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locktorture.c
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// 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_DESCRIPTION("torture test facility for locking");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
torture_param(int, acq_writer_lim, 0, "Write_acquisition time limit (jiffies).");
torture_param(int, call_rcu_chains, 0, "Self-propagate call_rcu() chains during test (0=disable).");
torture_param(int, long_hold, 100, "Do occasional long hold of lock (ms), 0=disable");
torture_param(int, nested_locks, 0, "Number of nested locks (max = 8)");
torture_param(int, nreaders_stress, -1, "Number of read-locking stress-test threads");
torture_param(int, nwriters_stress, -1, "Number of write-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, rt_boost, 2,
"Do periodic rt-boost. 0=Disable, 1=Only for rt_mutex, 2=For all lock types.");
torture_param(int, rt_boost_factor, 50, "A factor determining how often rt-boost happens.");
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");
torture_param(int, writer_fifo, 0, "Run writers at sched_set_fifo() priority");
/* Going much higher trips "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" errors */
#define MAX_NESTED_LOCKS 8
static char *torture_type = IS_ENABLED(CONFIG_PREEMPT_RT) ? "raw_spin_lock" : "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 cpumask_var_t bind_readers; // Bind the readers to the specified set of CPUs.
static cpumask_var_t bind_writers; // Bind the writers to the specified set of CPUs.
// Parse a cpumask kernel parameter. If there are more users later on,
// this might need to got to a more central location.
static int param_set_cpumask(const char *val, const struct kernel_param *kp)
{
cpumask_var_t *cm_bind = kp->arg;
int ret;
char *s;
if (!alloc_cpumask_var(cm_bind, GFP_KERNEL)) {
s = "Out of memory";
ret = -ENOMEM;
goto out_err;
}
ret = cpulist_parse(val, *cm_bind);
if (!ret)
return ret;
s = "Bad CPU range";
out_err:
pr_warn("%s: %s, all CPUs set\n", kp->name, s);
cpumask_setall(*cm_bind);
return ret;
}
// Output a cpumask kernel parameter.
static int param_get_cpumask(char *buffer, const struct kernel_param *kp)
{
cpumask_var_t *cm_bind = kp->arg;
return sprintf(buffer, "%*pbl", cpumask_pr_args(*cm_bind));
}
static bool cpumask_nonempty(cpumask_var_t mask)
{
return cpumask_available(mask) && !cpumask_empty(mask);
}
static const struct kernel_param_ops lt_bind_ops = {
.set = param_set_cpumask,
.get = param_get_cpumask,
};
module_param_cb(bind_readers, <_bind_ops, &bind_readers, 0644);
module_param_cb(bind_writers, <_bind_ops, &bind_writers, 0644);
long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask);
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;
};
struct call_rcu_chain {
struct rcu_head crc_rh;
bool crc_stop;
};
struct call_rcu_chain *call_rcu_chain_list;
/* 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 (*nested_lock)(int tid, u32 lockset);
int (*writelock)(int tid);
void (*write_delay)(struct torture_random_state *trsp);
void (*task_boost)(struct torture_random_state *trsp);
void (*writeunlock)(int tid);
void (*nested_unlock)(int tid, u32 lockset);
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)
{
/* We want a long delay occasionally to force massive contention. */
if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
mdelay(long_hold);
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_rt_boost(struct torture_random_state *trsp)
{
const unsigned int factor = rt_boost_factor;
if (!rt_task(current)) {
/*
* Boost priority once every rt_boost_factor 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 10 * rt_boost_factor
* 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_rt_boost(struct torture_random_state *trsp)
{
if (rt_boost != 2)
return;
__torture_rt_boost(trsp);
}
static struct lock_torture_ops lock_busted_ops = {
.writelock = torture_lock_busted_write_lock,
.write_delay = torture_lock_busted_write_delay,
.task_boost = torture_rt_boost,
.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;
unsigned long j;
/* We want a short delay mostly to emulate likely code, and
* we want a long delay occasionally to force massive contention.
*/
if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) {
j = jiffies;
mdelay(long_hold);
pr_alert("%s: delay = %lu jiffies.\n", __func__, jiffies - j);
}
if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 200 * 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_rt_boost,
.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_rt_boost,
.writeunlock = torture_lock_spin_write_unlock_irq,
.readlock = NULL,
.read_delay = NULL,
.readunlock = NULL,
.name = "spin_lock_irq"
};
static DEFINE_RAW_SPINLOCK(torture_raw_spinlock);
static int torture_raw_spin_lock_write_lock(int tid __maybe_unused)
__acquires(torture_raw_spinlock)
{
raw_spin_lock(&torture_raw_spinlock);
return 0;
}
static void torture_raw_spin_lock_write_unlock(int tid __maybe_unused)
__releases(torture_raw_spinlock)
{
raw_spin_unlock(&torture_raw_spinlock);
}
static struct lock_torture_ops raw_spin_lock_ops = {
.writelock = torture_raw_spin_lock_write_lock,
.write_delay = torture_spin_lock_write_delay,
.task_boost = torture_rt_boost,
.writeunlock = torture_raw_spin_lock_write_unlock,
.readlock = NULL,
.read_delay = NULL,
.readunlock = NULL,
.name = "raw_spin_lock"
};
static int torture_raw_spin_lock_write_lock_irq(int tid __maybe_unused)
__acquires(torture_raw_spinlock)
{
unsigned long flags;
raw_spin_lock_irqsave(&torture_raw_spinlock, flags);
cxt.cur_ops->flags = flags;
return 0;
}
static void torture_raw_spin_lock_write_unlock_irq(int tid __maybe_unused)
__releases(torture_raw_spinlock)
{
raw_spin_unlock_irqrestore(&torture_raw_spinlock, cxt.cur_ops->flags);
}
static struct lock_torture_ops raw_spin_lock_irq_ops = {
.writelock = torture_raw_spin_lock_write_lock_irq,
.write_delay = torture_spin_lock_write_delay,
.task_boost = torture_rt_boost,
.writeunlock = torture_raw_spin_lock_write_unlock_irq,
.readlock = NULL,
.read_delay = NULL,
.readunlock = NULL,
.name = "raw_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;
/* We want a short delay mostly to emulate likely code, and
* we want a long delay occasionally to force massive contention.
*/
if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
mdelay(long_hold);
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;
/* We want a short delay mostly to emulate likely code, and
* we want a long delay occasionally to force massive contention.
*/
if (long_hold && !(torture_random(trsp) % (cxt.nrealreaders_stress * 2000 * long_hold)))
mdelay(long_hold);
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_rt_boost,
.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_rt_boost,
.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 struct mutex torture_nested_mutexes[MAX_NESTED_LOCKS];
static struct lock_class_key nested_mutex_keys[MAX_NESTED_LOCKS];
static void torture_mutex_init(void)
{
int i;
for (i = 0; i < MAX_NESTED_LOCKS; i++)
__mutex_init(&torture_nested_mutexes[i], __func__,
&nested_mutex_keys[i]);
}
static int torture_mutex_nested_lock(int tid __maybe_unused,
u32 lockset)
{
int i;
for (i = 0; i < nested_locks; i++)
if (lockset & (1 << i))
mutex_lock(&torture_nested_mutexes[i]);
return 0;
}
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)
{
/* We want a long delay occasionally to force massive contention. */
if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
mdelay(long_hold * 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 void torture_mutex_nested_unlock(int tid __maybe_unused,
u32 lockset)
{
int i;
for (i = nested_locks - 1; i >= 0; i--)
if (lockset & (1 << i))
mutex_unlock(&torture_nested_mutexes[i]);
}
static struct lock_torture_ops mutex_lock_ops = {
.init = torture_mutex_init,
.nested_lock = torture_mutex_nested_lock,
.writelock = torture_mutex_lock,
.write_delay = torture_mutex_delay,
.task_boost = torture_rt_boost,
.writeunlock = torture_mutex_unlock,
.nested_unlock = torture_mutex_nested_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_rt_boost,
.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 struct rt_mutex torture_nested_rtmutexes[MAX_NESTED_LOCKS];
static struct lock_class_key nested_rtmutex_keys[MAX_NESTED_LOCKS];
static void torture_rtmutex_init(void)
{
int i;
for (i = 0; i < MAX_NESTED_LOCKS; i++)
__rt_mutex_init(&torture_nested_rtmutexes[i], __func__,
&nested_rtmutex_keys[i]);
}
static int torture_rtmutex_nested_lock(int tid __maybe_unused,
u32 lockset)
{
int i;
for (i = 0; i < nested_locks; i++)
if (lockset & (1 << i))
rt_mutex_lock(&torture_nested_rtmutexes[i]);
return 0;
}
static int torture_rtmutex_lock(int tid __maybe_unused)
__acquires(torture_rtmutex)
{
rt_mutex_lock(&torture_rtmutex);
return 0;
}
static void torture_rtmutex_delay(struct torture_random_state *trsp)
{
const unsigned long shortdelay_us = 2;
/*
* We want a short delay mostly to emulate likely code, and
* we want a long delay occasionally to force massive contention.
*/
if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
mdelay(long_hold);
if (!(torture_random(trsp) %
(cxt.nrealwriters_stress * 200 * 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 void torture_rt_boost_rtmutex(struct torture_random_state *trsp)
{
if (!rt_boost)
return;
__torture_rt_boost(trsp);
}
static void torture_rtmutex_nested_unlock(int tid __maybe_unused,
u32 lockset)
{
int i;
for (i = nested_locks - 1; i >= 0; i--)
if (lockset & (1 << i))
rt_mutex_unlock(&torture_nested_rtmutexes[i]);
}
static struct lock_torture_ops rtmutex_lock_ops = {
.init = torture_rtmutex_init,
.nested_lock = torture_rtmutex_nested_lock,
.writelock = torture_rtmutex_lock,
.write_delay = torture_rtmutex_delay,
.task_boost = torture_rt_boost_rtmutex,
.writeunlock = torture_rtmutex_unlock,
.nested_unlock = torture_rtmutex_nested_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)
{
/* We want a long delay occasionally to force massive contention. */
if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
mdelay(long_hold * 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)
{
/* We want a long delay occasionally to force massive contention. */
if (long_hold && !(torture_random(trsp) % (cxt.nrealreaders_stress * 2000 * long_hold)))
mdelay(long_hold * 2);
else
mdelay(long_hold / 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_rt_boost,
.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_rt_boost,
.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)
{
unsigned long j;
unsigned long j1;
u32 lockset_mask;
struct lock_stress_stats *lwsp = arg;
DEFINE_TORTURE_RANDOM(rand);
bool skip_main_lock;
int tid = lwsp - cxt.lwsa;
VERBOSE_TOROUT_STRING("lock_torture_writer task started");
if (!rt_task(current))
set_user_nice(current, MAX_NICE);
do {
if ((torture_random(&rand) & 0xfffff) == 0)
schedule_timeout_uninterruptible(1);
lockset_mask = torture_random(&rand);
/*
* When using nested_locks, we want to occasionally
* skip the main lock so we can avoid always serializing
* the lock chains on that central lock. By skipping the
* main lock occasionally, we can create different
* contention patterns (allowing for multiple disjoint
* blocked trees)
*/
skip_main_lock = (nested_locks &&
!(torture_random(&rand) % 100));
cxt.cur_ops->task_boost(&rand);
if (cxt.cur_ops->nested_lock)
cxt.cur_ops->nested_lock(tid, lockset_mask);
if (!skip_main_lock) {
if (acq_writer_lim > 0)
j = jiffies;
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... */
if (acq_writer_lim > 0) {
j1 = jiffies;
WARN_ONCE(time_after(j1, j + acq_writer_lim),
"%s: Lock acquisition took %lu jiffies.\n",
__func__, j1 - j);
}
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);
}
if (cxt.cur_ops->nested_unlock)
cxt.cur_ops->nested_unlock(tid, lockset_mask);
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);