From 8a21d26ef89e7360c4a176d83e8990e1ae2f2f3f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 3 Nov 2011 07:44:04 -0700 Subject: [PATCH] Revert "perf: Add PM notifiers to fix CPU hotplug races" This reverts commit 59cc60ae8981f13b8ce40a6a52f862a9a1848566. It causes a resume regression for Andi on his Acer Aspire 1830T post 3.1. The screen just stays black after wakeup. Also, it really looks like the wrong way to suspend and resume perf events: I think they should be done as part of the CPU suspend and resume, rather than as a notifier that does smp_call_function(). Reported-by: Andi Kleen Acked-by: Ingo Molnar Cc: Peter Zijlstra Cc: Rafael J. Wysocki Signed-off-by: Linus Torvalds --- kernel/events/core.c | 97 +------------------------------------------- 1 file changed, 2 insertions(+), 95 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 12a0287e03582..e1253faa34ddc 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -29,7 +29,6 @@ #include #include #include -#include #include #include #include @@ -6853,7 +6852,7 @@ static void __cpuinit perf_event_init_cpu(int cpu) struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); mutex_lock(&swhash->hlist_mutex); - if (swhash->hlist_refcount > 0 && !swhash->swevent_hlist) { + if (swhash->hlist_refcount > 0) { struct swevent_hlist *hlist; hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); @@ -6942,14 +6941,7 @@ perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { unsigned int cpu = (long)hcpu; - /* - * Ignore suspend/resume action, the perf_pm_notifier will - * take care of that. - */ - if (action & CPU_TASKS_FROZEN) - return NOTIFY_OK; - - switch (action) { + switch (action & ~CPU_TASKS_FROZEN) { case CPU_UP_PREPARE: case CPU_DOWN_FAILED: @@ -6968,90 +6960,6 @@ perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) return NOTIFY_OK; } -static void perf_pm_resume_cpu(void *unused) -{ - struct perf_cpu_context *cpuctx; - struct perf_event_context *ctx; - struct pmu *pmu; - int idx; - - idx = srcu_read_lock(&pmus_srcu); - list_for_each_entry_rcu(pmu, &pmus, entry) { - cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); - ctx = cpuctx->task_ctx; - - perf_ctx_lock(cpuctx, ctx); - perf_pmu_disable(cpuctx->ctx.pmu); - - cpu_ctx_sched_out(cpuctx, EVENT_ALL); - if (ctx) - ctx_sched_out(ctx, cpuctx, EVENT_ALL); - - perf_pmu_enable(cpuctx->ctx.pmu); - perf_ctx_unlock(cpuctx, ctx); - } - srcu_read_unlock(&pmus_srcu, idx); -} - -static void perf_pm_suspend_cpu(void *unused) -{ - struct perf_cpu_context *cpuctx; - struct perf_event_context *ctx; - struct pmu *pmu; - int idx; - - idx = srcu_read_lock(&pmus_srcu); - list_for_each_entry_rcu(pmu, &pmus, entry) { - cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); - ctx = cpuctx->task_ctx; - - perf_ctx_lock(cpuctx, ctx); - perf_pmu_disable(cpuctx->ctx.pmu); - - perf_event_sched_in(cpuctx, ctx, current); - - perf_pmu_enable(cpuctx->ctx.pmu); - perf_ctx_unlock(cpuctx, ctx); - } - srcu_read_unlock(&pmus_srcu, idx); -} - -static int perf_resume(void) -{ - get_online_cpus(); - smp_call_function(perf_pm_resume_cpu, NULL, 1); - put_online_cpus(); - - return NOTIFY_OK; -} - -static int perf_suspend(void) -{ - get_online_cpus(); - smp_call_function(perf_pm_suspend_cpu, NULL, 1); - put_online_cpus(); - - return NOTIFY_OK; -} - -static int perf_pm(struct notifier_block *self, unsigned long action, void *ptr) -{ - switch (action) { - case PM_POST_HIBERNATION: - case PM_POST_SUSPEND: - return perf_resume(); - case PM_HIBERNATION_PREPARE: - case PM_SUSPEND_PREPARE: - return perf_suspend(); - default: - return NOTIFY_DONE; - } -} - -static struct notifier_block perf_pm_notifier = { - .notifier_call = perf_pm, -}; - void __init perf_event_init(void) { int ret; @@ -7066,7 +6974,6 @@ void __init perf_event_init(void) perf_tp_register(); perf_cpu_notifier(perf_cpu_notify); register_reboot_notifier(&perf_reboot_notifier); - register_pm_notifier(&perf_pm_notifier); ret = init_hw_breakpoint(); WARN(ret, "hw_breakpoint initialization failed with: %d", ret); -- 2.39.5