From patchwork Thu Feb 6 05:50:37 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: preeti X-Patchwork-Id: 3593141 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id AAE19C02DC for ; Thu, 6 Feb 2014 05:54:21 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D26C420154 for ; Thu, 6 Feb 2014 05:54:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5A4F62014A for ; Thu, 6 Feb 2014 05:54:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751885AbaBFFyS (ORCPT ); Thu, 6 Feb 2014 00:54:18 -0500 Received: from e7.ny.us.ibm.com ([32.97.182.137]:51460 "EHLO e7.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755231AbaBFFyR (ORCPT ); Thu, 6 Feb 2014 00:54:17 -0500 Received: from /spool/local by e7.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Thu, 6 Feb 2014 00:54:14 -0500 Received: from b01cxnp22036.gho.pok.ibm.com (b01cxnp22036.gho.pok.ibm.com [9.57.198.26]) by d01dlp03.pok.ibm.com (Postfix) with ESMTP id 59D58C90041; Thu, 6 Feb 2014 00:54:11 -0500 (EST) Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by b01cxnp22036.gho.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s165sEFn62521462; Thu, 6 Feb 2014 05:54:14 GMT Received: from d01av02.pok.ibm.com (localhost [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s165sC3h025109; Thu, 6 Feb 2014 00:54:13 -0500 Received: from [192.168.2.5] ([9.79.200.235]) by d01av02.pok.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id s165s4sH024925; Thu, 6 Feb 2014 00:54:06 -0500 Subject: [PATCH V3 3/3] time/cpuidle:Handle failed call to BROADCAST_ENTER on archs with CPUIDLE_FLAG_TIMER_STOP set To: rafael.j.wysocki@intel.com, linux-pm@vger.kernel.org, peterz@infradead.org, fweisbec@gmail.com, daniel.lezcano@linaro.org, linux-kernel@vger.kernel.org, paulus@samba.org, benh@kernel.crashing.org, tglx@linutronix.de, linuxppc-dev@lists.ozlabs.org, mingo@kernel.org From: Preeti U Murthy Cc: deepthi@linux.vnet.ibm.com, paulmck@linux.vnet.ibm.com, svaidy@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com Date: Thu, 06 Feb 2014 11:20:37 +0530 Message-ID: <20140206055036.4595.86947.stgit@preeti> In-Reply-To: <20140206054158.4595.17827.stgit@preeti> References: <20140206054158.4595.17827.stgit@preeti> User-Agent: StGit/0.16-38-g167d MIME-Version: 1.0 X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14020605-5806-0000-0000-00002411AF7A Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-7.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Some archs set the CPUIDLE_FLAG_TIMER_STOP flag for idle states in which the local timers stop. The cpuidle_idle_call() currently handles such idle states by calling into the broadcast framework so as to wakeup CPUs at their next wakeup event. With the hrtimer mode of broadcast, the BROADCAST_ENTER call into the broadcast frameowork can fail for archs that do not have an external clock device to handle wakeups and the CPU in question has to thus be made the stand by CPU. This patch handles such cases by failing the call into cpuidle so that the arch can take some default action. The arch will certainly not enter a similar idle state because a failed cpuidle call will also implicitly indicate that the broadcast framework has not registered this CPU to be woken up. Hence we are safe if we fail the cpuidle call. In the process move the functions that trace idle statistics just before and after the entry and exit into idle states respectively. In other scenarios where the call to cpuidle fails, we end up not tracing idle entry and exit since a decision on an idle state could not be taken. Similarly when the call to broadcast framework fails, we skip tracing idle statistics because we are in no further position to take a decision on an alternative idle state to enter into. Signed-off-by: Preeti U Murthy Acked-by: Rafael J. Wysocki --- drivers/cpuidle/cpuidle.c | 38 +++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 15 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index a55e68f..8f42033 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -117,15 +117,19 @@ int cpuidle_idle_call(void) { struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); struct cpuidle_driver *drv; - int next_state, entered_state; - bool broadcast; + int next_state, entered_state, ret = 0; + bool broadcast = false; - if (off || !initialized) - return -ENODEV; + if (off || !initialized) { + ret = -ENODEV; + goto out; + } /* check if the device is ready */ - if (!dev || !dev->enabled) - return -EBUSY; + if (!dev || !dev->enabled) { + ret = -EBUSY; + goto out; + } drv = cpuidle_get_cpu_driver(dev); @@ -137,15 +141,18 @@ int cpuidle_idle_call(void) if (cpuidle_curr_governor->reflect) cpuidle_curr_governor->reflect(dev, next_state); local_irq_enable(); - return 0; + goto out; } - trace_cpu_idle_rcuidle(next_state, dev->cpu); - broadcast = !!(drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP); - if (broadcast) - clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu); + if (broadcast) { + ret = clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu); + if (ret) + goto out; + } + + trace_cpu_idle_rcuidle(next_state, dev->cpu); if (cpuidle_state_is_coupled(dev, drv, next_state)) entered_state = cpuidle_enter_state_coupled(dev, drv, @@ -153,16 +160,17 @@ int cpuidle_idle_call(void) else entered_state = cpuidle_enter_state(dev, drv, next_state); - if (broadcast) - clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu); - trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); /* give the governor an opportunity to reflect on the outcome */ if (cpuidle_curr_governor->reflect) cpuidle_curr_governor->reflect(dev, entered_state); - return 0; +out: if (broadcast) + clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu); + + + return ret; } /**