From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id ED0416B005C for ; Thu, 15 Jan 2009 06:31:00 -0500 (EST) Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by e28smtp03.in.ibm.com (8.13.1/8.13.1) with ESMTP id n0FBUilU011469 for ; Thu, 15 Jan 2009 17:00:44 +0530 Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id n0FBUm4g4350180 for ; Thu, 15 Jan 2009 17:00:48 +0530 Received: from d28av02.in.ibm.com (loopback [127.0.0.1]) by d28av02.in.ibm.com (8.13.1/8.13.3) with ESMTP id n0FBUhLj005045 for ; Thu, 15 Jan 2009 22:30:43 +1100 Date: Thu, 15 Jan 2009 17:00:37 +0530 From: Balbir Singh 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> Sender: owner-linux-mm@kvack.org 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 List-ID: * 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org