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Commit 6a930700 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

perf counters: clean up state transitions 



Impact: cleanup

Introduce a proper enum for the 3 states of a counter:

	PERF_COUNTER_STATE_OFF		= -1
	PERF_COUNTER_STATE_INACTIVE	=  0
	PERF_COUNTER_STATE_ACTIVE	=  1

and rename counter->active to counter->state and propagate the
changes everywhere.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 1d1c7ddb

arch/x86/kernel/cpu/perf_counter.c

+1 −1
Original line number Original line 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):

	 * Then store sibling timestamps (if any):

	 */

	 */

	list_for_each_entry(counter, &group_leader->sibling_list, list_entry) {

	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

			 * When counter was not in the overflow mask, we have to

			 * read it from hardware. We read it as well, when it

			 * read it from hardware. We read it as well, when it

include/linux/perf_counter.h

+10 −1
Original line number Original line Diff line number Diff line
@@ -127,6 +127,15 @@ struct hw_perf_counter_ops { 
	void (*hw_perf_counter_read)	(struct perf_counter *counter);

	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:

 * struct perf_counter - performance counter kernel representation:

 */

 */
@@ -136,7 +145,7 @@ struct perf_counter { 
	struct perf_counter		*group_leader;

	struct perf_counter		*group_leader;

	const struct hw_perf_counter_ops *hw_ops;

	const struct hw_perf_counter_ops *hw_ops;





	int				active;

	enum perf_counter_active_state	state;

#if BITS_PER_LONG == 64

#if BITS_PER_LONG == 64

	atomic64_t			count;

	atomic64_t			count;

#else

#else

kernel/perf_counter.c

+14 −15
Original line number Original line Diff line number Diff line
@@ -167,9 +167,9 @@ static void __perf_counter_remove_from_context(void *info) 




	spin_lock(&ctx->lock);

	spin_lock(&ctx->lock);





	if (counter->active) {

	if (counter->state == PERF_COUNTER_STATE_ACTIVE) {

		counter->hw_ops->hw_perf_counter_disable(counter);

		counter->hw_ops->hw_perf_counter_disable(counter);

		counter->active = 0;

		counter->state = PERF_COUNTER_STATE_INACTIVE;

		ctx->nr_active--;

		ctx->nr_active--;

		cpuctx->active_oncpu--;

		cpuctx->active_oncpu--;

		counter->task = NULL;

		counter->task = NULL;
@@ -281,7 +281,7 @@ static void __perf_install_in_context(void *info) 




	if (cpuctx->active_oncpu < perf_max_counters) {

	if (cpuctx->active_oncpu < perf_max_counters) {

		counter->hw_ops->hw_perf_counter_enable(counter);

		counter->hw_ops->hw_perf_counter_enable(counter);

		counter->active = 1;

		counter->state = PERF_COUNTER_STATE_ACTIVE;

		counter->oncpu = cpu;

		counter->oncpu = cpu;

		ctx->nr_active++;

		ctx->nr_active++;

		cpuctx->active_oncpu++;

		cpuctx->active_oncpu++;
@@ -328,7 +328,6 @@ retry: 




	spin_lock_irq(&ctx->lock);

	spin_lock_irq(&ctx->lock);

	/*

	/*

	 * If the context is active and the counter has not been added

	 * we need to retry the smp call.

	 * we need to retry the smp call.

	 */

	 */

	if (ctx->nr_active && list_empty(&counter->list_entry)) {

	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_cpu_context *cpuctx,

		  struct perf_counter_context *ctx)

		  struct perf_counter_context *ctx)

{

{

	if (!counter->active)

	if (counter->state != PERF_COUNTER_STATE_ACTIVE)

		return;

		return;





	counter->hw_ops->hw_perf_counter_disable(counter);

	counter->hw_ops->hw_perf_counter_disable(counter);

	counter->active	=  0;

	counter->state = PERF_COUNTER_STATE_INACTIVE;

	counter->oncpu = -1;

	counter->oncpu = -1;





	cpuctx->active_oncpu--;

	cpuctx->active_oncpu--;
@@ -415,11 +414,11 @@ counter_sched_in(struct perf_counter *counter, 
		 struct perf_counter_context *ctx,

		 struct perf_counter_context *ctx,

		 int cpu)

		 int cpu)

{

{

	if (counter->active == -1)

	if (counter->state == PERF_COUNTER_STATE_OFF)

		return;

		return;





	counter->hw_ops->hw_perf_counter_enable(counter);

	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 */

	counter->oncpu = cpu;	/* TODO: put 'cpu' into cpuctx->cpu */





	cpuctx->active_oncpu++;

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

	perf_flags = hw_perf_save_disable();





	list_for_each_entry(counter, &ctx->counter_list, list_entry) {

	list_for_each_entry(counter, &ctx->counter_list, list_entry) {

		WARN_ON_ONCE(counter->active == 1);

		WARN_ON_ONCE(counter->state == PERF_COUNTER_STATE_ACTIVE);

		counter->active = -1;

		counter->state = PERF_COUNTER_STATE_OFF;

	}

	}

	hw_perf_restore(perf_flags);

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

	perf_flags = hw_perf_save_disable();





	list_for_each_entry(counter, &ctx->counter_list, list_entry) {

	list_for_each_entry(counter, &ctx->counter_list, list_entry) {

		if (counter->active != -1)

		if (counter->state != PERF_COUNTER_STATE_OFF)

			continue;

			continue;

		counter->active = 0;

		counter->state = PERF_COUNTER_STATE_INACTIVE;

	}

	}

	hw_perf_restore(perf_flags);

	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

	 * If counter is enabled and currently active on a CPU, update the

	 * value in the counter structure:

	 * value in the counter structure:

	 */

	 */

	if (counter->active) {

	if (counter->state == PERF_COUNTER_STATE_ACTIVE) {

		smp_call_function_single(counter->oncpu,

		smp_call_function_single(counter->oncpu,

					 __hw_perf_counter_read, counter, 1);

					 __hw_perf_counter_read, counter, 1);

	}

	}
@@ -673,7 +672,7 @@ static struct perf_data *perf_switch_irq_data(struct perf_counter *counter) 




retry:

retry:

	spin_lock_irq(&ctx->lock);

	spin_lock_irq(&ctx->lock);

	if (!counter->active) {

	if (counter->state != PERF_COUNTER_STATE_ACTIVE) {

		counter->irqdata = counter->usrdata;

		counter->irqdata = counter->usrdata;

		counter->usrdata = oldirqdata;

		counter->usrdata = oldirqdata;

		spin_unlock_irq(&ctx->lock);

		spin_unlock_irq(&ctx->lock);