From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id B3091900225 for ; Fri, 24 Jun 2011 07:46:33 -0400 (EDT) Received: by bwd14 with SMTP id 14so152808bwd.14 for ; Fri, 24 Jun 2011 04:46:30 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110624075742.GA10455@tiehlicka.suse.cz> References: <20110622120635.GB14343@tiehlicka.suse.cz> <20110622121516.GA28359@infradead.org> <20110622123204.GC14343@tiehlicka.suse.cz> <20110623150842.d13492cd.kamezawa.hiroyu@jp.fujitsu.com> <20110623074133.GA31593@tiehlicka.suse.cz> <20110623170811.16f4435f.kamezawa.hiroyu@jp.fujitsu.com> <20110623090204.GE31593@tiehlicka.suse.cz> <20110623190157.1bc8cbb9.kamezawa.hiroyu@jp.fujitsu.com> <20110624075742.GA10455@tiehlicka.suse.cz> Date: Fri, 24 Jun 2011 20:46:29 +0900 Message-ID: Subject: Re: [PATCH] mm: preallocate page before lock_page at filemap COW. (WasRe: [PATCH V2] mm: Do not keep page locked during page fault while charging it for memcg From: Hiroyuki Kamezawa Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: KAMEZAWA Hiroyuki , Christoph Hellwig , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Hugh Dickins , Rik van Riel , Michel Lespinasse , Mel Gorman , Lutz Vieweg 2011/6/24 Michal Hocko : > Sorry, forgot to send my > Reviewed-by: Michal Hocko > Thanks. > I still have concerns about this way to handle the issue. See the follow > up discussion in other thread (https://lkml.org/lkml/2011/6/23/135). > > Anyway I think that we do not have many other options to handle this. > Either we unlock, charge, lock&restes or we preallocate, fault in > I agree. > Or am I missing some other ways how to do it? What do others think about > these approaches? > Yes, I'd like to hear other mm specialists' suggestion. and I'll think other way, again. Anyway, memory reclaim with holding a lock_page() can cause big latency or starvation especially when memcg is used. It's better to avoid it. Thanks, -Kame -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org