Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932233Ab0HDB3I (ORCPT ); Tue, 3 Aug 2010 21:29:08 -0400 Received: from TYO202.gate.nec.co.jp ([202.32.8.206]:36130 "EHLO tyo202.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757858Ab0HDB3G (ORCPT ); Tue, 3 Aug 2010 21:29:06 -0400 Date: Wed, 4 Aug 2010 10:25:27 +0900 From: Daisuke Nishimura To: KAMEZAWA Hiroyuki Cc: linux-mm@kvack.org, "balbir@linux.vnet.ibm.com" , vgoyal@redhat.com, m-ikeda@ds.jp.nec.com, gthelen@google.com, "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" , Daisuke Nishimura Subject: Re: [PATCH -mm 3/5] memcg scalable file stat accounting method Message-Id: <20100804102527.d3bb4afc.nishimura@mxp.nes.nec.co.jp> In-Reply-To: <20100804101150.d7b05ce2.kamezawa.hiroyu@jp.fujitsu.com> References: <20100802191113.05c982e4.kamezawa.hiroyu@jp.fujitsu.com> <20100802191559.6af0cded.kamezawa.hiroyu@jp.fujitsu.com> <20100804095513.6fef0a3d.nishimura@mxp.nes.nec.co.jp> <20100804101150.d7b05ce2.kamezawa.hiroyu@jp.fujitsu.com> X-Mailer: Sylpheed 3.0.3 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1296 Lines: 44 On Wed, 4 Aug 2010 10:11:50 +0900 KAMEZAWA Hiroyuki wrote: > On Wed, 4 Aug 2010 09:55:13 +0900 > Daisuke Nishimura wrote: > > > > @@ -1074,7 +1075,49 @@ static unsigned int get_swappiness(struc > > > return swappiness; > > > } > > > > > > -/* A routine for testing mem is not under move_account */ > > > +static void mem_cgroup_start_move(struct mem_cgroup *mem) > > > +{ > > > + int cpu; > > > + /* for fast checking in mem_cgroup_update_file_stat() etc..*/ > > > + spin_lock(&mc.lock); > > > + for_each_possible_cpu(cpu) > > > + per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1; > > > + spin_unlock(&mc.lock); > > > + > > > + synchronize_rcu(); > > > +} > > > + > > > +static void mem_cgroup_end_move(struct mem_cgroup *mem) > > > +{ > > > + int cpu; > > > + > > > + if (!mem) > > > + return; > > Is this check necessary? > > > > Yes, I hit NULL here. > That happens migration=off case, IIRC. > Ah, you're right. Thank you for your clarification. Daisuke Nishimura. -- 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/