Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752458Ab0G1Csw (ORCPT ); Tue, 27 Jul 2010 22:48:52 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:46383 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751704Ab0G1Csv (ORCPT ); Tue, 27 Jul 2010 22:48:51 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Wed, 28 Jul 2010 11:44:02 +0900 From: KAMEZAWA Hiroyuki To: Vivek Goyal Cc: "linux-mm@kvack.org" , "nishimura@mxp.nes.nec.co.jp" , "balbir@linux.vnet.ibm.com" , gthelen@google.com, m-ikeda@ds.jp.nec.com, "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" Subject: Re: [RFC][PATCH 4/7][memcg] memcg use ID in page_cgroup Message-Id: <20100728114402.571b8ec6.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20100728023904.GE12642@redhat.com> References: <20100727165155.8b458b7f.kamezawa.hiroyu@jp.fujitsu.com> <20100727165629.6f98145c.kamezawa.hiroyu@jp.fujitsu.com> <20100728023904.GE12642@redhat.com> Organization: FUJITSU Co. LTD. 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: 2503 Lines: 60 On Tue, 27 Jul 2010 22:39:04 -0400 Vivek Goyal wrote: > On Tue, Jul 27, 2010 at 04:56:29PM +0900, KAMEZAWA Hiroyuki wrote: > > From: KAMEZAWA Hiroyuki > > > > Now, addresses of memory cgroup can be calculated by their ID without complex. > > This patch relplaces pc->mem_cgroup from a pointer to a unsigned short. > > On 64bit architecture, this offers us more 6bytes room per page_cgroup. > > Use 2bytes for blkio-cgroup's page tracking. More 4bytes will be used for > > some light-weight concurrent access. > > > > We may able to move this id onto flags field but ...go step by step. > > > > Signed-off-by: KAMEZAWA Hiroyuki > > --- > > include/linux/page_cgroup.h | 3 ++- > > mm/memcontrol.c | 40 +++++++++++++++++++++++++--------------- > > mm/page_cgroup.c | 2 +- > > 3 files changed, 28 insertions(+), 17 deletions(-) > > > > Index: mmotm-0719/include/linux/page_cgroup.h > > =================================================================== > > --- mmotm-0719.orig/include/linux/page_cgroup.h > > +++ mmotm-0719/include/linux/page_cgroup.h > > @@ -12,7 +12,8 @@ > > */ > > struct page_cgroup { > > unsigned long flags; > > - struct mem_cgroup *mem_cgroup; > > + unsigned short mem_cgroup; /* ID of assigned memory cgroup */ > > + unsigned short blk_cgroup; /* Not Used..but will be. */ > > So later I shall have to use virtually indexed arrays in blkio controller? > Or you are just using virtually indexed arrays for lookup speed and > I can continue to use css_lookup() and not worry about using virtually > indexed arrays. > yes. you can use css_lookup() even if it's slow. > So the idea is that when a page is allocated, also store the blk_group > id and once that page is submitted for writeback, we should be able > to associate it to right blkio group? > blk_cgroup id can be attached whenever you wants. please overwrite page_cgroup->blk_cgroup when it's necessary. Did you read Ikeda's patch ? I myself doesn't have patches at this point. This is just for make a room for recording blkio-ID, which was requested for a year. Hmm, but page-allocation-time doesn't sound very good for me. Thanks. -Kame -- 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/