From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx185.postini.com [74.125.245.185]) by kanga.kvack.org (Postfix) with SMTP id D39EC6B004F for ; Thu, 19 Jan 2012 19:49:40 -0500 (EST) Received: from m2.gw.fujitsu.co.jp (unknown [10.0.50.72]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 5DF673EE0BC for ; Fri, 20 Jan 2012 09:49:39 +0900 (JST) Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 4353645DE6C for ; Fri, 20 Jan 2012 09:49:39 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 16E15266D12 for ; Fri, 20 Jan 2012 09:49:39 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 026BEE08002 for ; Fri, 20 Jan 2012 09:49:39 +0900 (JST) Received: from m107.s.css.fujitsu.com (m107.s.css.fujitsu.com [10.240.81.147]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 934C2E08007 for ; Fri, 20 Jan 2012 09:49:38 +0900 (JST) Date: Fri, 20 Jan 2012 09:48:21 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFC] [PATCH 1/7 v2] memcg: remove unnecessary check in mem_cgroup_update_page_stat() Message-Id: <20120120094821.7f23e5a1.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20120113173001.ee5260ca.kamezawa.hiroyu@jp.fujitsu.com> <20120113173227.df2baae3.kamezawa.hiroyu@jp.fujitsu.com> <20120117151619.GA21348@tiehlicka.suse.cz> <20120118085558.6ed1a988.kamezawa.hiroyu@jp.fujitsu.com> <20120118130102.GC31112@tiehlicka.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Ying Han Cc: Michal Hocko , "linux-mm@kvack.org" , "hugh.dickins@tiscali.co.uk" , "hannes@cmpxchg.org" , cgroups@vger.kernel.org, "bsingharora@gmail.com" On Thu, 19 Jan 2012 12:07:22 -0800 Ying Han wrote: > On Wed, Jan 18, 2012 at 5:01 AM, Michal Hocko wrote: > > On Wed 18-01-12 08:55:58, KAMEZAWA Hiroyuki wrote: > >> On Tue, 17 Jan 2012 16:16:20 +0100 > >> Michal Hocko wrote: > >> > >> > On Fri 13-01-12 17:32:27, KAMEZAWA Hiroyuki wrote: > >> > > > >> > > From 788aebf15f3fa37940e0745cab72547e20683bf2 Mon Sep 17 00:00:00 2001 > >> > > From: KAMEZAWA Hiroyuki > >> > > Date: Thu, 12 Jan 2012 16:08:33 +0900 > >> > > Subject: [PATCH 1/7] memcg: remove unnecessary check in mem_cgroup_update_page_stat() > >> > > > >> > > commit 10ea69f1182b removes move_lock_page_cgroup() in thp-split path. > >> > > So, this PageTransHuge() check is unnecessary, too. > >> > > >> > I do not see commit like that in the tree. I guess you meant > >> > memcg: make mem_cgroup_split_huge_fixup() more efficient which is not > >> > merged yet, right? > >> > > >> > >> This commit in the linux-next. > > > > Referring to commits from linux-next is tricky as it changes all the > > time. I guess that the full commit subject should be sufficient. > > > >> > > Note: > >> > > A - considering when mem_cgroup_update_page_stat() is called, > >> > > A A there will be no race between split_huge_page() and update_page_stat(). > >> > > A A All required locks are held in higher level. > >> > > >> > We should never have THP page in this path in the first place. So why > >> > not changing this to VM_BUG_ON(PageTransHuge). > >> > > >> > >> Ying Han considers to support mlock stat. > > > > OK, got it. What about the following updated changelog instead? > > > > === > > We do not have to check PageTransHuge in mem_cgroup_update_page_stat > > and fallback into the locked accounting because both move charge and thp > > one nitpick. Should it be "move account" instead of "move charge"? > Ah, yes. you'r right. Considering Michal's comment, I'll update and post v3. 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