perf counters: clean up state transitions (6a930700) · Commits · 戴 / test

arch/x86/kernel/cpu/perf_counter.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -332,7 +332,7 @@ perf_handle_group(struct perf_counter sibling, u64 status, u64 *overflown)
		* Then store sibling timestamps (if any):
		*/
		list_for_each_entry(counter, &group_leader->sibling_list, list_entry) {
		if (!counter->active) {
		if (counter->state != PERF_COUNTER_STATE_ACTIVE) {
		/*
		* When counter was not in the overflow mask, we have to
		* read it from hardware. We read it as well, when it

include/linux/perf_counter.h

+10 −1

Original line number	Diff line number	Diff line
		@@ -127,6 +127,15 @@ struct hw_perf_counter_ops {
		void (hw_perf_counter_read) (struct perf_counter counter);
		};

		/**
		* enum perf_counter_active_state - the states of a counter
		*/
		enum perf_counter_active_state {
		PERF_COUNTER_STATE_OFF = -1,
		PERF_COUNTER_STATE_INACTIVE = 0,
		PERF_COUNTER_STATE_ACTIVE = 1,
		};

		/**
		* struct perf_counter - performance counter kernel representation:
		*/
		@@ -136,7 +145,7 @@ struct perf_counter {
		struct perf_counter *group_leader;
		const struct hw_perf_counter_ops *hw_ops;

		int active;
		enum perf_counter_active_state state;
		#if BITS_PER_LONG == 64
		atomic64_t count;
		#else

kernel/perf_counter.c

+14 −15

Original line number	Diff line number	Diff line
		@@ -167,9 +167,9 @@ static void __perf_counter_remove_from_context(void *info)

		spin_lock(&ctx->lock);

		if (counter->active) {
		if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
		counter->hw_ops->hw_perf_counter_disable(counter);
		counter->active = 0;
		counter->state = PERF_COUNTER_STATE_INACTIVE;
		ctx->nr_active--;
		cpuctx->active_oncpu--;
		counter->task = NULL;
		@@ -281,7 +281,7 @@ static void __perf_install_in_context(void *info)

		if (cpuctx->active_oncpu < perf_max_counters) {
		counter->hw_ops->hw_perf_counter_enable(counter);
		counter->active = 1;
		counter->state = PERF_COUNTER_STATE_ACTIVE;
		counter->oncpu = cpu;
		ctx->nr_active++;
		cpuctx->active_oncpu++;
		@@ -328,7 +328,6 @@ retry:

		spin_lock_irq(&ctx->lock);
		/*
		* If the context is active and the counter has not been added
		* we need to retry the smp call.
		*/
		if (ctx->nr_active && list_empty(&counter->list_entry)) {
		@@ -353,11 +352,11 @@ counter_sched_out(struct perf_counter *counter,
		struct perf_cpu_context *cpuctx,
		struct perf_counter_context *ctx)
		{
		if (!counter->active)
		if (counter->state != PERF_COUNTER_STATE_ACTIVE)
		return;

		counter->hw_ops->hw_perf_counter_disable(counter);
		counter->active = 0;
		counter->state = PERF_COUNTER_STATE_INACTIVE;
		counter->oncpu = -1;

		cpuctx->active_oncpu--;
		@@ -415,11 +414,11 @@ counter_sched_in(struct perf_counter *counter,
		struct perf_counter_context *ctx,
		int cpu)
		{
		if (counter->active == -1)
		if (counter->state == PERF_COUNTER_STATE_OFF)
		return;

		counter->hw_ops->hw_perf_counter_enable(counter);
		counter->active = 1;
		counter->state = PERF_COUNTER_STATE_ACTIVE;
		counter->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */

		cpuctx->active_oncpu++;
		@@ -506,8 +505,8 @@ int perf_counter_task_disable(void)
		perf_flags = hw_perf_save_disable();

		list_for_each_entry(counter, &ctx->counter_list, list_entry) {
		WARN_ON_ONCE(counter->active == 1);
		counter->active = -1;
		WARN_ON_ONCE(counter->state == PERF_COUNTER_STATE_ACTIVE);
		counter->state = PERF_COUNTER_STATE_OFF;
		}
		hw_perf_restore(perf_flags);

		@@ -540,9 +539,9 @@ int perf_counter_task_enable(void)
		perf_flags = hw_perf_save_disable();

		list_for_each_entry(counter, &ctx->counter_list, list_entry) {
		if (counter->active != -1)
		if (counter->state != PERF_COUNTER_STATE_OFF)
		continue;
		counter->active = 0;
		counter->state = PERF_COUNTER_STATE_INACTIVE;
		}
		hw_perf_restore(perf_flags);

		@@ -620,7 +619,7 @@ static u64 perf_counter_read(struct perf_counter *counter)
		* If counter is enabled and currently active on a CPU, update the
		* value in the counter structure:
		*/
		if (counter->active) {
		if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
		smp_call_function_single(counter->oncpu,
		__hw_perf_counter_read, counter, 1);
		}
		@@ -673,7 +672,7 @@ static struct perf_data perf_switch_irq_data(struct perf_counter counter)

		retry:
		spin_lock_irq(&ctx->lock);
		if (!counter->active) {
		if (counter->state != PERF_COUNTER_STATE_ACTIVE) {
		counter->irqdata = counter->usrdata;
		counter->usrdata = oldirqdata;
		spin_unlock_irq(&ctx->lock);

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