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perf counters: clean up state transitions

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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: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2008-12-11 15:17:03 +01:00
parent 1d1c7ddbfa
commit 6a930700c8
3 changed files with 25 additions and 17 deletions
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2
arch/x86/kernel/cpu/perf_counter.c
View File

@ -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

11
include/linux/perf_counter.h
View File

@ -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

29
kernel/perf_counter.c
View File

@ -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)) {
@ -353,12 +352,12 @@ 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->oncpu = -1;
counter->state = PERF_COUNTER_STATE_INACTIVE;
counter->oncpu = -1;
cpuctx->active_oncpu--;
ctx->nr_active--;
@ -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);