linux/kernel/locking/locktorture.c
Paul E. McKenney af5f6e27d5 locktorture: Count lock readers
Currently, the lock_is_read_held variable is bool, so that a reader sets
it to true just after lock acquisition and then to false just before
lock release.  This works in a rough statistical sense, but can result
in false negatives just after one of a pair of concurrent readers has
released the lock.  This approach does have low overhead, but at the
expense of the setting to true potentially never leaving the reader's
store buffer, thus resulting in an unconditional false negative.

This commit therefore converts this variable to atomic_t and makes
the reader use atomic_inc() just after acquisition and atomic_dec()
just before release.  This does increase overhead, but this increase is
negligible compared to the 10-microsecond lock hold time.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-07-27 11:39:30 -07:00

1118 lines
29 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Module-based torture test facility for locking
*
* Copyright (C) IBM Corporation, 2014
*
* Authors: Paul E. McKenney <paulmck@linux.ibm.com>
* Davidlohr Bueso <dave@stgolabs.net>
* Based on kernel/rcu/torture.c.
*/
#define pr_fmt(fmt) fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/sched/rt.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <uapi/linux/sched/types.h>
#include <linux/rtmutex.h>
#include <linux/atomic.h>
#include <linux/moduleparam.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/torture.h>
#include <linux/reboot.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
torture_param(int, nwriters_stress, -1,
"Number of write-locking stress-test threads");
torture_param(int, nreaders_stress, -1,
"Number of read-locking stress-test threads");
torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
torture_param(int, onoff_interval, 0,
"Time between CPU hotplugs (s), 0=disable");
torture_param(int, shuffle_interval, 3,
"Number of jiffies between shuffles, 0=disable");
torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
torture_param(int, stat_interval, 60,
"Number of seconds between stats printk()s");
torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
torture_param(int, verbose, 1,
"Enable verbose debugging printk()s");
static char *torture_type = "spin_lock";
module_param(torture_type, charp, 0444);
MODULE_PARM_DESC(torture_type,
"Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
static struct task_struct *stats_task;
static struct task_struct **writer_tasks;
static struct task_struct **reader_tasks;
static bool lock_is_write_held;
static atomic_t lock_is_read_held;
static unsigned long last_lock_release;
struct lock_stress_stats {
long n_lock_fail;
long n_lock_acquired;
};
/* Forward reference. */
static void lock_torture_cleanup(void);
/*
* Operations vector for selecting different types of tests.
*/
struct lock_torture_ops {
void (*init)(void);
void (*exit)(void);
int (*writelock)(int tid);
void (*write_delay)(struct torture_random_state *trsp);
void (*task_boost)(struct torture_random_state *trsp);
void (*writeunlock)(int tid);
int (*readlock)(int tid);
void (*read_delay)(struct torture_random_state *trsp);
void (*readunlock)(int tid);
unsigned long flags; /* for irq spinlocks */
const char *name;
};
struct lock_torture_cxt {
int nrealwriters_stress;
int nrealreaders_stress;
bool debug_lock;
bool init_called;
atomic_t n_lock_torture_errors;
struct lock_torture_ops *cur_ops;
struct lock_stress_stats *lwsa; /* writer statistics */
struct lock_stress_stats *lrsa; /* reader statistics */
};
static struct lock_torture_cxt cxt = { 0, 0, false, false,
ATOMIC_INIT(0),
NULL, NULL};
/*
* Definitions for lock torture testing.
*/
static int torture_lock_busted_write_lock(int tid __maybe_unused)
{
return 0; /* BUGGY, do not use in real life!!! */
}
static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
{
const unsigned long longdelay_ms = 100;
/* We want a long delay occasionally to force massive contention. */
if (!(torture_random(trsp) %
(cxt.nrealwriters_stress * 2000 * longdelay_ms)))
mdelay(longdelay_ms);
if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
torture_preempt_schedule(); /* Allow test to be preempted. */
}
static void torture_lock_busted_write_unlock(int tid __maybe_unused)
{
/* BUGGY, do not use in real life!!! */
}
static void torture_boost_dummy(struct torture_random_state *trsp)
{
/* Only rtmutexes care about priority */
}
static struct lock_torture_ops lock_busted_ops = {
.writelock = torture_lock_busted_write_lock,
.write_delay = torture_lock_busted_write_delay,
.task_boost = torture_boost_dummy,
.writeunlock = torture_lock_busted_write_unlock,
.readlock = NULL,
.read_delay = NULL,
.readunlock = NULL,
.name = "lock_busted"
};
static DEFINE_SPINLOCK(torture_spinlock);
static int torture_spin_lock_write_lock(int tid __maybe_unused)
__acquires(torture_spinlock)
{
spin_lock(&torture_spinlock);
return 0;
}
static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
{
const unsigned long shortdelay_us = 2;
const unsigned long longdelay_ms = 100;
/* We want a short delay mostly to emulate likely code, and
* we want a long delay occasionally to force massive contention.
*/
if (!(torture_random(trsp) %
(cxt.nrealwriters_stress * 2000 * longdelay_ms)))
mdelay(longdelay_ms);
if (!(torture_random(trsp) %
(cxt.nrealwriters_stress * 2 * shortdelay_us)))
udelay(shortdelay_us);
if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
torture_preempt_schedule(); /* Allow test to be preempted. */
}
static void torture_spin_lock_write_unlock(int tid __maybe_unused)
__releases(torture_spinlock)
{
spin_unlock(&torture_spinlock);
}
static struct lock_torture_ops spin_lock_ops = {
.writelock = torture_spin_lock_write_lock,
.write_delay = torture_spin_lock_write_delay,
.task_boost = torture_boost_dummy,
.writeunlock = torture_spin_lock_write_unlock,
.readlock = NULL,
.read_delay = NULL,
.readunlock = NULL,
.name = "spin_lock"
};
static int torture_spin_lock_write_lock_irq(int tid __maybe_unused)
__acquires(torture_spinlock)
{
unsigned long flags;
spin_lock_irqsave(&torture_spinlock, flags);
cxt.cur_ops->flags = flags;
return 0;
}
static void torture_lock_spin_write_unlock_irq(int tid __maybe_unused)
__releases(torture_spinlock)
{
spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
}
static struct lock_torture_ops spin_lock_irq_ops = {
.writelock = torture_spin_lock_write_lock_irq,
.write_delay = torture_spin_lock_write_delay,
.task_boost = torture_boost_dummy,
.writeunlock = torture_lock_spin_write_unlock_irq,
.readlock = NULL,
.read_delay = NULL,
.readunlock = NULL,
.name = "spin_lock_irq"
};
static DEFINE_RWLOCK(torture_rwlock);
static int torture_rwlock_write_lock(int tid __maybe_unused)
__acquires(torture_rwlock)
{
write_lock(&torture_rwlock);
return 0;
}
static void torture_rwlock_write_delay(struct torture_random_state *trsp)
{
const unsigned long shortdelay_us = 2;
const unsigned long longdelay_ms = 100;
/* We want a short delay mostly to emulate likely code, and
* we want a long delay occasionally to force massive contention.
*/
if (!(torture_random(trsp) %
(cxt.nrealwriters_stress * 2000 * longdelay_ms)))
mdelay(longdelay_ms);
else
udelay(shortdelay_us);
}
static void torture_rwlock_write_unlock(int tid __maybe_unused)
__releases(torture_rwlock)
{
write_unlock(&torture_rwlock);
}
static int torture_rwlock_read_lock(int tid __maybe_unused)
__acquires(torture_rwlock)
{
read_lock(&torture_rwlock);
return 0;
}
static void torture_rwlock_read_delay(struct torture_random_state *trsp)
{
const unsigned long shortdelay_us = 10;
const unsigned long longdelay_ms = 100;
/* We want a short delay mostly to emulate likely code, and
* we want a long delay occasionally to force massive contention.
*/
if (!(torture_random(trsp) %
(cxt.nrealreaders_stress * 2000 * longdelay_ms)))
mdelay(longdelay_ms);
else
udelay(shortdelay_us);
}
static void torture_rwlock_read_unlock(int tid __maybe_unused)
__releases(torture_rwlock)
{
read_unlock(&torture_rwlock);
}
static struct lock_torture_ops rw_lock_ops = {
.writelock = torture_rwlock_write_lock,
.write_delay = torture_rwlock_write_delay,
.task_boost = torture_boost_dummy,
.writeunlock = torture_rwlock_write_unlock,
.readlock = torture_rwlock_read_lock,
.read_delay = torture_rwlock_read_delay,
.readunlock = torture_rwlock_read_unlock,
.name = "rw_lock"
};
static int torture_rwlock_write_lock_irq(int tid __maybe_unused)
__acquires(torture_rwlock)
{
unsigned long flags;
write_lock_irqsave(&torture_rwlock, flags);
cxt.cur_ops->flags = flags;
return 0;
}
static void torture_rwlock_write_unlock_irq(int tid __maybe_unused)
__releases(torture_rwlock)
{
write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
}
static int torture_rwlock_read_lock_irq(int tid __maybe_unused)
__acquires(torture_rwlock)
{
unsigned long flags;
read_lock_irqsave(&torture_rwlock, flags);
cxt.cur_ops->flags = flags;
return 0;
}
static void torture_rwlock_read_unlock_irq(int tid __maybe_unused)
__releases(torture_rwlock)
{
read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
}
static struct lock_torture_ops rw_lock_irq_ops = {
.writelock = torture_rwlock_write_lock_irq,
.write_delay = torture_rwlock_write_delay,
.task_boost = torture_boost_dummy,
.writeunlock = torture_rwlock_write_unlock_irq,
.readlock = torture_rwlock_read_lock_irq,
.read_delay = torture_rwlock_read_delay,
.readunlock = torture_rwlock_read_unlock_irq,
.name = "rw_lock_irq"
};
static DEFINE_MUTEX(torture_mutex);
static int torture_mutex_lock(int tid __maybe_unused)
__acquires(torture_mutex)
{
mutex_lock(&torture_mutex);
return 0;
}
static void torture_mutex_delay(struct torture_random_state *trsp)
{
const unsigned long longdelay_ms = 100;
/* We want a long delay occasionally to force massive contention. */
if (!(torture_random(trsp) %
(cxt.nrealwriters_stress * 2000 * longdelay_ms)))
mdelay(longdelay_ms * 5);
else
mdelay(longdelay_ms / 5);
if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
torture_preempt_schedule(); /* Allow test to be preempted. */
}
static void torture_mutex_unlock(int tid __maybe_unused)
__releases(torture_mutex)
{
mutex_unlock(&torture_mutex);
}
static struct lock_torture_ops mutex_lock_ops = {
.writelock = torture_mutex_lock,
.write_delay = torture_mutex_delay,
.task_boost = torture_boost_dummy,
.writeunlock = torture_mutex_unlock,
.readlock = NULL,
.read_delay = NULL,
.readunlock = NULL,
.name = "mutex_lock"
};
#include <linux/ww_mutex.h>
/*
* The torture ww_mutexes should belong to the same lock class as
* torture_ww_class to avoid lockdep problem. The ww_mutex_init()
* function is called for initialization to ensure that.
*/
static DEFINE_WD_CLASS(torture_ww_class);
static struct ww_mutex torture_ww_mutex_0, torture_ww_mutex_1, torture_ww_mutex_2;
static struct ww_acquire_ctx *ww_acquire_ctxs;
static void torture_ww_mutex_init(void)
{
ww_mutex_init(&torture_ww_mutex_0, &torture_ww_class);
ww_mutex_init(&torture_ww_mutex_1, &torture_ww_class);
ww_mutex_init(&torture_ww_mutex_2, &torture_ww_class);
ww_acquire_ctxs = kmalloc_array(cxt.nrealwriters_stress,
sizeof(*ww_acquire_ctxs),
GFP_KERNEL);
if (!ww_acquire_ctxs)
VERBOSE_TOROUT_STRING("ww_acquire_ctx: Out of memory");
}
static void torture_ww_mutex_exit(void)
{
kfree(ww_acquire_ctxs);
}
static int torture_ww_mutex_lock(int tid)
__acquires(torture_ww_mutex_0)
__acquires(torture_ww_mutex_1)
__acquires(torture_ww_mutex_2)
{
LIST_HEAD(list);
struct reorder_lock {
struct list_head link;
struct ww_mutex *lock;
} locks[3], *ll, *ln;
struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
locks[0].lock = &torture_ww_mutex_0;
list_add(&locks[0].link, &list);
locks[1].lock = &torture_ww_mutex_1;
list_add(&locks[1].link, &list);
locks[2].lock = &torture_ww_mutex_2;
list_add(&locks[2].link, &list);
ww_acquire_init(ctx, &torture_ww_class);
list_for_each_entry(ll, &list, link) {
int err;
err = ww_mutex_lock(ll->lock, ctx);
if (!err)
continue;
ln = ll;
list_for_each_entry_continue_reverse(ln, &list, link)
ww_mutex_unlock(ln->lock);
if (err != -EDEADLK)
return err;
ww_mutex_lock_slow(ll->lock, ctx);
list_move(&ll->link, &list);
}
return 0;
}
static void torture_ww_mutex_unlock(int tid)
__releases(torture_ww_mutex_0)
__releases(torture_ww_mutex_1)
__releases(torture_ww_mutex_2)
{
struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
ww_mutex_unlock(&torture_ww_mutex_0);
ww_mutex_unlock(&torture_ww_mutex_1);
ww_mutex_unlock(&torture_ww_mutex_2);
ww_acquire_fini(ctx);
}
static struct lock_torture_ops ww_mutex_lock_ops = {
.init = torture_ww_mutex_init,
.exit = torture_ww_mutex_exit,
.writelock = torture_ww_mutex_lock,
.write_delay = torture_mutex_delay,
.task_boost = torture_boost_dummy,
.writeunlock = torture_ww_mutex_unlock,
.readlock = NULL,
.read_delay = NULL,
.readunlock = NULL,
.name = "ww_mutex_lock"
};
#ifdef CONFIG_RT_MUTEXES
static DEFINE_RT_MUTEX(torture_rtmutex);
static int torture_rtmutex_lock(int tid __maybe_unused)
__acquires(torture_rtmutex)
{
rt_mutex_lock(&torture_rtmutex);
return 0;
}
static void torture_rtmutex_boost(struct torture_random_state *trsp)
{
const unsigned int factor = 50000; /* yes, quite arbitrary */
if (!rt_task(current)) {
/*
* Boost priority once every ~50k operations. When the
* task tries to take the lock, the rtmutex it will account
* for the new priority, and do any corresponding pi-dance.
*/
if (trsp && !(torture_random(trsp) %
(cxt.nrealwriters_stress * factor))) {
sched_set_fifo(current);
} else /* common case, do nothing */
return;
} else {
/*
* The task will remain boosted for another ~500k operations,
* then restored back to its original prio, and so forth.
*
* When @trsp is nil, we want to force-reset the task for
* stopping the kthread.
*/
if (!trsp || !(torture_random(trsp) %
(cxt.nrealwriters_stress * factor * 2))) {
sched_set_normal(current, 0);
} else /* common case, do nothing */
return;
}
}
static void torture_rtmutex_delay(struct torture_random_state *trsp)
{
const unsigned long shortdelay_us = 2;
const unsigned long longdelay_ms = 100;
/*
* We want a short delay mostly to emulate likely code, and
* we want a long delay occasionally to force massive contention.
*/
if (!(torture_random(trsp) %
(cxt.nrealwriters_stress * 2000 * longdelay_ms)))
mdelay(longdelay_ms);
if (!(torture_random(trsp) %
(cxt.nrealwriters_stress * 2 * shortdelay_us)))
udelay(shortdelay_us);
if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
torture_preempt_schedule(); /* Allow test to be preempted. */
}
static void torture_rtmutex_unlock(int tid __maybe_unused)
__releases(torture_rtmutex)
{
rt_mutex_unlock(&torture_rtmutex);
}
static struct lock_torture_ops rtmutex_lock_ops = {
.writelock = torture_rtmutex_lock,
.write_delay = torture_rtmutex_delay,
.task_boost = torture_rtmutex_boost,
.writeunlock = torture_rtmutex_unlock,
.readlock = NULL,
.read_delay = NULL,
.readunlock = NULL,
.name = "rtmutex_lock"
};
#endif
static DECLARE_RWSEM(torture_rwsem);
static int torture_rwsem_down_write(int tid __maybe_unused)
__acquires(torture_rwsem)
{
down_write(&torture_rwsem);
return 0;
}
static void torture_rwsem_write_delay(struct torture_random_state *trsp)
{
const unsigned long longdelay_ms = 100;
/* We want a long delay occasionally to force massive contention. */
if (!(torture_random(trsp) %
(cxt.nrealwriters_stress * 2000 * longdelay_ms)))
mdelay(longdelay_ms * 10);
else
mdelay(longdelay_ms / 10);
if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
torture_preempt_schedule(); /* Allow test to be preempted. */
}
static void torture_rwsem_up_write(int tid __maybe_unused)
__releases(torture_rwsem)
{
up_write(&torture_rwsem);
}
static int torture_rwsem_down_read(int tid __maybe_unused)
__acquires(torture_rwsem)
{
down_read(&torture_rwsem);
return 0;
}
static void torture_rwsem_read_delay(struct torture_random_state *trsp)
{
const unsigned long longdelay_ms = 100;
/* We want a long delay occasionally to force massive contention. */
if (!(torture_random(trsp) %
(cxt.nrealreaders_stress * 2000 * longdelay_ms)))
mdelay(longdelay_ms * 2);
else
mdelay(longdelay_ms / 2);
if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
torture_preempt_schedule(); /* Allow test to be preempted. */
}
static void torture_rwsem_up_read(int tid __maybe_unused)
__releases(torture_rwsem)
{
up_read(&torture_rwsem);
}
static struct lock_torture_ops rwsem_lock_ops = {
.writelock = torture_rwsem_down_write,
.write_delay = torture_rwsem_write_delay,
.task_boost = torture_boost_dummy,
.writeunlock = torture_rwsem_up_write,
.readlock = torture_rwsem_down_read,
.read_delay = torture_rwsem_read_delay,
.readunlock = torture_rwsem_up_read,
.name = "rwsem_lock"
};
#include <linux/percpu-rwsem.h>
static struct percpu_rw_semaphore pcpu_rwsem;
static void torture_percpu_rwsem_init(void)
{
BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
}
static void torture_percpu_rwsem_exit(void)
{
percpu_free_rwsem(&pcpu_rwsem);
}
static int torture_percpu_rwsem_down_write(int tid __maybe_unused)
__acquires(pcpu_rwsem)
{
percpu_down_write(&pcpu_rwsem);
return 0;
}
static void torture_percpu_rwsem_up_write(int tid __maybe_unused)
__releases(pcpu_rwsem)
{
percpu_up_write(&pcpu_rwsem);
}
static int torture_percpu_rwsem_down_read(int tid __maybe_unused)
__acquires(pcpu_rwsem)
{
percpu_down_read(&pcpu_rwsem);
return 0;
}
static void torture_percpu_rwsem_up_read(int tid __maybe_unused)
__releases(pcpu_rwsem)
{
percpu_up_read(&pcpu_rwsem);
}
static struct lock_torture_ops percpu_rwsem_lock_ops = {
.init = torture_percpu_rwsem_init,
.exit = torture_percpu_rwsem_exit,
.writelock = torture_percpu_rwsem_down_write,
.write_delay = torture_rwsem_write_delay,
.task_boost = torture_boost_dummy,
.writeunlock = torture_percpu_rwsem_up_write,
.readlock = torture_percpu_rwsem_down_read,
.read_delay = torture_rwsem_read_delay,
.readunlock = torture_percpu_rwsem_up_read,
.name = "percpu_rwsem_lock"
};
/*
* Lock torture writer kthread. Repeatedly acquires and releases
* the lock, checking for duplicate acquisitions.
*/
static int lock_torture_writer(void *arg)
{
struct lock_stress_stats *lwsp = arg;
int tid = lwsp - cxt.lwsa;
DEFINE_TORTURE_RANDOM(rand);
VERBOSE_TOROUT_STRING("lock_torture_writer task started");
set_user_nice(current, MAX_NICE);
do {
if ((torture_random(&rand) & 0xfffff) == 0)
schedule_timeout_uninterruptible(1);
cxt.cur_ops->task_boost(&rand);
cxt.cur_ops->writelock(tid);
if (WARN_ON_ONCE(lock_is_write_held))
lwsp->n_lock_fail++;
lock_is_write_held = true;
if (WARN_ON_ONCE(atomic_read(&lock_is_read_held)))
lwsp->n_lock_fail++; /* rare, but... */
lwsp->n_lock_acquired++;
cxt.cur_ops->write_delay(&rand);
lock_is_write_held = false;
WRITE_ONCE(last_lock_release, jiffies);
cxt.cur_ops->writeunlock(tid);
stutter_wait("lock_torture_writer");
} while (!torture_must_stop());
cxt.cur_ops->task_boost(NULL); /* reset prio */
torture_kthread_stopping("lock_torture_writer");
return 0;
}
/*
* Lock torture reader kthread. Repeatedly acquires and releases
* the reader lock.
*/
static int lock_torture_reader(void *arg)
{
struct lock_stress_stats *lrsp = arg;
int tid = lrsp - cxt.lrsa;
DEFINE_TORTURE_RANDOM(rand);
VERBOSE_TOROUT_STRING("lock_torture_reader task started");
set_user_nice(current, MAX_NICE);
do {
if ((torture_random(&rand) & 0xfffff) == 0)
schedule_timeout_uninterruptible(1);
cxt.cur_ops->readlock(tid);
atomic_inc(&lock_is_read_held);
if (WARN_ON_ONCE(lock_is_write_held))
lrsp->n_lock_fail++; /* rare, but... */
lrsp->n_lock_acquired++;
cxt.cur_ops->read_delay(&rand);
atomic_dec(&lock_is_read_held);
cxt.cur_ops->readunlock(tid);
stutter_wait("lock_torture_reader");
} while (!torture_must_stop());
torture_kthread_stopping("lock_torture_reader");
return 0;
}
/*
* Create an lock-torture-statistics message in the specified buffer.
*/
static void __torture_print_stats(char *page,
struct lock_stress_stats *statp, bool write)
{
long cur;
bool fail = false;
int i, n_stress;
long max = 0, min = statp ? data_race(statp[0].n_lock_acquired) : 0;
long long sum = 0;
n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
for (i = 0; i < n_stress; i++) {
if (data_race(statp[i].n_lock_fail))
fail = true;
cur = data_race(statp[i].n_lock_acquired);
sum += cur;
if (max < cur)
max = cur;
if (min > cur)
min = cur;
}
page += sprintf(page,
"%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
write ? "Writes" : "Reads ",
sum, max, min,
!onoff_interval && max / 2 > min ? "???" : "",
fail, fail ? "!!!" : "");
if (fail)
atomic_inc(&cxt.n_lock_torture_errors);
}
/*
* Print torture statistics. Caller must ensure that there is only one
* call to this function at a given time!!! This is normally accomplished
* by relying on the module system to only have one copy of the module
* loaded, and then by giving the lock_torture_stats kthread full control
* (or the init/cleanup functions when lock_torture_stats thread is not
* running).
*/
static void lock_torture_stats_print(void)
{
int size = cxt.nrealwriters_stress * 200 + 8192;
char *buf;
if (cxt.cur_ops->readlock)
size += cxt.nrealreaders_stress * 200 + 8192;
buf = kmalloc(size, GFP_KERNEL);
if (!buf) {
pr_err("lock_torture_stats_print: Out of memory, need: %d",
size);
return;
}
__torture_print_stats(buf, cxt.lwsa, true);
pr_alert("%s", buf);
kfree(buf);
if (cxt.cur_ops->readlock) {
buf = kmalloc(size, GFP_KERNEL);
if (!buf) {
pr_err("lock_torture_stats_print: Out of memory, need: %d",
size);
return;
}
__torture_print_stats(buf, cxt.lrsa, false);
pr_alert("%s", buf);
kfree(buf);
}
}
/*
* Periodically prints torture statistics, if periodic statistics printing
* was specified via the stat_interval module parameter.
*
* No need to worry about fullstop here, since this one doesn't reference
* volatile state or register callbacks.
*/
static int lock_torture_stats(void *arg)
{
VERBOSE_TOROUT_STRING("lock_torture_stats task started");
do {
schedule_timeout_interruptible(stat_interval * HZ);
lock_torture_stats_print();
torture_shutdown_absorb("lock_torture_stats");
} while (!torture_must_stop());
torture_kthread_stopping("lock_torture_stats");
return 0;
}
static inline void
lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
const char *tag)
{
pr_alert("%s" TORTURE_FLAG
"--- %s%s: nwriters_stress=%d nreaders_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
torture_type, tag, cxt.debug_lock ? " [debug]": "",
cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval,
verbose, shuffle_interval, stutter, shutdown_secs,
onoff_interval, onoff_holdoff);
}
static void lock_torture_cleanup(void)
{
int i;
if (torture_cleanup_begin())
return;
/*
* Indicates early cleanup, meaning that the test has not run,
* such as when passing bogus args when loading the module.
* However cxt->cur_ops.init() may have been invoked, so beside
* perform the underlying torture-specific cleanups, cur_ops.exit()
* will be invoked if needed.
*/
if (!cxt.lwsa && !cxt.lrsa)
goto end;
if (writer_tasks) {
for (i = 0; i < cxt.nrealwriters_stress; i++)
torture_stop_kthread(lock_torture_writer,
writer_tasks[i]);
kfree(writer_tasks);
writer_tasks = NULL;
}
if (reader_tasks) {
for (i = 0; i < cxt.nrealreaders_stress; i++)
torture_stop_kthread(lock_torture_reader,
reader_tasks[i]);
kfree(reader_tasks);
reader_tasks = NULL;
}
torture_stop_kthread(lock_torture_stats, stats_task);
lock_torture_stats_print(); /* -After- the stats thread is stopped! */
if (atomic_read(&cxt.n_lock_torture_errors))
lock_torture_print_module_parms(cxt.cur_ops,
"End of test: FAILURE");
else if (torture_onoff_failures())
lock_torture_print_module_parms(cxt.cur_ops,
"End of test: LOCK_HOTPLUG");
else
lock_torture_print_module_parms(cxt.cur_ops,
"End of test: SUCCESS");
kfree(cxt.lwsa);
cxt.lwsa = NULL;
kfree(cxt.lrsa);
cxt.lrsa = NULL;
end:
if (cxt.init_called) {
if (cxt.cur_ops->exit)
cxt.cur_ops->exit();
cxt.init_called = false;
}
torture_cleanup_end();
}
static int __init lock_torture_init(void)
{
int i, j;
int firsterr = 0;
static struct lock_torture_ops *torture_ops[] = {
&lock_busted_ops,
&spin_lock_ops, &spin_lock_irq_ops,
&rw_lock_ops, &rw_lock_irq_ops,
&mutex_lock_ops,
&ww_mutex_lock_ops,
#ifdef CONFIG_RT_MUTEXES
&rtmutex_lock_ops,
#endif
&rwsem_lock_ops,
&percpu_rwsem_lock_ops,
};
if (!torture_init_begin(torture_type, verbose))
return -EBUSY;
/* Process args and tell the world that the torturer is on the job. */
for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
cxt.cur_ops = torture_ops[i];
if (strcmp(torture_type, cxt.cur_ops->name) == 0)
break;
}
if (i == ARRAY_SIZE(torture_ops)) {
pr_alert("lock-torture: invalid torture type: \"%s\"\n",
torture_type);
pr_alert("lock-torture types:");
for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
pr_alert(" %s", torture_ops[i]->name);
pr_alert("\n");
firsterr = -EINVAL;
goto unwind;
}
if (nwriters_stress == 0 &&
(!cxt.cur_ops->readlock || nreaders_stress == 0)) {
pr_alert("lock-torture: must run at least one locking thread\n");
firsterr = -EINVAL;
goto unwind;
}
if (nwriters_stress >= 0)
cxt.nrealwriters_stress = nwriters_stress;
else
cxt.nrealwriters_stress = 2 * num_online_cpus();
if (cxt.cur_ops->init) {
cxt.cur_ops->init();
cxt.init_called = true;
}
#ifdef CONFIG_DEBUG_MUTEXES
if (str_has_prefix(torture_type, "mutex"))
cxt.debug_lock = true;
#endif
#ifdef CONFIG_DEBUG_RT_MUTEXES
if (str_has_prefix(torture_type, "rtmutex"))
cxt.debug_lock = true;
#endif
#ifdef CONFIG_DEBUG_SPINLOCK
if ((str_has_prefix(torture_type, "spin")) ||
(str_has_prefix(torture_type, "rw_lock")))
cxt.debug_lock = true;
#endif
/* Initialize the statistics so that each run gets its own numbers. */
if (nwriters_stress) {
lock_is_write_held = false;
cxt.lwsa = kmalloc_array(cxt.nrealwriters_stress,
sizeof(*cxt.lwsa),
GFP_KERNEL);
if (cxt.lwsa == NULL) {
VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
firsterr = -ENOMEM;
goto unwind;
}
for (i = 0; i < cxt.nrealwriters_stress; i++) {
cxt.lwsa[i].n_lock_fail = 0;
cxt.lwsa[i].n_lock_acquired = 0;
}
}
if (cxt.cur_ops->readlock) {
if (nreaders_stress >= 0)
cxt.nrealreaders_stress = nreaders_stress;
else {
/*
* By default distribute evenly the number of
* readers and writers. We still run the same number
* of threads as the writer-only locks default.
*/
if (nwriters_stress < 0) /* user doesn't care */
cxt.nrealwriters_stress = num_online_cpus();
cxt.nrealreaders_stress = cxt.nrealwriters_stress;
}
if (nreaders_stress) {
cxt.lrsa = kmalloc_array(cxt.nrealreaders_stress,
sizeof(*cxt.lrsa),
GFP_KERNEL);
if (cxt.lrsa == NULL) {
VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
firsterr = -ENOMEM;
kfree(cxt.lwsa);
cxt.lwsa = NULL;
goto unwind;
}
for (i = 0; i < cxt.nrealreaders_stress; i++) {
cxt.lrsa[i].n_lock_fail = 0;
cxt.lrsa[i].n_lock_acquired = 0;
}
}
}
lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
/* Prepare torture context. */
if (onoff_interval > 0) {
firsterr = torture_onoff_init(onoff_holdoff * HZ,
onoff_interval * HZ, NULL);
if (firsterr)
goto unwind;
}
if (shuffle_interval > 0) {
firsterr = torture_shuffle_init(shuffle_interval);
if (firsterr)
goto unwind;
}
if (shutdown_secs > 0) {
firsterr = torture_shutdown_init(shutdown_secs,
lock_torture_cleanup);
if (firsterr)
goto unwind;
}
if (stutter > 0) {
firsterr = torture_stutter_init(stutter, stutter);
if (firsterr)
goto unwind;
}
if (nwriters_stress) {
writer_tasks = kcalloc(cxt.nrealwriters_stress,
sizeof(writer_tasks[0]),
GFP_KERNEL);
if (writer_tasks == NULL) {
VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
firsterr = -ENOMEM;
goto unwind;
}
}
if (cxt.cur_ops->readlock) {
reader_tasks = kcalloc(cxt.nrealreaders_stress,
sizeof(reader_tasks[0]),
GFP_KERNEL);
if (reader_tasks == NULL) {
VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
kfree(writer_tasks);
writer_tasks = NULL;
firsterr = -ENOMEM;
goto unwind;
}
}
/*
* Create the kthreads and start torturing (oh, those poor little locks).
*
* TODO: Note that we interleave writers with readers, giving writers a
* slight advantage, by creating its kthread first. This can be modified
* for very specific needs, or even let the user choose the policy, if
* ever wanted.
*/
for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
j < cxt.nrealreaders_stress; i++, j++) {
if (i >= cxt.nrealwriters_stress)
goto create_reader;
/* Create writer. */
firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
writer_tasks[i]);
if (firsterr)
goto unwind;
create_reader:
if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
continue;
/* Create reader. */
firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
reader_tasks[j]);
if (firsterr)
goto unwind;
}
if (stat_interval > 0) {
firsterr = torture_create_kthread(lock_torture_stats, NULL,
stats_task);
if (firsterr)
goto unwind;
}
torture_init_end();
return 0;
unwind:
torture_init_end();
lock_torture_cleanup();
if (shutdown_secs) {
WARN_ON(!IS_MODULE(CONFIG_LOCK_TORTURE_TEST));
kernel_power_off();
}
return firsterr;
}
module_init(lock_torture_init);
module_exit(lock_torture_cleanup);