Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934047Ab3EAAzf (ORCPT ); Tue, 30 Apr 2013 20:55:35 -0400 Received: from e39.co.us.ibm.com ([32.97.110.160]:34020 "EHLO e39.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760460Ab3EAAz3 (ORCPT ); Tue, 30 Apr 2013 20:55:29 -0400 Date: Tue, 30 Apr 2013 17:55:23 -0700 From: "Paul E. McKenney" To: Stephen Boyd Cc: Thomas Gleixner , Russell King - ARM Linux , Kevin Hilman , LKML , linux-arch@vger.kernel.org, Linus Torvalds , Andrew Morton , Rusty Russell , Ingo Molnar , Peter Zijlstra , "Srivatsa S. Bhat" , Magnus Damm Subject: Re: [patch 08/34] arm: Use generic idle loop Message-ID: <20130501005523.GN3780@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <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> <51806682.4040003@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51806682.4040003@codeaurora.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13050100-3620-0000-0000-000002458D6D Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3418 Lines: 83 On Tue, Apr 30, 2013 at 05:49:06PM -0700, Stephen Boyd wrote: > On 04/25/13 14:01, Thomas Gleixner wrote: > > 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 ? > > Yes I think so. Hopefully Russell King or Paul McKenney can ack this patch. > > > > >> ----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 >From an RCU perspective: Acked-by: Paul E. McKenney > >> --- > >> 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 > >> > >> > > > -- > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > hosted by The Linux Foundation > -- 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/