1/*
   2 * Read-Copy Update module-based torture test facility
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License as published by
   6 * the Free Software Foundation; either version 2 of the License, or
   7 * (at your option) any later version.
   8 *
   9 * This program is distributed in the hope that it will be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write to the Free Software
  16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17 *
  18 * Copyright (C) IBM Corporation, 2005, 2006
  19 *
  20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
  21 *	  Josh Triplett <josh@freedesktop.org>
  22 *
  23 * See also:  Documentation/RCU/torture.txt
  24 */
  25#include <linux/types.h>
  26#include <linux/kernel.h>
  27#include <linux/init.h>
  28#include <linux/module.h>
  29#include <linux/kthread.h>
  30#include <linux/err.h>
  31#include <linux/spinlock.h>
  32#include <linux/smp.h>
  33#include <linux/rcupdate.h>
  34#include <linux/interrupt.h>
  35#include <linux/sched.h>
  36#include <linux/atomic.h>
  37#include <linux/bitops.h>
  38#include <linux/completion.h>
  39#include <linux/moduleparam.h>
  40#include <linux/percpu.h>
  41#include <linux/notifier.h>
  42#include <linux/reboot.h>
  43#include <linux/freezer.h>
  44#include <linux/cpu.h>
  45#include <linux/delay.h>
  46#include <linux/stat.h>
  47#include <linux/srcu.h>
  48#include <linux/slab.h>
  49#include <asm/byteorder.h>
  50
  51MODULE_LICENSE("GPL");
  52MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and "
  53	      "Josh Triplett <josh@freedesktop.org>");
  54
  55static int nreaders = -1;	/* # reader threads, defaults to 2*ncpus */
  56static int nfakewriters = 4;	/* # fake writer threads */
  57static int stat_interval;	/* Interval between stats, in seconds. */
  58				/*  Defaults to "only at end of test". */
  59static int verbose;		/* Print more debug info. */
  60static int test_no_idle_hz;	/* Test RCU's support for tickless idle CPUs. */
  61static int shuffle_interval = 3; /* Interval between shuffles (in sec)*/
  62static int stutter = 5;		/* Start/stop testing interval (in sec) */
  63static int irqreader = 1;	/* RCU readers from irq (timers). */
  64static int fqs_duration = 0;	/* Duration of bursts (us), 0 to disable. */
  65static int fqs_holdoff = 0;	/* Hold time within burst (us). */
  66static int fqs_stutter = 3;	/* Wait time between bursts (s). */
 
 
 
 
 
 
  67static int test_boost = 1;	/* Test RCU prio boost: 0=no, 1=maybe, 2=yes. */
  68static int test_boost_interval = 7; /* Interval between boost tests, seconds. */
  69static int test_boost_duration = 4; /* Duration of each boost test, seconds. */
  70static char *torture_type = "rcu"; /* What RCU implementation to torture. */
  71
  72module_param(nreaders, int, 0444);
  73MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
  74module_param(nfakewriters, int, 0444);
  75MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads");
  76module_param(stat_interval, int, 0444);
  77MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
  78module_param(verbose, bool, 0444);
  79MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
  80module_param(test_no_idle_hz, bool, 0444);
  81MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
  82module_param(shuffle_interval, int, 0444);
  83MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
  84module_param(stutter, int, 0444);
  85MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
  86module_param(irqreader, int, 0444);
  87MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers");
  88module_param(fqs_duration, int, 0444);
  89MODULE_PARM_DESC(fqs_duration, "Duration of fqs bursts (us)");
  90module_param(fqs_holdoff, int, 0444);
  91MODULE_PARM_DESC(fqs_holdoff, "Holdoff time within fqs bursts (us)");
  92module_param(fqs_stutter, int, 0444);
  93MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)");
 
 
 
 
 
 
 
 
 
 
 
 
  94module_param(test_boost, int, 0444);
  95MODULE_PARM_DESC(test_boost, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
  96module_param(test_boost_interval, int, 0444);
  97MODULE_PARM_DESC(test_boost_interval, "Interval between boost tests, seconds.");
  98module_param(test_boost_duration, int, 0444);
  99MODULE_PARM_DESC(test_boost_duration, "Duration of each boost test, seconds.");
 100module_param(torture_type, charp, 0444);
 101MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
 102
 103#define TORTURE_FLAG "-torture:"
 104#define PRINTK_STRING(s) \
 105	do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
 106#define VERBOSE_PRINTK_STRING(s) \
 107	do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
 108#define VERBOSE_PRINTK_ERRSTRING(s) \
 109	do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
 110
 111static char printk_buf[4096];
 112
 113static int nrealreaders;
 114static struct task_struct *writer_task;
 115static struct task_struct **fakewriter_tasks;
 116static struct task_struct **reader_tasks;
 117static struct task_struct *stats_task;
 118static struct task_struct *shuffler_task;
 119static struct task_struct *stutter_task;
 120static struct task_struct *fqs_task;
 121static struct task_struct *boost_tasks[NR_CPUS];
 
 
 
 
 
 
 
 122
 123#define RCU_TORTURE_PIPE_LEN 10
 124
 125struct rcu_torture {
 126	struct rcu_head rtort_rcu;
 127	int rtort_pipe_count;
 128	struct list_head rtort_free;
 129	int rtort_mbtest;
 130};
 131
 132static LIST_HEAD(rcu_torture_freelist);
 133static struct rcu_torture __rcu *rcu_torture_current;
 134static unsigned long rcu_torture_current_version;
 135static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
 136static DEFINE_SPINLOCK(rcu_torture_lock);
 137static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
 138	{ 0 };
 139static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
 140	{ 0 };
 141static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
 142static atomic_t n_rcu_torture_alloc;
 143static atomic_t n_rcu_torture_alloc_fail;
 144static atomic_t n_rcu_torture_free;
 145static atomic_t n_rcu_torture_mberror;
 146static atomic_t n_rcu_torture_error;
 
 147static long n_rcu_torture_boost_ktrerror;
 148static long n_rcu_torture_boost_rterror;
 149static long n_rcu_torture_boost_failure;
 150static long n_rcu_torture_boosts;
 151static long n_rcu_torture_timers;
 
 
 
 
 
 
 152static struct list_head rcu_torture_removed;
 153static cpumask_var_t shuffle_tmp_mask;
 154
 155static int stutter_pause_test;
 156
 157#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
 158#define RCUTORTURE_RUNNABLE_INIT 1
 159#else
 160#define RCUTORTURE_RUNNABLE_INIT 0
 161#endif
 162int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
 
 
 163
 164#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
 165#define rcu_can_boost() 1
 166#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
 167#define rcu_can_boost() 0
 168#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
 169
 
 170static unsigned long boost_starttime;	/* jiffies of next boost test start. */
 171DEFINE_MUTEX(boost_mutex);		/* protect setting boost_starttime */
 172					/*  and boost task create/destroy. */
 
 
 
 
 173
 174/* Mediate rmmod and system shutdown.  Concurrent rmmod & shutdown illegal! */
 175
 176#define FULLSTOP_DONTSTOP 0	/* Normal operation. */
 177#define FULLSTOP_SHUTDOWN 1	/* System shutdown with rcutorture running. */
 178#define FULLSTOP_RMMOD    2	/* Normal rmmod of rcutorture. */
 179static int fullstop = FULLSTOP_RMMOD;
 180/*
 181 * Protect fullstop transitions and spawning of kthreads.
 182 */
 183static DEFINE_MUTEX(fullstop_mutex);
 184
 
 
 
 185/*
 186 * Detect and respond to a system shutdown.
 187 */
 188static int
 189rcutorture_shutdown_notify(struct notifier_block *unused1,
 190			   unsigned long unused2, void *unused3)
 191{
 192	mutex_lock(&fullstop_mutex);
 193	if (fullstop == FULLSTOP_DONTSTOP)
 194		fullstop = FULLSTOP_SHUTDOWN;
 195	else
 196		printk(KERN_WARNING /* but going down anyway, so... */
 197		       "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
 198	mutex_unlock(&fullstop_mutex);
 199	return NOTIFY_DONE;
 200}
 201
 202/*
 203 * Absorb kthreads into a kernel function that won't return, so that
 204 * they won't ever access module text or data again.
 205 */
 206static void rcutorture_shutdown_absorb(char *title)
 207{
 208	if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
 209		printk(KERN_NOTICE
 210		       "rcutorture thread %s parking due to system shutdown\n",
 211		       title);
 212		schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
 213	}
 214}
 215
 216/*
 217 * Allocate an element from the rcu_tortures pool.
 218 */
 219static struct rcu_torture *
 220rcu_torture_alloc(void)
 221{
 222	struct list_head *p;
 223
 224	spin_lock_bh(&rcu_torture_lock);
 225	if (list_empty(&rcu_torture_freelist)) {
 226		atomic_inc(&n_rcu_torture_alloc_fail);
 227		spin_unlock_bh(&rcu_torture_lock);
 228		return NULL;
 229	}
 230	atomic_inc(&n_rcu_torture_alloc);
 231	p = rcu_torture_freelist.next;
 232	list_del_init(p);
 233	spin_unlock_bh(&rcu_torture_lock);
 234	return container_of(p, struct rcu_torture, rtort_free);
 235}
 236
 237/*
 238 * Free an element to the rcu_tortures pool.
 239 */
 240static void
 241rcu_torture_free(struct rcu_torture *p)
 242{
 243	atomic_inc(&n_rcu_torture_free);
 244	spin_lock_bh(&rcu_torture_lock);
 245	list_add_tail(&p->rtort_free, &rcu_torture_freelist);
 246	spin_unlock_bh(&rcu_torture_lock);
 247}
 248
 249struct rcu_random_state {
 250	unsigned long rrs_state;
 251	long rrs_count;
 252};
 253
 254#define RCU_RANDOM_MULT 39916801  /* prime */
 255#define RCU_RANDOM_ADD	479001701 /* prime */
 256#define RCU_RANDOM_REFRESH 10000
 257
 258#define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
 259
 260/*
 261 * Crude but fast random-number generator.  Uses a linear congruential
 262 * generator, with occasional help from cpu_clock().
 263 */
 264static unsigned long
 265rcu_random(struct rcu_random_state *rrsp)
 266{
 267	if (--rrsp->rrs_count < 0) {
 268		rrsp->rrs_state += (unsigned long)local_clock();
 269		rrsp->rrs_count = RCU_RANDOM_REFRESH;
 270	}
 271	rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
 272	return swahw32(rrsp->rrs_state);
 273}
 274
 275static void
 276rcu_stutter_wait(char *title)
 277{
 278	while (stutter_pause_test || !rcutorture_runnable) {
 279		if (rcutorture_runnable)
 280			schedule_timeout_interruptible(1);
 281		else
 282			schedule_timeout_interruptible(round_jiffies_relative(HZ));
 283		rcutorture_shutdown_absorb(title);
 284	}
 285}
 286
 287/*
 288 * Operations vector for selecting different types of tests.
 289 */
 290
 291struct rcu_torture_ops {
 292	void (*init)(void);
 293	void (*cleanup)(void);
 294	int (*readlock)(void);
 295	void (*read_delay)(struct rcu_random_state *rrsp);
 296	void (*readunlock)(int idx);
 297	int (*completed)(void);
 298	void (*deferred_free)(struct rcu_torture *p);
 299	void (*sync)(void);
 
 300	void (*cb_barrier)(void);
 301	void (*fqs)(void);
 302	int (*stats)(char *page);
 303	int irq_capable;
 304	int can_boost;
 305	char *name;
 306};
 307
 308static struct rcu_torture_ops *cur_ops;
 309
 310/*
 311 * Definitions for rcu torture testing.
 312 */
 313
 314static int rcu_torture_read_lock(void) __acquires(RCU)
 315{
 316	rcu_read_lock();
 317	return 0;
 318}
 319
 320static void rcu_read_delay(struct rcu_random_state *rrsp)
 321{
 322	const unsigned long shortdelay_us = 200;
 323	const unsigned long longdelay_ms = 50;
 324
 325	/* We want a short delay sometimes to make a reader delay the grace
 326	 * period, and we want a long delay occasionally to trigger
 327	 * force_quiescent_state. */
 328
 329	if (!(rcu_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
 330		mdelay(longdelay_ms);
 331	if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
 332		udelay(shortdelay_us);
 333#ifdef CONFIG_PREEMPT
 334	if (!preempt_count() && !(rcu_random(rrsp) % (nrealreaders * 20000)))
 335		preempt_schedule();  /* No QS if preempt_disable() in effect */
 336#endif
 337}
 338
 339static void rcu_torture_read_unlock(int idx) __releases(RCU)
 340{
 341	rcu_read_unlock();
 342}
 343
 344static int rcu_torture_completed(void)
 345{
 346	return rcu_batches_completed();
 347}
 348
 349static void
 350rcu_torture_cb(struct rcu_head *p)
 351{
 352	int i;
 353	struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
 354
 355	if (fullstop != FULLSTOP_DONTSTOP) {
 356		/* Test is ending, just drop callbacks on the floor. */
 357		/* The next initialization will pick up the pieces. */
 358		return;
 359	}
 360	i = rp->rtort_pipe_count;
 361	if (i > RCU_TORTURE_PIPE_LEN)
 362		i = RCU_TORTURE_PIPE_LEN;
 363	atomic_inc(&rcu_torture_wcount[i]);
 364	if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
 365		rp->rtort_mbtest = 0;
 366		rcu_torture_free(rp);
 367	} else
 368		cur_ops->deferred_free(rp);
 369}
 370
 371static int rcu_no_completed(void)
 372{
 373	return 0;
 374}
 375
 376static void rcu_torture_deferred_free(struct rcu_torture *p)
 377{
 378	call_rcu(&p->rtort_rcu, rcu_torture_cb);
 379}
 380
 381static struct rcu_torture_ops rcu_ops = {
 382	.init		= NULL,
 383	.cleanup	= NULL,
 384	.readlock	= rcu_torture_read_lock,
 385	.read_delay	= rcu_read_delay,
 386	.readunlock	= rcu_torture_read_unlock,
 387	.completed	= rcu_torture_completed,
 388	.deferred_free	= rcu_torture_deferred_free,
 389	.sync		= synchronize_rcu,
 
 390	.cb_barrier	= rcu_barrier,
 391	.fqs		= rcu_force_quiescent_state,
 392	.stats		= NULL,
 393	.irq_capable	= 1,
 394	.can_boost	= rcu_can_boost(),
 395	.name		= "rcu"
 396};
 397
 398static void rcu_sync_torture_deferred_free(struct rcu_torture *p)
 399{
 400	int i;
 401	struct rcu_torture *rp;
 402	struct rcu_torture *rp1;
 403
 404	cur_ops->sync();
 405	list_add(&p->rtort_free, &rcu_torture_removed);
 406	list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
 407		i = rp->rtort_pipe_count;
 408		if (i > RCU_TORTURE_PIPE_LEN)
 409			i = RCU_TORTURE_PIPE_LEN;
 410		atomic_inc(&rcu_torture_wcount[i]);
 411		if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
 412			rp->rtort_mbtest = 0;
 413			list_del(&rp->rtort_free);
 414			rcu_torture_free(rp);
 415		}
 416	}
 417}
 418
 419static void rcu_sync_torture_init(void)
 420{
 421	INIT_LIST_HEAD(&rcu_torture_removed);
 422}
 423
 424static struct rcu_torture_ops rcu_sync_ops = {
 425	.init		= rcu_sync_torture_init,
 426	.cleanup	= NULL,
 427	.readlock	= rcu_torture_read_lock,
 428	.read_delay	= rcu_read_delay,
 429	.readunlock	= rcu_torture_read_unlock,
 430	.completed	= rcu_torture_completed,
 431	.deferred_free	= rcu_sync_torture_deferred_free,
 432	.sync		= synchronize_rcu,
 
 433	.cb_barrier	= NULL,
 434	.fqs		= rcu_force_quiescent_state,
 435	.stats		= NULL,
 436	.irq_capable	= 1,
 437	.can_boost	= rcu_can_boost(),
 438	.name		= "rcu_sync"
 439};
 440
 441static struct rcu_torture_ops rcu_expedited_ops = {
 442	.init		= rcu_sync_torture_init,
 443	.cleanup	= NULL,
 444	.readlock	= rcu_torture_read_lock,
 445	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
 446	.readunlock	= rcu_torture_read_unlock,
 447	.completed	= rcu_no_completed,
 448	.deferred_free	= rcu_sync_torture_deferred_free,
 449	.sync		= synchronize_rcu_expedited,
 
 450	.cb_barrier	= NULL,
 451	.fqs		= rcu_force_quiescent_state,
 452	.stats		= NULL,
 453	.irq_capable	= 1,
 454	.can_boost	= rcu_can_boost(),
 455	.name		= "rcu_expedited"
 456};
 457
 458/*
 459 * Definitions for rcu_bh torture testing.
 460 */
 461
 462static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
 463{
 464	rcu_read_lock_bh();
 465	return 0;
 466}
 467
 468static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
 469{
 470	rcu_read_unlock_bh();
 471}
 472
 473static int rcu_bh_torture_completed(void)
 474{
 475	return rcu_batches_completed_bh();
 476}
 477
 478static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
 479{
 480	call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
 481}
 482
 483struct rcu_bh_torture_synchronize {
 484	struct rcu_head head;
 485	struct completion completion;
 486};
 487
 488static void rcu_bh_torture_wakeme_after_cb(struct rcu_head *head)
 489{
 490	struct rcu_bh_torture_synchronize *rcu;
 491
 492	rcu = container_of(head, struct rcu_bh_torture_synchronize, head);
 493	complete(&rcu->completion);
 494}
 495
 496static void rcu_bh_torture_synchronize(void)
 497{
 498	struct rcu_bh_torture_synchronize rcu;
 499
 500	init_rcu_head_on_stack(&rcu.head);
 501	init_completion(&rcu.completion);
 502	call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb);
 503	wait_for_completion(&rcu.completion);
 504	destroy_rcu_head_on_stack(&rcu.head);
 505}
 506
 507static struct rcu_torture_ops rcu_bh_ops = {
 508	.init		= NULL,
 509	.cleanup	= NULL,
 510	.readlock	= rcu_bh_torture_read_lock,
 511	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
 512	.readunlock	= rcu_bh_torture_read_unlock,
 513	.completed	= rcu_bh_torture_completed,
 514	.deferred_free	= rcu_bh_torture_deferred_free,
 515	.sync		= rcu_bh_torture_synchronize,
 
 516	.cb_barrier	= rcu_barrier_bh,
 517	.fqs		= rcu_bh_force_quiescent_state,
 518	.stats		= NULL,
 519	.irq_capable	= 1,
 520	.name		= "rcu_bh"
 521};
 522
 523static struct rcu_torture_ops rcu_bh_sync_ops = {
 524	.init		= rcu_sync_torture_init,
 525	.cleanup	= NULL,
 526	.readlock	= rcu_bh_torture_read_lock,
 527	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
 528	.readunlock	= rcu_bh_torture_read_unlock,
 529	.completed	= rcu_bh_torture_completed,
 530	.deferred_free	= rcu_sync_torture_deferred_free,
 531	.sync		= rcu_bh_torture_synchronize,
 
 532	.cb_barrier	= NULL,
 533	.fqs		= rcu_bh_force_quiescent_state,
 534	.stats		= NULL,
 535	.irq_capable	= 1,
 536	.name		= "rcu_bh_sync"
 537};
 538
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 539/*
 540 * Definitions for srcu torture testing.
 541 */
 542
 543static struct srcu_struct srcu_ctl;
 544
 545static void srcu_torture_init(void)
 546{
 547	init_srcu_struct(&srcu_ctl);
 548	rcu_sync_torture_init();
 549}
 550
 551static void srcu_torture_cleanup(void)
 552{
 553	synchronize_srcu(&srcu_ctl);
 554	cleanup_srcu_struct(&srcu_ctl);
 555}
 556
 557static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
 558{
 559	return srcu_read_lock(&srcu_ctl);
 560}
 561
 562static void srcu_read_delay(struct rcu_random_state *rrsp)
 563{
 564	long delay;
 565	const long uspertick = 1000000 / HZ;
 566	const long longdelay = 10;
 567
 568	/* We want there to be long-running readers, but not all the time. */
 569
 570	delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
 571	if (!delay)
 572		schedule_timeout_interruptible(longdelay);
 573	else
 574		rcu_read_delay(rrsp);
 575}
 576
 577static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
 578{
 579	srcu_read_unlock(&srcu_ctl, idx);
 580}
 581
 582static int srcu_torture_completed(void)
 583{
 584	return srcu_batches_completed(&srcu_ctl);
 585}
 586
 
 
 
 
 
 587static void srcu_torture_synchronize(void)
 588{
 589	synchronize_srcu(&srcu_ctl);
 590}
 591
 592static int srcu_torture_stats(char *page)
 593{
 594	int cnt = 0;
 595	int cpu;
 596	int idx = srcu_ctl.completed & 0x1;
 597
 598	cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):",
 599		       torture_type, TORTURE_FLAG, idx);
 600	for_each_possible_cpu(cpu) {
 601		cnt += sprintf(&page[cnt], " %d(%d,%d)", cpu,
 602			       per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
 603			       per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
 604	}
 605	cnt += sprintf(&page[cnt], "\n");
 606	return cnt;
 607}
 608
 609static struct rcu_torture_ops srcu_ops = {
 610	.init		= srcu_torture_init,
 611	.cleanup	= srcu_torture_cleanup,
 612	.readlock	= srcu_torture_read_lock,
 613	.read_delay	= srcu_read_delay,
 614	.readunlock	= srcu_torture_read_unlock,
 615	.completed	= srcu_torture_completed,
 616	.deferred_free	= rcu_sync_torture_deferred_free,
 617	.sync		= srcu_torture_synchronize,
 
 618	.cb_barrier	= NULL,
 619	.stats		= srcu_torture_stats,
 620	.name		= "srcu"
 621};
 622
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 623static void srcu_torture_synchronize_expedited(void)
 624{
 625	synchronize_srcu_expedited(&srcu_ctl);
 626}
 627
 628static struct rcu_torture_ops srcu_expedited_ops = {
 629	.init		= srcu_torture_init,
 630	.cleanup	= srcu_torture_cleanup,
 631	.readlock	= srcu_torture_read_lock,
 632	.read_delay	= srcu_read_delay,
 633	.readunlock	= srcu_torture_read_unlock,
 634	.completed	= srcu_torture_completed,
 635	.deferred_free	= rcu_sync_torture_deferred_free,
 636	.sync		= srcu_torture_synchronize_expedited,
 
 637	.cb_barrier	= NULL,
 638	.stats		= srcu_torture_stats,
 639	.name		= "srcu_expedited"
 640};
 641
 642/*
 643 * Definitions for sched torture testing.
 644 */
 645
 646static int sched_torture_read_lock(void)
 647{
 648	preempt_disable();
 649	return 0;
 650}
 651
 652static void sched_torture_read_unlock(int idx)
 653{
 654	preempt_enable();
 655}
 656
 657static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
 658{
 659	call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
 660}
 661
 662static void sched_torture_synchronize(void)
 663{
 664	synchronize_sched();
 665}
 666
 667static struct rcu_torture_ops sched_ops = {
 668	.init		= rcu_sync_torture_init,
 669	.cleanup	= NULL,
 670	.readlock	= sched_torture_read_lock,
 671	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
 672	.readunlock	= sched_torture_read_unlock,
 673	.completed	= rcu_no_completed,
 674	.deferred_free	= rcu_sched_torture_deferred_free,
 675	.sync		= sched_torture_synchronize,
 676	.cb_barrier	= rcu_barrier_sched,
 677	.fqs		= rcu_sched_force_quiescent_state,
 678	.stats		= NULL,
 679	.irq_capable	= 1,
 680	.name		= "sched"
 681};
 682
 683static struct rcu_torture_ops sched_sync_ops = {
 684	.init		= rcu_sync_torture_init,
 685	.cleanup	= NULL,
 686	.readlock	= sched_torture_read_lock,
 687	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
 688	.readunlock	= sched_torture_read_unlock,
 689	.completed	= rcu_no_completed,
 690	.deferred_free	= rcu_sync_torture_deferred_free,
 691	.sync		= sched_torture_synchronize,
 692	.cb_barrier	= NULL,
 693	.fqs		= rcu_sched_force_quiescent_state,
 694	.stats		= NULL,
 695	.name		= "sched_sync"
 696};
 697
 698static struct rcu_torture_ops sched_expedited_ops = {
 699	.init		= rcu_sync_torture_init,
 700	.cleanup	= NULL,
 701	.readlock	= sched_torture_read_lock,
 702	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
 703	.readunlock	= sched_torture_read_unlock,
 704	.completed	= rcu_no_completed,
 705	.deferred_free	= rcu_sync_torture_deferred_free,
 706	.sync		= synchronize_sched_expedited,
 707	.cb_barrier	= NULL,
 708	.fqs		= rcu_sched_force_quiescent_state,
 709	.stats		= NULL,
 710	.irq_capable	= 1,
 711	.name		= "sched_expedited"
 712};
 713
 714/*
 715 * RCU torture priority-boost testing.  Runs one real-time thread per
 716 * CPU for moderate bursts, repeatedly registering RCU callbacks and
 717 * spinning waiting for them to be invoked.  If a given callback takes
 718 * too long to be invoked, we assume that priority inversion has occurred.
 719 */
 720
 721struct rcu_boost_inflight {
 722	struct rcu_head rcu;
 723	int inflight;
 724};
 725
 726static void rcu_torture_boost_cb(struct rcu_head *head)
 727{
 728	struct rcu_boost_inflight *rbip =
 729		container_of(head, struct rcu_boost_inflight, rcu);
 730
 731	smp_mb(); /* Ensure RCU-core accesses precede clearing ->inflight */
 732	rbip->inflight = 0;
 733}
 734
 735static int rcu_torture_boost(void *arg)
 736{
 737	unsigned long call_rcu_time;
 738	unsigned long endtime;
 739	unsigned long oldstarttime;
 740	struct rcu_boost_inflight rbi = { .inflight = 0 };
 741	struct sched_param sp;
 742
 743	VERBOSE_PRINTK_STRING("rcu_torture_boost started");
 744
 745	/* Set real-time priority. */
 746	sp.sched_priority = 1;
 747	if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
 748		VERBOSE_PRINTK_STRING("rcu_torture_boost RT prio failed!");
 749		n_rcu_torture_boost_rterror++;
 750	}
 751
 752	init_rcu_head_on_stack(&rbi.rcu);
 753	/* Each pass through the following loop does one boost-test cycle. */
 754	do {
 755		/* Wait for the next test interval. */
 756		oldstarttime = boost_starttime;
 757		while (jiffies - oldstarttime > ULONG_MAX / 2) {
 758			schedule_timeout_uninterruptible(1);
 759			rcu_stutter_wait("rcu_torture_boost");
 760			if (kthread_should_stop() ||
 761			    fullstop != FULLSTOP_DONTSTOP)
 762				goto checkwait;
 763		}
 764
 765		/* Do one boost-test interval. */
 766		endtime = oldstarttime + test_boost_duration * HZ;
 767		call_rcu_time = jiffies;
 768		while (jiffies - endtime > ULONG_MAX / 2) {
 769			/* If we don't have a callback in flight, post one. */
 770			if (!rbi.inflight) {
 771				smp_mb(); /* RCU core before ->inflight = 1. */
 772				rbi.inflight = 1;
 773				call_rcu(&rbi.rcu, rcu_torture_boost_cb);
 774				if (jiffies - call_rcu_time >
 775					 test_boost_duration * HZ - HZ / 2) {
 776					VERBOSE_PRINTK_STRING("rcu_torture_boost boosting failed");
 777					n_rcu_torture_boost_failure++;
 778				}
 779				call_rcu_time = jiffies;
 780			}
 781			cond_resched();
 782			rcu_stutter_wait("rcu_torture_boost");
 783			if (kthread_should_stop() ||
 784			    fullstop != FULLSTOP_DONTSTOP)
 785				goto checkwait;
 786		}
 787
 788		/*
 789		 * Set the start time of the next test interval.
 790		 * Yes, this is vulnerable to long delays, but such
 791		 * delays simply cause a false negative for the next
 792		 * interval.  Besides, we are running at RT priority,
 793		 * so delays should be relatively rare.
 794		 */
 795		while (oldstarttime == boost_starttime) {
 
 796			if (mutex_trylock(&boost_mutex)) {
 797				boost_starttime = jiffies +
 798						  test_boost_interval * HZ;
 799				n_rcu_torture_boosts++;
 800				mutex_unlock(&boost_mutex);
 801				break;
 802			}
 803			schedule_timeout_uninterruptible(1);
 804		}
 805
 806		/* Go do the stutter. */
 807checkwait:	rcu_stutter_wait("rcu_torture_boost");
 808	} while (!kthread_should_stop() && fullstop  == FULLSTOP_DONTSTOP);
 809
 810	/* Clean up and exit. */
 811	VERBOSE_PRINTK_STRING("rcu_torture_boost task stopping");
 812	destroy_rcu_head_on_stack(&rbi.rcu);
 813	rcutorture_shutdown_absorb("rcu_torture_boost");
 814	while (!kthread_should_stop() || rbi.inflight)
 815		schedule_timeout_uninterruptible(1);
 816	smp_mb(); /* order accesses to ->inflight before stack-frame death. */
 
 817	return 0;
 818}
 819
 820/*
 821 * RCU torture force-quiescent-state kthread.  Repeatedly induces
 822 * bursts of calls to force_quiescent_state(), increasing the probability
 823 * of occurrence of some important types of race conditions.
 824 */
 825static int
 826rcu_torture_fqs(void *arg)
 827{
 828	unsigned long fqs_resume_time;
 829	int fqs_burst_remaining;
 830
 831	VERBOSE_PRINTK_STRING("rcu_torture_fqs task started");
 832	do {
 833		fqs_resume_time = jiffies + fqs_stutter * HZ;
 834		while (jiffies - fqs_resume_time > LONG_MAX) {
 
 835			schedule_timeout_interruptible(1);
 836		}
 837		fqs_burst_remaining = fqs_duration;
 838		while (fqs_burst_remaining > 0) {
 
 839			cur_ops->fqs();
 840			udelay(fqs_holdoff);
 841			fqs_burst_remaining -= fqs_holdoff;
 842		}
 843		rcu_stutter_wait("rcu_torture_fqs");
 844	} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
 845	VERBOSE_PRINTK_STRING("rcu_torture_fqs task stopping");
 846	rcutorture_shutdown_absorb("rcu_torture_fqs");
 847	while (!kthread_should_stop())
 848		schedule_timeout_uninterruptible(1);
 849	return 0;
 850}
 851
 852/*
 853 * RCU torture writer kthread.  Repeatedly substitutes a new structure
 854 * for that pointed to by rcu_torture_current, freeing the old structure
 855 * after a series of grace periods (the "pipeline").
 856 */
 857static int
 858rcu_torture_writer(void *arg)
 859{
 860	int i;
 861	long oldbatch = rcu_batches_completed();
 862	struct rcu_torture *rp;
 863	struct rcu_torture *old_rp;
 864	static DEFINE_RCU_RANDOM(rand);
 865
 866	VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
 867	set_user_nice(current, 19);
 868
 869	do {
 870		schedule_timeout_uninterruptible(1);
 871		rp = rcu_torture_alloc();
 872		if (rp == NULL)
 873			continue;
 874		rp->rtort_pipe_count = 0;
 875		udelay(rcu_random(&rand) & 0x3ff);
 876		old_rp = rcu_dereference_check(rcu_torture_current,
 877					       current == writer_task);
 878		rp->rtort_mbtest = 1;
 879		rcu_assign_pointer(rcu_torture_current, rp);
 880		smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
 881		if (old_rp) {
 882			i = old_rp->rtort_pipe_count;
 883			if (i > RCU_TORTURE_PIPE_LEN)
 884				i = RCU_TORTURE_PIPE_LEN;
 885			atomic_inc(&rcu_torture_wcount[i]);
 886			old_rp->rtort_pipe_count++;
 887			cur_ops->deferred_free(old_rp);
 888		}
 889		rcutorture_record_progress(++rcu_torture_current_version);
 890		oldbatch = cur_ops->completed();
 891		rcu_stutter_wait("rcu_torture_writer");
 892	} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
 893	VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
 894	rcutorture_shutdown_absorb("rcu_torture_writer");
 895	while (!kthread_should_stop())
 896		schedule_timeout_uninterruptible(1);
 897	return 0;
 898}
 899
 900/*
 901 * RCU torture fake writer kthread.  Repeatedly calls sync, with a random
 902 * delay between calls.
 903 */
 904static int
 905rcu_torture_fakewriter(void *arg)
 906{
 907	DEFINE_RCU_RANDOM(rand);
 908
 909	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
 910	set_user_nice(current, 19);
 911
 912	do {
 913		schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
 914		udelay(rcu_random(&rand) & 0x3ff);
 915		cur_ops->sync();
 916		rcu_stutter_wait("rcu_torture_fakewriter");
 917	} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
 918
 919	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
 920	rcutorture_shutdown_absorb("rcu_torture_fakewriter");
 921	while (!kthread_should_stop())
 922		schedule_timeout_uninterruptible(1);
 923	return 0;
 924}
 925
 
 
 
 
 
 
 
 
 
 
 
 
 926/*
 927 * RCU torture reader from timer handler.  Dereferences rcu_torture_current,
 928 * incrementing the corresponding element of the pipeline array.  The
 929 * counter in the element should never be greater than 1, otherwise, the
 930 * RCU implementation is broken.
 931 */
 932static void rcu_torture_timer(unsigned long unused)
 933{
 934	int idx;
 935	int completed;
 936	static DEFINE_RCU_RANDOM(rand);
 937	static DEFINE_SPINLOCK(rand_lock);
 938	struct rcu_torture *p;
 939	int pipe_count;
 940
 941	idx = cur_ops->readlock();
 942	completed = cur_ops->completed();
 943	p = rcu_dereference_check(rcu_torture_current,
 944				  rcu_read_lock_bh_held() ||
 945				  rcu_read_lock_sched_held() ||
 946				  srcu_read_lock_held(&srcu_ctl));
 947	if (p == NULL) {
 948		/* Leave because rcu_torture_writer is not yet underway */
 949		cur_ops->readunlock(idx);
 950		return;
 951	}
 
 952	if (p->rtort_mbtest == 0)
 953		atomic_inc(&n_rcu_torture_mberror);
 954	spin_lock(&rand_lock);
 955	cur_ops->read_delay(&rand);
 956	n_rcu_torture_timers++;
 957	spin_unlock(&rand_lock);
 958	preempt_disable();
 959	pipe_count = p->rtort_pipe_count;
 960	if (pipe_count > RCU_TORTURE_PIPE_LEN) {
 961		/* Should not happen, but... */
 962		pipe_count = RCU_TORTURE_PIPE_LEN;
 963	}
 
 
 964	__this_cpu_inc(rcu_torture_count[pipe_count]);
 965	completed = cur_ops->completed() - completed;
 966	if (completed > RCU_TORTURE_PIPE_LEN) {
 967		/* Should not happen, but... */
 968		completed = RCU_TORTURE_PIPE_LEN;
 969	}
 970	__this_cpu_inc(rcu_torture_batch[completed]);
 971	preempt_enable();
 972	cur_ops->readunlock(idx);
 973}
 974
 975/*
 976 * RCU torture reader kthread.  Repeatedly dereferences rcu_torture_current,
 977 * incrementing the corresponding element of the pipeline array.  The
 978 * counter in the element should never be greater than 1, otherwise, the
 979 * RCU implementation is broken.
 980 */
 981static int
 982rcu_torture_reader(void *arg)
 983{
 984	int completed;
 985	int idx;
 986	DEFINE_RCU_RANDOM(rand);
 987	struct rcu_torture *p;
 988	int pipe_count;
 989	struct timer_list t;
 990
 991	VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
 992	set_user_nice(current, 19);
 993	if (irqreader && cur_ops->irq_capable)
 994		setup_timer_on_stack(&t, rcu_torture_timer, 0);
 995
 996	do {
 997		if (irqreader && cur_ops->irq_capable) {
 998			if (!timer_pending(&t))
 999				mod_timer(&t, jiffies + 1);
1000		}
1001		idx = cur_ops->readlock();
1002		completed = cur_ops->completed();
1003		p = rcu_dereference_check(rcu_torture_current,
1004					  rcu_read_lock_bh_held() ||
1005					  rcu_read_lock_sched_held() ||
1006					  srcu_read_lock_held(&srcu_ctl));
1007		if (p == NULL) {
1008			/* Wait for rcu_torture_writer to get underway */
1009			cur_ops->readunlock(idx);
1010			schedule_timeout_interruptible(HZ);
1011			continue;
1012		}
 
1013		if (p->rtort_mbtest == 0)
1014			atomic_inc(&n_rcu_torture_mberror);
1015		cur_ops->read_delay(&rand);
1016		preempt_disable();
1017		pipe_count = p->rtort_pipe_count;
1018		if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1019			/* Should not happen, but... */
1020			pipe_count = RCU_TORTURE_PIPE_LEN;
1021		}
 
 
1022		__this_cpu_inc(rcu_torture_count[pipe_count]);
1023		completed = cur_ops->completed() - completed;
1024		if (completed > RCU_TORTURE_PIPE_LEN) {
1025			/* Should not happen, but... */
1026			completed = RCU_TORTURE_PIPE_LEN;
1027		}
1028		__this_cpu_inc(rcu_torture_batch[completed]);
1029		preempt_enable();
1030		cur_ops->readunlock(idx);
1031		schedule();
1032		rcu_stutter_wait("rcu_torture_reader");
1033	} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1034	VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
1035	rcutorture_shutdown_absorb("rcu_torture_reader");
1036	if (irqreader && cur_ops->irq_capable)
1037		del_timer_sync(&t);
1038	while (!kthread_should_stop())
1039		schedule_timeout_uninterruptible(1);
1040	return 0;
1041}
1042
1043/*
1044 * Create an RCU-torture statistics message in the specified buffer.
1045 */
1046static int
1047rcu_torture_printk(char *page)
1048{
1049	int cnt = 0;
1050	int cpu;
1051	int i;
1052	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1053	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1054
1055	for_each_possible_cpu(cpu) {
1056		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1057			pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1058			batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1059		}
1060	}
1061	for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1062		if (pipesummary[i] != 0)
1063			break;
1064	}
1065	cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
1066	cnt += sprintf(&page[cnt],
1067		       "rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d "
1068		       "rtmbe: %d rtbke: %ld rtbre: %ld "
1069		       "rtbf: %ld rtb: %ld nt: %ld",
 
 
1070		       rcu_torture_current,
1071		       rcu_torture_current_version,
1072		       list_empty(&rcu_torture_freelist),
1073		       atomic_read(&n_rcu_torture_alloc),
1074		       atomic_read(&n_rcu_torture_alloc_fail),
1075		       atomic_read(&n_rcu_torture_free),
1076		       atomic_read(&n_rcu_torture_mberror),
1077		       n_rcu_torture_boost_ktrerror,
1078		       n_rcu_torture_boost_rterror,
1079		       n_rcu_torture_boost_failure,
1080		       n_rcu_torture_boosts,
1081		       n_rcu_torture_timers);
 
 
 
 
 
 
 
 
1082	if (atomic_read(&n_rcu_torture_mberror) != 0 ||
 
1083	    n_rcu_torture_boost_ktrerror != 0 ||
1084	    n_rcu_torture_boost_rterror != 0 ||
1085	    n_rcu_torture_boost_failure != 0)
1086		cnt += sprintf(&page[cnt], " !!!");
1087	cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
1088	if (i > 1) {
1089		cnt += sprintf(&page[cnt], "!!! ");
1090		atomic_inc(&n_rcu_torture_error);
1091		WARN_ON_ONCE(1);
1092	}
1093	cnt += sprintf(&page[cnt], "Reader Pipe: ");
1094	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1095		cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
1096	cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
1097	cnt += sprintf(&page[cnt], "Reader Batch: ");
1098	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1099		cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
1100	cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
1101	cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
1102	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1103		cnt += sprintf(&page[cnt], " %d",
1104			       atomic_read(&rcu_torture_wcount[i]));
1105	}
1106	cnt += sprintf(&page[cnt], "\n");
1107	if (cur_ops->stats)
1108		cnt += cur_ops->stats(&page[cnt]);
1109	return cnt;
1110}
1111
1112/*
1113 * Print torture statistics.  Caller must ensure that there is only
1114 * one call to this function at a given time!!!  This is normally
1115 * accomplished by relying on the module system to only have one copy
1116 * of the module loaded, and then by giving the rcu_torture_stats
1117 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1118 * thread is not running).
1119 */
1120static void
1121rcu_torture_stats_print(void)
1122{
1123	int cnt;
1124
1125	cnt = rcu_torture_printk(printk_buf);
1126	printk(KERN_ALERT "%s", printk_buf);
1127}
1128
1129/*
1130 * Periodically prints torture statistics, if periodic statistics printing
1131 * was specified via the stat_interval module parameter.
1132 *
1133 * No need to worry about fullstop here, since this one doesn't reference
1134 * volatile state or register callbacks.
1135 */
1136static int
1137rcu_torture_stats(void *arg)
1138{
1139	VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
1140	do {
1141		schedule_timeout_interruptible(stat_interval * HZ);
1142		rcu_torture_stats_print();
1143		rcutorture_shutdown_absorb("rcu_torture_stats");
1144	} while (!kthread_should_stop());
1145	VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
1146	return 0;
1147}
1148
1149static int rcu_idle_cpu;	/* Force all torture tasks off this CPU */
1150
1151/* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
1152 * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
1153 */
1154static void rcu_torture_shuffle_tasks(void)
1155{
1156	int i;
1157
1158	cpumask_setall(shuffle_tmp_mask);
1159	get_online_cpus();
1160
1161	/* No point in shuffling if there is only one online CPU (ex: UP) */
1162	if (num_online_cpus() == 1) {
1163		put_online_cpus();
1164		return;
1165	}
1166
1167	if (rcu_idle_cpu != -1)
1168		cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
1169
1170	set_cpus_allowed_ptr(current, shuffle_tmp_mask);
1171
1172	if (reader_tasks) {
1173		for (i = 0; i < nrealreaders; i++)
1174			if (reader_tasks[i])
1175				set_cpus_allowed_ptr(reader_tasks[i],
1176						     shuffle_tmp_mask);
1177	}
1178
1179	if (fakewriter_tasks) {
1180		for (i = 0; i < nfakewriters; i++)
1181			if (fakewriter_tasks[i])
1182				set_cpus_allowed_ptr(fakewriter_tasks[i],
1183						     shuffle_tmp_mask);
1184	}
1185
1186	if (writer_task)
1187		set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
1188
1189	if (stats_task)
1190		set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
1191
1192	if (rcu_idle_cpu == -1)
1193		rcu_idle_cpu = num_online_cpus() - 1;
1194	else
1195		rcu_idle_cpu--;
1196
1197	put_online_cpus();
1198}
1199
1200/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
1201 * system to become idle at a time and cut off its timer ticks. This is meant
1202 * to test the support for such tickless idle CPU in RCU.
1203 */
1204static int
1205rcu_torture_shuffle(void *arg)
1206{
1207	VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
1208	do {
1209		schedule_timeout_interruptible(shuffle_interval * HZ);
1210		rcu_torture_shuffle_tasks();
1211		rcutorture_shutdown_absorb("rcu_torture_shuffle");
1212	} while (!kthread_should_stop());
1213	VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
1214	return 0;
1215}
1216
1217/* Cause the rcutorture test to "stutter", starting and stopping all
1218 * threads periodically.
1219 */
1220static int
1221rcu_torture_stutter(void *arg)
1222{
1223	VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
1224	do {
1225		schedule_timeout_interruptible(stutter * HZ);
1226		stutter_pause_test = 1;
1227		if (!kthread_should_stop())
1228			schedule_timeout_interruptible(stutter * HZ);
1229		stutter_pause_test = 0;
1230		rcutorture_shutdown_absorb("rcu_torture_stutter");
1231	} while (!kthread_should_stop());
1232	VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
1233	return 0;
1234}
1235
1236static inline void
1237rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, char *tag)
1238{
1239	printk(KERN_ALERT "%s" TORTURE_FLAG
1240		"--- %s: nreaders=%d nfakewriters=%d "
1241		"stat_interval=%d verbose=%d test_no_idle_hz=%d "
1242		"shuffle_interval=%d stutter=%d irqreader=%d "
1243		"fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1244		"test_boost=%d/%d test_boost_interval=%d "
1245		"test_boost_duration=%d\n",
 
1246		torture_type, tag, nrealreaders, nfakewriters,
1247		stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1248		stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1249		test_boost, cur_ops->can_boost,
1250		test_boost_interval, test_boost_duration);
 
1251}
1252
1253static struct notifier_block rcutorture_shutdown_nb = {
1254	.notifier_call = rcutorture_shutdown_notify,
1255};
1256
1257static void rcutorture_booster_cleanup(int cpu)
1258{
1259	struct task_struct *t;
1260
1261	if (boost_tasks[cpu] == NULL)
1262		return;
1263	mutex_lock(&boost_mutex);
1264	VERBOSE_PRINTK_STRING("Stopping rcu_torture_boost task");
1265	t = boost_tasks[cpu];
1266	boost_tasks[cpu] = NULL;
1267	mutex_unlock(&boost_mutex);
1268
1269	/* This must be outside of the mutex, otherwise deadlock! */
1270	kthread_stop(t);
 
1271}
1272
1273static int rcutorture_booster_init(int cpu)
1274{
1275	int retval;
1276
1277	if (boost_tasks[cpu] != NULL)
1278		return 0;  /* Already created, nothing more to do. */
1279
1280	/* Don't allow time recalculation while creating a new task. */
1281	mutex_lock(&boost_mutex);
1282	VERBOSE_PRINTK_STRING("Creating rcu_torture_boost task");
1283	boost_tasks[cpu] = kthread_create(rcu_torture_boost, NULL,
1284					  "rcu_torture_boost");
 
1285	if (IS_ERR(boost_tasks[cpu])) {
1286		retval = PTR_ERR(boost_tasks[cpu]);
1287		VERBOSE_PRINTK_STRING("rcu_torture_boost task create failed");
1288		n_rcu_torture_boost_ktrerror++;
1289		boost_tasks[cpu] = NULL;
1290		mutex_unlock(&boost_mutex);
1291		return retval;
1292	}
1293	kthread_bind(boost_tasks[cpu], cpu);
1294	wake_up_process(boost_tasks[cpu]);
1295	mutex_unlock(&boost_mutex);
1296	return 0;
1297}
1298
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1299static int rcutorture_cpu_notify(struct notifier_block *self,
1300				 unsigned long action, void *hcpu)
1301{
1302	long cpu = (long)hcpu;
1303
1304	switch (action) {
1305	case CPU_ONLINE:
1306	case CPU_DOWN_FAILED:
1307		(void)rcutorture_booster_init(cpu);
1308		break;
1309	case CPU_DOWN_PREPARE:
1310		rcutorture_booster_cleanup(cpu);
1311		break;
1312	default:
1313		break;
1314	}
1315	return NOTIFY_OK;
1316}
1317
1318static struct notifier_block rcutorture_cpu_nb = {
1319	.notifier_call = rcutorture_cpu_notify,
1320};
1321
1322static void
1323rcu_torture_cleanup(void)
1324{
1325	int i;
1326
1327	mutex_lock(&fullstop_mutex);
1328	rcutorture_record_test_transition();
1329	if (fullstop == FULLSTOP_SHUTDOWN) {
1330		printk(KERN_WARNING /* but going down anyway, so... */
1331		       "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
1332		mutex_unlock(&fullstop_mutex);
1333		schedule_timeout_uninterruptible(10);
1334		if (cur_ops->cb_barrier != NULL)
1335			cur_ops->cb_barrier();
1336		return;
1337	}
1338	fullstop = FULLSTOP_RMMOD;
1339	mutex_unlock(&fullstop_mutex);
1340	unregister_reboot_notifier(&rcutorture_shutdown_nb);
 
 
1341	if (stutter_task) {
1342		VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
1343		kthread_stop(stutter_task);
1344	}
1345	stutter_task = NULL;
1346	if (shuffler_task) {
1347		VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
1348		kthread_stop(shuffler_task);
1349		free_cpumask_var(shuffle_tmp_mask);
1350	}
1351	shuffler_task = NULL;
1352
1353	if (writer_task) {
1354		VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
1355		kthread_stop(writer_task);
1356	}
1357	writer_task = NULL;
1358
1359	if (reader_tasks) {
1360		for (i = 0; i < nrealreaders; i++) {
1361			if (reader_tasks[i]) {
1362				VERBOSE_PRINTK_STRING(
1363					"Stopping rcu_torture_reader task");
1364				kthread_stop(reader_tasks[i]);
1365			}
1366			reader_tasks[i] = NULL;
1367		}
1368		kfree(reader_tasks);
1369		reader_tasks = NULL;
1370	}
1371	rcu_torture_current = NULL;
1372
1373	if (fakewriter_tasks) {
1374		for (i = 0; i < nfakewriters; i++) {
1375			if (fakewriter_tasks[i]) {
1376				VERBOSE_PRINTK_STRING(
1377					"Stopping rcu_torture_fakewriter task");
1378				kthread_stop(fakewriter_tasks[i]);
1379			}
1380			fakewriter_tasks[i] = NULL;
1381		}
1382		kfree(fakewriter_tasks);
1383		fakewriter_tasks = NULL;
1384	}
1385
1386	if (stats_task) {
1387		VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
1388		kthread_stop(stats_task);
1389	}
1390	stats_task = NULL;
1391
1392	if (fqs_task) {
1393		VERBOSE_PRINTK_STRING("Stopping rcu_torture_fqs task");
1394		kthread_stop(fqs_task);
1395	}
1396	fqs_task = NULL;
1397	if ((test_boost == 1 && cur_ops->can_boost) ||
1398	    test_boost == 2) {
1399		unregister_cpu_notifier(&rcutorture_cpu_nb);
1400		for_each_possible_cpu(i)
1401			rcutorture_booster_cleanup(i);
1402	}
 
 
 
 
 
 
1403
1404	/* Wait for all RCU callbacks to fire.  */
1405
1406	if (cur_ops->cb_barrier != NULL)
1407		cur_ops->cb_barrier();
1408
1409	rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
1410
1411	if (cur_ops->cleanup)
1412		cur_ops->cleanup();
1413	if (atomic_read(&n_rcu_torture_error))
1414		rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
 
 
 
 
1415	else
1416		rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1417}
1418
1419static int __init
1420rcu_torture_init(void)
1421{
1422	int i;
1423	int cpu;
1424	int firsterr = 0;
 
1425	static struct rcu_torture_ops *torture_ops[] =
1426		{ &rcu_ops, &rcu_sync_ops, &rcu_expedited_ops,
1427		  &rcu_bh_ops, &rcu_bh_sync_ops,
1428		  &srcu_ops, &srcu_expedited_ops,
 
1429		  &sched_ops, &sched_sync_ops, &sched_expedited_ops, };
1430
1431	mutex_lock(&fullstop_mutex);
1432
1433	/* Process args and tell the world that the torturer is on the job. */
1434	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1435		cur_ops = torture_ops[i];
1436		if (strcmp(torture_type, cur_ops->name) == 0)
1437			break;
1438	}
1439	if (i == ARRAY_SIZE(torture_ops)) {
1440		printk(KERN_ALERT "rcu-torture: invalid torture type: \"%s\"\n",
1441		       torture_type);
1442		printk(KERN_ALERT "rcu-torture types:");
1443		for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1444			printk(KERN_ALERT " %s", torture_ops[i]->name);
1445		printk(KERN_ALERT "\n");
1446		mutex_unlock(&fullstop_mutex);
1447		return -EINVAL;
1448	}
1449	if (cur_ops->fqs == NULL && fqs_duration != 0) {
1450		printk(KERN_ALERT "rcu-torture: ->fqs NULL and non-zero "
1451				  "fqs_duration, fqs disabled.\n");
1452		fqs_duration = 0;
1453	}
1454	if (cur_ops->init)
1455		cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1456
1457	if (nreaders >= 0)
1458		nrealreaders = nreaders;
1459	else
1460		nrealreaders = 2 * num_online_cpus();
1461	rcu_torture_print_module_parms(cur_ops, "Start of test");
1462	fullstop = FULLSTOP_DONTSTOP;
1463
1464	/* Set up the freelist. */
1465
1466	INIT_LIST_HEAD(&rcu_torture_freelist);
1467	for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1468		rcu_tortures[i].rtort_mbtest = 0;
1469		list_add_tail(&rcu_tortures[i].rtort_free,
1470			      &rcu_torture_freelist);
1471	}
1472
1473	/* Initialize the statistics so that each run gets its own numbers. */
1474
1475	rcu_torture_current = NULL;
1476	rcu_torture_current_version = 0;
1477	atomic_set(&n_rcu_torture_alloc, 0);
1478	atomic_set(&n_rcu_torture_alloc_fail, 0);
1479	atomic_set(&n_rcu_torture_free, 0);
1480	atomic_set(&n_rcu_torture_mberror, 0);
1481	atomic_set(&n_rcu_torture_error, 0);
 
1482	n_rcu_torture_boost_ktrerror = 0;
1483	n_rcu_torture_boost_rterror = 0;
1484	n_rcu_torture_boost_failure = 0;
1485	n_rcu_torture_boosts = 0;
1486	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1487		atomic_set(&rcu_torture_wcount[i], 0);
1488	for_each_possible_cpu(cpu) {
1489		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1490			per_cpu(rcu_torture_count, cpu)[i] = 0;
1491			per_cpu(rcu_torture_batch, cpu)[i] = 0;
1492		}
1493	}
1494
1495	/* Start up the kthreads. */
1496
1497	VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
1498	writer_task = kthread_run(rcu_torture_writer, NULL,
1499				  "rcu_torture_writer");
1500	if (IS_ERR(writer_task)) {
1501		firsterr = PTR_ERR(writer_task);
1502		VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
1503		writer_task = NULL;
1504		goto unwind;
1505	}
1506	fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
1507				   GFP_KERNEL);
1508	if (fakewriter_tasks == NULL) {
1509		VERBOSE_PRINTK_ERRSTRING("out of memory");
1510		firsterr = -ENOMEM;
1511		goto unwind;
1512	}
1513	for (i = 0; i < nfakewriters; i++) {
1514		VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
1515		fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
1516						  "rcu_torture_fakewriter");
1517		if (IS_ERR(fakewriter_tasks[i])) {
1518			firsterr = PTR_ERR(fakewriter_tasks[i]);
1519			VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
1520			fakewriter_tasks[i] = NULL;
1521			goto unwind;
1522		}
1523	}
1524	reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1525			       GFP_KERNEL);
1526	if (reader_tasks == NULL) {
1527		VERBOSE_PRINTK_ERRSTRING("out of memory");
1528		firsterr = -ENOMEM;
1529		goto unwind;
1530	}
1531	for (i = 0; i < nrealreaders; i++) {
1532		VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
1533		reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
1534					      "rcu_torture_reader");
1535		if (IS_ERR(reader_tasks[i])) {
1536			firsterr = PTR_ERR(reader_tasks[i]);
1537			VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
1538			reader_tasks[i] = NULL;
1539			goto unwind;
1540		}
1541	}
1542	if (stat_interval > 0) {
1543		VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
1544		stats_task = kthread_run(rcu_torture_stats, NULL,
1545					"rcu_torture_stats");
1546		if (IS_ERR(stats_task)) {
1547			firsterr = PTR_ERR(stats_task);
1548			VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
1549			stats_task = NULL;
1550			goto unwind;
1551		}
1552	}
1553	if (test_no_idle_hz) {
1554		rcu_idle_cpu = num_online_cpus() - 1;
1555
1556		if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
1557			firsterr = -ENOMEM;
1558			VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
1559			goto unwind;
1560		}
1561
1562		/* Create the shuffler thread */
1563		shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
1564					  "rcu_torture_shuffle");
1565		if (IS_ERR(shuffler_task)) {
1566			free_cpumask_var(shuffle_tmp_mask);
1567			firsterr = PTR_ERR(shuffler_task);
1568			VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
1569			shuffler_task = NULL;
1570			goto unwind;
1571		}
1572	}
1573	if (stutter < 0)
1574		stutter = 0;
1575	if (stutter) {
1576		/* Create the stutter thread */
1577		stutter_task = kthread_run(rcu_torture_stutter, NULL,
1578					  "rcu_torture_stutter");
1579		if (IS_ERR(stutter_task)) {
1580			firsterr = PTR_ERR(stutter_task);
1581			VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
1582			stutter_task = NULL;
1583			goto unwind;
1584		}
1585	}
1586	if (fqs_duration < 0)
1587		fqs_duration = 0;
1588	if (fqs_duration) {
1589		/* Create the stutter thread */
1590		fqs_task = kthread_run(rcu_torture_fqs, NULL,
1591				       "rcu_torture_fqs");
1592		if (IS_ERR(fqs_task)) {
1593			firsterr = PTR_ERR(fqs_task);
1594			VERBOSE_PRINTK_ERRSTRING("Failed to create fqs");
1595			fqs_task = NULL;
1596			goto unwind;
1597		}
1598	}
1599	if (test_boost_interval < 1)
1600		test_boost_interval = 1;
1601	if (test_boost_duration < 2)
1602		test_boost_duration = 2;
1603	if ((test_boost == 1 && cur_ops->can_boost) ||
1604	    test_boost == 2) {
1605		int retval;
1606
1607		boost_starttime = jiffies + test_boost_interval * HZ;
1608		register_cpu_notifier(&rcutorture_cpu_nb);
1609		for_each_possible_cpu(i) {
1610			if (cpu_is_offline(i))
1611				continue;  /* Heuristic: CPU can go offline. */
1612			retval = rcutorture_booster_init(i);
1613			if (retval < 0) {
1614				firsterr = retval;
1615				goto unwind;
1616			}
1617		}
1618	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1619	register_reboot_notifier(&rcutorture_shutdown_nb);
 
 
 
 
 
 
 
 
 
 
1620	rcutorture_record_test_transition();
1621	mutex_unlock(&fullstop_mutex);
1622	return 0;
1623
1624unwind:
1625	mutex_unlock(&fullstop_mutex);
1626	rcu_torture_cleanup();
1627	return firsterr;
1628}
1629
1630module_init(rcu_torture_init);
1631module_exit(rcu_torture_cleanup);