From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754154AbaIDPrP (ORCPT ); Thu, 4 Sep 2014 11:47:15 -0400 Received: from casper.infradead.org ([85.118.1.10]:47337 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751229AbaIDPrO (ORCPT ); Thu, 4 Sep 2014 11:47:14 -0400 Date: Thu, 4 Sep 2014 17:47:10 +0200 From: Peter Zijlstra To: "Liu, Chuansheng" Cc: Daniel Lezcano , "luto@amacapital.net" , "rjw@rjwysocki.net" , "mingo@redhat.com" , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Liu, Changcheng" , "Wang, Xiaoming" , "Chakravarty, Souvik K" Subject: Re: [PATCH 3/3] cpuidle: Using the wake_up_all_idle_cpus() to wake up all idle cpus Message-ID: <20140904154710.GH346@worktop.programming.kicks-ass.net> References: <1409815075-4180-1-git-send-email-chuansheng.liu@intel.com> <1409815075-4180-3-git-send-email-chuansheng.liu@intel.com> <540862AA.7060907@linaro.org> <27240C0AC20F114CBF8149A2696CBE4A01E6B3E3@SHSMSX101.ccr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <27240C0AC20F114CBF8149A2696CBE4A01E6B3E3@SHSMSX101.ccr.corp.intel.com> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 04, 2014 at 01:39:38PM +0000, Liu, Chuansheng wrote: > > So IIUC, kick_all_cpus_sync is a broken function, right ? > kick_all_cpus_sync has other callers, and those other callers want the > old behavior. I think this should be a new function. Correct, things like arch/powerpc/mm/pgtable_64.c:pmdp_clear_flush() really want the old behaviour. It basically uses local_irq_disable()/local_irq_enable() vs kick_all_cpus_sync() as a RCU like serialization primitive.