This commit adds the irq_release module parameter, which specifies how often hazard pointers will be released from an smp_call_function_single() handler. For example, a value of 10 would result in one of of ten hazard-pointer acquisitions taking place in a handler, and probably also death by excessive numbers of handlers. A value of zero disables, and a value of -1 makes the frequency decrease as a function of the number of CPUs.
Signed-off-by: Paul E. McKenney <[email protected]> --- kernel/rcu/hazptrtorture.c | 32 +++++++++++++++++++++++++++++--- 1 file changed, 29 insertions(+), 3 deletions(-) diff --git a/kernel/rcu/hazptrtorture.c b/kernel/rcu/hazptrtorture.c index 0752cedb2f5570..fb25f8351659a4 100644 --- a/kernel/rcu/hazptrtorture.c +++ b/kernel/rcu/hazptrtorture.c @@ -33,6 +33,8 @@ MODULE_AUTHOR("Paul E. McKenney <[email protected]>"); torture_param(int, defer_modulus, -1, "Defer once per specified # of hazptr ops, zero to disable"); torture_param(int, irq_acquire, -1, "Acquire hazard pointers from irq handlers once per specified #, zero to disable"); +torture_param(int, irq_release, -1, + "Release hazard pointers from irq handlers once per specified #, zero to disable"); torture_param(int, kthread_do_pending_ms, -1, "Delay between cleanups for deferred hazard pointers (ms), zero to disable"); torture_param(int, nreaders, -1, "Number of hazard-pointer reader threads"); @@ -364,6 +366,16 @@ static void hazptr_torture_acquire(void *hppp_in) hppp->hpp_htp = cur_ops->readlock(&hppp->hpp_hc); } +/* + * Release a hazard pointer from an smp_call_function handler. + */ +static void hazptr_torture_release(void *hppp_in) +{ + struct hazptr_pending *hppp = hppp_in; + + cur_ops->readunlock(&hppp->hpp_hc, hppp->hpp_htp); +} + /* * Do the delay, the accounting, and the release. This in intended to * be invoked from hazptr_torture_reader, but also for hazard pointers @@ -372,6 +384,7 @@ static void hazptr_torture_acquire(void *hppp_in) static void hazptr_torture_reader_tail(struct hazptr_pending *hppp, struct torture_random_state *trsp) { + int cpu; struct hazptr_ctx *hcp = &hppp->hpp_hc; struct hazptr_torture *htp = hppp->hpp_htp; int pipe_count; @@ -388,7 +401,13 @@ hazptr_torture_reader_tail(struct hazptr_pending *hppp, struct torture_random_st rcu_ftrace_dump(DUMP_ALL); __this_cpu_inc(hazptr_torture_count[pipe_count]); preempt_enable(); - cur_ops->readunlock(hcp, htp); + if (irq_release && !(torture_random(trsp) % irq_release)) { + guard(preempt)(); + cpu = cpumask_next_wrap(smp_processor_id(), cpu_online_mask); + smp_call_function_single(cpu, hazptr_torture_release, hppp, 1); + } else { + cur_ops->readunlock(hcp, htp); + } } /* @@ -660,14 +679,14 @@ hazptr_torture_print_module_parms(struct hazptr_torture_ops *cur_ops, const char { pr_alert("%s" TORTURE_FLAG "--- %s: nreaders=%d nwriters=%d " - "defer_modulus=%d irq_acquire=%d kthread_do_pending_ms=%d " + "defer_modulus=%d irq_acquire=%d irq_release=%d kthread_do_pending_ms=%d " "onoff_interval=%d onoff_holdoff=%d " "preempt_duration=%d preempt_interval=%d " "reader_sleep_us=%d " "shuffle_interval=%d shutdown_secs=%d stat_interval=%d stutter=%d " "verbose=%d\n", torture_type, tag, nrealreaders, nwriters, - defer_modulus, irq_acquire, kthread_do_pending_ms, + defer_modulus, irq_acquire, irq_release, kthread_do_pending_ms, onoff_interval, onoff_holdoff, preempt_duration, preempt_interval, reader_sleep_us, @@ -818,6 +837,13 @@ static int __init hazptr_torture_init(void) WARN_ON(IS_BUILTIN(CONFIG_HAZPTR_TORTURE_TEST)); irq_acquire = 0; } + if (irq_release == -1) { + irq_release = 1000 * nr_cpu_ids; + } else if (irq_release < 0) { + pr_alert("Cannot have irq_release (%d) < -1, disabling.\n", irq_release); + WARN_ON(IS_BUILTIN(CONFIG_HAZPTR_TORTURE_TEST)); + irq_release = 0; + } reader_tasks = kzalloc_objs(reader_tasks[0], nrealreaders); for (i = 0; i < nrealreaders; i++) { firsterr = torture_create_kthread(hazptr_torture_reader, (void *)i, -- 2.40.1
