diff options
Diffstat (limited to 'kernel/rcutorture.c')
| -rw-r--r-- | kernel/rcutorture.c | 492 |
1 files changed, 0 insertions, 492 deletions
diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c deleted file mode 100644 index 9b58f1eff3c..00000000000 --- a/kernel/rcutorture.c +++ /dev/null @@ -1,492 +0,0 @@ -/* - * Read-Copy Update /proc-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 - * - * Authors: Paul E. McKenney <paulmck@us.ibm.com> - * - * 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/module.h> -#include <linux/completion.h> -#include <linux/moduleparam.h> -#include <linux/percpu.h> -#include <linux/notifier.h> -#include <linux/rcuref.h> -#include <linux/cpu.h> -#include <linux/random.h> -#include <linux/delay.h> -#include <linux/byteorder/swabb.h> -#include <linux/stat.h> - -MODULE_LICENSE("GPL"); - -static int nreaders = -1; /* # reader threads, defaults to 4*ncpus */ -static int stat_interval = 0; /* Interval between stats, in seconds. */ - /* Defaults to "only at end of test". */ -static int verbose = 0; /* Print more debug info. */ - -MODULE_PARM(nreaders, "i"); -MODULE_PARM_DESC(nreaders, "Number of RCU reader threads"); -MODULE_PARM(stat_interval, "i"); -MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s"); -MODULE_PARM(verbose, "i"); -MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s"); -#define TORTURE_FLAG "rcutorture: " -#define PRINTK_STRING(s) \ - do { printk(KERN_ALERT TORTURE_FLAG s "\n"); } while (0) -#define VERBOSE_PRINTK_STRING(s) \ - do { if (verbose) printk(KERN_ALERT TORTURE_FLAG s "\n"); } while (0) -#define VERBOSE_PRINTK_ERRSTRING(s) \ - do { if (verbose) printk(KERN_ALERT TORTURE_FLAG "!!! " s "\n"); } while (0) - -static char printk_buf[4096]; - -static int nrealreaders; -static struct task_struct *writer_task; -static struct task_struct **reader_tasks; -static struct task_struct *stats_task; - -#define RCU_TORTURE_PIPE_LEN 10 - -struct rcu_torture { - struct rcu_head rtort_rcu; - int rtort_pipe_count; - struct list_head rtort_free; -}; - -static int fullstop = 0; /* stop generating callbacks at test end. */ -static LIST_HEAD(rcu_torture_freelist); -static struct rcu_torture *rcu_torture_current = NULL; -static long rcu_torture_current_version = 0; -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]; -atomic_t n_rcu_torture_alloc; -atomic_t n_rcu_torture_alloc_fail; -atomic_t n_rcu_torture_free; - -/* - * Allocate an element from the rcu_tortures pool. - */ -struct rcu_torture * -rcu_torture_alloc(void) -{ - struct list_head *p; - - spin_lock(&rcu_torture_lock); - if (list_empty(&rcu_torture_freelist)) { - atomic_inc(&n_rcu_torture_alloc_fail); - spin_unlock(&rcu_torture_lock); - return NULL; - } - atomic_inc(&n_rcu_torture_alloc); - p = rcu_torture_freelist.next; - list_del_init(p); - spin_unlock(&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(&rcu_torture_lock); - list_add_tail(&p->rtort_free, &rcu_torture_freelist); - spin_unlock(&rcu_torture_lock); -} - -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) { - /* 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) - rcu_torture_free(rp); - else - call_rcu(p, rcu_torture_cb); -} - -struct rcu_random_state { - unsigned long rrs_state; - unsigned 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 get_random_bytes(). - */ -static long -rcu_random(struct rcu_random_state *rrsp) -{ - long refresh; - - if (--rrsp->rrs_count < 0) { - get_random_bytes(&refresh, sizeof(refresh)); - rrsp->rrs_state += refresh; - rrsp->rrs_count = RCU_RANDOM_REFRESH; - } - rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD; - return swahw32(rrsp->rrs_state); -} - -/* - * 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"); - do { - schedule_timeout_uninterruptible(1); - if (rcu_batches_completed() == oldbatch) - continue; - if ((rp = rcu_torture_alloc()) == NULL) - continue; - rp->rtort_pipe_count = 0; - udelay(rcu_random(&rand) & 0x3ff); - old_rp = rcu_torture_current; - rcu_assign_pointer(rcu_torture_current, rp); - smp_wmb(); - if (old_rp != NULL) { - 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++; - call_rcu(&old_rp->rtort_rcu, rcu_torture_cb); - } - rcu_torture_current_version++; - oldbatch = rcu_batches_completed(); - } while (!kthread_should_stop() && !fullstop); - VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping"); - while (!kthread_should_stop()) - schedule_timeout_uninterruptible(1); - return 0; -} - -/* - * 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; - DEFINE_RCU_RANDOM(rand); - struct rcu_torture *p; - int pipe_count; - - VERBOSE_PRINTK_STRING("rcu_torture_reader task started"); - do { - rcu_read_lock(); - completed = rcu_batches_completed(); - p = rcu_dereference(rcu_torture_current); - if (p == NULL) { - /* Wait for rcu_torture_writer to get underway */ - rcu_read_unlock(); - schedule_timeout_interruptible(HZ); - continue; - } - udelay(rcu_random(&rand) & 0x7f); - 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; - } - ++__get_cpu_var(rcu_torture_count)[pipe_count]; - completed = rcu_batches_completed() - completed; - if (completed > RCU_TORTURE_PIPE_LEN) { - /* Should not happen, but... */ - completed = RCU_TORTURE_PIPE_LEN; - } - ++__get_cpu_var(rcu_torture_batch)[completed]; - preempt_enable(); - rcu_read_unlock(); - schedule(); - } while (!kthread_should_stop() && !fullstop); - VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping"); - 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_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], "rcutorture: "); - cnt += sprintf(&page[cnt], - "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d", - 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)); - cnt += sprintf(&page[cnt], "\nrcutorture: "); - if (i > 1) - cnt += sprintf(&page[cnt], "!!! "); - 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], "\nrcutorture: "); - cnt += sprintf(&page[cnt], "Reader Batch: "); - for (i = 0; i < RCU_TORTURE_PIPE_LEN; i++) - cnt += sprintf(&page[cnt], " %ld", batchsummary[i]); - cnt += sprintf(&page[cnt], "\nrcutorture: "); - 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"); - 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(); - } while (!kthread_should_stop()); - VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping"); - return 0; -} - -static void -rcu_torture_cleanup(void) -{ - int i; - - fullstop = 1; - if (writer_task != NULL) { - VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task"); - kthread_stop(writer_task); - } - writer_task = NULL; - - if (reader_tasks != NULL) { - for (i = 0; i < nrealreaders; i++) { - if (reader_tasks[i] != NULL) { - 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 (stats_task != NULL) { - VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task"); - kthread_stop(stats_task); - } - stats_task = NULL; - - /* Wait for all RCU callbacks to fire. */ - - for (i = 0; i < RCU_TORTURE_PIPE_LEN; i++) - synchronize_rcu(); - rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ - PRINTK_STRING("--- End of test"); -} - -static int -rcu_torture_init(void) -{ - int i; - int cpu; - int firsterr = 0; - - /* Process args and tell the world that the torturer is on the job. */ - - if (nreaders >= 0) - nrealreaders = nreaders; - else - nrealreaders = 2 * num_online_cpus(); - printk(KERN_ALERT TORTURE_FLAG - "--- Start of test: nreaders=%d stat_interval=%d verbose=%d\n", - nrealreaders, stat_interval, verbose); - fullstop = 0; - - /* Set up the freelist. */ - - INIT_LIST_HEAD(&rcu_torture_freelist); - for (i = 0; i < sizeof(rcu_tortures) / sizeof(rcu_tortures[0]); i++) { - 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); - for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) - atomic_set(&rcu_torture_wcount[i], 0); - for_each_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; - } - reader_tasks = kmalloc(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; - } - } - return 0; - -unwind: - rcu_torture_cleanup(); - return firsterr; -} - -module_init(rcu_torture_init); -module_exit(rcu_torture_cleanup); |