linux/kernel/trace/trace_workqueue.c
Zhaolei f3c4ae26e9 trace_workqueue: remove blank line between each cpu
The blankline between each cpu's workqueue stat is not necessary, because
the cpu number is enough to part them by eye.
Old style also caused a blankline below headline, and made code complex
by using lock, disableirq and get cpu var.

Old style:
 # CPU  INSERTED  EXECUTED   NAME
 # |      |         |          |

   0   8644       8644       events/0
   0      0          0       cpuset
   ...
   0      1          1       kdmflush

   1  35365      35365       events/1
   ...

New style:
 # CPU  INSERTED  EXECUTED   NAME
 # |      |         |          |

   0   8644       8644       events/0
   0      0          0       cpuset
   ...
   0      1          1       kdmflush
   1  35365      35365       events/1
   ...

[ Impact: provide more readable code ]

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 01:14:26 +02:00

276 lines
6.7 KiB
C

/*
* Workqueue statistical tracer.
*
* Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com>
*
*/
#include <trace/events/workqueue.h>
#include <linux/list.h>
#include <linux/percpu.h>
#include "trace_stat.h"
#include "trace.h"
/* A cpu workqueue thread */
struct cpu_workqueue_stats {
struct list_head list;
int cpu;
pid_t pid;
/* Can be inserted from interrupt or user context, need to be atomic */
atomic_t inserted;
/*
* Don't need to be atomic, works are serialized in a single workqueue thread
* on a single CPU.
*/
unsigned int executed;
};
/* List of workqueue threads on one cpu */
struct workqueue_global_stats {
struct list_head list;
spinlock_t lock;
};
/* Don't need a global lock because allocated before the workqueues, and
* never freed.
*/
static DEFINE_PER_CPU(struct workqueue_global_stats, all_workqueue_stat);
#define workqueue_cpu_stat(cpu) (&per_cpu(all_workqueue_stat, cpu))
/* Insertion of a work */
static void
probe_workqueue_insertion(struct task_struct *wq_thread,
struct work_struct *work)
{
int cpu = cpumask_first(&wq_thread->cpus_allowed);
struct cpu_workqueue_stats *node;
unsigned long flags;
spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
list_for_each_entry(node, &workqueue_cpu_stat(cpu)->list, list) {
if (node->pid == wq_thread->pid) {
atomic_inc(&node->inserted);
goto found;
}
}
pr_debug("trace_workqueue: entry not found\n");
found:
spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
}
/* Execution of a work */
static void
probe_workqueue_execution(struct task_struct *wq_thread,
struct work_struct *work)
{
int cpu = cpumask_first(&wq_thread->cpus_allowed);
struct cpu_workqueue_stats *node;
unsigned long flags;
spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
list_for_each_entry(node, &workqueue_cpu_stat(cpu)->list, list) {
if (node->pid == wq_thread->pid) {
node->executed++;
goto found;
}
}
pr_debug("trace_workqueue: entry not found\n");
found:
spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
}
/* Creation of a cpu workqueue thread */
static void probe_workqueue_creation(struct task_struct *wq_thread, int cpu)
{
struct cpu_workqueue_stats *cws;
unsigned long flags;
WARN_ON(cpu < 0);
/* Workqueues are sometimes created in atomic context */
cws = kzalloc(sizeof(struct cpu_workqueue_stats), GFP_ATOMIC);
if (!cws) {
pr_warning("trace_workqueue: not enough memory\n");
return;
}
INIT_LIST_HEAD(&cws->list);
cws->cpu = cpu;
cws->pid = wq_thread->pid;
spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
list_add_tail(&cws->list, &workqueue_cpu_stat(cpu)->list);
spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
}
/* Destruction of a cpu workqueue thread */
static void probe_workqueue_destruction(struct task_struct *wq_thread)
{
/* Workqueue only execute on one cpu */
int cpu = cpumask_first(&wq_thread->cpus_allowed);
struct cpu_workqueue_stats *node, *next;
unsigned long flags;
spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
list_for_each_entry_safe(node, next, &workqueue_cpu_stat(cpu)->list,
list) {
if (node->pid == wq_thread->pid) {
list_del(&node->list);
kfree(node);
goto found;
}
}
pr_debug("trace_workqueue: don't find workqueue to destroy\n");
found:
spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
}
static struct cpu_workqueue_stats *workqueue_stat_start_cpu(int cpu)
{
unsigned long flags;
struct cpu_workqueue_stats *ret = NULL;
spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
if (!list_empty(&workqueue_cpu_stat(cpu)->list))
ret = list_entry(workqueue_cpu_stat(cpu)->list.next,
struct cpu_workqueue_stats, list);
spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
return ret;
}
static void *workqueue_stat_start(struct tracer_stat *trace)
{
int cpu;
void *ret = NULL;
for_each_possible_cpu(cpu) {
ret = workqueue_stat_start_cpu(cpu);
if (ret)
return ret;
}
return NULL;
}
static void *workqueue_stat_next(void *prev, int idx)
{
struct cpu_workqueue_stats *prev_cws = prev;
int cpu = prev_cws->cpu;
unsigned long flags;
void *ret = NULL;
spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
if (list_is_last(&prev_cws->list, &workqueue_cpu_stat(cpu)->list)) {
spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
do {
cpu = cpumask_next(cpu, cpu_possible_mask);
if (cpu >= nr_cpu_ids)
return NULL;
} while (!(ret = workqueue_stat_start_cpu(cpu)));
return ret;
}
spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
return list_entry(prev_cws->list.next, struct cpu_workqueue_stats,
list);
}
static int workqueue_stat_show(struct seq_file *s, void *p)
{
struct cpu_workqueue_stats *cws = p;
struct pid *pid;
struct task_struct *tsk;
pid = find_get_pid(cws->pid);
if (pid) {
tsk = get_pid_task(pid, PIDTYPE_PID);
if (tsk) {
seq_printf(s, "%3d %6d %6u %s\n", cws->cpu,
atomic_read(&cws->inserted), cws->executed,
tsk->comm);
put_task_struct(tsk);
}
put_pid(pid);
}
return 0;
}
static int workqueue_stat_headers(struct seq_file *s)
{
seq_printf(s, "# CPU INSERTED EXECUTED NAME\n");
seq_printf(s, "# | | | |\n");
return 0;
}
struct tracer_stat workqueue_stats __read_mostly = {
.name = "workqueues",
.stat_start = workqueue_stat_start,
.stat_next = workqueue_stat_next,
.stat_show = workqueue_stat_show,
.stat_headers = workqueue_stat_headers
};
int __init stat_workqueue_init(void)
{
if (register_stat_tracer(&workqueue_stats)) {
pr_warning("Unable to register workqueue stat tracer\n");
return 1;
}
return 0;
}
fs_initcall(stat_workqueue_init);
/*
* Workqueues are created very early, just after pre-smp initcalls.
* So we must register our tracepoints at this stage.
*/
int __init trace_workqueue_early_init(void)
{
int ret, cpu;
ret = register_trace_workqueue_insertion(probe_workqueue_insertion);
if (ret)
goto out;
ret = register_trace_workqueue_execution(probe_workqueue_execution);
if (ret)
goto no_insertion;
ret = register_trace_workqueue_creation(probe_workqueue_creation);
if (ret)
goto no_execution;
ret = register_trace_workqueue_destruction(probe_workqueue_destruction);
if (ret)
goto no_creation;
for_each_possible_cpu(cpu) {
spin_lock_init(&workqueue_cpu_stat(cpu)->lock);
INIT_LIST_HEAD(&workqueue_cpu_stat(cpu)->list);
}
return 0;
no_creation:
unregister_trace_workqueue_creation(probe_workqueue_creation);
no_execution:
unregister_trace_workqueue_execution(probe_workqueue_execution);
no_insertion:
unregister_trace_workqueue_insertion(probe_workqueue_insertion);
out:
pr_warning("trace_workqueue: unable to trace workqueues\n");
return 1;
}
early_initcall(trace_workqueue_early_init);