diff options
| -rw-r--r-- | Documentation/RCU/torture.txt | 15 | ||||
| -rw-r--r-- | kernel/rcutorture.c | 194 |
2 files changed, 200 insertions, 9 deletions
diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt index 375d3fb7143..4ddf3913fd8 100644 --- a/Documentation/RCU/torture.txt +++ b/Documentation/RCU/torture.txt @@ -47,6 +47,16 @@ irqreader Says to invoke RCU readers from irq level. This is currently permit this. (Or, more accurately, variants of RCU that do -not- permit this know to ignore this variable.) +n_barrier_cbs If this is nonzero, RCU barrier testing will be conducted, + in which case n_barrier_cbs specifies the number of + RCU callbacks (and corresponding kthreads) to use for + this testing. The value cannot be negative. If you + specify this to be non-zero when torture_type indicates a + synchronous RCU implementation (one for which a member of + the synchronize_rcu() rather than the call_rcu() family is + used -- see the documentation for torture_type below), an + error will be reported and no testing will be carried out. + nfakewriters This is the number of RCU fake writer threads to run. Fake writer threads repeatedly use the synchronous "wait for current readers" function of the interface selected by @@ -188,7 +198,7 @@ OUTPUT The statistics output is as follows: rcu-torture:--- Start of test: nreaders=16 nfakewriters=4 stat_interval=30 verbose=0 test_no_idle_hz=1 shuffle_interval=3 stutter=5 irqreader=1 fqs_duration=0 fqs_holdoff=0 fqs_stutter=3 test_boost=1/0 test_boost_interval=7 test_boost_duration=4 - rcu-torture: rtc: (null) ver: 155441 tfle: 0 rta: 155441 rtaf: 8884 rtf: 155440 rtmbe: 0 rtbke: 0 rtbre: 0 rtbf: 0 rtb: 0 nt: 3055767 + rcu-torture: rtc: (null) ver: 155441 tfle: 0 rta: 155441 rtaf: 8884 rtf: 155440 rtmbe: 0 rtbe: 0 rtbke: 0 rtbre: 0 rtbf: 0 rtb: 0 nt: 3055767 rcu-torture: Reader Pipe: 727860534 34213 0 0 0 0 0 0 0 0 0 rcu-torture: Reader Batch: 727877838 17003 0 0 0 0 0 0 0 0 0 rcu-torture: Free-Block Circulation: 155440 155440 155440 155440 155440 155440 155440 155440 155440 155440 0 @@ -230,6 +240,9 @@ o "rtmbe": A non-zero value indicates that rcutorture believes that rcu_assign_pointer() and rcu_dereference() are not working correctly. This value should be zero. +o "rtbe": A non-zero value indicates that one of the rcu_barrier() + family of functions is not working correctly. + o "rtbke": rcutorture was unable to create the real-time kthreads used to force RCU priority inversion. This value should be zero. diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index 1463a063644..8cd262b4149 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -64,6 +64,7 @@ static int irqreader = 1; /* RCU readers from irq (timers). */ static int fqs_duration; /* Duration of bursts (us), 0 to disable. */ static int fqs_holdoff; /* Hold time within burst (us). */ static int fqs_stutter = 3; /* Wait time between bursts (s). */ +static int n_barrier_cbs; /* Number of callbacks to test RCU barriers. */ static int onoff_interval; /* Wait time between CPU hotplugs, 0=disable. */ static int onoff_holdoff; /* Seconds after boot before CPU hotplugs. */ static int shutdown_secs; /* Shutdown time (s). <=0 for no shutdown. */ @@ -96,6 +97,8 @@ 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(n_barrier_cbs, int, 0444); +MODULE_PARM_DESC(n_barrier_cbs, "# of callbacks/kthreads for barrier testing"); module_param(onoff_interval, int, 0444); MODULE_PARM_DESC(onoff_interval, "Time between CPU hotplugs (s), 0=disable"); module_param(onoff_holdoff, int, 0444); @@ -139,6 +142,8 @@ static struct task_struct *shutdown_task; static struct task_struct *onoff_task; #endif /* #ifdef CONFIG_HOTPLUG_CPU */ static struct task_struct *stall_task; +static struct task_struct **barrier_cbs_tasks; +static struct task_struct *barrier_task; #define RCU_TORTURE_PIPE_LEN 10 @@ -164,6 +169,7 @@ 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_barrier_error; static long n_rcu_torture_boost_ktrerror; static long n_rcu_torture_boost_rterror; static long n_rcu_torture_boost_failure; @@ -173,6 +179,8 @@ static long n_offline_attempts; static long n_offline_successes; static long n_online_attempts; static long n_online_successes; +static long n_barrier_attempts; +static long n_barrier_successes; static struct list_head rcu_torture_removed; static cpumask_var_t shuffle_tmp_mask; @@ -197,6 +205,10 @@ static unsigned long shutdown_time; /* jiffies to system shutdown. */ static unsigned long boost_starttime; /* jiffies of next boost test start. */ DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */ /* and boost task create/destroy. */ +static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */ +static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */ +static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */ +static DECLARE_WAIT_QUEUE_HEAD(barrier_wq); /* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */ @@ -327,6 +339,7 @@ struct rcu_torture_ops { int (*completed)(void); void (*deferred_free)(struct rcu_torture *p); void (*sync)(void); + void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); void (*cb_barrier)(void); void (*fqs)(void); int (*stats)(char *page); @@ -417,6 +430,7 @@ static struct rcu_torture_ops rcu_ops = { .completed = rcu_torture_completed, .deferred_free = rcu_torture_deferred_free, .sync = synchronize_rcu, + .call = call_rcu, .cb_barrier = rcu_barrier, .fqs = rcu_force_quiescent_state, .stats = NULL, @@ -460,6 +474,7 @@ static struct rcu_torture_ops rcu_sync_ops = { .completed = rcu_torture_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = synchronize_rcu, + .call = NULL, .cb_barrier = NULL, .fqs = rcu_force_quiescent_state, .stats = NULL, @@ -477,6 +492,7 @@ static struct rcu_torture_ops rcu_expedited_ops = { .completed = rcu_no_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = synchronize_rcu_expedited, + .call = NULL, .cb_barrier = NULL, .fqs = rcu_force_quiescent_state, .stats = NULL, @@ -519,6 +535,7 @@ static struct rcu_torture_ops rcu_bh_ops = { .completed = rcu_bh_torture_completed, .deferred_free = rcu_bh_torture_deferred_free, .sync = synchronize_rcu_bh, + .call = call_rcu_bh, .cb_barrier = rcu_barrier_bh, .fqs = rcu_bh_force_quiescent_state, .stats = NULL, @@ -535,6 +552,7 @@ static struct rcu_torture_ops rcu_bh_sync_ops = { .completed = rcu_bh_torture_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = synchronize_rcu_bh, + .call = NULL, .cb_barrier = NULL, .fqs = rcu_bh_force_quiescent_state, .stats = NULL, @@ -551,6 +569,7 @@ static struct rcu_torture_ops rcu_bh_expedited_ops = { .completed = rcu_bh_torture_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = synchronize_rcu_bh_expedited, + .call = NULL, .cb_barrier = NULL, .fqs = rcu_bh_force_quiescent_state, .stats = NULL, @@ -637,6 +656,7 @@ static struct rcu_torture_ops srcu_ops = { .completed = srcu_torture_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = srcu_torture_synchronize, + .call = NULL, .cb_barrier = NULL, .stats = srcu_torture_stats, .name = "srcu" @@ -661,6 +681,7 @@ static struct rcu_torture_ops srcu_raw_ops = { .completed = srcu_torture_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = srcu_torture_synchronize, + .call = NULL, .cb_barrier = NULL, .stats = srcu_torture_stats, .name = "srcu_raw" @@ -680,6 +701,7 @@ static struct rcu_torture_ops srcu_expedited_ops = { .completed = srcu_torture_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = srcu_torture_synchronize_expedited, + .call = NULL, .cb_barrier = NULL, .stats = srcu_torture_stats, .name = "srcu_expedited" @@ -1129,7 +1151,8 @@ rcu_torture_printk(char *page) "rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d " "rtmbe: %d rtbke: %ld rtbre: %ld " "rtbf: %ld rtb: %ld nt: %ld " - "onoff: %ld/%ld:%ld/%ld", + "onoff: %ld/%ld:%ld/%ld " + "barrier: %ld/%ld:%ld", rcu_torture_current, rcu_torture_current_version, list_empty(&rcu_torture_freelist), @@ -1145,14 +1168,17 @@ rcu_torture_printk(char *page) n_online_successes, n_online_attempts, n_offline_successes, - n_offline_attempts); + n_offline_attempts, + n_barrier_successes, + n_barrier_attempts, + n_rcu_torture_barrier_error); + cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); if (atomic_read(&n_rcu_torture_mberror) != 0 || + n_rcu_torture_barrier_error != 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) { + n_rcu_torture_boost_failure != 0 || + i > 1) { cnt += sprintf(&page[cnt], "!!! "); atomic_inc(&n_rcu_torture_error); WARN_ON_ONCE(1); @@ -1560,6 +1586,151 @@ static void rcu_torture_stall_cleanup(void) stall_task = NULL; } +/* Callback function for RCU barrier testing. */ +void rcu_torture_barrier_cbf(struct rcu_head *rcu) +{ + atomic_inc(&barrier_cbs_invoked); +} + +/* kthread function to register callbacks used to test RCU barriers. */ +static int rcu_torture_barrier_cbs(void *arg) +{ + long myid = (long)arg; + struct rcu_head rcu; + + init_rcu_head_on_stack(&rcu); + VERBOSE_PRINTK_STRING("rcu_torture_barrier_cbs task started"); + set_user_nice(current, 19); + do { + wait_event(barrier_cbs_wq[myid], + atomic_read(&barrier_cbs_count) == n_barrier_cbs || + kthread_should_stop() || + fullstop != FULLSTOP_DONTSTOP); + if (kthread_should_stop() || fullstop != FULLSTOP_DONTSTOP) + break; + cur_ops->call(&rcu, rcu_torture_barrier_cbf); + if (atomic_dec_and_test(&barrier_cbs_count)) + wake_up(&barrier_wq); + } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP); + VERBOSE_PRINTK_STRING("rcu_torture_barrier_cbs task stopping"); + rcutorture_shutdown_absorb("rcu_torture_barrier_cbs"); + while (!kthread_should_stop()) + schedule_timeout_interruptible(1); + cur_ops->cb_barrier(); + destroy_rcu_head_on_stack(&rcu); + return 0; +} + +/* kthread function to drive and coordinate RCU barrier testing. */ +static int rcu_torture_barrier(void *arg) +{ + int i; + + VERBOSE_PRINTK_STRING("rcu_torture_barrier task starting"); + do { + atomic_set(&barrier_cbs_invoked, 0); + atomic_set(&barrier_cbs_count, n_barrier_cbs); + /* wake_up() path contains the required barriers. */ + for (i = 0; i < n_barrier_cbs; i++) + wake_up(&barrier_cbs_wq[i]); + wait_event(barrier_wq, + atomic_read(&barrier_cbs_count) == 0 || + kthread_should_stop() || + fullstop != FULLSTOP_DONTSTOP); + if (kthread_should_stop() || fullstop != FULLSTOP_DONTSTOP) + break; + n_barrier_attempts++; + cur_ops->cb_barrier(); + if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) { + n_rcu_torture_barrier_error++; + WARN_ON_ONCE(1); + } + n_barrier_successes++; + schedule_timeout_interruptible(HZ / 10); + } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP); + VERBOSE_PRINTK_STRING("rcu_torture_barrier task stopping"); + rcutorture_shutdown_absorb("rcu_torture_barrier_cbs"); + while (!kthread_should_stop()) + schedule_timeout_interruptible(1); + return 0; +} + +/* Initialize RCU barrier testing. */ +static int rcu_torture_barrier_init(void) +{ + int i; + int ret; + + if (n_barrier_cbs == 0) + return 0; + if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) { + printk(KERN_ALERT "%s" TORTURE_FLAG + " Call or barrier ops missing for %s,\n", + torture_type, cur_ops->name); + printk(KERN_ALERT "%s" TORTURE_FLAG + " RCU barrier testing omitted from run.\n", + torture_type); + return 0; + } + atomic_set(&barrier_cbs_count, 0); + atomic_set(&barrier_cbs_invoked, 0); + barrier_cbs_tasks = + kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]), + GFP_KERNEL); + barrier_cbs_wq = + kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]), + GFP_KERNEL); + if (barrier_cbs_tasks == NULL || barrier_cbs_wq == 0) + return -ENOMEM; + for (i = 0; i < n_barrier_cbs; i++) { + init_waitqueue_head(&barrier_cbs_wq[i]); + barrier_cbs_tasks[i] = kthread_run(rcu_torture_barrier_cbs, + (void *)i, + "rcu_torture_barrier_cbs"); + if (IS_ERR(barrier_cbs_tasks[i])) { + ret = PTR_ERR(barrier_cbs_tasks[i]); + VERBOSE_PRINTK_ERRSTRING("Failed to create rcu_torture_barrier_cbs"); + barrier_cbs_tasks[i] = NULL; + return ret; + } + } + barrier_task = kthread_run(rcu_torture_barrier, NULL, + "rcu_torture_barrier"); + if (IS_ERR(barrier_task)) { + ret = PTR_ERR(barrier_task); + VERBOSE_PRINTK_ERRSTRING("Failed to create rcu_torture_barrier"); + barrier_task = NULL; + } + return 0; +} + +/* Clean up after RCU barrier testing. */ +static void rcu_torture_barrier_cleanup(void) +{ + int i; + + if (barrier_task != NULL) { + VERBOSE_PRINTK_STRING("Stopping rcu_torture_barrier task"); + kthread_stop(barrier_task); + barrier_task = NULL; + } + if (barrier_cbs_tasks != NULL) { + for (i = 0; i < n_barrier_cbs; i++) { + if (barrier_cbs_tasks[i] != NULL) { + VERBOSE_PRINTK_STRING("Stopping rcu_torture_barrier_cbs task"); + kthread_stop(barrier_cbs_tasks[i]); + barrier_cbs_tasks[i] = NULL; + } + } + kfree(barrier_cbs_tasks); + barrier_cbs_tasks = NULL; + } + if (barrier_cbs_wq != NULL) { + kfree(barrier_cbs_wq); + barrier_cbs_wq = NULL; + } +} + static int rcutorture_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { @@ -1602,6 +1773,7 @@ rcu_torture_cleanup(void) fullstop = FULLSTOP_RMMOD; mutex_unlock(&fullstop_mutex); unregister_reboot_notifier(&rcutorture_shutdown_nb); + rcu_torture_barrier_cleanup(); rcu_torture_stall_cleanup(); if (stutter_task) { VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task"); @@ -1681,7 +1853,7 @@ rcu_torture_cleanup(void) if (cur_ops->cleanup) cur_ops->cleanup(); - if (atomic_read(&n_rcu_torture_error)) + if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); else if (n_online_successes != n_online_attempts || n_offline_successes != n_offline_attempts) @@ -1697,6 +1869,7 @@ rcu_torture_init(void) int i; int cpu; int firsterr = 0; + int retval; static struct rcu_torture_ops *torture_ops[] = { &rcu_ops, &rcu_sync_ops, &rcu_expedited_ops, &rcu_bh_ops, &rcu_bh_sync_ops, &rcu_bh_expedited_ops, @@ -1754,6 +1927,7 @@ rcu_torture_init(void) atomic_set(&n_rcu_torture_free, 0); atomic_set(&n_rcu_torture_mberror, 0); atomic_set(&n_rcu_torture_error, 0); + n_rcu_torture_barrier_error = 0; n_rcu_torture_boost_ktrerror = 0; n_rcu_torture_boost_rterror = 0; n_rcu_torture_boost_failure = 0; @@ -1877,7 +2051,6 @@ rcu_torture_init(void) 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); @@ -1913,6 +2086,11 @@ rcu_torture_init(void) firsterr = i; goto unwind; } + retval = rcu_torture_barrier_init(); + if (retval != 0) { + firsterr = retval; + goto unwind; + } rcutorture_record_test_transition(); mutex_unlock(&fullstop_mutex); return 0; |