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authorLucas Stach <l.stach@pengutronix.de>2015-07-20 18:34:50 +0200
committerIngo Molnar <mingo@kernel.org>2015-07-21 08:18:51 +0200
commit63caae8480921773b46adec0b6ddac9a844a042f (patch)
treef1bfb0d5537fc05a021aeb17532775b17f7cdb1f
parent399595f248cb25dccb6044b53c47c44c174dc23d (diff)
downloadarm64-stable-rc-63caae8480921773b46adec0b6ddac9a844a042f.tar.gz
sched/idle: Move latency tracing stop/start calls deeper inside the idle loop
Make sure to stop tracing only once we are past a point where all latency tracing events have been processed (irqs are not enabled again). This has the slight advantage of capturing more latency related events in the idle path, but most importantly it makes sure that latency tracing doesn't get re-enabled inadvertently when new events are coming in. This makes the irqsoff latency tracer useful again, as we stop capturing CPU sleep time as IRQ latency. Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel@pengutronix.de Cc: patchwork-lst@pengutronix.de Link: http://lkml.kernel.org/r/1437410090-3747-1-git-send-email-l.stach@pengutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--drivers/cpuidle/cpuidle.c4
-rw-r--r--kernel/sched/idle.c14
2 files changed, 9 insertions, 9 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index e8e2775c3821..a5d9f2e470ea 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -118,6 +118,7 @@ static void enter_freeze_proper(struct cpuidle_driver *drv,
* cpuidle mechanism enables interrupts and doing that with timekeeping
* suspended is generally unsafe.
*/
+ stop_critical_timings();
drv->states[index].enter_freeze(dev, drv, index);
WARN_ON(!irqs_disabled());
/*
@@ -126,6 +127,7 @@ static void enter_freeze_proper(struct cpuidle_driver *drv,
* critical sections, so tell RCU about that.
*/
RCU_NONIDLE(tick_unfreeze());
+ start_critical_timings();
}
/**
@@ -190,7 +192,9 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
trace_cpu_idle_rcuidle(index, dev->cpu);
time_start = ktime_get();
+ stop_critical_timings();
entered_state = target_state->enter(dev, drv, index);
+ start_critical_timings();
time_end = ktime_get();
trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 594275ed2620..8f177c73ae19 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -83,10 +83,13 @@ void __weak arch_cpu_idle(void)
*/
void default_idle_call(void)
{
- if (current_clr_polling_and_test())
+ if (current_clr_polling_and_test()) {
local_irq_enable();
- else
+ } else {
+ stop_critical_timings();
arch_cpu_idle();
+ start_critical_timings();
+ }
}
static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
@@ -141,12 +144,6 @@ static void cpuidle_idle_call(void)
}
/*
- * During the idle period, stop measuring the disabled irqs
- * critical sections latencies
- */
- stop_critical_timings();
-
- /*
* Tell the RCU framework we are entering an idle section,
* so no more rcu read side critical sections and one more
* step to the grace period
@@ -198,7 +195,6 @@ exit_idle:
local_irq_enable();
rcu_idle_exit();
- start_critical_timings();
}
DEFINE_PER_CPU(bool, cpu_dead_idle);