Merge "perf: Fix event cleanup across CPU hotplugs" (f87eaf90) · Commits · e / devices / android_kernel_xiaomi_nabu

arch/arm64/kernel/perf_event.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -707,8 +707,8 @@ static irqreturn_t armv8pmu_handle_irq(int irq_num, void *dev)
		struct perf_event *event = cpuc->events[idx];
		struct hw_perf_event *hwc;

		/* Ignore if we don't have an event. */
		if (!event)
		/* Ignore if we don't have an event or if it's a zombie event */
		if (!event \|\| event->state == PERF_EVENT_STATE_ZOMBIE)
		continue;

		/*

drivers/perf/arm_pmu.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -659,6 +659,15 @@ static void cpu_pm_pmu_setup(struct arm_pmu *armpmu, unsigned long cmd)
		continue;

		event = hw_events->events[idx];
		if (!event)
		continue;

		/*
		* Check if an attempt was made to free this event during
		* the CPU went offline.
		*/
		if (event->state == PERF_EVENT_STATE_ZOMBIE)
		continue;

		switch (cmd) {
		case CPU_PM_ENTER:

include/linux/perf_event.h

+4 −1

Original line number	Diff line number	Diff line
		@@ -490,7 +490,8 @@ struct perf_addr_filters_head {
		* enum perf_event_active_state - the states of a event
		*/
		enum perf_event_active_state {
		PERF_EVENT_STATE_DEAD = -4,
		PERF_EVENT_STATE_DEAD = -5,
		PERF_EVENT_STATE_ZOMBIE = -4,
		PERF_EVENT_STATE_EXIT = -3,
		PERF_EVENT_STATE_ERROR = -2,
		PERF_EVENT_STATE_OFF = -1,
		@@ -705,6 +706,8 @@ struct perf_event {
		#endif

		struct list_head sb_list;

		struct list_head zombie_entry;
		#endif /* CONFIG_PERF_EVENTS */
		};

kernel/events/core.c

+57 −0

Original line number	Diff line number	Diff line
		@@ -4357,6 +4357,14 @@ static void put_event(struct perf_event *event)
		_free_event(event);
		}

		/*
		* Maintain a zombie list to collect all the zombie events
		*/
		#if defined CONFIG_HOTPLUG_CPU \|\| defined CONFIG_KEXEC_CORE
		static LIST_HEAD(zombie_list);
		static DEFINE_SPINLOCK(zombie_list_lock);
		#endif

		/*
		* Kill an event dead; while event:refcount will preserve the event
		* object, it will not preserve its functionality. Once the last 'user'
		@@ -4367,6 +4375,26 @@ int perf_event_release_kernel(struct perf_event *event)
		struct perf_event_context *ctx = event->ctx;
		struct perf_event child, tmp;

		/*
		* If the cpu associated to this event is offline, set the event as a
		* zombie event. The cleanup of the cpu would be done if the CPU is
		* back online.
		*/
		#if defined CONFIG_HOTPLUG_CPU \|\| defined CONFIG_KEXEC_CORE
		if (!cpu_online(event->cpu)) {
		if (event->state == PERF_EVENT_STATE_ZOMBIE)
		return 0;

		event->state = PERF_EVENT_STATE_ZOMBIE;

		spin_lock(&zombie_list_lock);
		list_add_tail(&event->zombie_entry, &zombie_list);
		spin_unlock(&zombie_list_lock);

		return 0;
		}
		#endif

		/*
		* If we got here through err_file: fput(event_file); we will not have
		* attached to a context yet.
		@@ -9559,6 +9587,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
		INIT_LIST_HEAD(&event->rb_entry);
		INIT_LIST_HEAD(&event->active_entry);
		INIT_LIST_HEAD(&event->addr_filters.list);
		INIT_LIST_HEAD(&event->zombie_entry);
		INIT_HLIST_NODE(&event->hlist_entry);


		@@ -11307,6 +11336,32 @@ check_hotplug_start_event(struct perf_event *event)
		event->pmu->start(event, 0);
		}

		static void perf_event_zombie_cleanup(unsigned int cpu)
		{
		struct perf_event event, tmp;

		spin_lock(&zombie_list_lock);

		list_for_each_entry_safe(event, tmp, &zombie_list, zombie_entry) {
		if (event->cpu != cpu)
		continue;

		list_del(&event->zombie_entry);
		spin_unlock(&zombie_list_lock);

		/*
		* The detachment of the event with the
		* PMU expects it to be in an active state
		*/
		event->state = PERF_EVENT_STATE_ACTIVE;
		perf_event_release_kernel(event);

		spin_lock(&zombie_list_lock);
		}

		spin_unlock(&zombie_list_lock);
		}

		int perf_event_start_swevents(unsigned int cpu)
		{
		struct perf_event_context *ctx;
		@@ -11314,6 +11369,8 @@ int perf_event_start_swevents(unsigned int cpu)
		struct perf_event *event;
		int idx;

		perf_event_zombie_cleanup(cpu);

		idx = srcu_read_lock(&pmus_srcu);
		list_for_each_entry_rcu(pmu, &pmus, entry) {
		ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;