Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754722Ab1FMVZq (ORCPT ); Mon, 13 Jun 2011 17:25:46 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:47812 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754345Ab1FMVZn (ORCPT ); Mon, 13 Jun 2011 17:25:43 -0400 Date: Mon, 13 Jun 2011 14:25:01 -0700 From: Andrew Morton To: KAMEZAWA Hiroyuki Cc: "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "nishimura@mxp.nes.nec.co.jp" , "bsingharora@gmail.com" , "hannes@cmpxchg.org" , Michal Hocko , Ying Han Subject: Re: [BUGFIX][PATCH 5/5] memcg: fix percpu cached charge draining frequency Message-Id: <20110613142501.15e14b2f.akpm@linux-foundation.org> In-Reply-To: <20110613121648.3d28afcd.kamezawa.hiroyu@jp.fujitsu.com> References: <20110613120054.3336e997.kamezawa.hiroyu@jp.fujitsu.com> <20110613121648.3d28afcd.kamezawa.hiroyu@jp.fujitsu.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) 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: 1556 Lines: 40 On Mon, 13 Jun 2011 12:16:48 +0900 KAMEZAWA Hiroyuki wrote: > >From 18b12e53f1cdf6d7feed1f9226c189c34866338c Mon Sep 17 00:00:00 2001 > From: KAMEZAWA Hiroyuki > Date: Mon, 13 Jun 2011 11:25:43 +0900 > Subject: [PATCH 5/5] memcg: fix percpu cached charge draining frequency > > For performance, memory cgroup caches some "charge" from res_counter > into per cpu cache. This works well but because it's cache, > it needs to be flushed in some cases. Typical cases are > 1. when someone hit limit. > 2. when rmdir() is called and need to charges to be 0. > > But "1" has problem. > > Recently, with large SMP machines, we see many kworker runs because > of flushing memcg's cache. Bad things in implementation are > that even if a cpu contains a cache for memcg not related to > a memcg which hits limit, drain code is called. > > This patch does > A) check percpu cache contains a useful data or not. > B) check other asynchronous percpu draining doesn't run. > C) don't call local cpu callback. > D) don't call at softlimit reclaim. > > > ... > > +DEFINE_MUTEX(percpu_charge_mutex); I made this static. If we later wish to give it kernel-wide scope then "percpu_charge_mutex" will not be a good choice of name. -- 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/