From mboxrd@z Thu Jan 1 00:00:00 1970 From: ccross@android.com (Colin Cross) Date: Fri, 18 May 2012 11:05:24 -0700 Subject: [PATCH 2/2] cpuidle: coupled: fix decrementing ready count In-Reply-To: <1337364324-12171-1-git-send-email-ccross@android.com> References: <1337364324-12171-1-git-send-email-ccross@android.com> Message-ID: <1337364324-12171-3-git-send-email-ccross@android.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org cpuidle_coupled_set_not_ready sometimes refuses to decrement the ready count in order to prevent a race condition. This makes it unsuitable for use when finished with idle. Add a new function cpuidle_coupled_set_done that decrements both the ready count and waiting count, and call it after idle is complete. Signed-off-by: Colin Cross --- drivers/cpuidle/coupled.c | 18 ++++++++++++++++-- 1 files changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c index b02810a..fc427fa 100644 --- a/drivers/cpuidle/coupled.c +++ b/drivers/cpuidle/coupled.c @@ -388,6 +388,21 @@ static void cpuidle_coupled_set_not_waiting(int cpu, } /** + * cpuidle_coupled_set_done - mark this cpu as leaving the ready loop + * @cpu: the current cpu + * @coupled: the struct coupled that contains the current cpu + * + * Marks this cpu as no longer in the ready and waiting loops. Decrements + * the waiting count first to prevent another cpu looping back in and seeing + * this cpu as waiting just before it exits idle. + */ +static void cpuidle_coupled_set_done(int cpu, struct cpuidle_coupled *coupled) +{ + cpuidle_coupled_set_not_waiting(cpu, coupled); + atomic_sub(MAX_WAITING_CPUS, &coupled->ready_waiting_counts); +} + +/** * cpuidle_coupled_clear_pokes - spin until the poke interrupt is processed * @cpu - this cpu * @@ -501,8 +516,7 @@ int cpuidle_enter_state_coupled(struct cpuidle_device *dev, entered_state = cpuidle_enter_state(dev, drv, next_state); - cpuidle_coupled_set_not_waiting(dev->cpu, coupled); - cpuidle_coupled_set_not_ready(coupled); + cpuidle_coupled_set_done(dev->cpu, coupled); out: /* -- 1.7.7.3