X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Frcutorture.c;h=c3e165c2318f16657023d7693dd6a77762945861;hb=8002cedc1adbf51e2d56091534ef7551b88329b4;hp=4f2c4272d59c91bda58823e8f6e04e121c85458d;hpb=9a69d1aeccf169d9a1e442c07d3a6e87f06a7b49;p=linux-2.6 diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index 4f2c4272d5..c3e165c231 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -15,9 +15,10 @@ * 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 + * Copyright (C) IBM Corporation, 2005, 2006 * * Authors: Paul E. McKenney + * Josh Triplett * * See also: Documentation/RCU/torture.txt */ @@ -34,39 +35,44 @@ #include #include #include -#include #include #include #include #include +#include #include -#include #include #include #include +#include MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Paul E. McKenney and " + "Josh Triplett "); -static int nreaders = -1; /* # reader threads, defaults to 4*ncpus */ +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 = 5; /* Interval between shuffles (in sec)*/ -static char *torture_type = "rcu"; /* What to torture. */ +static char *torture_type = "rcu"; /* What RCU implementation to torture. */ -module_param(nreaders, int, 0); +module_param(nreaders, int, 0444); MODULE_PARM_DESC(nreaders, "Number of RCU reader threads"); -module_param(stat_interval, int, 0); +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, 0); +module_param(verbose, bool, 0444); MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s"); -module_param(test_no_idle_hz, bool, 0); +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, 0); +module_param(shuffle_interval, int, 0444); MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles"); -module_param(torture_type, charp, 0); -MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh)"); +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) \ @@ -80,6 +86,7 @@ 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; @@ -104,11 +111,12 @@ static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) = 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; -atomic_t n_rcu_torture_mberror; -atomic_t n_rcu_torture_error; +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 struct list_head rcu_torture_removed; /* * Allocate an element from the rcu_tortures pool. @@ -145,7 +153,7 @@ rcu_torture_free(struct rcu_torture *p) struct rcu_random_state { unsigned long rrs_state; - unsigned long rrs_count; + long rrs_count; }; #define RCU_RANDOM_MULT 39916801 /* prime */ @@ -156,16 +164,14 @@ struct rcu_random_state { /* * Crude but fast random-number generator. Uses a linear congruential - * generator, with occasional help from get_random_bytes(). + * generator, with occasional help from cpu_clock(). */ -static long +static unsigned 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_state += + (unsigned long)cpu_clock(raw_smp_processor_id()); rrsp->rrs_count = RCU_RANDOM_REFRESH; } rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD; @@ -180,9 +186,11 @@ struct rcu_torture_ops { void (*init)(void); void (*cleanup)(void); int (*readlock)(void); + void (*readdelay)(struct rcu_random_state *rrsp); void (*readunlock)(int idx); int (*completed)(void); void (*deferredfree)(struct rcu_torture *p); + void (*sync)(void); int (*stats)(char *page); char *name; }; @@ -198,6 +206,18 @@ static int rcu_torture_read_lock(void) __acquires(RCU) return 0; } +static void rcu_read_delay(struct rcu_random_state *rrsp) +{ + long delay; + const long longdelay = 200; + + /* We want there to be long-running readers, but not all the time. */ + + delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay); + if (!delay) + udelay(longdelay); +} + static void rcu_torture_read_unlock(int idx) __releases(RCU) { rcu_read_unlock(); @@ -239,13 +259,54 @@ static struct rcu_torture_ops rcu_ops = { .init = NULL, .cleanup = NULL, .readlock = rcu_torture_read_lock, + .readdelay = rcu_read_delay, .readunlock = rcu_torture_read_unlock, .completed = rcu_torture_completed, .deferredfree = rcu_torture_deferred_free, + .sync = synchronize_rcu, .stats = NULL, .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, + .readdelay = rcu_read_delay, + .readunlock = rcu_torture_read_unlock, + .completed = rcu_torture_completed, + .deferredfree = rcu_sync_torture_deferred_free, + .sync = synchronize_rcu, + .stats = NULL, + .name = "rcu_sync" +}; + /* * Definitions for rcu_bh torture testing. */ @@ -271,19 +332,172 @@ 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_completion(&rcu.completion); + call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb); + wait_for_completion(&rcu.completion); +} + static struct rcu_torture_ops rcu_bh_ops = { .init = NULL, .cleanup = NULL, .readlock = rcu_bh_torture_read_lock, + .readdelay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = rcu_bh_torture_read_unlock, .completed = rcu_bh_torture_completed, .deferredfree = rcu_bh_torture_deferred_free, + .sync = rcu_bh_torture_synchronize, .stats = NULL, .name = "rcu_bh" }; -static struct rcu_torture_ops *torture_ops[] = - { &rcu_ops, &rcu_bh_ops, NULL }; +static struct rcu_torture_ops rcu_bh_sync_ops = { + .init = rcu_sync_torture_init, + .cleanup = NULL, + .readlock = rcu_bh_torture_read_lock, + .readdelay = rcu_read_delay, /* just reuse rcu's version. */ + .readunlock = rcu_bh_torture_read_unlock, + .completed = rcu_bh_torture_completed, + .deferredfree = rcu_sync_torture_deferred_free, + .sync = rcu_bh_torture_synchronize, + .stats = NULL, + .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); +} + +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, + .readdelay = srcu_read_delay, + .readunlock = srcu_torture_read_unlock, + .completed = srcu_torture_completed, + .deferredfree = rcu_sync_torture_deferred_free, + .sync = srcu_torture_synchronize, + .stats = srcu_torture_stats, + .name = "srcu" +}; + +/* + * 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 int sched_torture_completed(void) +{ + return 0; +} + +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, + .readdelay = rcu_read_delay, /* just reuse rcu's version. */ + .readunlock = sched_torture_read_unlock, + .completed = sched_torture_completed, + .deferredfree = rcu_sync_torture_deferred_free, + .sync = sched_torture_synchronize, + .stats = NULL, + .name = "sched" +}; /* * RCU torture writer kthread. Repeatedly substitutes a new structure @@ -312,7 +526,7 @@ rcu_torture_writer(void *arg) rp->rtort_mbtest = 1; rcu_assign_pointer(rcu_torture_current, rp); smp_wmb(); - if (old_rp != NULL) { + if (old_rp) { i = old_rp->rtort_pipe_count; if (i > RCU_TORTURE_PIPE_LEN) i = RCU_TORTURE_PIPE_LEN; @@ -329,6 +543,30 @@ rcu_torture_writer(void *arg) 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(); + } while (!kthread_should_stop() && !fullstop); + + VERBOSE_PRINTK_STRING("rcu_torture_fakewriter 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 @@ -359,7 +597,7 @@ rcu_torture_reader(void *arg) } if (p->rtort_mbtest == 0) atomic_inc(&n_rcu_torture_mberror); - udelay(rcu_random(&rand) & 0x7f); + cur_ops->readdelay(&rand); preempt_disable(); pipe_count = p->rtort_pipe_count; if (pipe_count > RCU_TORTURE_PIPE_LEN) { @@ -437,7 +675,7 @@ rcu_torture_printk(char *page) atomic_read(&rcu_torture_wcount[i])); } cnt += sprintf(&page[cnt], "\n"); - if (cur_ops->stats != NULL) + if (cur_ops->stats) cnt += cur_ops->stats(&page[cnt]); return cnt; } @@ -483,7 +721,7 @@ 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. */ -void rcu_torture_shuffle_tasks(void) +static void rcu_torture_shuffle_tasks(void) { cpumask_t tmp_mask = CPU_MASK_ALL; int i; @@ -501,12 +739,18 @@ void rcu_torture_shuffle_tasks(void) set_cpus_allowed(current, tmp_mask); - if (reader_tasks != NULL) { + if (reader_tasks) { for (i = 0; i < nrealreaders; i++) if (reader_tasks[i]) set_cpus_allowed(reader_tasks[i], tmp_mask); } + if (fakewriter_tasks) { + for (i = 0; i < nfakewriters; i++) + if (fakewriter_tasks[i]) + set_cpus_allowed(fakewriter_tasks[i], tmp_mask); + } + if (writer_task) set_cpus_allowed(writer_task, tmp_mask); @@ -540,11 +784,12 @@ rcu_torture_shuffle(void *arg) static inline void rcu_torture_print_module_parms(char *tag) { - printk(KERN_ALERT "%s" TORTURE_FLAG "--- %s: nreaders=%d " + printk(KERN_ALERT "%s" TORTURE_FLAG + "--- %s: nreaders=%d nfakewriters=%d " "stat_interval=%d verbose=%d test_no_idle_hz=%d " "shuffle_interval = %d\n", - torture_type, tag, nrealreaders, stat_interval, verbose, - test_no_idle_hz, shuffle_interval); + torture_type, tag, nrealreaders, nfakewriters, + stat_interval, verbose, test_no_idle_hz, shuffle_interval); } static void @@ -553,21 +798,21 @@ rcu_torture_cleanup(void) int i; fullstop = 1; - if (shuffler_task != NULL) { + if (shuffler_task) { VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task"); kthread_stop(shuffler_task); } shuffler_task = NULL; - if (writer_task != NULL) { + if (writer_task) { VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task"); kthread_stop(writer_task); } writer_task = NULL; - if (reader_tasks != NULL) { + if (reader_tasks) { for (i = 0; i < nrealreaders; i++) { - if (reader_tasks[i] != NULL) { + if (reader_tasks[i]) { VERBOSE_PRINTK_STRING( "Stopping rcu_torture_reader task"); kthread_stop(reader_tasks[i]); @@ -579,7 +824,20 @@ rcu_torture_cleanup(void) } rcu_torture_current = NULL; - if (stats_task != 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); } @@ -590,7 +848,7 @@ rcu_torture_cleanup(void) rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ - if (cur_ops->cleanup != NULL) + if (cur_ops->cleanup) cur_ops->cleanup(); if (atomic_read(&n_rcu_torture_error)) rcu_torture_print_module_parms("End of test: FAILURE"); @@ -598,27 +856,28 @@ rcu_torture_cleanup(void) rcu_torture_print_module_parms("End of test: SUCCESS"); } -static int +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_bh_ops, &rcu_bh_sync_ops, + &srcu_ops, &sched_ops, }; /* Process args and tell the world that the torturer is on the job. */ - - for (i = 0; cur_ops = torture_ops[i], cur_ops != NULL; i++) { + for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { cur_ops = torture_ops[i]; - if (strcmp(torture_type, cur_ops->name) == 0) { + if (strcmp(torture_type, cur_ops->name) == 0) break; - } } - if (cur_ops == NULL) { + if (i == ARRAY_SIZE(torture_ops)) { printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n", torture_type); return (-EINVAL); } - if (cur_ops->init != NULL) + if (cur_ops->init) cur_ops->init(); /* no "goto unwind" prior to this point!!! */ if (nreaders >= 0) @@ -631,7 +890,7 @@ rcu_torture_init(void) /* Set up the freelist. */ INIT_LIST_HEAD(&rcu_torture_freelist); - for (i = 0; i < sizeof(rcu_tortures) / sizeof(rcu_tortures[0]); i++) { + 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); @@ -666,7 +925,25 @@ rcu_torture_init(void) writer_task = NULL; goto unwind; } - reader_tasks = kmalloc(nrealreaders * sizeof(reader_tasks[0]), + 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");