From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754751AbaEHKsB (ORCPT ); Thu, 8 May 2014 06:48:01 -0400 Received: from terminus.zytor.com ([198.137.202.10]:33453 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753056AbaEHKsA (ORCPT ); Thu, 8 May 2014 06:48:00 -0400 Date: Thu, 8 May 2014 03:47:27 -0700 From: tip-bot for Peter Zijlstra Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, nicolas.pitre@linaro.org, tglx@linutronix.de, daniel.lezcano@linaro.org Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, nicolas.pitre@linaro.org, tglx@linutronix.de, daniel.lezcano@linaro.org To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/idle: Delay clearing the polling bit Git-Commit-ID: c444117f0f39d59733ec23da67c44424df529230 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: c444117f0f39d59733ec23da67c44424df529230 Gitweb: http://git.kernel.org/tip/c444117f0f39d59733ec23da67c44424df529230 Author: Peter Zijlstra AuthorDate: Fri, 11 Apr 2014 13:47:16 +0200 Committer: Ingo Molnar CommitDate: Thu, 8 May 2014 09:16:58 +0200 sched/idle: Delay clearing the polling bit With the generic idle functions assuming !polling we should only clear the polling bit at the very last opportunity in order to avoid spurious IPIs. Ideally we'd flip the default to polling, but that means auditing all arch idle functions. Signed-off-by: Peter Zijlstra Acked-by: Nicolas Pitre Cc: Daniel Lezcano Cc: Linus Torvalds Link: http://lkml.kernel.org/n/tip-vq7719foqzf6z5h4j7eh7f9e@git.kernel.org Signed-off-by: Ingo Molnar --- kernel/sched/idle.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 8f4390a..ed67f0c 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -78,12 +78,10 @@ static int cpuidle_idle_call(void) /* * Check if the idle task must be rescheduled. If it is the - * case, exit the function after re-enabling the local irq and - * set again the polling flag + * case, exit the function after re-enabling the local irq. */ - if (current_clr_polling_and_test()) { + if (need_resched()) { local_irq_enable(); - __current_set_polling(); return 0; } @@ -127,7 +125,7 @@ static int cpuidle_idle_call(void) broadcast = !!(drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP); - if (broadcast) + if (broadcast) { /* * Tell the time framework to switch * to a broadcast timer because our @@ -139,6 +137,7 @@ static int cpuidle_idle_call(void) ret = clockevents_notify( CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu); + } if (!ret) { trace_cpu_idle_rcuidle(next_state, dev->cpu); @@ -175,8 +174,12 @@ static int cpuidle_idle_call(void) * We can't use the cpuidle framework, let's use the default * idle routine */ - if (ret) - arch_cpu_idle(); + if (ret) { + if (!current_clr_polling_and_test()) + arch_cpu_idle(); + else + local_irq_enable(); + } __current_set_polling();