diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 18 | ||||
| -rw-r--r-- | kernel/rcu/rcutorture.c | 86 |
2 files changed, 103 insertions, 1 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 5ae8608ca9f5..0a104be4ad86 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2881,6 +2881,24 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Lazy RCU callbacks are those which RCU can prove do nothing more than free memory. + rcutorture.cbflood_inter_holdoff= [KNL] + Set holdoff time (jiffies) between successive + callback-flood tests. + + rcutorture.cbflood_intra_holdoff= [KNL] + Set holdoff time (jiffies) between successive + bursts of callbacks within a given callback-flood + test. + + rcutorture.cbflood_n_burst= [KNL] + Set the number of bursts making up a given + callback-flood test. Set this to zero to + disable callback-flood testing. + + rcutorture.cbflood_n_per_burst= [KNL] + Set the number of callbacks to be registered + in a given burst of a callback-flood test. + rcutorture.fqs_duration= [KNL] Set duration of force_quiescent_state bursts. diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index ff4f0c756dee..0bcd53adac73 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -49,11 +49,19 @@ #include <linux/trace_clock.h> #include <asm/byteorder.h> #include <linux/torture.h> +#include <linux/vmalloc.h> MODULE_LICENSE("GPL"); MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>"); +torture_param(int, cbflood_inter_holdoff, HZ, + "Holdoff between floods (jiffies)"); +torture_param(int, cbflood_intra_holdoff, 1, + "Holdoff between bursts (jiffies)"); +torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable"); +torture_param(int, cbflood_n_per_burst, 20000, + "# callbacks per burst in flood"); torture_param(int, fqs_duration, 0, "Duration of fqs bursts (us), 0 to disable"); torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)"); @@ -96,10 +104,12 @@ module_param(torture_type, charp, 0444); MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)"); static int nrealreaders; +static int ncbflooders; 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 **cbflood_task; static struct task_struct *fqs_task; static struct task_struct *boost_tasks[NR_CPUS]; static struct task_struct *stall_task; @@ -138,6 +148,7 @@ static long n_rcu_torture_boosts; static long n_rcu_torture_timers; static long n_barrier_attempts; static long n_barrier_successes; +static atomic_long_t n_cbfloods; static struct list_head rcu_torture_removed; static int rcu_torture_writer_state; @@ -707,6 +718,58 @@ checkwait: stutter_wait("rcu_torture_boost"); return 0; } +static void rcu_torture_cbflood_cb(struct rcu_head *rhp) +{ +} + +/* + * RCU torture callback-flood kthread. Repeatedly induces bursts of calls + * to call_rcu() or analogous, increasing the probability of occurrence + * of callback-overflow corner cases. + */ +static int +rcu_torture_cbflood(void *arg) +{ + int err = 1; + int i; + int j; + struct rcu_head *rhp; + + if (cbflood_n_per_burst > 0 && + cbflood_inter_holdoff > 0 && + cbflood_intra_holdoff > 0 && + cur_ops->call && + cur_ops->cb_barrier) { + rhp = vmalloc(sizeof(*rhp) * + cbflood_n_burst * cbflood_n_per_burst); + err = !rhp; + } + if (err) { + VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM"); + while (!torture_must_stop()) + schedule_timeout_interruptible(HZ); + return 0; + } + VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started"); + do { + schedule_timeout_interruptible(cbflood_inter_holdoff); + atomic_long_inc(&n_cbfloods); + WARN_ON(signal_pending(current)); + for (i = 0; i < cbflood_n_burst; i++) { + for (j = 0; j < cbflood_n_per_burst; j++) { + cur_ops->call(&rhp[i * cbflood_n_per_burst + j], + rcu_torture_cbflood_cb); + } + schedule_timeout_interruptible(cbflood_intra_holdoff); + WARN_ON(signal_pending(current)); + } + cur_ops->cb_barrier(); + stutter_wait("rcu_torture_cbflood"); + } while (!torture_must_stop()); + torture_kthread_stopping("rcu_torture_cbflood"); + return 0; +} + /* * RCU torture force-quiescent-state kthread. Repeatedly induces * bursts of calls to force_quiescent_state(), increasing the probability @@ -1075,10 +1138,11 @@ rcu_torture_stats_print(void) n_rcu_torture_boosts, n_rcu_torture_timers); torture_onoff_stats(); - pr_cont("barrier: %ld/%ld:%ld\n", + pr_cont("barrier: %ld/%ld:%ld ", n_barrier_successes, n_barrier_attempts, n_rcu_torture_barrier_error); + pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods)); pr_alert("%s%s ", torture_type, TORTURE_FLAG); if (atomic_read(&n_rcu_torture_mberror) != 0 || @@ -1432,6 +1496,8 @@ rcu_torture_cleanup(void) torture_stop_kthread(rcu_torture_stats, stats_task); torture_stop_kthread(rcu_torture_fqs, fqs_task); + for (i = 0; i < ncbflooders; i++) + torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]); if ((test_boost == 1 && cur_ops->can_boost) || test_boost == 2) { unregister_cpu_notifier(&rcutorture_cpu_nb); @@ -1678,6 +1744,24 @@ rcu_torture_init(void) goto unwind; if (object_debug) rcu_test_debug_objects(); + if (cbflood_n_burst > 0) { + /* Create the cbflood threads */ + ncbflooders = (num_online_cpus() + 3) / 4; + cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task), + GFP_KERNEL); + if (!cbflood_task) { + VERBOSE_TOROUT_ERRSTRING("out of memory"); + firsterr = -ENOMEM; + goto unwind; + } + for (i = 0; i < ncbflooders; i++) { + firsterr = torture_create_kthread(rcu_torture_cbflood, + NULL, + cbflood_task[i]); + if (firsterr) + goto unwind; + } + } rcutorture_record_test_transition(); torture_init_end(); return 0; |