From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759127Ab3DYVBL (ORCPT ); Thu, 25 Apr 2013 17:01:11 -0400 Received: from www.linutronix.de ([62.245.132.108]:46145 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755022Ab3DYVBJ (ORCPT ); Thu, 25 Apr 2013 17:01:09 -0400 Date: Thu, 25 Apr 2013 23:01:02 +0200 (CEST) From: Thomas Gleixner To: Stephen Boyd cc: Russell King - ARM Linux , Kevin Hilman , LKML , linux-arch@vger.kernel.org, Linus Torvalds , Andrew Morton , Rusty Russell , Paul McKenney , Ingo Molnar , Peter Zijlstra , "Srivatsa S. Bhat" , Magnus Damm Subject: Re: [patch 08/34] arm: Use generic idle loop In-Reply-To: <51798C1D.9090405@codeaurora.org> Message-ID: References: <20130321214930.752934102@linutronix.de> <20130321215233.826238797@linutronix.de> <87zjxv9lga.fsf@linaro.org> <20130325114808.GQ4977@n2100.arm.linux.org.uk> <20130408214719.GN17995@n2100.arm.linux.org.uk> <20130409093836.GA14496@n2100.arm.linux.org.uk> <51798C1D.9090405@codeaurora.org> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 25 Apr 2013, Stephen Boyd wrote: > On 04/09/13 02:38, Russell King - ARM Linux wrote: > > On Tue, Apr 09, 2013 at 11:20:31AM +0200, Thomas Gleixner wrote: > >> On Mon, 8 Apr 2013, Russell King - ARM Linux wrote: > >>> On Mon, Mar 25, 2013 at 03:02:39PM +0100, Thomas Gleixner wrote: > >>> So, how can I review these changes when all there is is a git URL, and > >>> I *do* not want to pull them into my tree without first looking at the > >>> patches, possibly reviewing them and *replying* with the patch inline? > >> the patches were CC'ed to LKML and linux-arch and I expected that you > >> are at least having the latter. Find the relevant patch inlined below. > > I've not been on linux-arch for a few years now, after it evolved into > > yet another lkml-like list with high traffic rates, where mainly specific > > x86 issues seemed to be discussed, rather than it being a way to contact > > all arch maintainers. > > > >> It is a counter. I looked carefully at all the various slightly > >> differently fcked up implementations and picked the counter based one > >> as it fits all requirements. > > Great, thanks. The attached patch looks fine to me. > > I'm pretty sure that we need to apply this patch now that > rcu_idle_enter()/exit() is called lower down in the idle loop. Kevin, > did you test hotplug? If the patch is agreed on, I guess I should take it via my idle consolidation branch, right ? > ----8<----- > > From: Stephen Boyd > Subject: [PATCH] ARM: smp: Drop RCU_NONIDLE usage in cpu_die() > > Before f7b861b (arm: Use generic idle loop, 2013-03-21) ARM would > kill the CPU within the rcu idle section. Now that the > rcu_idle_enter()/exit() pair have been pushed lower down in the > idle loop this is no longer true and so using RCU_NONIDLE here is > no longer necessary and also harmful because RCU is not actually > idle at this point. > > Signed-off-by: Stephen Boyd > --- > arch/arm/kernel/smp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c > index 4619177..78f1eb5 100644 > --- a/arch/arm/kernel/smp.c > +++ b/arch/arm/kernel/smp.c > @@ -233,7 +233,7 @@ void __ref cpu_die(void) > mb(); > > /* Tell __cpu_die() that this CPU is now safe to dispose of */ > - RCU_NONIDLE(complete(&cpu_died)); > + complete(&cpu_died); > > /* > * actual CPU shutdown procedure is at least platform (if not > > -- > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > hosted by The Linux Foundation > >