Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754882AbaGIG4f (ORCPT ); Wed, 9 Jul 2014 02:56:35 -0400 Received: from mail-qa0-f42.google.com ([209.85.216.42]:46623 "EHLO mail-qa0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751542AbaGIG4c (ORCPT ); Wed, 9 Jul 2014 02:56:32 -0400 From: Viresh Kumar To: tglx@linutronix.de Cc: linaro-kernel@lists.linaro.org, linux-kernel@vger.kernel.org, fweisbec@gmail.com, arvind.chauhan@arm.com, preeti@linux.vnet.ibm.com, khilman@linaro.org, Viresh Kumar , Ingo Molnar , Peter Zijlstra Subject: [RFC 6/7] rtmutex: don't check for active hrtimer after adding it Date: Wed, 9 Jul 2014 12:25:38 +0530 Message-Id: X-Mailer: git-send-email 2.0.0.rc2 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org hrtimer_start*() family never fails to enqueue a hrtimer to a clock-base. The only special case is when the hrtimer was in past. If it is getting enqueued to local CPUs's clock-base, we raise a softirq and exit, else we handle that on next interrupt on remote CPU. At several places in the kernel, we try to make sure if hrtimer was added properly or not by calling hrtimer_active(), like: hrtimer_start(timer, expires, mode); if (hrtimer_active(timer)) { /* Added successfully */ } else { /* Was added in the past */ } As hrtimer_start*() never fails, hrtimer_active() is guaranteed to return '1'. So, there is no point calling hrtimer_active(). This patch updates rtmutex core to get this fixed. Cc: Ingo Molnar Cc: Peter Zijlstra Signed-off-by: Viresh Kumar --- kernel/locking/rtmutex.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index fc60594..9ea8830 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -922,11 +922,8 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state, set_current_state(state); /* Setup the timer, when timeout != NULL */ - if (unlikely(timeout)) { + if (unlikely(timeout)) hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS); - if (!hrtimer_active(&timeout->timer)) - timeout->task = NULL; - } ret = task_blocks_on_rt_mutex(lock, &waiter, current, detect_deadlock); -- 2.0.0.rc2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/