Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936746Ab3DIBxF (ORCPT ); Mon, 8 Apr 2013 21:53:05 -0400 Received: from e9.ny.us.ibm.com ([32.97.182.139]:33505 "EHLO e9.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751736Ab3DIBxD (ORCPT ); Mon, 8 Apr 2013 21:53:03 -0400 Message-ID: <51637470.5030906@linux.vnet.ibm.com> Date: Mon, 08 Apr 2013 18:52:48 -0700 From: Cody P Schafer User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130308 Thunderbird/17.0.4 MIME-Version: 1.0 To: KOSAKI Motohiro CC: Andrew Morton , Mel Gorman , Linux MM , LKML Subject: Re: [PATCH 2/3] mm/page_alloc: convert zone_pcp_update() to use on_each_cpu() instead of stop_machine() References: <1365194030-28939-1-git-send-email-cody@linux.vnet.ibm.com> <1365194030-28939-3-git-send-email-cody@linux.vnet.ibm.com> <5161931A.8060501@gmail.com> <5162FF18.8010802@linux.vnet.ibm.com> <516319FF.6030104@gmail.com> <51631F4D.7050504@linux.vnet.ibm.com> <5163424A.4000106@gmail.com> In-Reply-To: <5163424A.4000106@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13040901-7182-0000-0000-00000625C508 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1346 Lines: 35 On 04/08/2013 03:18 PM, KOSAKI Motohiro wrote: > (4/8/13 3:49 PM), Cody P Schafer wrote:> >> If this turns out to be an issue, schedule_on_each_cpu() could be an >> alternative. > > no way. schedule_on_each_cpu() is more problematic and it should be removed > in the future. > schedule_on_each_cpu() can only be used when caller task don't have any lock. > otherwise it may make deadlock. I wasn't aware of that. Just to be clear, the deadlock you're referring to isn't the same one refered to in commit b71ab8c2025caef8db719aa41af0ed735dc543cd Author: Tejun Heo Date: Tue Jun 29 10:07:14 2010 +0200 workqueue: increase max_active of keventd and kill current_is_keventd() and commit 65a64464349883891e21e74af16c05d6e1eeb4e9 Author: Andi Kleen Date: Wed Oct 14 06:22:47 2009 +0200 HWPOISON: Allow schedule_on_each_cpu() from keventd If you're referencing some other deadlock, could you please provide a link to the relevant discussion? (I'd really like to add a note to schedule_on_each_cpu()'s doc comment about it so others can avoid that pitfall). -- 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/