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linux/kernel/rcutorture.c

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/*
* Read-Copy Update module-based torture test facility
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2005, 2006
*
* Authors: Paul E. McKenney <paulmck@us.ibm.com>
* Josh Triplett <josh@freedesktop.org>
*
* See also: Documentation/RCU/torture.txt
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/rcupdate.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <asm/atomic.h>
#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/freezer.h>
#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/stat.h>
#include <linux/srcu.h>
#include <linux/slab.h>
#include <asm/byteorder.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and "
"Josh Triplett <josh@freedesktop.org>");
static int nreaders = -1; /* # reader threads, defaults to 2*ncpus */
static int nfakewriters = 4; /* # fake writer threads */
static int stat_interval; /* Interval between stats, in seconds. */
/* Defaults to "only at end of test". */
static int verbose; /* Print more debug info. */
static int test_no_idle_hz; /* Test RCU's support for tickless idle CPUs. */
static int shuffle_interval = 3; /* Interval between shuffles (in sec)*/
static int stutter = 5; /* Start/stop testing interval (in sec) */
static int irqreader = 1; /* RCU readers from irq (timers). */
static int fqs_duration = 0; /* Duration of bursts (us), 0 to disable. */
static int fqs_holdoff = 0; /* Hold time within burst (us). */
static int fqs_stutter = 3; /* Wait time between bursts (s). */
static int test_boost = 1; /* Test RCU prio boost: 0=no, 1=maybe, 2=yes. */
static int test_boost_interval = 7; /* Interval between boost tests, seconds. */
static int test_boost_duration = 4; /* Duration of each boost test, seconds. */
static char *torture_type = "rcu"; /* What RCU implementation to torture. */
module_param(nreaders, int, 0444);
MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
module_param(nfakewriters, int, 0444);
MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads");
module_param(stat_interval, int, 0444);
MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
module_param(verbose, bool, 0444);
MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
module_param(test_no_idle_hz, bool, 0444);
MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
module_param(shuffle_interval, int, 0444);
MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
module_param(stutter, int, 0444);
MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
module_param(irqreader, int, 0444);
MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers");
module_param(fqs_duration, int, 0444);
MODULE_PARM_DESC(fqs_duration, "Duration of fqs bursts (us)");
module_param(fqs_holdoff, int, 0444);
MODULE_PARM_DESC(fqs_holdoff, "Holdoff time within fqs bursts (us)");
module_param(fqs_stutter, int, 0444);
MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)");
module_param(test_boost, int, 0444);
MODULE_PARM_DESC(test_boost, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
module_param(test_boost_interval, int, 0444);
MODULE_PARM_DESC(test_boost_interval, "Interval between boost tests, seconds.");
module_param(test_boost_duration, int, 0444);
MODULE_PARM_DESC(test_boost_duration, "Duration of each boost test, seconds.");
module_param(torture_type, charp, 0444);
MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
#define TORTURE_FLAG "-torture:"
#define PRINTK_STRING(s) \
do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
#define VERBOSE_PRINTK_STRING(s) \
do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
#define VERBOSE_PRINTK_ERRSTRING(s) \
do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
static char printk_buf[4096];
static int nrealreaders;
static struct task_struct *writer_task;
static struct task_struct **fakewriter_tasks;
static struct task_struct **reader_tasks;
static struct task_struct *stats_task;
static struct task_struct *shuffler_task;
static struct task_struct *stutter_task;
static struct task_struct *fqs_task;
static struct task_struct *boost_tasks[NR_CPUS];
#define RCU_TORTURE_PIPE_LEN 10
struct rcu_torture {
struct rcu_head rtort_rcu;
int rtort_pipe_count;
struct list_head rtort_free;
int rtort_mbtest;
};
static LIST_HEAD(rcu_torture_freelist);
static struct rcu_torture __rcu *rcu_torture_current;
static unsigned long rcu_torture_current_version;
static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
static DEFINE_SPINLOCK(rcu_torture_lock);
static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
{ 0 };
static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
{ 0 };
static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
static atomic_t n_rcu_torture_alloc;
static atomic_t n_rcu_torture_alloc_fail;
static atomic_t n_rcu_torture_free;
static atomic_t n_rcu_torture_mberror;
static atomic_t n_rcu_torture_error;
static long n_rcu_torture_boost_ktrerror;
static long n_rcu_torture_boost_rterror;
static long n_rcu_torture_boost_failure;
static long n_rcu_torture_boosts;
static long n_rcu_torture_timers;
static struct list_head rcu_torture_removed;
static cpumask_var_t shuffle_tmp_mask;
static int stutter_pause_test;
#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
#define RCUTORTURE_RUNNABLE_INIT 1
#else
#define RCUTORTURE_RUNNABLE_INIT 0
#endif
int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
#define rcu_can_boost() 1
#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
#define rcu_can_boost() 0
#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
static unsigned long boost_starttime; /* jiffies of next boost test start. */
DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
/* and boost task create/destroy. */
/* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
#define FULLSTOP_DONTSTOP 0 /* Normal operation. */
#define FULLSTOP_SHUTDOWN 1 /* System shutdown with rcutorture running. */
#define FULLSTOP_RMMOD 2 /* Normal rmmod of rcutorture. */
static int fullstop = FULLSTOP_RMMOD;
/*
* Protect fullstop transitions and spawning of kthreads.
*/
static DEFINE_MUTEX(fullstop_mutex);
/*
* Detect and respond to a system shutdown.
*/
static int
rcutorture_shutdown_notify(struct notifier_block *unused1,
unsigned long unused2, void *unused3)
{
mutex_lock(&fullstop_mutex);
if (fullstop == FULLSTOP_DONTSTOP)
fullstop = FULLSTOP_SHUTDOWN;
else
printk(KERN_WARNING /* but going down anyway, so... */
"Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
mutex_unlock(&fullstop_mutex);
return NOTIFY_DONE;
}
/*
* Absorb kthreads into a kernel function that won't return, so that
* they won't ever access module text or data again.
*/
static void rcutorture_shutdown_absorb(char *title)
{
if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
printk(KERN_NOTICE
"rcutorture thread %s parking due to system shutdown\n",
title);
schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
}
}
/*
* Allocate an element from the rcu_tortures pool.
*/
static struct rcu_torture *
rcu_torture_alloc(void)
{
struct list_head *p;
spin_lock_bh(&rcu_torture_lock);
if (list_empty(&rcu_torture_freelist)) {
atomic_inc(&n_rcu_torture_alloc_fail);
spin_unlock_bh(&rcu_torture_lock);
return NULL;
}
atomic_inc(&n_rcu_torture_alloc);
p = rcu_torture_freelist.next;
list_del_init(p);
spin_unlock_bh(&rcu_torture_lock);
return container_of(p, struct rcu_torture, rtort_free);
}
/*
* Free an element to the rcu_tortures pool.
*/
static void
rcu_torture_free(struct rcu_torture *p)
{
atomic_inc(&n_rcu_torture_free);
spin_lock_bh(&rcu_torture_lock);
list_add_tail(&p->rtort_free, &rcu_torture_freelist);
spin_unlock_bh(&rcu_torture_lock);
}
struct rcu_random_state {
unsigned long rrs_state;
long rrs_count;
};
#define RCU_RANDOM_MULT 39916801 /* prime */
#define RCU_RANDOM_ADD 479001701 /* prime */
#define RCU_RANDOM_REFRESH 10000
#define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
/*
* Crude but fast random-number generator. Uses a linear congruential
* generator, with occasional help from cpu_clock().
*/
static unsigned long
rcu_random(struct rcu_random_state *rrsp)
{
if (--rrsp->rrs_count < 0) {
rrsp->rrs_state += (unsigned long)local_clock();
rrsp->rrs_count = RCU_RANDOM_REFRESH;
}
rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
return swahw32(rrsp->rrs_state);
}
static void
rcu_stutter_wait(char *title)
{
while (stutter_pause_test || !rcutorture_runnable) {
if (rcutorture_runnable)
schedule_timeout_interruptible(1);
else
schedule_timeout_interruptible(round_jiffies_relative(HZ));
rcutorture_shutdown_absorb(title);
}
}
/*
* Operations vector for selecting different types of tests.
*/
struct rcu_torture_ops {
void (*init)(void);
void (*cleanup)(void);
int (*readlock)(void);
void (*read_delay)(struct rcu_random_state *rrsp);
void (*readunlock)(int idx);
int (*completed)(void);
void (*deferred_free)(struct rcu_torture *p);
void (*sync)(void);
void (*cb_barrier)(void);
void (*fqs)(void);
int (*stats)(char *page);
int irq_capable;
int can_boost;
char *name;
};
static struct rcu_torture_ops *cur_ops;
/*
* Definitions for rcu torture testing.
*/
static int rcu_torture_read_lock(void) __acquires(RCU)
{
rcu_read_lock();
return 0;
}
static void rcu_read_delay(struct rcu_random_state *rrsp)
{
const unsigned long shortdelay_us = 200;
const unsigned long longdelay_ms = 50;
/* We want a short delay sometimes to make a reader delay the grace
* period, and we want a long delay occasionally to trigger
* force_quiescent_state. */
if (!(rcu_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
mdelay(longdelay_ms);
if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
udelay(shortdelay_us);
#ifdef CONFIG_PREEMPT
if (!preempt_count() && !(rcu_random(rrsp) % (nrealreaders * 20000)))
preempt_schedule(); /* No QS if preempt_disable() in effect */
#endif
}
static void rcu_torture_read_unlock(int idx) __releases(RCU)
{
rcu_read_unlock();
}
static int rcu_torture_completed(void)
{
return rcu_batches_completed();
}
static void
rcu_torture_cb(struct rcu_head *p)
{
int i;
struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
if (fullstop != FULLSTOP_DONTSTOP) {
/* Test is ending, just drop callbacks on the floor. */
/* The next initialization will pick up the pieces. */
return;
}
i = rp->rtort_pipe_count;
if (i > RCU_TORTURE_PIPE_LEN)
i = RCU_TORTURE_PIPE_LEN;
atomic_inc(&rcu_torture_wcount[i]);
if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
rp->rtort_mbtest = 0;
rcu_torture_free(rp);
} else
cur_ops->deferred_free(rp);
}
static int rcu_no_completed(void)
{
return 0;
}
static void rcu_torture_deferred_free(struct rcu_torture *p)
{
call_rcu(&p->rtort_rcu, rcu_torture_cb);
}
static struct rcu_torture_ops rcu_ops = {
.init = NULL,
.cleanup = NULL,
.readlock = rcu_torture_read_lock,
.read_delay = rcu_read_delay,
.readunlock = rcu_torture_read_unlock,
.completed = rcu_torture_completed,
.deferred_free = rcu_torture_deferred_free,
.sync = synchronize_rcu,
.cb_barrier = rcu_barrier,
.fqs = rcu_force_quiescent_state,
.stats = NULL,
.irq_capable = 1,
.can_boost = rcu_can_boost(),
.name = "rcu"
};
static void rcu_sync_torture_deferred_free(struct rcu_torture *p)
{
int i;
struct rcu_torture *rp;
struct rcu_torture *rp1;
cur_ops->sync();
list_add(&p->rtort_free, &rcu_torture_removed);
list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
i = rp->rtort_pipe_count;
if (i > RCU_TORTURE_PIPE_LEN)
i = RCU_TORTURE_PIPE_LEN;
atomic_inc(&rcu_torture_wcount[i]);
if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
rp->rtort_mbtest = 0;
list_del(&rp->rtort_free);
rcu_torture_free(rp);
}
}
}
static void rcu_sync_torture_init(void)
{
INIT_LIST_HEAD(&rcu_torture_removed);
}
static struct rcu_torture_ops rcu_sync_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
.readlock = rcu_torture_read_lock,
.read_delay = rcu_read_delay,
.readunlock = rcu_torture_read_unlock,
.completed = rcu_torture_completed,
.deferred_free = rcu_sync_torture_deferred_free,
.sync = synchronize_rcu,
.cb_barrier = NULL,
.fqs = rcu_force_quiescent_state,
.stats = NULL,
.irq_capable = 1,
.can_boost = rcu_can_boost(),
.name = "rcu_sync"
};
static struct rcu_torture_ops rcu_expedited_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
.readlock = rcu_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = rcu_torture_read_unlock,
.completed = rcu_no_completed,
.deferred_free = rcu_sync_torture_deferred_free,
.sync = synchronize_rcu_expedited,
.cb_barrier = NULL,
.fqs = rcu_force_quiescent_state,
.stats = NULL,
.irq_capable = 1,
.can_boost = rcu_can_boost(),
.name = "rcu_expedited"
};
/*
* Definitions for rcu_bh torture testing.
*/
static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
{
rcu_read_lock_bh();
return 0;
}
static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
{
rcu_read_unlock_bh();
}
static int rcu_bh_torture_completed(void)
{
return rcu_batches_completed_bh();
}
static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
{
call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
}
struct rcu_bh_torture_synchronize {
struct rcu_head head;
struct completion completion;
};
static void rcu_bh_torture_wakeme_after_cb(struct rcu_head *head)
{
struct rcu_bh_torture_synchronize *rcu;
rcu = container_of(head, struct rcu_bh_torture_synchronize, head);
complete(&rcu->completion);
}
static void rcu_bh_torture_synchronize(void)
{
struct rcu_bh_torture_synchronize rcu;
init_rcu_head_on_stack(&rcu.head);
init_completion(&rcu.completion);
call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb);
wait_for_completion(&rcu.completion);
destroy_rcu_head_on_stack(&rcu.head);
}
static struct rcu_torture_ops rcu_bh_ops = {
.init = NULL,
.cleanup = NULL,
.readlock = rcu_bh_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = rcu_bh_torture_read_unlock,
.completed = rcu_bh_torture_completed,
.deferred_free = rcu_bh_torture_deferred_free,
.sync = rcu_bh_torture_synchronize,
.cb_barrier = rcu_barrier_bh,
.fqs = rcu_bh_force_quiescent_state,
.stats = NULL,
.irq_capable = 1,
.name = "rcu_bh"
};
static struct rcu_torture_ops rcu_bh_sync_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
.readlock = rcu_bh_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = rcu_bh_torture_read_unlock,
.completed = rcu_bh_torture_completed,
.deferred_free = rcu_sync_torture_deferred_free,
.sync = rcu_bh_torture_synchronize,
.cb_barrier = NULL,
.fqs = rcu_bh_force_quiescent_state,
.stats = NULL,
.irq_capable = 1,
.name = "rcu_bh_sync"
};
/*
* Definitions for srcu torture testing.
*/
static struct srcu_struct srcu_ctl;
static void srcu_torture_init(void)
{
init_srcu_struct(&srcu_ctl);
rcu_sync_torture_init();
}
static void srcu_torture_cleanup(void)
{
synchronize_srcu(&srcu_ctl);
cleanup_srcu_struct(&srcu_ctl);
}
static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
{
return srcu_read_lock(&srcu_ctl);
}
static void srcu_read_delay(struct rcu_random_state *rrsp)
{
long delay;
const long uspertick = 1000000 / HZ;
const long longdelay = 10;
/* We want there to be long-running readers, but not all the time. */
delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
if (!delay)
schedule_timeout_interruptible(longdelay);
else
rcu_read_delay(rrsp);
}
static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
{
srcu_read_unlock(&srcu_ctl, idx);
}
static int srcu_torture_completed(void)
{
return srcu_batches_completed(&srcu_ctl);
}
static void srcu_torture_synchronize(void)
{
synchronize_srcu(&srcu_ctl);
}
static int srcu_torture_stats(char *page)
{
int cnt = 0;
int cpu;
int idx = srcu_ctl.completed & 0x1;
cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):",
torture_type, TORTURE_FLAG, idx);
for_each_possible_cpu(cpu) {
cnt += sprintf(&page[cnt], " %d(%d,%d)", cpu,
per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
}
cnt += sprintf(&page[cnt], "\n");
return cnt;
}
static struct rcu_torture_ops srcu_ops = {
.init = srcu_torture_init,
.cleanup = srcu_torture_cleanup,
.readlock = srcu_torture_read_lock,
.read_delay = srcu_read_delay,
.readunlock = srcu_torture_read_unlock,
.completed = srcu_torture_completed,
.deferred_free = rcu_sync_torture_deferred_free,
.sync = srcu_torture_synchronize,
.cb_barrier = NULL,
.stats = srcu_torture_stats,
.name = "srcu"
};
static void srcu_torture_synchronize_expedited(void)
{
synchronize_srcu_expedited(&srcu_ctl);
}
static struct rcu_torture_ops srcu_expedited_ops = {
.init = srcu_torture_init,
.cleanup = srcu_torture_cleanup,
.readlock = srcu_torture_read_lock,
.read_delay = srcu_read_delay,
.readunlock = srcu_torture_read_unlock,
.completed = srcu_torture_completed,
.deferred_free = rcu_sync_torture_deferred_free,
.sync = srcu_torture_synchronize_expedited,
.cb_barrier = NULL,
.stats = srcu_torture_stats,
.name = "srcu_expedited"
};
/*
* Definitions for sched torture testing.
*/
static int sched_torture_read_lock(void)
{
preempt_disable();
return 0;
}
static void sched_torture_read_unlock(int idx)
{
preempt_enable();
}
static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
{
call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
}
static void sched_torture_synchronize(void)
{
synchronize_sched();
}
static struct rcu_torture_ops sched_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
.readlock = sched_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = sched_torture_read_unlock,
.completed = rcu_no_completed,
.deferred_free = rcu_sched_torture_deferred_free,
.sync = sched_torture_synchronize,
.cb_barrier = rcu_barrier_sched,
.fqs = rcu_sched_force_quiescent_state,
.stats = NULL,
.irq_capable = 1,
.name = "sched"
};
static struct rcu_torture_ops sched_sync_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
.readlock = sched_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = sched_torture_read_unlock,
.completed = rcu_no_completed,
.deferred_free = rcu_sync_torture_deferred_free,
.sync = sched_torture_synchronize,
.cb_barrier = NULL,
.fqs = rcu_sched_force_quiescent_state,
.stats = NULL,
.name = "sched_sync"
};
static struct rcu_torture_ops sched_expedited_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
.readlock = sched_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = sched_torture_read_unlock,
.completed = rcu_no_completed,
.deferred_free = rcu_sync_torture_deferred_free,
.sync = synchronize_sched_expedited,
.cb_barrier = NULL,
.fqs = rcu_sched_force_quiescent_state,
.stats = NULL,
.irq_capable = 1,
.name = "sched_expedited"
};
/*
* RCU torture priority-boost testing. Runs one real-time thread per
* CPU for moderate bursts, repeatedly registering RCU callbacks and
* spinning waiting for them to be invoked. If a given callback takes
* too long to be invoked, we assume that priority inversion has occurred.
*/
struct rcu_boost_inflight {
struct rcu_head rcu;
int inflight;
};
static void rcu_torture_boost_cb(struct rcu_head *head)
{
struct rcu_boost_inflight *rbip =
container_of(head, struct rcu_boost_inflight, rcu);
smp_mb(); /* Ensure RCU-core accesses precede clearing ->inflight */
rbip->inflight = 0;
}
static int rcu_torture_boost(void *arg)
{
unsigned long call_rcu_time;
unsigned long endtime;
unsigned long oldstarttime;
struct rcu_boost_inflight rbi = { .inflight = 0 };
struct sched_param sp;
VERBOSE_PRINTK_STRING("rcu_torture_boost started");
/* Set real-time priority. */
sp.sched_priority = 1;
if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
VERBOSE_PRINTK_STRING("rcu_torture_boost RT prio failed!");
n_rcu_torture_boost_rterror++;
}
init_rcu_head_on_stack(&rbi.rcu);
/* Each pass through the following loop does one boost-test cycle. */
do {
/* Wait for the next test interval. */
oldstarttime = boost_starttime;
while (jiffies - oldstarttime > ULONG_MAX / 2) {
schedule_timeout_uninterruptible(1);
rcu_stutter_wait("rcu_torture_boost");
if (kthread_should_stop() ||
fullstop != FULLSTOP_DONTSTOP)
goto checkwait;
}
/* Do one boost-test interval. */
endtime = oldstarttime + test_boost_duration * HZ;
call_rcu_time = jiffies;
while (jiffies - endtime > ULONG_MAX / 2) {
/* If we don't have a callback in flight, post one. */
if (!rbi.inflight) {
smp_mb(); /* RCU core before ->inflight = 1. */
rbi.inflight = 1;
call_rcu(&rbi.rcu, rcu_torture_boost_cb);
if (jiffies - call_rcu_time >
test_boost_duration * HZ - HZ / 2) {
VERBOSE_PRINTK_STRING("rcu_torture_boost boosting failed");
n_rcu_torture_boost_failure++;
}
call_rcu_time = jiffies;
}
cond_resched();
rcu_stutter_wait("rcu_torture_boost");
if (kthread_should_stop() ||
fullstop != FULLSTOP_DONTSTOP)
goto checkwait;
}
/*
* Set the start time of the next test interval.
* Yes, this is vulnerable to long delays, but such
* delays simply cause a false negative for the next
* interval. Besides, we are running at RT priority,
* so delays should be relatively rare.
*/
while (oldstarttime == boost_starttime) {
if (mutex_trylock(&boost_mutex)) {
boost_starttime = jiffies +
test_boost_interval * HZ;
n_rcu_torture_boosts++;
mutex_unlock(&boost_mutex);
break;
}
schedule_timeout_uninterruptible(1);
}
/* Go do the stutter. */
checkwait: rcu_stutter_wait("rcu_torture_boost");
} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
/* Clean up and exit. */
VERBOSE_PRINTK_STRING("rcu_torture_boost task stopping");
destroy_rcu_head_on_stack(&rbi.rcu);
rcutorture_shutdown_absorb("rcu_torture_boost");
while (!kthread_should_stop() || rbi.inflight)
schedule_timeout_uninterruptible(1);
smp_mb(); /* order accesses to ->inflight before stack-frame death. */
return 0;
}
/*
* RCU torture force-quiescent-state kthread. Repeatedly induces
* bursts of calls to force_quiescent_state(), increasing the probability
* of occurrence of some important types of race conditions.
*/
static int
rcu_torture_fqs(void *arg)
{
unsigned long fqs_resume_time;
int fqs_burst_remaining;
VERBOSE_PRINTK_STRING("rcu_torture_fqs task started");
do {
fqs_resume_time = jiffies + fqs_stutter * HZ;
while (jiffies - fqs_resume_time > LONG_MAX) {
schedule_timeout_interruptible(1);
}
fqs_burst_remaining = fqs_duration;
while (fqs_burst_remaining > 0) {
cur_ops->fqs();
udelay(fqs_holdoff);
fqs_burst_remaining -= fqs_holdoff;
}
rcu_stutter_wait("rcu_torture_fqs");
} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
VERBOSE_PRINTK_STRING("rcu_torture_fqs task stopping");
rcutorture_shutdown_absorb("rcu_torture_fqs");
while (!kthread_should_stop())
schedule_timeout_uninterruptible(1);
return 0;
}
/*
* RCU torture writer kthread. Repeatedly substitutes a new structure
* for that pointed to by rcu_torture_current, freeing the old structure
* after a series of grace periods (the "pipeline").
*/
static int
rcu_torture_writer(void *arg)
{
int i;
long oldbatch = rcu_batches_completed();
struct rcu_torture *rp;
struct rcu_torture *old_rp;
static DEFINE_RCU_RANDOM(rand);
VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
set_user_nice(current, 19);
do {
schedule_timeout_uninterruptible(1);
rp = rcu_torture_alloc();
if (rp == NULL)
continue;
rp->rtort_pipe_count = 0;
udelay(rcu_random(&rand) & 0x3ff);
old_rp = rcu_dereference_check(rcu_torture_current,
current == writer_task);
rp->rtort_mbtest = 1;
rcu_assign_pointer(rcu_torture_current, rp);
smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
if (old_rp) {
i = old_rp->rtort_pipe_count;
if (i > RCU_TORTURE_PIPE_LEN)
i = RCU_TORTURE_PIPE_LEN;
atomic_inc(&rcu_torture_wcount[i]);
old_rp->rtort_pipe_count++;
cur_ops->deferred_free(old_rp);
}
rcutorture_record_progress(++rcu_torture_current_version);
oldbatch = cur_ops->completed();
rcu_stutter_wait("rcu_torture_writer");
} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
rcutorture_shutdown_absorb("rcu_torture_writer");
while (!kthread_should_stop())
schedule_timeout_uninterruptible(1);
return 0;
}
/*
* RCU torture fake writer kthread. Repeatedly calls sync, with a random
* delay between calls.
*/
static int
rcu_torture_fakewriter(void *arg)
{
DEFINE_RCU_RANDOM(rand);
VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
set_user_nice(current, 19);
do {
schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
udelay(rcu_random(&rand) & 0x3ff);
cur_ops->sync();
rcu_stutter_wait("rcu_torture_fakewriter");
} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
rcutorture_shutdown_absorb("rcu_torture_fakewriter");
while (!kthread_should_stop())
schedule_timeout_uninterruptible(1);
return 0;
}
/*
* RCU torture reader from timer handler. Dereferences rcu_torture_current,
* incrementing the corresponding element of the pipeline array. The
* counter in the element should never be greater than 1, otherwise, the
* RCU implementation is broken.
*/
static void rcu_torture_timer(unsigned long unused)
{
int idx;
int completed;
static DEFINE_RCU_RANDOM(rand);
static DEFINE_SPINLOCK(rand_lock);
struct rcu_torture *p;
int pipe_count;
idx = cur_ops->readlock();
completed = cur_ops->completed();
p = rcu_dereference_check(rcu_torture_current,
rcu_read_lock_held() ||
rcu_read_lock_bh_held() ||
rcu_read_lock_sched_held() ||
srcu_read_lock_held(&srcu_ctl));
if (p == NULL) {
/* Leave because rcu_torture_writer is not yet underway */
cur_ops->readunlock(idx);
return;
}
if (p->rtort_mbtest == 0)
atomic_inc(&n_rcu_torture_mberror);
spin_lock(&rand_lock);
cur_ops->read_delay(&rand);
n_rcu_torture_timers++;
spin_unlock(&rand_lock);
preempt_disable();
pipe_count = p->rtort_pipe_count;
if (pipe_count > RCU_TORTURE_PIPE_LEN) {
/* Should not happen, but... */
pipe_count = RCU_TORTURE_PIPE_LEN;
}
__this_cpu_inc(rcu_torture_count[pipe_count]);
completed = cur_ops->completed() - completed;
if (completed > RCU_TORTURE_PIPE_LEN) {
/* Should not happen, but... */
completed = RCU_TORTURE_PIPE_LEN;
}
__this_cpu_inc(rcu_torture_batch[completed]);
preempt_enable();
cur_ops->readunlock(idx);
}
/*
* RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
* incrementing the corresponding element of the pipeline array. The
* counter in the element should never be greater than 1, otherwise, the
* RCU implementation is broken.
*/
static int
rcu_torture_reader(void *arg)
{
int completed;
int idx;
DEFINE_RCU_RANDOM(rand);
struct rcu_torture *p;
int pipe_count;
struct timer_list t;
VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
set_user_nice(current, 19);
if (irqreader && cur_ops->irq_capable)
setup_timer_on_stack(&t, rcu_torture_timer, 0);
do {
if (irqreader && cur_ops->irq_capable) {
if (!timer_pending(&t))
mod_timer(&t, jiffies + 1);
}
idx = cur_ops->readlock();
completed = cur_ops->completed();
p = rcu_dereference_check(rcu_torture_current,
rcu_read_lock_held() ||
rcu_read_lock_bh_held() ||
rcu_read_lock_sched_held() ||
srcu_read_lock_held(&srcu_ctl));
if (p == NULL) {
/* Wait for rcu_torture_writer to get underway */
cur_ops->readunlock(idx);
schedule_timeout_interruptible(HZ);
continue;
}
if (p->rtort_mbtest == 0)
atomic_inc(&n_rcu_torture_mberror);
cur_ops->read_delay(&rand);
preempt_disable();
pipe_count = p->rtort_pipe_count;
if (pipe_count > RCU_TORTURE_PIPE_LEN) {
/* Should not happen, but... */
pipe_count = RCU_TORTURE_PIPE_LEN;
}
__this_cpu_inc(rcu_torture_count[pipe_count]);
completed = cur_ops->completed() - completed;
if (completed > RCU_TORTURE_PIPE_LEN) {
/* Should not happen, but... */
completed = RCU_TORTURE_PIPE_LEN;
}
__this_cpu_inc(rcu_torture_batch[completed]);
preempt_enable();
cur_ops->readunlock(idx);
schedule();
rcu_stutter_wait("rcu_torture_reader");
} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
rcutorture_shutdown_absorb("rcu_torture_reader");
if (irqreader && cur_ops->irq_capable)
del_timer_sync(&t);
while (!kthread_should_stop())
schedule_timeout_uninterruptible(1);
return 0;
}
/*
* Create an RCU-torture statistics message in the specified buffer.
*/
static int
rcu_torture_printk(char *page)
{
int cnt = 0;
int cpu;
int i;
long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
for_each_possible_cpu(cpu) {
for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
}
}
for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
if (pipesummary[i] != 0)
break;
}
cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
cnt += sprintf(&page[cnt],
"rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d "
"rtmbe: %d rtbke: %ld rtbre: %ld "
"rtbf: %ld rtb: %ld nt: %ld",
rcu_torture_current,
rcu_torture_current_version,
list_empty(&rcu_torture_freelist),
atomic_read(&n_rcu_torture_alloc),
atomic_read(&n_rcu_torture_alloc_fail),
atomic_read(&n_rcu_torture_free),
atomic_read(&n_rcu_torture_mberror),
n_rcu_torture_boost_ktrerror,
n_rcu_torture_boost_rterror,
n_rcu_torture_boost_failure,
n_rcu_torture_boosts,
n_rcu_torture_timers);
if (atomic_read(&n_rcu_torture_mberror) != 0 ||
n_rcu_torture_boost_ktrerror != 0 ||
n_rcu_torture_boost_rterror != 0 ||
n_rcu_torture_boost_failure != 0)
cnt += sprintf(&page[cnt], " !!!");
cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
if (i > 1) {
cnt += sprintf(&page[cnt], "!!! ");
atomic_inc(&n_rcu_torture_error);
WARN_ON_ONCE(1);
}
cnt += sprintf(&page[cnt], "Reader Pipe: ");
for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
cnt += sprintf(&page[cnt], "Reader Batch: ");
for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
cnt += sprintf(&page[cnt], " %d",
atomic_read(&rcu_torture_wcount[i]));
}
cnt += sprintf(&page[cnt], "\n");
if (cur_ops->stats)
cnt += cur_ops->stats(&page[cnt]);
return cnt;
}
/*
* 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 rcu_torture_stats
* kthread full control (or the init/cleanup functions when rcu_torture_stats
* thread is not running).
*/
static void
rcu_torture_stats_print(void)
{
int cnt;
cnt = rcu_torture_printk(printk_buf);
printk(KERN_ALERT "%s", printk_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
rcu_torture_stats(void *arg)
{
VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
do {
schedule_timeout_interruptible(stat_interval * HZ);
rcu_torture_stats_print();
rcutorture_shutdown_absorb("rcu_torture_stats");
} while (!kthread_should_stop());
VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
return 0;
}
static int rcu_idle_cpu; /* Force all torture tasks off this CPU */
/* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
* is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
*/
static void rcu_torture_shuffle_tasks(void)
{
int i;
cpumask_setall(shuffle_tmp_mask);
get_online_cpus();
/* No point in shuffling if there is only one online CPU (ex: UP) */
if (num_online_cpus() == 1) {
put_online_cpus();
return;
}
if (rcu_idle_cpu != -1)
cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
set_cpus_allowed_ptr(current, shuffle_tmp_mask);
if (reader_tasks) {
for (i = 0; i < nrealreaders; i++)
if (reader_tasks[i])
set_cpus_allowed_ptr(reader_tasks[i],
shuffle_tmp_mask);
}
if (fakewriter_tasks) {
for (i = 0; i < nfakewriters; i++)
if (fakewriter_tasks[i])
set_cpus_allowed_ptr(fakewriter_tasks[i],
shuffle_tmp_mask);
}
if (writer_task)
set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
if (stats_task)
set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
if (rcu_idle_cpu == -1)
rcu_idle_cpu = num_online_cpus() - 1;
else
rcu_idle_cpu--;
put_online_cpus();
}
/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
* system to become idle at a time and cut off its timer ticks. This is meant
* to test the support for such tickless idle CPU in RCU.
*/
static int
rcu_torture_shuffle(void *arg)
{
VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
do {
schedule_timeout_interruptible(shuffle_interval * HZ);
rcu_torture_shuffle_tasks();
rcutorture_shutdown_absorb("rcu_torture_shuffle");
} while (!kthread_should_stop());
VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
return 0;
}
/* Cause the rcutorture test to "stutter", starting and stopping all
* threads periodically.
*/
static int
rcu_torture_stutter(void *arg)
{
VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
do {
schedule_timeout_interruptible(stutter * HZ);
stutter_pause_test = 1;
if (!kthread_should_stop())
schedule_timeout_interruptible(stutter * HZ);
stutter_pause_test = 0;
rcutorture_shutdown_absorb("rcu_torture_stutter");
} while (!kthread_should_stop());
VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
return 0;
}
static inline void
rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, char *tag)
{
printk(KERN_ALERT "%s" TORTURE_FLAG
"--- %s: nreaders=%d nfakewriters=%d "
"stat_interval=%d verbose=%d test_no_idle_hz=%d "
"shuffle_interval=%d stutter=%d irqreader=%d "
"fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
"test_boost=%d/%d test_boost_interval=%d "
"test_boost_duration=%d\n",
torture_type, tag, nrealreaders, nfakewriters,
stat_interval, verbose, test_no_idle_hz, shuffle_interval,
stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
test_boost, cur_ops->can_boost,
test_boost_interval, test_boost_duration);
}
static struct notifier_block rcutorture_shutdown_nb = {
.notifier_call = rcutorture_shutdown_notify,
};
static void rcutorture_booster_cleanup(int cpu)
{
struct task_struct *t;
if (boost_tasks[cpu] == NULL)
return;
mutex_lock(&boost_mutex);
VERBOSE_PRINTK_STRING("Stopping rcu_torture_boost task");
t = boost_tasks[cpu];
boost_tasks[cpu] = NULL;
mutex_unlock(&boost_mutex);
/* This must be outside of the mutex, otherwise deadlock! */
kthread_stop(t);
}
static int rcutorture_booster_init(int cpu)
{
int retval;
if (boost_tasks[cpu] != NULL)
return 0; /* Already created, nothing more to do. */
/* Don't allow time recalculation while creating a new task. */
mutex_lock(&boost_mutex);
VERBOSE_PRINTK_STRING("Creating rcu_torture_boost task");
boost_tasks[cpu] = kthread_create(rcu_torture_boost, NULL,
"rcu_torture_boost");
if (IS_ERR(boost_tasks[cpu])) {
retval = PTR_ERR(boost_tasks[cpu]);
VERBOSE_PRINTK_STRING("rcu_torture_boost task create failed");
n_rcu_torture_boost_ktrerror++;
boost_tasks[cpu] = NULL;
mutex_unlock(&boost_mutex);
return retval;
}
kthread_bind(boost_tasks[cpu], cpu);
wake_up_process(boost_tasks[cpu]);
mutex_unlock(&boost_mutex);
return 0;
}
static int rcutorture_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
long cpu = (long)hcpu;
switch (action) {
case CPU_ONLINE:
case CPU_DOWN_FAILED:
(void)rcutorture_booster_init(cpu);
break;
case CPU_DOWN_PREPARE:
rcutorture_booster_cleanup(cpu);
break;
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block rcutorture_cpu_nb = {
.notifier_call = rcutorture_cpu_notify,
};
static void
rcu_torture_cleanup(void)
{
int i;
mutex_lock(&fullstop_mutex);
rcutorture_record_test_transition();
if (fullstop == FULLSTOP_SHUTDOWN) {
printk(KERN_WARNING /* but going down anyway, so... */
"Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
mutex_unlock(&fullstop_mutex);
schedule_timeout_uninterruptible(10);
if (cur_ops->cb_barrier != NULL)
cur_ops->cb_barrier();
return;
}
fullstop = FULLSTOP_RMMOD;
mutex_unlock(&fullstop_mutex);
unregister_reboot_notifier(&rcutorture_shutdown_nb);
if (stutter_task) {
VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
kthread_stop(stutter_task);
}
stutter_task = NULL;
if (shuffler_task) {
VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
kthread_stop(shuffler_task);
free_cpumask_var(shuffle_tmp_mask);
}
shuffler_task = NULL;
if (writer_task) {
VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
kthread_stop(writer_task);
}
writer_task = NULL;
if (reader_tasks) {
for (i = 0; i < nrealreaders; i++) {
if (reader_tasks[i]) {
VERBOSE_PRINTK_STRING(
"Stopping rcu_torture_reader task");
kthread_stop(reader_tasks[i]);
}
reader_tasks[i] = NULL;
}
kfree(reader_tasks);
reader_tasks = NULL;
}
rcu_torture_current = NULL;
if (fakewriter_tasks) {
for (i = 0; i < nfakewriters; i++) {
if (fakewriter_tasks[i]) {
VERBOSE_PRINTK_STRING(
"Stopping rcu_torture_fakewriter task");
kthread_stop(fakewriter_tasks[i]);
}
fakewriter_tasks[i] = NULL;
}
kfree(fakewriter_tasks);
fakewriter_tasks = NULL;
}
if (stats_task) {
VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
kthread_stop(stats_task);
}
stats_task = NULL;
if (fqs_task) {
VERBOSE_PRINTK_STRING("Stopping rcu_torture_fqs task");
kthread_stop(fqs_task);
}
fqs_task = NULL;
if ((test_boost == 1 && cur_ops->can_boost) ||
test_boost == 2) {
unregister_cpu_notifier(&rcutorture_cpu_nb);
for_each_possible_cpu(i)
rcutorture_booster_cleanup(i);
}
/* Wait for all RCU callbacks to fire. */
if (cur_ops->cb_barrier != NULL)
cur_ops->cb_barrier();
rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
if (cur_ops->cleanup)
cur_ops->cleanup();
if (atomic_read(&n_rcu_torture_error))
rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
else
rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
}
static int __init
rcu_torture_init(void)
{
int i;
int cpu;
int firsterr = 0;
static struct rcu_torture_ops *torture_ops[] =
{ &rcu_ops, &rcu_sync_ops, &rcu_expedited_ops,
&rcu_bh_ops, &rcu_bh_sync_ops,
&srcu_ops, &srcu_expedited_ops,
&sched_ops, &sched_sync_ops, &sched_expedited_ops, };
mutex_lock(&fullstop_mutex);
/* Process args and tell the world that the torturer is on the job. */
for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
cur_ops = torture_ops[i];
if (strcmp(torture_type, cur_ops->name) == 0)
break;
}
if (i == ARRAY_SIZE(torture_ops)) {
printk(KERN_ALERT "rcu-torture: invalid torture type: \"%s\"\n",
torture_type);
printk(KERN_ALERT "rcu-torture types:");
for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
printk(KERN_ALERT " %s", torture_ops[i]->name);
printk(KERN_ALERT "\n");
mutex_unlock(&fullstop_mutex);
return -EINVAL;
}
if (cur_ops->fqs == NULL && fqs_duration != 0) {
printk(KERN_ALERT "rcu-torture: ->fqs NULL and non-zero "
"fqs_duration, fqs disabled.\n");
fqs_duration = 0;
}
if (cur_ops->init)
cur_ops->init(); /* no "goto unwind" prior to this point!!! */
if (nreaders >= 0)
nrealreaders = nreaders;
else
nrealreaders = 2 * num_online_cpus();
rcu_torture_print_module_parms(cur_ops, "Start of test");
fullstop = FULLSTOP_DONTSTOP;
/* Set up the freelist. */
INIT_LIST_HEAD(&rcu_torture_freelist);
for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
rcu_tortures[i].rtort_mbtest = 0;
list_add_tail(&rcu_tortures[i].rtort_free,
&rcu_torture_freelist);
}
/* Initialize the statistics so that each run gets its own numbers. */
rcu_torture_current = NULL;
rcu_torture_current_version = 0;
atomic_set(&n_rcu_torture_alloc, 0);
atomic_set(&n_rcu_torture_alloc_fail, 0);
atomic_set(&n_rcu_torture_free, 0);
atomic_set(&n_rcu_torture_mberror, 0);
atomic_set(&n_rcu_torture_error, 0);
n_rcu_torture_boost_ktrerror = 0;
n_rcu_torture_boost_rterror = 0;
n_rcu_torture_boost_failure = 0;
n_rcu_torture_boosts = 0;
for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
atomic_set(&rcu_torture_wcount[i], 0);
for_each_possible_cpu(cpu) {
for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
per_cpu(rcu_torture_count, cpu)[i] = 0;
per_cpu(rcu_torture_batch, cpu)[i] = 0;
}
}
/* Start up the kthreads. */
VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
writer_task = kthread_run(rcu_torture_writer, NULL,
"rcu_torture_writer");
if (IS_ERR(writer_task)) {
firsterr = PTR_ERR(writer_task);
VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
writer_task = NULL;
goto unwind;
}
fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
GFP_KERNEL);
if (fakewriter_tasks == NULL) {
VERBOSE_PRINTK_ERRSTRING("out of memory");
firsterr = -ENOMEM;
goto unwind;
}
for (i = 0; i < nfakewriters; i++) {
VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
"rcu_torture_fakewriter");
if (IS_ERR(fakewriter_tasks[i])) {
firsterr = PTR_ERR(fakewriter_tasks[i]);
VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
fakewriter_tasks[i] = NULL;
goto unwind;
}
}
reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
GFP_KERNEL);
if (reader_tasks == NULL) {
VERBOSE_PRINTK_ERRSTRING("out of memory");
firsterr = -ENOMEM;
goto unwind;
}
for (i = 0; i < nrealreaders; i++) {
VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
"rcu_torture_reader");
if (IS_ERR(reader_tasks[i])) {
firsterr = PTR_ERR(reader_tasks[i]);
VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
reader_tasks[i] = NULL;
goto unwind;
}
}
if (stat_interval > 0) {
VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
stats_task = kthread_run(rcu_torture_stats, NULL,
"rcu_torture_stats");
if (IS_ERR(stats_task)) {
firsterr = PTR_ERR(stats_task);
VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
stats_task = NULL;
goto unwind;
}
}
if (test_no_idle_hz) {
rcu_idle_cpu = num_online_cpus() - 1;
if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
firsterr = -ENOMEM;
VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
goto unwind;
}
/* Create the shuffler thread */
shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
"rcu_torture_shuffle");
if (IS_ERR(shuffler_task)) {
free_cpumask_var(shuffle_tmp_mask);
firsterr = PTR_ERR(shuffler_task);
VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
shuffler_task = NULL;
goto unwind;
}
}
if (stutter < 0)
stutter = 0;
if (stutter) {
/* Create the stutter thread */
stutter_task = kthread_run(rcu_torture_stutter, NULL,
"rcu_torture_stutter");
if (IS_ERR(stutter_task)) {
firsterr = PTR_ERR(stutter_task);
VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
stutter_task = NULL;
goto unwind;
}
}
if (fqs_duration < 0)
fqs_duration = 0;
if (fqs_duration) {
/* Create the stutter thread */
fqs_task = kthread_run(rcu_torture_fqs, NULL,
"rcu_torture_fqs");
if (IS_ERR(fqs_task)) {
firsterr = PTR_ERR(fqs_task);
VERBOSE_PRINTK_ERRSTRING("Failed to create fqs");
fqs_task = NULL;
goto unwind;
}
}
if (test_boost_interval < 1)
test_boost_interval = 1;
if (test_boost_duration < 2)
test_boost_duration = 2;
if ((test_boost == 1 && cur_ops->can_boost) ||
test_boost == 2) {
int retval;
boost_starttime = jiffies + test_boost_interval * HZ;
register_cpu_notifier(&rcutorture_cpu_nb);
for_each_possible_cpu(i) {
if (cpu_is_offline(i))
continue; /* Heuristic: CPU can go offline. */
retval = rcutorture_booster_init(i);
if (retval < 0) {
firsterr = retval;
goto unwind;
}
}
}
register_reboot_notifier(&rcutorture_shutdown_nb);
rcutorture_record_test_transition();
mutex_unlock(&fullstop_mutex);
return 0;
unwind:
mutex_unlock(&fullstop_mutex);
rcu_torture_cleanup();
return firsterr;
}
module_init(rcu_torture_init);
module_exit(rcu_torture_cleanup);
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