Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762980AbZAOLa4 (ORCPT ); Thu, 15 Jan 2009 06:30:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754215AbZAOLas (ORCPT ); Thu, 15 Jan 2009 06:30:48 -0500 Received: from e28smtp06.in.ibm.com ([59.145.155.6]:41996 "EHLO e28smtp06.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754066AbZAOLar (ORCPT ); Thu, 15 Jan 2009 06:30:47 -0500 Date: Thu, 15 Jan 2009 17:00:37 +0530 From: Balbir Singh To: KOSAKI Motohiro Cc: KAMEZAWA Hiroyuki , Daisuke Nishimura , linux-mm@kvack.org, linux-kernel@vger.kernel.org, lizf@cn.fujitsu.com, menage@google.com, Hugh Dickins Subject: Re: [PATCH] mark_page_accessed() in do_swap_page() move latter than memcg charge Message-ID: <20090115113037.GH30358@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <20090109043257.GB9737@balbir.in.ibm.com> <20090109134736.a995fc49.kamezawa.hiroyu@jp.fujitsu.com> <20090115200545.EBE6.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20090115200545.EBE6.KOSAKI.MOTOHIRO@jp.fujitsu.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2507 Lines: 92 * KOSAKI Motohiro [2009-01-15 20:08:36]: > > sorry for late responce. > > > > In this case we've hit a case where the page is valid and the pc is > > > not. This does fix the problem, but won't this impact us getting > > > correct reclaim stats and thus indirectly impact the working of > > > pressure? > > > > > - If retruns NULL, only global LRU's status is updated. > > > > Because this page is not belongs to any memcg, we cannot update > > any counters. But yes, your point is a concern. > > > > Maybe moving acitvate_page() to > > == > > do_swap_page() > > { > > > > - activate_page() > > mem_cgroup_try_charge().. > > .... > > mem_cgroup_commit_charge().... > > .... > > + activate_page() > > } > > == > > is necessary. How do you think, kosaki ? > > > OK. it makes sense. and my test found no bug. > > == > > mark_page_accessed() update reclaim_stat statics. > but currently, memcg charge is called after mark_page_accessed(). > > then, mark_page_accessed() don't update memcg statics correctly. > > fixing here. > Changelog needs to be a bit more elaborate, may be talk about invalid pointer we hit if mark_page_accessed is not moved, etc. > Signed-off-by: KOSAKI Motohiro > Cc: KAMEZAWA Hiroyuki > Cc: Daisuke Nishimura > Cc: Balbir Singh > > --- > mm/memory.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > Index: b/mm/memory.c > =================================================================== > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -2426,8 +2426,6 @@ static int do_swap_page(struct mm_struct > count_vm_event(PGMAJFAULT); > } > > - mark_page_accessed(page); > - > lock_page(page); > delayacct_clear_flag(DELAYACCT_PF_SWAPIN); > > @@ -2480,6 +2478,8 @@ static int do_swap_page(struct mm_struct > try_to_free_swap(page); > unlock_page(page); > > + mark_page_accessed(page); > + > if (write_access) { > ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte); > if (ret & VM_FAULT_ERROR) > > > Looks good to me otherwise Reviewed-by: Balbir Singh -- Balbir -- 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/