->manager)
|
|
pr_cont(" manager: %d",
|
|
task_pid_nr(pool->manager->task));
|
|
list_for_each_entry(worker, &pool->idle_list, entry) {
|
|
pr_cont(" %s", first ? "idle: " : "");
|
|
pr_cont_worker_id(worker);
|
|
first = false;
|
|
}
|
|
pr_cont("\n");
|
|
printk_deferred_exit();
|
|
next_pool:
|
|
raw_spin_unlock_irqrestore(&pool->lock, irq_flags);
|
|
/*
|
|
* We could be printing a lot from atomic context, e.g.
|
|
* sysrq-t -> show_all_workqueues(). Avoid triggering
|
|
* hard lockup.
|
|
*/
|
|
touch_nmi_watchdog();
|
|
|
|
}
|
|
|
|
/**
|
|
* show_all_workqueues - dump workqueue state
|
|
*
|
|
* Called from a sysrq handler and prints out all busy workqueues and pools.
|
|
*/
|
|
void show_all_workqueues(void)
|
|
{
|
|
struct workqueue_struct *wq;
|
|
struct worker_pool *pool;
|
|
int pi;
|
|
|
|
rcu_read_lock();
|
|
|
|
pr_info("Showing busy workqueues and worker pools:\n");
|
|
|
|
list_for_each_entry_rcu(wq, &workqueues, list)
|
|
show_one_workqueue(wq);
|
|
|
|
for_each_pool(pool, pi)
|
|
show_one_worker_pool(pool);
|
|
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
/**
|
|
* show_freezable_workqueues - dump freezable workqueue state
|
|
*
|
|
* Called from try_to_freeze_tasks() and prints out all freezable workqueues
|
|
* still busy.
|
|
*/
|
|
void show_freezable_workqueues(void)
|
|
{
|
|
struct workqueue_struct *wq;
|
|
|
|
rcu_read_lock();
|
|
|
|
pr_info("Showing freezable workqueues that are still busy:\n");
|
|
|
|
list_for_each_entry_rcu(wq, &workqueues, list) {
|
|
if (!(wq->flags & WQ_FREEZABLE))
|
|
continue;
|
|
show_one_workqueue(wq);
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
/* used to show worker information through /proc/PID/{comm,stat,status} */
|
|
void wq_worker_comm(char *buf, size_t size, struct task_struct *task)
|
|
{
|
|
int off;
|
|
|
|
/* always show the actual comm */
|
|
off = strscpy(buf, task->comm, size);
|
|
if (off < 0)
|
|
return;
|
|
|
|
/* stabilize PF_WQ_WORKER and worker pool association */
|
|
mutex_lock(&wq_pool_attach_mutex);
|
|
|
|
if (task->flags & PF_WQ_WORKER) {
|
|
struct worker *worker = kthread_data(task);
|
|
struct worker_pool *pool = worker->pool;
|
|
|
|
if (pool) {
|
|
raw_spin_lock_irq(&pool->lock);
|
|
/*
|
|
* ->desc tracks information (wq name or
|
|
* set_worker_desc()) for the latest execution. If
|
|
* current, prepend '+', otherwise '-'.
|
|
*/
|
|
if (worker->desc[0] != '\0') {
|
|
if (worker->current_work)
|
|
scnprintf(buf + off, size - off, "+%s",
|
|
worker->desc);
|
|
else
|
|
scnprintf(buf + off, size - off, "-%s",
|
|
worker->desc);
|
|
}
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
}
|
|
}
|
|
|
|
mutex_unlock(&wq_pool_attach_mutex);
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
/*
|
|
* CPU hotplug.
|
|
*
|
|
* There are two challenges in supporting CPU hotplug. Firstly, there
|
|
* are a lot of assumptions on strong associations among work, pwq and
|
|
* pool which make migrating pending and scheduled works very
|
|
* difficult to implement without impacting hot paths. Secondly,
|
|
* worker pools serve mix of short, long and very long running works making
|
|
* blocked draining impractical.
|
|
*
|
|
* This is solved by allowing the pools to be disassociated from the CPU
|
|
* running as an unbound one and allowing it to be reattached later if the
|
|
* cpu comes back online.
|
|
*/
|
|
|
|
static void unbind_workers(int cpu)
|
|
{
|
|
struct worker_pool *pool;
|
|
struct worker *worker;
|
|
|
|
for_each_cpu_worker_pool(pool, cpu) {
|
|
mutex_lock(&wq_pool_attach_mutex);
|
|
raw_spin_lock_irq(&pool->lock);
|
|
|
|
/*
|
|
* We've blocked all attach/detach operations. Make all workers
|
|
* unbound and set DISASSOCIATED. Before this, all workers
|
|
* must be on the cpu. After this, they may become diasporas.
|
|
* And the preemption disabled section in their sched callbacks
|
|
* are guaranteed to see WORKER_UNBOUND since the code here
|
|
* is on the same cpu.
|
|
*/
|
|
for_each_pool_worker(worker, pool)
|
|
worker->flags |= WORKER_UNBOUND;
|
|
|
|
pool->flags |= POOL_DISASSOCIATED;
|
|
|
|
/*
|
|
* The handling of nr_running in sched callbacks are disabled
|
|
* now. Zap nr_running. After this, nr_running stays zero and
|
|
* need_more_worker() and keep_working() are always true as
|
|
* long as the worklist is not empty. This pool now behaves as
|
|
* an unbound (in terms of concurrency management) pool which
|
|
* are served by workers tied to the pool.
|
|
*/
|
|
pool->nr_running = 0;
|
|
|
|
/*
|
|
* With concurrency management just turned off, a busy
|
|
* worker blocking could lead to lengthy stalls. Kick off
|
|
* unbound chain execution of currently pending work items.
|
|
*/
|
|
kick_pool(pool);
|
|
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
|
|
for_each_pool_worker(worker, pool)
|
|
unbind_worker(worker);
|
|
|
|
mutex_unlock(&wq_pool_attach_mutex);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* rebind_workers - rebind all workers of a pool to the associated CPU
|
|
* @pool: pool of interest
|
|
*
|
|
* @pool->cpu is coming online. Rebind all workers to the CPU.
|
|
*/
|
|
static void rebind_workers(struct worker_pool *pool)
|
|
{
|
|
struct worker *worker;
|
|
|
|
lockdep_assert_held(&wq_pool_attach_mutex);
|
|
|
|
/*
|
|
* Restore CPU affinity of all workers. As all idle workers should
|
|
* be on the run-queue of the associated CPU before any local
|
|
* wake-ups for concurrency management happen, restore CPU affinity
|
|
* of all workers first and then clear UNBOUND. As we're called
|
|
* from CPU_ONLINE, the following shouldn't fail.
|
|
*/
|
|
for_each_pool_worker(worker, pool) {
|
|
kthread_set_per_cpu(worker->task, pool->cpu);
|
|
WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task,
|
|
pool_allowed_cpus(pool)) < 0);
|
|
}
|
|
|
|
raw_spin_lock_irq(&pool->lock);
|
|
|
|
pool->flags &= ~POOL_DISASSOCIATED;
|
|
|
|
for_each_pool_worker(worker, pool) {
|
|
unsigned int worker_flags = worker->flags;
|
|
|
|
/*
|
|
* We want to clear UNBOUND but can't directly call
|
|
* worker_clr_flags() or adjust nr_running. Atomically
|
|
* replace UNBOUND with another NOT_RUNNING flag REBOUND.
|
|
* @worker will clear REBOUND using worker_clr_flags() when
|
|
* it initiates the next execution cycle thus restoring
|
|
* concurrency management. Note that when or whether
|
|
* @worker clears REBOUND doesn't affect correctness.
|
|
*
|
|
* WRITE_ONCE() is necessary because @worker->flags may be
|
|
* tested without holding any lock in
|
|
* wq_worker_running(). Without it, NOT_RUNNING test may
|
|
* fail incorrectly leading to premature concurrency
|
|
* management operations.
|
|
*/
|
|
WARN_ON_ONCE(!(worker_flags & WORKER_UNBOUND));
|
|
worker_flags |= WORKER_REBOUND;
|
|
worker_flags &= ~WORKER_UNBOUND;
|
|
WRITE_ONCE(worker->flags, worker_flags);
|
|
}
|
|
|
|
raw_spin_unlock_irq(&pool->lock);
|
|
}
|
|
|
|
/**
|
|
* restore_unbound_workers_cpumask - restore cpumask of unbound workers
|
|
* @pool: unbound pool of interest
|
|
* @cpu: the CPU which is coming up
|
|
*
|
|
* An unbound pool may end up with a cpumask which doesn't have any online
|
|
* CPUs. When a worker of such pool get scheduled, the scheduler resets
|
|
* its cpus_allowed. If @cpu is in @pool's cpumask which didn't have any
|
|
* online CPU before, cpus_allowed of all its workers should be restored.
|
|
*/
|
|
static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu)
|
|
{
|
|
static cpumask_t cpumask;
|
|
struct worker *worker;
|
|
|
|
lockdep_assert_held(&wq_pool_attach_mutex);
|
|
|
|
/* is @cpu allowed for @pool? */
|
|
if (!cpumask_test_cpu(cpu, pool->attrs->cpumask))
|
|
return;
|
|
|
|
cpumask_and(&cpumask, pool->attrs->cpumask, cpu_online_mask);
|
|
|
|
/* as we're called from CPU_ONLINE, the following shouldn't fail */
|
|
for_each_pool_worker(worker, pool)
|
|
WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, &cpumask) < 0);
|
|
}
|
|
|
|
int workqueue_prepare_cpu(unsigned int cpu)
|
|
{
|
|
struct worker_pool *pool;
|
|
|
|
for_each_cpu_worker_pool(pool, cpu) {
|
|
if (pool->nr_workers)
|
|
continue;
|
|
if (!create_worker(pool))
|
|
return -ENOMEM;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int workqueue_online_cpu(unsigned int cpu)
|
|
{
|
|
struct worker_pool *pool;
|
|
struct workqueue_struct *wq;
|
|
int pi;
|
|
|
|
mutex_lock(&wq_pool_mutex);
|
|
|
|
for_each_pool(pool, pi) {
|
|
/* BH pools aren't affected by hotplug */
|
|
if (pool->flags & POOL_BH)
|
|
continue;
|
|
|
|
mutex_lock(&wq_pool_attach_mutex);
|
|
if (pool->cpu == cpu)
|
|
rebind_workers(pool);
|
|
else if (pool->cpu < 0)
|
|
restore_unbound_workers_cpumask(pool, cpu);
|
|
mutex_unlock(&wq_pool_attach_mutex);
|
|
}
|
|
|
|
/* update pod affinity of unbound workqueues */
|
|
list_for_each_entry(wq, &workqueues, list) {
|
|
struct workqueue_attrs *attrs = wq->unbound_attrs;
|
|
|
|
if (attrs) {
|
|
const struct wq_pod_type *pt = wqattrs_pod_type(attrs);
|
|
int tcpu;
|
|
|
|
for_each_cpu(tcpu, pt->pod_cpus[pt->cpu_pod[cpu]])
|
|
wq_update_pod(wq, tcpu, cpu, true);
|
|
|
|
mutex_lock(&wq->mutex);
|
|
wq_update_node_max_active(wq, -1);
|
|
mutex_unlock(&wq->mutex);
|
|
}
|
|
}
|
|
|
|
mutex_unlock(&wq_pool_mutex);
|
|
return 0;
|
|
}
|
|
|
|
int workqueue_offline_cpu(unsigned int cpu)
|
|
{
|
|
struct workqueue_struct *wq;
|
|
|
|
/* unbinding per-cpu workers should happen on the local CPU */
|
|
if (WARN_ON(cpu != smp_processor_id()))
|
|
return -1;
|
|
|
|
unbind_workers(cpu);
|
|
|
|
/* update pod affinity of unbound workqueues */
|
|
mutex_lock(&wq_pool_mutex);
|
|
list_for_each_entry(wq, &workqueues, list) {
|
|
struct workqueue_attrs *attrs = wq->unbound_attrs;
|
|
|
|
if (attrs) {
|
|
const struct wq_pod_type *pt = wqattrs_pod_type(attrs);
|
|
int tcpu;
|
|
|
|
for_each_cpu(tcpu, pt->pod_cpus[pt->cpu_pod[cpu]])
|
|
wq_update_pod(wq, tcpu, cpu, false);
|
|
|
|
mutex_lock(&wq->mutex);
|
|
wq_update_node_max_active(wq, cpu);
|
|
mutex_unlock(&wq->mutex);
|
|
}
|
|
}
|
|
mutex_unlock(&wq_pool_mutex);
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct work_for_cpu {
|
|
struct work_struct work;
|
|
long (*fn)(void *);
|
|
void *arg;
|
|
long ret;
|
|
};
|
|
|
|
static void work_for_cpu_fn(struct work_struct *work)
|
|
{
|
|
struct work_for_cpu *wfc = container_of(work, struct work_for_cpu, work);
|
|
|
|
wfc->ret = wfc->fn(wfc->arg);
|
|
}
|
|
|
|
/**
|
|
* work_on_cpu_key - run a function in thread context on a particular cpu
|
|
* @cpu: the cpu to run on
|
|
* @fn: the function to run
|
|
* @arg: the function arg
|
|
* @key: The lock class key for lock debugging purposes
|
|
*
|
|
* It is up to the caller to ensure that the cpu doesn't go offline.
|
|
* The caller must not hold any locks which would prevent @fn from completing.
|
|
*
|
|
* Return: The value @fn returns.
|
|
*/
|
|
long work_on_cpu_key(int cpu, long (*fn)(void *),
|
|
void *arg, struct lock_class_key *key)
|
|
{
|
|
struct work_for_cpu wfc = { .fn = fn, .arg = arg };
|
|
|
|
INIT_WORK_ONSTACK_KEY(&wfc.work, work_for_cpu_fn, key);
|
|
schedule_work_on(cpu, &wfc.work);
|
|
flush_work(&wfc.work);
|
|
destroy_work_on_stack(&wfc.work);
|
|
return wfc.ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(work_on_cpu_key);
|
|
|
|
/**
|
|
* work_on_cpu_safe_key - run a function in thread context on a particular cpu
|
|
* @cpu: the cpu to run on
|
|
* @fn: the function to run
|
|
* @arg: the function argument
|
|
* @key: The lock class key for lock debugging purposes
|
|
*
|
|
* Disables CPU hotplug and calls work_on_cpu(). The caller must not hold
|
|
* any locks which would prevent @fn from completing.
|
|
*
|
|
* Return: The value @fn returns.
|
|
*/
|
|
long work_on_cpu_safe_key(int cpu, long (*fn)(void *),
|
|
void *arg, struct lock_class_key *key)
|
|
{
|
|
long ret = -ENODEV;
|
|
|
|
cpus_read_lock();
|
|
if (cpu_online(cpu))
|
|
ret = work_on_cpu_key(cpu, fn, arg, key);
|
|
cpus_read_unlock();
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(work_on_cpu_safe_key);
|
|
#endif /* CONFIG_SMP */
|
|
|
|
#ifdef CONFIG_FREEZER
|
|
|
|
/**
|
|
* freeze_workqueues_begin - begin freezing workqueues
|
|
*
|
|
* Start freezing workqueues. After this function returns, all freezable
|
|
* workqueues will queue new works to their inactive_works list instead of
|
|
* pool->worklist.
|
|
*
|
|
* CONTEXT:
|
|
* Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's.
|
|
*/
|
|
void freeze_workqueues_begin(void)
|
|
{
|
|
struct workqueue_struct *wq;
|
|
|
|
mutex_lock(&wq_pool_mutex);
|
|
|
|
WARN_ON_ONCE(workqueue_freezing);
|
|
workqueue_freezing = true;
|
|
|
|
list_for_each_entry(wq, &workqueues, list) {
|
|
mutex_lock(&wq->mutex);
|
|
wq_adjust_max_active(wq);
|
|
mutex_unlock(&wq->mutex);
|
|
}
|
|
|
|
mutex_unlock(&wq_pool_mutex);
|
|
}
|
|
|
|
/**
|
|
* freeze_workqueues_busy - are freezable workqueues still busy?
|
|
*
|
|
* Check whether freezing is complete. This function must be called
|
|
* between freeze_workqueues_begin() and thaw_workqueues().
|
|
*
|
|
* CONTEXT:
|
|
* Grabs and releases wq_pool_mutex.
|
|
*
|
|
* Return:
|
|
* %true if some freezable workqueues are still busy. %false if freezing
|
|
* is complete.
|
|
*/
|
|
bool freeze_workqueues_busy(void)
|
|
{
|
|
bool busy = false;
|
|
struct workqueue_struct *wq;
|
|
struct pool_workqueue *pwq;
|
|
|
|
mutex_lock(&wq_pool_mutex);
|
|
|
|
WARN_ON_ONCE(!workqueue_freezing);
|
|
|
|
list_for_each_entry(wq, &workqueues, list) {
|
|
if (!(wq->flags & WQ_FREEZABLE))
|
|
continue;
|
|
/*
|
|
* nr_active is monotonically decreasing. It's safe
|
|
* to peek without lock.
|
|
*/
|
|
rcu_read_lock();
|
|
for_each_pwq(pwq, wq) {
|
|
WARN_ON_ONCE(pwq->nr_active < 0);
|
|
if (pwq->nr_active) {
|
|
busy = true;
|
|
rcu_read_unlock();
|
|
goto out_unlock;
|
|
}
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
out_unlock:
|
|
mutex_unlock(&wq_pool_mutex);
|
|
return busy;
|
|
}
|
|
|
|
/**
|
|
* thaw_workqueues - thaw workqueues
|
|
*
|
|
* Thaw workqueues. Normal queueing is restored and all collected
|
|
* frozen works are transferred to their respective pool worklists.
|
|
*
|
|
* CONTEXT:
|
|
* Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's.
|
|
*/
|
|
void thaw_workqueues(void)
|
|
{
|
|
struct workqueue_struct *wq;
|
|
|
|
mutex_lock(&wq_pool_mutex);
|
|
|
|
if (!workqueue_freezing)
|
|
goto out_unlock;
|
|
|
|
workqueue_freezing = false;
|
|
|
|
/* restore max_active and repopulate worklist */
|
|
list_for_each_entry(wq, &workqueues, list) {
|
|
mutex_lock(&wq->mutex);
|
|
wq_adjust_max_active(wq);
|
|
mutex_unlock(&wq->mutex);
|
|
}
|
|
|
|
out_unlock:
|
|
mutex_unlock(&wq_pool_mutex);
|
|
}
|
|
#endif /* CONFIG_FREEZER */
|
|
|
|
static int workqueue_apply_unbound_cpumask(const cpumask_var_t unbound_cpumask)
|
|
{
|
|
LIST_HEAD(ctxs);
|
|
int ret = 0;
|
|
struct workqueue_struct *wq;
|
|
struct apply_wqattrs_ctx *ctx, *n;
|
|
|
|
lockdep_assert_held(&wq_pool_mutex);
|
|
|
|
list_for_each_entry(wq, &workqueues, list) {
|
|
if (!(wq->flags & WQ_UNBOUND) || (wq->flags & __WQ_DESTROYING))
|
|
continue;
|
|
|
|
ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs, unbound_cpumask);
|
|
if (IS_ERR(ctx)) {
|
|
ret = PTR_ERR(ctx);
|
|
break;
|
|
}
|
|
|
|
list_add_tail(&ctx->list, &ctxs);
|
|
}
|
|
|
|
list_for_each_entry_safe(ctx, n, &ctxs, list) {
|
|
if (!ret)
|
|
apply_wqattrs_commit(ctx);
|
|
apply_wqattrs_cleanup(ctx);
|
|
}
|
|
|
|
if (!ret) {
|
|
mutex_lock(&wq_pool_attach_mutex);
|
|
cpumask_copy(wq_unbound_cpumask, unbound_cpumask);
|
|
mutex_unlock(&wq_pool_attach_mutex);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* workqueue_unbound_exclude_cpumask - Exclude given CPUs from unbound cpumask
|
|
* @exclude_cpumask: the cpumask to be excluded from wq_unbound_cpumask
|
|
*
|
|
* This function can be called from cpuset code to provide a set of isolated
|
|
* CPUs that should be excluded from wq_unbound_cpumask. The caller must hold
|
|
* either cpus_read_lock or cpus_write_lock.
|
|
*/
|
|
int workqueue_unbound_exclude_cpumask(cpumask_var_t exclude_cpumask)
|
|
{
|
|
cpumask_var_t cpumask;
|
|
int ret = 0;
|
|
|
|
if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL))
|
|
return -ENOMEM;
|
|
|
|
lockdep_assert_cpus_held();
|
|
mutex_lock(&wq_pool_mutex);
|
|
|
|
/* Save the current isolated cpumask & export it via sysfs */
|
|
cpumask_copy(wq_isolated_cpumask, exclude_cpumask);
|
|
|
|
/*
|
|
* If the operation fails, it will fall back to
|
|
* wq_requested_unbound_cpumask which is initially set to
|
|
* (HK_TYPE_WQ ∩ HK_TYPE_DOMAIN) house keeping mask and rewritten
|
|
* by any subsequent write to workqueue/cpumask sysfs file.
|
|
*/
|
|
if (!cpumask_andnot(cpumask, wq_requested_unbound_cpumask, exclude_cpumask))
|
|
cpumask_copy(cpumask, wq_requested_unbound_cpumask);
|
|
if (!cpumask_equal(cpumask, wq_unbound_cpumask))
|
|
ret = workqueue_apply_unbound_cpumask(cpumask);
|
|
|
|
mutex_unlock(&wq_pool_mutex);
|
|
free_cpumask_var(cpumask);
|
|
return ret;
|
|
}
|
|
|
|
static int parse_affn_scope(const char *val)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < ARRAY_SIZE(wq_affn_names); i++) {
|
|
if (!strncasecmp(val, wq_affn_names[i], strlen(wq_affn_names[i])))
|
|
return i;
|
|
}
|
|
return -EINVAL;
|
|
}
|
|
|
|
static int wq_affn_dfl_set(const char *val, const struct kernel_param *kp)
|
|
{
|
|
struct workqueue_struct *wq;
|
|
int affn, cpu;
|
|
|
|
affn = parse_affn_scope(val);
|
|
if (affn < 0)
|
|
return affn;
|
|
if (affn == WQ_AFFN_DFL)
|
|
return -EINVAL;
|
|
|
|
cpus_read_lock();
|
|
mutex_lock(&wq_pool_mutex);
|
|
|
|
wq_affn_dfl = affn;
|
|
|
|
list_for_each_entry(wq, &workqueues, list) {
|
|
for_each_online_cpu(cpu) {
|
|
wq_update_pod(wq, cpu, cpu, true);
|
|
}
|
|
}
|
|
|
|
mutex_unlock(&wq_pool_mutex);
|
|
cpus_read_unlock();
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int wq_affn_dfl_get(char *buffer, const struct kernel_param *kp)
|
|
{
|
|
return scnprintf(buffer, PAGE_SIZE, "%s\n", wq_affn_names[wq_affn_dfl]);
|
|
}
|
|
|
|
static const struct kernel_param_ops wq_affn_dfl_ops = {
|
|
.set = wq_affn_dfl_set,
|
|
.get = wq_affn_dfl_get,
|
|
};
|
|
|
|
module_param_cb(default_affinity_scope, &wq_affn_dfl_ops, NULL, 0644);
|
|
|
|
#ifdef CONFIG_SYSFS
|
|
/*
|
|
* Workqueues with WQ_SYSFS flag set is visible to userland via
|
|
* /sys/bus/workqueue/devices/WQ_NAME. All visible workqueues have the
|
|
* following attributes.
|
|
*
|
|
* per_cpu RO bool : whether the workqueue is per-cpu or unbound
|
|
* max_active RW int : maximum number of in-flight work items
|
|
*
|
|
* Unbound workqueues have the following extra attributes.
|
|
*
|
|
* nice RW int : nice value of the workers
|
|
* cpumask RW mask : bitmask of allowed CPUs for the workers
|
|
* affinity_scope RW str : worker CPU affinity scope (cache, numa, none)
|
|
* affinity_strict RW bool : worker CPU affinity is strict
|
|
*/
|
|
struct wq_device {
|
|
struct workqueue_struct *wq;
|
|
struct device dev;
|
|
};
|
|
|
|
static struct workqueue_struct *dev_to_wq(struct device *dev)
|
|
{
|
|
struct wq_device *wq_dev = container_of(dev, struct wq_device, dev);
|
|
|
|
return wq_dev->wq;
|
|
}
|
|
|
|
static ssize_t per_cpu_show(struct device *dev, struct device_attribute *attr,
|
|
char *buf)
|
|
{
|
|
struct workqueue_struct *wq = dev_to_wq(dev);
|
|
|
|
return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)!(wq->flags & WQ_UNBOUND));
|
|
}
|
|
static DEVICE_ATTR_RO(per_cpu);
|
|
|
|
static ssize_t max_active_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct workqueue_struct *wq = dev_to_wq(dev);
|
|
|
|
return scnprintf(buf, PAGE_SIZE, "%d\n", wq->saved_max_active);
|
|
}
|
|
|
|
static ssize_t max_active_store(struct device *dev,
|
|
struct device_attribute *attr, const char *buf,
|
|
size_t count)
|
|
{
|
|
struct workqueue_struct *wq = dev_to_wq(dev);
|
|
int val;
|
|
|
|
if (sscanf(buf, "%d", &val) != 1 || val <= 0)
|
|
return -EINVAL;
|
|
|
|
workqueue_set_max_active(wq, val);
|
|
return count;
|
|
}
|
|
static DEVICE_ATTR_RW(max_active);
|
|
|
|
static struct attribute *wq_sysfs_attrs[] = {
|
|
&dev_attr_per_cpu.attr,
|
|
&dev_attr_max_active.attr,
|
|
NULL,
|
|
};
|
|
ATTRIBUTE_GROUPS(wq_sysfs);
|
|
|
|
static void apply_wqattrs_lock(void)
|
|
{
|
|
/* CPUs should stay stable across pwq creations and installations */
|
|
cpus_read_lock();
|
|
mutex_lock(&wq_pool_mutex);
|
|
}
|
|
|
|
static void apply_wqattrs_unlock(void)
|
|
{
|
|
mutex_unlock(&wq_pool_mutex);
|
|
cpus_read_unlock();
|
|
}
|
|
|
|
static ssize_t wq_nice_show(struct device *dev, struct device_attribute *attr,
|
|
char *buf)
|
|
{
|
|
struct workqueue_struct *wq = dev_to_wq(dev);
|
|
int written;
|
|
|
|
mutex_lock(&wq->mutex);
|
|
written = scnprintf(buf, PAGE_SIZE, "%d\n", wq->unbound_attrs->nice);
|
|
mutex_unlock(&wq->mutex);
|
|
|
|
return written;
|
|
}
|
|
|
|
/* prepare workqueue_attrs for sysfs store operations */
|
|
static struct workqueue_attrs *wq_sysfs_prep_attrs(struct workqueue_struct *wq)
|
|
{
|
|
struct workqueue_attrs *attrs;
|
|
|
|
lockdep_assert_held(&wq_pool_mutex);
|
|
|
|
attrs = alloc_workqueue_attrs();
|
|
if (!attrs)
|
|
return NULL;
|
|
|
|
copy_workqueue_attrs(attrs, wq->unbound_attrs);
|
|
return attrs;
|
|
}
|
|
|
|
static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
struct workqueue_struct *wq = dev_to_wq(dev);
|
|
struct workqueue_attrs *attrs;
|
|
int ret = -ENOMEM;
|
|
|
|
apply_wqattrs_lock();
|
|
|
|
attrs = wq_sysfs_prep_attrs(wq);
|
|
if (!attrs)
|
|
goto out_unlock;
|
|
|
|
if (sscanf(buf, "%d", &attrs->nice) == 1 &&
|
|
attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE)
|
|
ret = apply_workqueue_attrs_locked(wq, attrs);
|
|
else
|
|
ret = -EINVAL;
|
|
|
|
out_unlock:
|
|
apply_wqattrs_unlock();
|
|
free_workqueue_attrs(attrs);
|
|
return ret ?: count;
|
|
}
|
|
|
|
static ssize_t wq_cpumask_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct workqueue_struct *wq = dev_to_wq(dev);
|
|
int written;
|
|
|
|
mutex_lock(&wq->mutex);
|
|
written = scnprintf(buf, PAGE_SIZE, "%*pb\n",
|
|
cpumask_pr_args(wq->unbound_attrs->cpumask));
|
|
mutex_unlock(&wq->mutex);
|
|
return written;
|
|
}
|
|
|
|
static ssize_t wq_cpumask_store(struct device *dev,
|
|
struct device_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
struct workqueue_struct *wq = dev_to_wq(dev);
|
|
struct workqueue_attrs *attrs;
|
|
int ret = -ENOMEM;
|
|
|
|
apply_wqattrs_lock();
|
|
|
|
attrs = wq_sysfs_prep_attrs(wq);
|
|
if (!attrs)
|
|
goto out_unlock;
|
|
|
|
ret = cpumask_parse(buf, attrs->cpumask);
|
|
if (!ret)
|
|
ret = apply_workqueue_attrs_locked(wq, attrs);
|
|
|
|
out_unlock:
|
|
apply_wqattrs_unlock();
|
|
free_workqueue_attrs(attrs);
|
|
return ret ?: count;
|
|
}
|
|
|
|
static ssize_t wq_affn_scope_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct workqueue_struct *wq = dev_to_wq(dev);
|
|
int written;
|
|
|
|
mutex_lock(&wq->mutex);
|
|
if (wq->unbound_attrs->affn_scope == WQ_AFFN_DFL)
|
|
written = scnprintf(buf, PAGE_SIZE, "%s (%s)\n",
|
|
wq_affn_names[WQ_AFFN_DFL],
|
|
wq_affn_names[wq_affn_dfl]);
|
|
else
|
|
written = scnprintf(buf, PAGE_SIZE, "%s\n",
|
|
wq_affn_names[wq->unbound_attrs->affn_scope]);
|
|
mutex_unlock(&wq->mutex);
|
|
|
|
return written;
|
|
}
|
|
|
|
static ssize_t wq_affn_scope_store(struct device *dev,
|
|
struct device_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
struct workqueue_struct *wq = dev_to_wq(dev);
|
|
struct workqueue_attrs *attrs;
|
|
int affn, ret = -ENOMEM;
|
|
|
|
affn = parse_affn_scope(buf);
|
|
if (affn < 0)
|
|
return affn;
|
|
|
|
apply_wqattrs_lock();
|
|
attrs = wq_sysfs_prep_attrs(wq);
|
|
if (attrs) {
|
|
attrs->affn_scope = affn;
|
|
ret = apply_workqueue_attrs_locked(wq, attrs);
|
|
}
|
|
apply_wqattrs_unlock();
|
|
free_workqueue_attrs(attrs);
|
|
return ret ?: count;
|
|
}
|
|
|
|
static ssize_t wq_affinity_strict_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct workqueue_struct *wq = dev_to_wq(dev);
|
|
|
|
return scnprintf(buf, PAGE_SIZE, "%d\n",
|
|
wq->unbound_attrs->affn_strict);
|
|
}
|
|
|
|
static ssize_t wq_affinity_strict_store(struct device *dev,
|
|
struct device_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
struct workqueue_struct *wq = dev_to_wq(dev);
|
|
struct workqueue_attrs *attrs;
|
|
int v, ret = -ENOMEM;
|
|
|
|
if (sscanf(buf, "%d", &v) != 1)
|
|
return -EINVAL;
|
|
|
|
apply_wqattrs_lock();
|
|
attrs = wq_sysfs_prep_attrs(wq);
|
|
if (attrs) {
|
|
attrs->affn_strict = (bool)v;
|
|
ret = apply_workqueue_attrs_locked(wq, attrs);
|
|
}
|
|
apply_wqattrs_unlock();
|
|
free_workqueue_attrs(attrs);
|
|
return ret ?: count;
|
|
}
|
|
|
|
static struct device_attribute wq_sysfs_unbound_attrs[] = {
|
|
__ATTR(nice, 0644, wq_nice_show, wq_nice_store),
|
|
__ATTR(cpumask, 0644, wq_cpumask_show, wq_cpumask_store),
|
|
__ATTR(affinity_scope, 0644, wq_affn_scope_show, wq_affn_scope_store),
|
|
__ATTR(affinity_strict, 0644, wq_affinity_strict_show, wq_affinity_strict_store),
|
|
__ATTR_NULL,
|
|
};
|
|
|
|
static const struct bus_type wq_subsys = {
|
|
.name = "workqueue",
|
|
.dev_groups = wq_sysfs_groups,
|
|
};
|
|
|
|
/**
|
|
* workqueue_set_unbound_cpumask - Set the low-level unbound cpumask
|
|
* @cpumask: the cpumask to set
|
|
*
|
|
* The low-level workqueues cpumask is a global cpumask that limits
|
|
* the affinity of all unbound workqueues. This function check the @cpumask
|
|
* and apply it to all unbound workqueues and updates all pwqs of them.
|
|
*
|
|
* Return: 0 - Success
|
|
* -EINVAL - Invalid @cpumask
|
|
* -ENOMEM - Failed to allocate memory for attrs or pwqs.
|
|
*/
|
|
static int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
|
|
{
|
|
int ret = -EINVAL;
|
|
|
|
/*
|
|
* Not excluding isolated cpus on purpose.
|
|
* If the user wishes to include them, we allow that.
|
|
*/
|
|
cpumask_and(cpumask, cpumask, cpu_possible_mask);
|
|
if (!cpumask_empty(cpumask)) {
|
|
apply_wqattrs_lock();
|
|
cpumask_copy(wq_requested_unbound_cpumask, cpumask);
|
|
if (cpumask_equal(cpumask, wq_unbound_cpumask)) {
|
|
ret = 0;
|
|
goto out_unlock;
|
|
}
|
|
|
|
ret = workqueue_apply_unbound_cpumask(cpumask);
|
|
|
|
out_unlock:
|
|
apply_wqattrs_unlock();
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t __wq_cpumask_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf, cpumask_var_t mask)
|
|
{
|
|
int written;
|
|
|
|
mutex_lock(&wq_pool_mutex);
|
|
written = scnprintf(buf, PAGE_SIZE, "%*pb\n", cpumask_pr_args(mask));
|
|
mutex_unlock(&wq_pool_mutex);
|
|
|
|
return written;
|
|
}
|
|
|
|
static ssize_t cpumask_requested_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
return __wq_cpumask_show(dev, attr, buf, wq_requested_unbound_cpumask);
|
|
}
|
|
static DEVICE_ATTR_RO(cpumask_requested);
|
|
|
|
static ssize_t cpumask_isolated_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
return __wq_cpumask_show(dev, attr, buf, wq_isolated_cpumask);
|
|
}
|
|
static DEVICE_ATTR_RO(cpumask_isolated);
|
|
|
|
static ssize_t cpumask_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
return __wq_cpumask_show(dev, attr, buf, wq_unbound_cpumask);
|
|
}
|
|
|
|
static ssize_t cpumask_store(struct device *dev,
|
|
struct device_attribute *attr, const char *buf, size_t count)
|
|
{
|
|
cpumask_var_t cpumask;
|
|
int ret;
|
|
|
|
if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL))
|
|
return -ENOMEM;
|
|
|
|
ret = cpumask_parse(buf, cpumask);
|
|
if (!ret)
|
|
ret = workqueue_set_unbound_cpumask(cpumask);
|
|
|
|
free_cpumask_var(cpumask);
|
|
return ret ? ret : count;
|
|
}
|
|
static DEVICE_ATTR_RW(cpumask);
|
|
|
|
static struct attribute *wq_sysfs_cpumask_attrs[] = {
|
|
&dev_attr_cpumask.attr,
|
|
&dev_attr_cpumask_requested.attr,
|
|
&dev_attr_cpumask_isolated.attr,
|
|
NULL,
|
|
};
|
|
ATTRIBUTE_GROUPS(wq_sysfs_cpumask);
|
|
|
|
static int __init wq_sysfs_init(void)
|
|
{
|
|
return subsys_virtual_register(&wq_subsys, wq_sysfs_cpumask_groups);
|
|
}
|
|
core_initcall(wq_sysfs_init);
|
|
|
|
static void wq_device_release(struct device *dev)
|
|
{
|
|
struct wq_device *wq_dev = container_of(dev, struct wq_device, dev);
|
|
|
|
kfree(wq_dev);
|
|
}
|
|
|
|
/**
|
|
* workqueue_sysfs_register - make a workqueue visible in sysfs
|
|
* @wq: the workqueue to register
|
|
*
|
|
* Expose @wq in sysfs under /sys/bus/workqueue/devices.
|
|
* alloc_workqueue*() automatically calls this function if WQ_SYSFS is set
|
|
* which is the preferred method.
|
|
*
|
|
* Workqueue user should use this function directly iff it wants to apply
|
|
* workqueue_attrs before making the workqueue visible in sysfs; otherwise,
|
|
* apply_workqueue_attrs() may race against userland updating the
|
|
* attributes.
|
|
*
|
|
* Return: 0 on success, -errno on failure.
|
|
*/
|
|
int workqueue_sysfs_register(struct workqueue_struct *wq)
|
|
{
|
|
struct wq_device *wq_dev;
|
|
int ret;
|
|
|
|
/*
|
|
* Adjusting max_active breaks ordering guarantee. Disallow exposing
|
|
* ordered workqueues.
|
|
*/
|
|
if (WARN_ON(wq->flags & __WQ_ORDERED))
|
|
return -EINVAL;
|
|
|
|
wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL);
|
|
if (!wq_dev)
|
|
return -ENOMEM;
|
|
|
|
wq_dev->wq = wq;
|
|
wq_dev->dev.bus = &wq_subsys;
|
|
wq_dev->dev.release = wq_device_release;
|
|
dev_set_name(&wq_dev->dev, "%s", wq->name);
|
|
|
|
/*
|
|
* unbound_attrs are created separately. Suppress uevent until
|
|
* everything is ready.
|
|
*/
|
|
dev_set_uevent_suppress(&wq_dev->dev, true);
|
|
|
|
ret = device_register(&wq_dev->dev);
|
|
if (ret) {
|
|
put_device(&wq_dev->dev);
|
|
wq->wq_dev = NULL;
|
|
return ret;
|
|
}
|
|
|
|
if (wq->flags & WQ_UNBOUND) {
|
|
struct device_attribute *attr;
|
|
|
|
for (attr = wq_sysfs_unbound_attrs; attr->attr.name; attr++) {
|
|
ret = device_create_file(&wq_dev->dev, attr);
|
|
if (ret) {
|
|
device_unregister(&wq_dev->dev);
|
|
wq->wq_dev = NULL;
|
|
return ret;
|
|
}
|
|
}
|
|
}
|
|
|
|
dev_set_uevent_suppress(&wq_dev->dev, false);
|
|
kobject_uevent(&wq_dev->dev.kobj, KOBJ_ADD);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* workqueue_sysfs_unregister - undo workqueue_sysfs_register()
|
|
* @wq: the workqueue to unregister
|
|
*
|
|
* If @wq is registered to sysfs by workqueue_sysfs_register(), unregister.
|
|
*/
|
|
static void workqueue_sysfs_unregister(struct workqueue_struct *wq)
|
|
{
|
|
struct wq_device *wq_dev = wq->wq_dev;
|
|
|
|
if (!wq->wq_dev)
|
|
return;
|
|
|
|
wq->wq_dev = NULL;
|
|
device_unregister(&wq_dev->dev);
|
|
}
|
|
#else /* CONFIG_SYSFS */
|
|
static void workqueue_sysfs_unregister(struct workqueue_struct *wq) { }
|
|
#endif /* CONFIG_SYSFS */
|
|
|
|
/*
|
|
* Workqueue watchdog.
|
|
*
|
|
* Stall may be caused by various bugs - missing WQ_MEM_RECLAIM, illegal
|
|
* flush dependency, a concurrency managed work item which stays RUNNING
|
|
* indefinitely. Workqueue stalls can be very difficult to debug as the
|
|
* usual warning mechanisms don't trigger and internal workqueue state is
|
|
* largely opaque.
|
|
*
|
|
* Workqueue watchdog monitors all worker pools periodically and dumps
|
|
* state if some pools failed to make forward progress for a while where
|
|
* forward progress is defined as the first item on ->worklist changing.
|
|
*
|
|
* This mechanism is controlled through the kernel parameter
|
|
* "workqueue.watchdog_thresh" which can be updated at runtime through the
|
|
* corresponding sysfs parameter file.
|
|
*/
|
|
#ifdef CONFIG_WQ_WATCHDOG
|
|
|
|
static unsigned long wq_watchdog_thresh = 30;
|
|
static struct timer_list wq_watchdog_timer;
|
|
|
|
static unsigned long wq_watchdog_touched = INITIAL_JIFFIES;
|
|
static DEFINE_PER_CPU(unsigned long, wq_watchdog_touched_cpu) = INITIAL_JIFFIES;
|
|
|
|
/*
|
|
* Show workers that might prevent the processing of pending work items.
|
|
* The only candidates are CPU-bound workers in the running state.
|
|
* Pending work items should be handled by another idle worker
|
|
* in all other situations.
|
|
*/
|
|
static void show_cpu_pool_hog(struct worker_pool *pool)
|
|
{
|
|
struct worker *worker;
|
|
unsigned long irq_flags;
|
|
int bkt;
|
|
|
|
raw_spin_lock_irqsave(&pool->lock, irq_flags);
|
|
|
|
hash_for_each(pool->busy_hash, bkt, worker, hentry) {
|
|
if (task_is_running(worker->task)) {
|
|
/*
|
|
* Defer printing to avoid deadlocks in console
|
|
* drivers that queue work while holding locks
|
|
* also taken in their write paths.
|
|
*/
|
|
printk_deferred_enter();
|
|
|
|
pr_info("pool %d:\n", pool->id);
|
|
sched_show_task(worker->task);
|
|
|
|
printk_deferred_exit();
|
|
}
|
|
}
|
|
|
|
raw_spin_unlock_irqrestore(&pool->lock, irq_flags);
|
|
}
|
|
|
|
static void show_cpu_pools_hogs(void)
|
|
{
|
|
struct worker_pool *pool;
|
|
int pi;
|
|
|
|
pr_info("Showing backtraces of running workers in stalled CPU-bound worker pools:\n");
|
|
|
|
rcu_read_lock();
|
|
|
|
for_each_pool(pool, pi) {
|
|
if (pool->cpu_stall)
|
|
show_cpu_pool_hog(pool);
|
|
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static void wq_watchdog_reset_touched(void)
|
|
{
|
|
int cpu;
|
|
|
|
wq_watchdog_touched = jiffies;
|
|
for_each_possible_cpu(cpu)
|
|
per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies;
|
|
}
|
|
|
|
static void wq_watchdog_timer_fn(struct timer_list *unused)
|
|
{
|
|
unsigned long thresh = READ_ONCE(wq_watchdog_thresh) * HZ;
|
|
bool lockup_detected = false;
|
|
bool cpu_pool_stall = false;
|
|
unsigned long now = jiffies;
|
|
struct worker_pool *pool;
|
|
int pi;
|
|
|
|
if (!thresh)
|
|
return;
|
|
|
|
rcu_read_lock();
|
|
|
|
for_each_pool(pool, pi) {
|
|
unsigned long pool_ts, touched, ts;
|
|
|
|
pool->cpu_stall = false;
|
|
if (list_empty(&pool->worklist))
|
|
continue;
|
|
|
|
/*
|
|
* If a virtual machine is stopped by the host it can look to
|
|
* the watchdog like a stall.
|
|
*/
|
|
kvm_check_and_clear_guest_paused();
|
|
|
|
/* get the latest of pool and touched timestamps */
|
|
if (pool->cpu >= 0)
|
|
touched = READ_ONCE(per_cpu(wq_watchdog_touched_cpu, pool->cpu));
|
|
else
|
|
touched = READ_ONCE(wq_watchdog_touched);
|
|
pool_ts = READ_ONCE(pool->watchdog_ts);
|
|
|
|
if (time_after(pool_ts, touched))
|
|
ts = pool_ts;
|
|
else
|
|
ts = touched;
|
|
|
|
/* did we stall? */
|
|
if (time_after(now, ts + thresh)) {
|
|
lockup_detected = true;
|
|
if (pool->cpu >= 0 && !(pool->flags & POOL_BH)) {
|
|
pool->cpu_stall = true;
|
|
cpu_pool_stall = true;
|
|
}
|
|
pr_emerg("BUG: workqueue lockup - pool");
|
|
pr_cont_pool_info(pool);
|
|
pr_cont(" stuck for %us!\n",
|
|
jiffies_to_msecs(now - pool_ts) / 1000);
|
|
}
|
|
|
|
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
|
|
if (lockup_detected)
|
|
show_all_workqueues();
|
|
|
|
if (cpu_pool_stall)
|
|
show_cpu_pools_hogs();
|
|
|
|
wq_watchdog_reset_touched();
|
|
mod_timer(&wq_watchdog_timer, jiffies + thresh);
|
|
}
|
|
|
|
notrace void wq_watchdog_touch(int cpu)
|
|
{
|
|
if (cpu >= 0)
|
|
per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies;
|
|
|
|
wq_watchdog_touched = jiffies;
|
|
}
|
|
|
|
static void wq_watchdog_set_thresh(unsigned long thresh)
|
|
{
|
|
wq_watchdog_thresh = 0;
|
|
del_timer_sync(&wq_watchdog_timer);
|
|
|
|
if (thresh) {
|
|
wq_watchdog_thresh = thresh;
|
|
wq_watchdog_reset_touched();
|
|
mod_timer(&wq_watchdog_timer, jiffies + thresh * HZ);
|
|
}
|
|
}
|
|
|
|
static int wq_watchdog_param_set_thresh(const char *val,
|
|
const struct kernel_param *kp)
|
|
{
|
|
unsigned long thresh;
|
|
int ret;
|
|
|
|
ret = kstrtoul(val, 0, &thresh);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (system_wq)
|
|
wq_watchdog_set_thresh(thresh);
|
|
else
|
|
wq_watchdog_thresh = thresh;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct kernel_param_ops wq_watchdog_thresh_ops = {
|
|
.set = wq_watchdog_param_set_thresh,
|
|
.get = param_get_ulong,
|
|
};
|
|
|
|
module_param_cb(watchdog_thresh, &wq_watchdog_thresh_ops, &wq_watchdog_thresh,
|
|
0644);
|
|
|
|
static void wq_watchdog_init(void)
|
|
{
|
|
timer_setup(&wq_watchdog_timer, wq_watchdog_timer_fn, TIMER_DEFERRABLE);
|
|
wq_watchdog_set_thresh(wq_watchdog_thresh);
|
|
}
|
|
|
|
#else /* CONFIG_WQ_WATCHDOG */
|
|
|
|
static inline void wq_watchdog_init(void) { }
|
|
|
|
#endif /* CONFIG_WQ_WATCHDOG */
|
|
|
|
static void bh_pool_kick_normal(struct irq_work *irq_work)
|
|
{
|
|
raise_softirq_irqoff(TASKLET_SOFTIRQ);
|
|
}
|
|
|
|
static void bh_pool_kick_highpri(struct irq_work *irq_work)
|
|
{
|
|
raise_softirq_irqoff(HI_SOFTIRQ);
|
|
}
|
|
|
|
static void __init restrict_unbound_cpumask(const char *name, const struct cpumask *mask)
|
|
{
|
|
if (!cpumask_intersects(wq_unbound_cpumask, mask)) {
|
|
pr_warn("workqueue: Restricting unbound_cpumask (%*pb) with %s (%*pb) leaves no CPU, ignoring\n",
|
|
cpumask_pr_args(wq_unbound_cpumask), name, cpumask_pr_args(mask));
|
|
return;
|
|
}
|
|
|
|
cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, mask);
|
|
}
|
|
|
|
static void __init init_cpu_worker_pool(struct worker_pool *pool, int cpu, int nice)
|
|
{
|
|
BUG_ON(init_worker_pool(pool));
|
|
pool->cpu = cpu;
|
|
cpumask_copy(pool->attrs->cpumask, cpumask_of(cpu));
|
|
cpumask_copy(pool->attrs->__pod_cpumask, cpumask_of(cpu));
|
|
pool->attrs->nice = nice;
|
|
pool->attrs->affn_strict = true;
|
|
pool->node = cpu_to_node(cpu);
|
|
|
|
/* alloc pool ID */
|
|
mutex_lock(&wq_pool_mutex);
|
|
BUG_ON(worker_pool_assign_id(pool));
|
|
mutex_unlock(&wq_pool_mutex);
|
|
}
|
|
|
|
/**
|
|
* workqueue_init_early - early init for workqueue subsystem
|
|
*
|
|
* This is the first step of three-staged workqueue subsystem initialization and
|
|
* invoked as soon as the bare basics - memory allocation, cpumasks and idr are
|
|
* up. It sets up all the data structures and system workqueues and allows early
|
|
* boot code to create workqueues and queue/cancel work items. Actual work item
|
|
* execution starts only after kthreads can be created and scheduled right
|
|
* before early initcalls.
|
|
*/
|
|
void __init workqueue_init_early(void)
|
|
{
|
|
struct wq_pod_type *pt = &wq_pod_types[WQ_AFFN_SYSTEM];
|
|
int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL };
|
|
void (*irq_work_fns[2])(struct irq_work *) = { bh_pool_kick_normal,
|
|
bh_pool_kick_highpri };
|
|
int i, cpu;
|
|
|
|
BUILD_BUG_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));
|
|
|
|
BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL));
|
|
BUG_ON(!alloc_cpumask_var(&wq_requested_unbound_cpumask, GFP_KERNEL));
|
|
BUG_ON(!zalloc_cpumask_var(&wq_isolated_cpumask, GFP_KERNEL));
|
|
|
|
cpumask_copy(wq_unbound_cpumask, cpu_possible_mask);
|
|
restrict_unbound_cpumask("HK_TYPE_WQ", housekeeping_cpumask(HK_TYPE_WQ));
|
|
restrict_unbound_cpumask("HK_TYPE_DOMAIN", housekeeping_cpumask(HK_TYPE_DOMAIN));
|
|
if (!cpumask_empty(&wq_cmdline_cpumask))
|
|
restrict_unbound_cpumask("workqueue.unbound_cpus", &wq_cmdline_cpumask);
|
|
|
|
cpumask_copy(wq_requested_unbound_cpumask, wq_unbound_cpumask);
|
|
|
|
pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);
|
|
|
|
wq_update_pod_attrs_buf = alloc_workqueue_attrs();
|
|
BUG_ON(!wq_update_pod_attrs_buf);
|
|
|
|
/*
|
|
* If nohz_full is enabled, set power efficient workqueue as unbound.
|
|
* This allows workqueue items to be moved to HK CPUs.
|
|
*/
|
|
if (housekeeping_enabled(HK_TYPE_TICK))
|
|
wq_power_efficient = true;
|
|
|
|
/* initialize WQ_AFFN_SYSTEM pods */
|
|
pt->pod_cpus = kcalloc(1, sizeof(pt->pod_cpus[0]), GFP_KERNEL);
|
|
pt->pod_node = kcalloc(1, sizeof(pt->pod_node[0]), GFP_KERNEL);
|
|
pt->cpu_pod = kcalloc(nr_cpu_ids, sizeof(pt->cpu_pod[0]), GFP_KERNEL);
|
|
BUG_ON(!pt->pod_cpus || !pt->pod_node || !pt->cpu_pod);
|
|
|
|
BUG_ON(!zalloc_cpumask_var_node(&pt->pod_cpus[0], GFP_KERNEL, NUMA_NO_NODE));
|
|
|
|
pt->nr_pods = 1;
|
|
cpumask_copy(pt->pod_cpus[0], cpu_possible_mask);
|
|
pt->pod_node[0] = NUMA_NO_NODE;
|
|
pt->cpu_pod[0] = 0;
|
|
|
|
/* initialize BH and CPU pools */
|
|
for_each_possible_cpu(cpu) {
|
|
struct worker_pool *pool;
|
|
|
|
i = 0;
|
|
for_each_bh_worker_pool(pool, cpu) {
|
|
init_cpu_worker_pool(pool, cpu, std_nice[i]);
|
|
pool->flags |= POOL_BH;
|
|
init_irq_work(bh_pool_irq_work(pool), irq_work_fns[i]);
|
|
i++;
|
|
}
|
|
|
|
i = 0;
|
|
for_each_cpu_worker_pool(pool, cpu)
|
|
init_cpu_worker_pool(pool, cpu, std_nice[i++]);
|
|
}
|
|
|
|
/* create default unbound and ordered wq attrs */
|
|
for (i = 0; i < NR_STD_WORKER_POOLS; i++) {
|
|
struct workqueue_attrs *attrs;
|
|
|
|
BUG_ON(!(attrs = alloc_workqueue_attrs()));
|
|
attrs->nice = std_nice[i];
|
|
unbound_std_wq_attrs[i] = attrs;
|
|
|
|
/*
|
|
* An ordered wq should have only one pwq as ordering is
|
|
* guaranteed by max_active which is enforced by pwqs.
|
|
*/
|
|
BUG_ON(!(attrs = alloc_workqueue_attrs()));
|
|
attrs->nice = std_nice[i];
|
|
attrs->ordered = true;
|
|
ordered_wq_attrs[i] = attrs;
|
|
}
|
|
|
|
system_wq = alloc_workqueue("events", 0, 0);
|
|
system_highpri_wq = alloc_workqueue("events_highpri", WQ_HIGHPRI, 0);
|
|
system_long_wq = alloc_workqueue("events_long", 0, 0);
|
|
system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND,
|
|
WQ_MAX_ACTIVE);
|
|
system_freezable_wq = alloc_workqueue("events_freezable",
|
|
WQ_FREEZABLE, 0);
|
|
system_power_efficient_wq = alloc_workqueue("events_power_efficient",
|
|
WQ_POWER_EFFICIENT, 0);
|
|
system_freezable_power_efficient_wq = alloc_workqueue("events_freezable_pwr_efficient",
|
|
WQ_FREEZABLE | WQ_POWER_EFFICIENT,
|
|
0);
|
|
system_bh_wq = alloc_workqueue("events_bh", WQ_BH, 0);
|
|
system_bh_highpri_wq = alloc_workqueue("events_bh_highpri",
|
|
WQ_BH | WQ_HIGHPRI, 0);
|
|
BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq ||
|
|
!system_unbound_wq || !system_freezable_wq ||
|
|
!system_power_efficient_wq ||
|
|
!system_freezable_power_efficient_wq ||
|
|
!system_bh_wq || !system_bh_highpri_wq);
|
|
}
|
|
|
|
static void __init wq_cpu_intensive_thresh_init(void)
|
|
{
|
|
unsigned long thresh;
|
|
unsigned long bogo;
|
|
|
|
pwq_release_worker = kthread_create_worker(0, "pool_workqueue_release");
|
|
BUG_ON(IS_ERR(pwq_release_worker));
|
|
|
|
/* if the user set it to a specific value, keep it */
|
|
if (wq_cpu_intensive_thresh_us != ULONG_MAX)
|
|
return;
|
|
|
|
/*
|
|
* The default of 10ms is derived from the fact that most modern (as of
|
|
* 2023) processors can do a lot in 10ms and that it's just below what
|
|
* most consider human-perceivable. However, the kernel also runs on a
|
|
* lot slower CPUs including microcontrollers where the threshold is way
|
|
* too low.
|
|
*
|
|
* Let's scale up the threshold upto 1 second if BogoMips is below 4000.
|
|
* This is by no means accurate but it doesn't have to be. The mechanism
|
|
* is still useful even when the threshold is fully scaled up. Also, as
|
|
* the reports would usually be applicable to everyone, some machines
|
|
* operating on longer thresholds won't significantly diminish their
|
|
* usefulness.
|
|
*/
|
|
thresh = 10 * USEC_PER_MSEC;
|
|
|
|
/* see init/calibrate.c for lpj -> BogoMIPS calculation */
|
|
bogo = max_t(unsigned long, loops_per_jiffy / 500000 * HZ, 1);
|
|
if (bogo < 4000)
|
|
thresh = min_t(unsigned long, thresh * 4000 / bogo, USEC_PER_SEC);
|
|
|
|
pr_debug("wq_cpu_intensive_thresh: lpj=%lu BogoMIPS=%lu thresh_us=%lu\n",
|
|
loops_per_jiffy, bogo, thresh);
|
|
|
|
wq_cpu_intensive_thresh_us = thresh;
|
|
}
|
|
|
|
/**
|
|
* workqueue_init - bring workqueue subsystem fully online
|
|
*
|
|
* This is the second step of three-staged workqueue subsystem initialization
|
|
* and invoked as soon as kthreads can be created and scheduled. Workqueues have
|
|
* been created and work items queued on them, but there are no kworkers
|
|
* executing the work items yet. Populate the worker pools with the initial
|
|
* workers and enable future kworker creations.
|
|
*/
|
|
void __init workqueue_init(void)
|
|
{
|
|
struct workqueue_struct *wq;
|
|
struct worker_pool *pool;
|
|
int cpu, bkt;
|
|
|
|
wq_cpu_intensive_thresh_init();
|
|
|
|
mutex_lock(&wq_pool_mutex);
|
|
|
|
/*
|
|
* Per-cpu pools created earlier could be missing node hint. Fix them
|
|
* up. Also, create a rescuer for workqueues that requested it.
|
|
*/
|
|
for_each_possible_cpu(cpu) {
|
|
for_each_bh_worker_pool(pool, cpu)
|
|
pool->node = cpu_to_node(cpu);
|
|
for_each_cpu_worker_pool(pool, cpu)
|
|
pool->node = cpu_to_node(cpu);
|
|
}
|
|
|
|
list_for_each_entry(wq, &workqueues, list) {
|
|
WARN(init_rescuer(wq),
|
|
"workqueue: failed to create early rescuer for %s",
|
|
wq->name);
|
|
}
|
|
|
|
mutex_unlock(&wq_pool_mutex);
|
|
|
|
/*
|
|
* Create the initial workers. A BH pool has one pseudo worker that
|
|
* represents the shared BH execution context and thus doesn't get
|
|
* affected by hotplug events. Create the BH pseudo workers for all
|
|
* possible CPUs here.
|
|
*/
|
|
for_each_possible_cpu(cpu)
|
|
for_each_bh_worker_pool(pool, cpu)
|
|
BUG_ON(!create_worker(pool));
|
|
|
|
for_each_online_cpu(cpu) {
|
|
for_each_cpu_worker_pool(pool, cpu) {
|
|
pool->flags &= ~POOL_DISASSOCIATED;
|
|
BUG_ON(!create_worker(pool));
|
|
}
|
|
}
|
|
|
|
hash_for_each(unbound_pool_hash, bkt, pool, hash_node)
|
|
BUG_ON(!create_worker(pool));
|
|
|
|
wq_online = true;
|
|
wq_watchdog_init();
|
|
}
|
|
|
|
/*
|
|
* Initialize @pt by first initializing @pt->cpu_pod[] with pod IDs according to
|
|
* @cpu_shares_pod(). Each subset of CPUs that share a pod is assigned a unique
|
|
* and consecutive pod ID. The rest of @pt is initialized accordingly.
|
|
*/
|
|
static void __init init_pod_type(struct wq_pod_type *pt,
|
|
bool (*cpus_share_pod)(int, int))
|
|
{
|
|
int cur, pre, cpu, pod;
|
|
|
|
pt->nr_pods = 0;
|
|
|
|
/* init @pt->cpu_pod[] according to @cpus_share_pod() */
|
|
pt->cpu_pod = kcalloc(nr_cpu_ids, sizeof(pt->cpu_pod[0]), GFP_KERNEL);
|
|
BUG_ON(!pt->cpu_pod);
|
|
|
|
for_each_possible_cpu(cur) {
|
|
for_each_possible_cpu(pre) {
|
|
if (pre >= cur) {
|
|
pt->cpu_pod[cur] = pt->nr_pods++;
|
|
break;
|
|
}
|
|
if (cpus_share_pod(cur, pre)) {
|
|
pt->cpu_pod[cur] = pt->cpu_pod[pre];
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* init the rest to match @pt->cpu_pod[] */
|
|
pt->pod_cpus = kcalloc(pt->nr_pods, sizeof(pt->pod_cpus[0]), GFP_KERNEL);
|
|
pt->pod_node = kcalloc(pt->nr_pods, sizeof(pt->pod_node[0]), GFP_KERNEL);
|
|
BUG_ON(!pt->pod_cpus || !pt->pod_node);
|
|
|
|
for (pod = 0; pod < pt->nr_pods; pod++)
|
|
BUG_ON(!zalloc_cpumask_var(&pt->pod_cpus[pod], GFP_KERNEL));
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
cpumask_set_cpu(cpu, pt->pod_cpus[pt->cpu_pod[cpu]]);
|
|
pt->pod_node[pt->cpu_pod[cpu]] = cpu_to_node(cpu);
|
|
}
|
|
}
|
|
|
|
static bool __init cpus_dont_share(int cpu0, int cpu1)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
static bool __init cpus_share_smt(int cpu0, int cpu1)
|
|
{
|
|
#ifdef CONFIG_SCHED_SMT
|
|
return cpumask_test_cpu(cpu0, cpu_smt_mask(cpu1));
|
|
#else
|
|
return false;
|
|
#endif
|
|
}
|
|
|
|
static bool __init cpus_share_numa(int cpu0, int cpu1)
|
|
{
|
|
return cpu_to_node(cpu0) == cpu_to_node(cpu1);
|
|
}
|
|
|
|
/**
|
|
* workqueue_init_topology - initialize CPU pods for unbound workqueues
|
|
*
|
|
* This is the third step of three-staged workqueue subsystem initialization and
|
|
* invoked after SMP and topology information are fully initialized. It
|
|
* initializes the unbound CPU pods accordingly.
|
|
*/
|
|
void __init workqueue_init_topology(void)
|
|
{
|
|
struct workqueue_struct *wq;
|
|
int cpu;
|
|
|
|
init_pod_type(&wq_pod_types[WQ_AFFN_CPU], cpus_dont_share);
|
|
init_pod_type(&wq_pod_types[WQ_AFFN_SMT], cpus_share_smt);
|
|
init_pod_type(&wq_pod_types[WQ_AFFN_CACHE], cpus_share_cache);
|
|
init_pod_type(&wq_pod_types[WQ_AFFN_NUMA], cpus_share_numa);
|
|
|
|
wq_topo_initialized = true;
|
|
|
|
mutex_lock(&wq_pool_mutex);
|
|
|
|
/*
|
|
* Workqueues allocated earlier would have all CPUs sharing the default
|
|
* worker pool. Explicitly call wq_update_pod() on all workqueue and CPU
|
|
* combinations to apply per-pod sharing.
|
|
*/
|
|
list_for_each_entry(wq, &workqueues, list) {
|
|
for_each_online_cpu(cpu)
|
|
wq_update_pod(wq, cpu, cpu, true);
|
|
if (wq->flags & WQ_UNBOUND) {
|
|
mutex_lock(&wq->mutex);
|
|
wq_update_node_max_active(wq, -1);
|
|
mutex_unlock(&wq->mutex);
|
|
}
|
|
}
|
|
|
|
mutex_unlock(&wq_pool_mutex);
|
|
}
|
|
|
|
void __warn_flushing_systemwide_wq(void)
|
|
{
|
|
pr_warn("WARNING: Flushing system-wide workqueues will be prohibited in near future.\n");
|
|
dump_stack();
|
|
}
|
|
EXPORT_SYMBOL(__warn_flushing_systemwide_wq);
|
|
|
|
static int __init workqueue_unbound_cpus_setup(char *str)
|
|
{
|
|
if (cpulist_parse(str, &wq_cmdline_cpumask) < 0) {
|
|
cpumask_clear(&wq_cmdline_cpumask);
|
|
pr_warn("workqueue.unbound_cpus: incorrect CPU range, using default\n");
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
__setup("workqueue.unbound_cpus=", workqueue_unbound_cpus_setup);
|