From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752643AbbDBMDQ (ORCPT ); Thu, 2 Apr 2015 08:03:16 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:47710 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752379AbbDBMDP (ORCPT ); Thu, 2 Apr 2015 08:03:15 -0400 Date: Thu, 2 Apr 2015 14:02:56 +0200 From: Peter Zijlstra To: Ingo Molnar Cc: Preeti U Murthy , mpe@ellerman.id.au, tglx@linutronix.de, rjw@rjwysocki.net, nicolas.pitre@linaro.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V2] clockevents: Fix cpu down race for hrtimer based broadcasting Message-ID: <20150402120256.GV23123@twins.programming.kicks-ass.net> References: <20150330092410.24979.59887.stgit@preeti.in.ibm.com> <20150402104226.GB21105@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150402104226.GB21105@gmail.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 02, 2015 at 12:42:27PM +0200, Ingo Molnar wrote: > So why not use a suitable CPU_DOWN* notifier for this, instead of open > coding it all into a random place in the hotplug machinery? Because notifiers are crap? ;-) Its entirely impossible to figure out what's happening to core code in hotplug. You need to go chase down and random order notifier things. I'm planning on taking out many of the core hotplug notifiers and hard coding their callbacks into the hotplug code. That way at least its clear wtf happens when. > Also, I improved the changelog (attached below), but decided against > applying it until these questions are cleared - please use that for > future versions of this patch. > Fixes: http://linuxppc.10917.n7.nabble.com/offlining-cpus-breakage-td88619.html You forgot to fix the Fixes line ;-) My copy has: Fixes: 5d1638acb9f6 ("tick: Introduce hrtimer based broadcast") From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2001:1868:205::9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 98B2D1A0AF2 for ; Thu, 2 Apr 2015 23:03:14 +1100 (AEDT) Date: Thu, 2 Apr 2015 14:02:56 +0200 From: Peter Zijlstra To: Ingo Molnar Subject: Re: [PATCH V2] clockevents: Fix cpu down race for hrtimer based broadcasting Message-ID: <20150402120256.GV23123@twins.programming.kicks-ass.net> References: <20150330092410.24979.59887.stgit@preeti.in.ibm.com> <20150402104226.GB21105@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20150402104226.GB21105@gmail.com> Cc: nicolas.pitre@linaro.org, rjw@rjwysocki.net, linux-kernel@vger.kernel.org, Preeti U Murthy , tglx@linutronix.de, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Apr 02, 2015 at 12:42:27PM +0200, Ingo Molnar wrote: > So why not use a suitable CPU_DOWN* notifier for this, instead of open > coding it all into a random place in the hotplug machinery? Because notifiers are crap? ;-) Its entirely impossible to figure out what's happening to core code in hotplug. You need to go chase down and random order notifier things. I'm planning on taking out many of the core hotplug notifiers and hard coding their callbacks into the hotplug code. That way at least its clear wtf happens when. > Also, I improved the changelog (attached below), but decided against > applying it until these questions are cleared - please use that for > future versions of this patch. > Fixes: http://linuxppc.10917.n7.nabble.com/offlining-cpus-breakage-td88619.html You forgot to fix the Fixes line ;-) My copy has: Fixes: 5d1638acb9f6 ("tick: Introduce hrtimer based broadcast")