From 01e04f466e12e883907937eb04a9010533363f55 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 27 Feb 2015 00:39:21 +0100 Subject: idle / sleep: Avoid excessive disabling and enabling interrupts Disabling interrupts at the end of cpuidle_enter_freeze() is not useful, because its caller, cpuidle_idle_call(), re-enables them right away after invoking it. To avoid that unnecessary back and forth dance with interrupts, make cpuidle_enter_freeze() enable interrupts after calling enter_freeze_proper() and drop the local_irq_disable() at its end, so that all of the code paths in it end up with interrupts enabled. Then, cpuidle_idle_call() will not need to re-enable interrupts after calling cpuidle_enter_freeze() any more, because the latter will return with interrupts enabled, in analogy with cpuidle_enter(). Reported-by: Lorenzo Pieralisi Signed-off-by: Rafael J. Wysocki Acked-by: Peter Zijlstra (Intel) --- drivers/cpuidle/cpuidle.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/cpuidle') diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 4d53458..b573f58 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -117,6 +117,8 @@ static void enter_freeze_proper(struct cpuidle_driver *drv, * If there are states with the ->enter_freeze callback, find the deepest of * them and enter it with frozen tick. Otherwise, find the deepest state * available and enter it normally. + * + * Returns with enabled interrupts. */ void cpuidle_enter_freeze(void) { @@ -132,6 +134,7 @@ void cpuidle_enter_freeze(void) index = cpuidle_find_deepest_state(drv, dev, true); if (index >= 0) { enter_freeze_proper(drv, dev, index); + local_irq_enable(); return; } @@ -144,9 +147,6 @@ void cpuidle_enter_freeze(void) cpuidle_enter(drv, dev, index); else arch_cpu_idle(); - - /* Interrupts are enabled again here. */ - local_irq_disable(); } /** -- cgit v1.1