perf: support hotplug (2d1400d6) · Commits · e / devices / android_kernel_xiaomi_markw

include/linux/perf_event.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -193,6 +193,8 @@ struct pmu {
		struct perf_cpu_context * __percpu pmu_cpu_context;
		int task_ctx_nr;
		int hrtimer_interval_ms;
		u32 events_across_hotplug:1,
		reserved:31;

		/*
		* Fully disable/enable this PMU, can be used to protect from the PMI

include/uapi/linux/perf_event.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -303,7 +303,8 @@ struct perf_event_attr {
		exclude_callchain_user : 1, /* exclude user callchains */
		mmap2 : 1, /* include mmap with inode data */
		comm_exec : 1, /* flag comm events that are due to an exec */
		__reserved_1 : 39;
		constraint_duplicate : 1,
		__reserved_1 : 38;

		union {
		__u32 wakeup_events; /* wakeup every n events */

kernel/events/core.c

+104 −5

Original line number	Diff line number	Diff line
		@@ -171,7 +171,11 @@ static struct srcu_struct pmus_srcu;
		* 1 - disallow cpu events for unpriv
		* 2 - disallow kernel profiling for unpriv
		*/
		#ifdef CONFIG_PERF_EVENTS_USERMODE
		int sysctl_perf_event_paranoid __read_mostly = -1;
		#else
		int sysctl_perf_event_paranoid __read_mostly = 1;
		#endif

		/* Minimum for 512 kiB + 1 user control page */
		int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
		@@ -1536,6 +1540,29 @@ static int __perf_remove_from_context(void *info)
		}


		#ifdef CONFIG_SMP
		static void perf_retry_remove(struct perf_event *event)
		{
		int up_ret;
		/*
		* CPU was offline. Bring it online so we can
		* gracefully exit a perf context.
		*/
		up_ret = cpu_up(event->cpu);
		if (!up_ret)
		/* Try the remove call once again. */
		cpu_function_call(event->cpu, __perf_remove_from_context,
		event);
		else
		pr_err("Failed to bring up CPU: %d, ret: %d\n",
		event->cpu, up_ret);
		}
		#else
		static void perf_retry_remove(struct perf_event *event)
		{
		}
		#endif

		/*
		* Remove the event from a task's (or a CPU's) list of events.
		*
		@@ -1549,7 +1576,8 @@ static int __perf_remove_from_context(void *info)
		* When called from perf_event_exit_task, it's OK because the
		* context has been detached from its task.
		*/
		static void perf_remove_from_context(struct perf_event *event, bool detach_group)
		static void __ref perf_remove_from_context(struct perf_event *event,
		bool detach_group)
		{
		struct perf_event_context *ctx = event->ctx;
		struct task_struct *task = ctx->task;
		@@ -1557,6 +1585,7 @@ static void perf_remove_from_context(struct perf_event *event, bool detach_group
		.event = event,
		.detach_group = detach_group,
		};
		int ret;

		lockdep_assert_held(&ctx->mutex);

		@@ -1567,7 +1596,11 @@ static void perf_remove_from_context(struct perf_event *event, bool detach_group
		* already called __perf_remove_from_context from
		* perf_event_exit_cpu.
		*/
		cpu_function_call(event->cpu, __perf_remove_from_context, &re);
		ret = cpu_function_call(event->cpu, __perf_remove_from_context,
		&re);
		if (ret == -ENXIO)
		perf_retry_remove(event);

		return;
		}

		@@ -3477,6 +3510,15 @@ EXPORT_SYMBOL_GPL(perf_event_release_kernel);

		static int perf_release(struct inode inode, struct file file)
		{
		struct perf_event *event = file->private_data;

		/*
		* Event can be in state OFF because of a constraint check.
		* Change to ACTIVE so that it gets cleaned up correctly.
		*/
		if ((event->state == PERF_EVENT_STATE_OFF) &&
		event->attr.constraint_duplicate)
		event->state = PERF_EVENT_STATE_ACTIVE;
		put_event(file->private_data);
		return 0;
		}
		@@ -6082,6 +6124,7 @@ static struct pmu perf_swevent = {
		.start = perf_swevent_start,
		.stop = perf_swevent_stop,
		.read = perf_swevent_read,
		.events_across_hotplug = 1,
		};

		#ifdef CONFIG_EVENT_TRACING
		@@ -6199,6 +6242,7 @@ static struct pmu perf_tracepoint = {
		.start = perf_swevent_start,
		.stop = perf_swevent_stop,
		.read = perf_swevent_read,
		.events_across_hotplug = 1,
		};

		static inline void perf_tp_register(void)
		@@ -6424,6 +6468,7 @@ static struct pmu perf_cpu_clock = {
		.start = cpu_clock_event_start,
		.stop = cpu_clock_event_stop,
		.read = cpu_clock_event_read,
		.events_across_hotplug = 1,
		};

		/*
		@@ -6502,6 +6547,7 @@ static struct pmu perf_task_clock = {
		.start = task_clock_event_start,
		.stop = task_clock_event_stop,
		.read = task_clock_event_read,
		.events_across_hotplug = 1,
		};

		static void perf_pmu_nop_void(struct pmu *pmu)
		@@ -8130,6 +8176,18 @@ static void __perf_event_exit_context(void *__info)
		rcu_read_unlock();
		}

		static void __perf_event_stop_swclock(void *__info)
		{
		struct perf_event_context *ctx = __info;
		struct perf_event event, tmp;

		list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
		if (event->attr.config == PERF_COUNT_SW_CPU_CLOCK &&
		event->attr.type == PERF_TYPE_SOFTWARE)
		cpu_clock_event_stop(event, 0);
		}
		}

		static void perf_event_exit_cpu_context(int cpu)
		{
		struct perf_event_context *ctx;
		@@ -8139,14 +8197,49 @@ static void perf_event_exit_cpu_context(int 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;

		mutex_lock(&ctx->mutex);
		smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
		/*
		* If keeping events across hotplugging is supported, do not
		* remove the event list, but keep it alive across CPU hotplug.
		* The context is exited via an fd close path when userspace
		* is done and the target CPU is online. If software clock
		* event is active, then stop hrtimer associated with it.
		* Start the timer when the CPU comes back online.
		*/
		if (!pmu->events_across_hotplug)
		smp_call_function_single(cpu, __perf_event_exit_context,
		ctx, 1);
		else
		smp_call_function_single(cpu, __perf_event_stop_swclock,
		ctx, 1);
		mutex_unlock(&ctx->mutex);
		}
		srcu_read_unlock(&pmus_srcu, idx);
		}

		static void perf_event_start_swclock(int cpu)
		{
		struct perf_event_context *ctx;
		struct pmu *pmu;
		int idx;
		struct perf_event event, tmp;

		idx = srcu_read_lock(&pmus_srcu);
		list_for_each_entry_rcu(pmu, &pmus, entry) {
		if (pmu->events_across_hotplug) {
		ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
		list_for_each_entry_safe(event, tmp, &ctx->event_list,
		event_entry) {
		if (event->attr.config ==
		PERF_COUNT_SW_CPU_CLOCK &&
		event->attr.type == PERF_TYPE_SOFTWARE)
		cpu_clock_event_start(event, 0);
		}
		}
		}
		srcu_read_unlock(&pmus_srcu, idx);
		}

		static void perf_event_exit_cpu(int cpu)
		{
		struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
		@@ -8160,6 +8253,7 @@ static void perf_event_exit_cpu(int cpu)
		}
		#else
		static inline void perf_event_exit_cpu(int cpu) { }
		static inline void perf_event_start_swclock(int cpu) { }
		#endif

		static int
		@@ -8198,6 +8292,11 @@ perf_cpu_notify(struct notifier_block self, unsigned long action, void hcpu)
		case CPU_DOWN_PREPARE:
		perf_event_exit_cpu(cpu);
		break;

		case CPU_STARTING:
		perf_event_start_swclock(cpu);
		break;

		default:
		break;
		}

kernel/events/hw_breakpoint.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -614,6 +614,7 @@ static struct pmu perf_breakpoint = {
		.start = hw_breakpoint_start,
		.stop = hw_breakpoint_stop,
		.read = hw_breakpoint_pmu_read,
		.events_across_hotplug = 1,
		};

		int __init init_hw_breakpoint(void)