Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752864AbbEHMnp (ORCPT ); Fri, 8 May 2015 08:43:45 -0400 Received: from foss.arm.com ([217.140.101.70]:52887 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751490AbbEHMnm (ORCPT ); Fri, 8 May 2015 08:43:42 -0400 Message-ID: <554CAF7A.6060609@arm.com> Date: Fri, 08 May 2015 13:43:38 +0100 From: Sudeep Holla User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Preeti U Murthy CC: "peterz@infradead.org" , "tglx@linutronix.de" , "rafael.j.wysocki@intel.com" , "daniel.lezcano@linaro.org" , Sudeep Holla , "rlippert@google.com" , "linux-pm@vger.kernel.org" , "linus.walleij@linaro.org" , "linux-kernel@vger.kernel.org" , "mingo@redhat.com" , "linuxppc-dev@lists.ozlabs.org" Subject: Re: [PATCH V3] cpuidle: Handle tick_broadcast_enter() failure gracefully References: <20150508073418.28491.4150.stgit@preeti.in.ibm.com> In-Reply-To: <20150508073418.28491.4150.stgit@preeti.in.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1256 Lines: 30 On 08/05/15 08:35, Preeti U Murthy wrote: > When a CPU has to enter an idle state where tick stops, it makes a call > to tick_broadcast_enter(). The call will fail if this CPU is the > broadcast CPU. Today, under such a circumstance, the arch cpuidle code > handles this CPU. This is not convincing because not only do we not > know what the arch cpuidle code does, but we also do not account for the > idle state residency time and usage of such a CPU. > > This scenario can be handled better by simply choosing an idle state > where in ticks do not stop. To accommodate this change move the setting > of runqueue idle state from the core to the cpuidle driver, else the > rq->idle_state will be set wrong. > > Signed-off-by: Preeti U Murthy I gave it a spin on ARM64 Juno platform with one of the CPU in broadcast mode and Vexpress TC2 with broadcast timer. I found no issues in both the cases. So, you can add: Tested-by: Sudeep Holla Regards, Sudeep -- 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/