From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751686Ab2GIFUI (ORCPT ); Mon, 9 Jul 2012 01:20:08 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:41198 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751370Ab2GIFTu (ORCPT ); Mon, 9 Jul 2012 01:19:50 -0400 Message-ID: <4FFA69F2.4090003@gmail.com> Date: Mon, 09 Jul 2012 13:19:46 +0800 From: Sha Zhengju User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.23) Gecko/20110922 Thunderbird/3.1.15 MIME-Version: 1.0 To: Fengguang Wu CC: linux-mm@kvack.org, cgroups@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com, gthelen@google.com, yinghan@google.com, akpm@linux-foundation.org, mhocko@suse.cz, linux-kernel@vger.kernel.org, Sha Zhengju Subject: Re: [PATCH 6/7] memcg: add per cgroup writeback pages accounting References: <1340880885-5427-1-git-send-email-handai.szj@taobao.com> <1340881562-5900-1-git-send-email-handai.szj@taobao.com> <20120708145309.GC18272@localhost> <4FFA51AB.30203@gmail.com> <20120709041437.GA10180@localhost> In-Reply-To: <20120709041437.GA10180@localhost> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/09/2012 12:14 PM, Fengguang Wu wrote: > On Mon, Jul 09, 2012 at 11:36:11AM +0800, Sha Zhengju wrote: >> On 07/08/2012 10:53 PM, Fengguang Wu wrote: >>>> @@ -2245,7 +2252,10 @@ int test_set_page_writeback(struct page *page) >>>> { >>>> struct address_space *mapping = page_mapping(page); >>>> int ret; >>>> + bool locked; >>>> + unsigned long flags; >>>> >>>> + mem_cgroup_begin_update_page_stat(page,&locked,&flags); >>>> if (mapping) { >>>> struct backing_dev_info *bdi = mapping->backing_dev_info; >>>> unsigned long flags; >>>> @@ -2272,6 +2282,8 @@ int test_set_page_writeback(struct page *page) >>>> } >>>> if (!ret) >>>> account_page_writeback(page); >>>> + >>>> + mem_cgroup_end_update_page_stat(page,&locked,&flags); >>>> return ret; >>>> >>>> } >>> Where is the MEM_CGROUP_STAT_FILE_WRITEBACK increased? >>> >> It's in account_page_writeback(). >> >> void account_page_writeback(struct page *page) >> { >> + mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_FILE_WRITEBACK); >> inc_zone_page_state(page, NR_WRITEBACK); >> } > I didn't find that chunk, perhaps it's lost due to rebase.. Ah? a bit weird... you can refer to the link http://thread.gmane.org/gmane.linux.kernel.cgroups/3134 which is an integral one. Thanks! >> There isn't a unified interface to dec/inc writeback accounting, so >> I just follow that. >> Maybe we can rework account_page_writeback() to also account >> dec in? > The current seperate inc/dec paths are fine. It sounds like > over-engineering if going any further. > > I'm a bit worried about some 3rd party kernel module to call > account_page_writeback() without mem_cgroup_begin/end_update_page_stat(). > Will that lead to serious locking issues, or merely inaccurate > accounting? > > Thanks, > Fengguang > -- > To unsubscribe from this list: send the line "unsubscribe cgroups" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html