From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751223AbdBWOFo (ORCPT ); Thu, 23 Feb 2017 09:05:44 -0500 Received: from mail-pf0-f182.google.com ([209.85.192.182]:36396 "EHLO mail-pf0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751049AbdBWOFm (ORCPT ); Thu, 23 Feb 2017 09:05:42 -0500 Subject: Re: 9908859acaa9 cpuidle/menu: add per CPU PM QoS resume latency consideration To: Mike Galbraith , "Rafael J. Wysocki" , Peter Zijlstra References: <1487768197.27533.5.camel@gmx.de> <20170222143910.GV6515@twins.programming.kicks-ass.net> <47a10932-b485-cf3f-bf39-ccf3026a960f@linaro.org> <2050688.jCOqd8xbcD@aspire.rjw.lan> <1487855304.4463.50.camel@gmx.de> Cc: LKML , Rik van Riel From: Alex Shi Message-ID: <6f016a9b-8968-e7c1-b1c7-c6b023431623@linaro.org> Date: Thu, 23 Feb 2017 21:58:47 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <1487855304.4463.50.camel@gmx.de> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/23/2017 09:08 PM, Mike Galbraith wrote: > On Thu, 2017-02-23 at 13:15 +0100, Rafael J. Wysocki wrote: >> On Wednesday, February 22, 2017 10:55:04 PM Alex Shi wrote: >>>> >>>> Its not hard; spinlock_t ends up being a mutex, and this is ran >>>> from the >>>> idle thread. What thread do you think we ought to run when we >>>> block >>>> idle? >>>> >>> >>> Straight right. >>> Thanks for explanations! :) >> >> I overlooked that, sorry. >> >> Shall we revert? >> >> I don't want RT to be broken because of this. > > Just whacking the lock would take care of that. The question is who is > gonna use this, and what does it really buy them? When I look at that > commit, an eyebrow raises, lock or no lock. > Right per cpu lock for per cpu data is unnecessary.