From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx150.postini.com [74.125.245.150]) by kanga.kvack.org (Postfix) with SMTP id 3E6206B0031 for ; Wed, 5 Jun 2013 17:02:58 -0400 (EDT) Received: by mail-vc0-f174.google.com with SMTP id kw10so1494731vcb.33 for ; Wed, 05 Jun 2013 14:02:57 -0700 (PDT) Message-ID: <51AFA786.1040608@gmail.com> Date: Wed, 05 Jun 2013 17:03:02 -0400 From: KOSAKI Motohiro MIME-Version: 1.0 Subject: Re: [PATCH 1/7] mm: remove ZONE_RECLAIM_LOCKED References: <1370445037-24144-1-git-send-email-aarcange@redhat.com> <1370445037-24144-2-git-send-email-aarcange@redhat.com> <51AFA185.9000909@gmail.com> <0000013f161c3f42-14ae4d9d-fd85-47dd-ba80-896e1e84a6fe-000000@email.amazonses.com> In-Reply-To: <0000013f161c3f42-14ae4d9d-fd85-47dd-ba80-896e1e84a6fe-000000@email.amazonses.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: KOSAKI Motohiro , Andrea Arcangeli , linux-mm@kvack.org, Mel Gorman , Rik van Riel , Hugh Dickins , Richard Davies , Shaohua Li , Rafael Aquini (6/5/13 4:51 PM), Christoph Lameter wrote: > On Wed, 5 Jun 2013, KOSAKI Motohiro wrote: > >> (6/5/13 11:10 AM), Andrea Arcangeli wrote: >>> Zone reclaim locked breaks zone_reclaim_mode=1. If more than one >>> thread allocates memory at the same time, it forces a premature >>> allocation into remote NUMA nodes even when there's plenty of clean >>> cache to reclaim in the local nodes. >>> >>> Signed-off-by: Andrea Arcangeli >> >> You should Christoph Lameter who make this lock. I've CCed. I couldn't >> find any problem in this removing. But I also didn't find a reason why >> this lock is needed. > > There was early on an issue with multiple zone reclaims from > different processors causing an extreme slowdown and the system would go > OOM. The flag was used to enforce that only a single zone reclaim pass was > occurring at one time on a zone. This minimized contention and avoided > the failure. OK. I've convinced now we can removed because sc->nr_to_reclaim protect us form this issue. Thank you, guys. Acked-by: KOSAKI Motohiro -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org