From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761782AbZFKJjN (ORCPT ); Thu, 11 Jun 2009 05:39:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758480AbZFKJi7 (ORCPT ); Thu, 11 Jun 2009 05:38:59 -0400 Received: from mail-gx0-f214.google.com ([209.85.217.214]:43486 "EHLO mail-gx0-f214.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751581AbZFKJi7 convert rfc822-to-8bit (ORCPT ); Thu, 11 Jun 2009 05:38:59 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=ggMTFtUqnAa0zXkNUFCsyRHubyXjeelM4+aUtwqKdnuU8SPAWtreNjA+nHrzHeLo0c pd3uB0PTf6Pe0P3f854wh50Ne3biRuPUqAmH7pnpkrfP0wFBvYuCv+8I2W8ayG2AytWT 9eKqVXl7BPdueeT5cEA7/roCQBIq2ubOww7Lw= MIME-Version: 1.0 In-Reply-To: <28c262360906110237u1f3d1877hae54a51575955549@mail.gmail.com> References: <20090611165535.cf46bf29.kamezawa.hiroyu@jp.fujitsu.com> <20090611170152.7a43b13b.kamezawa.hiroyu@jp.fujitsu.com> <20090611172249.6D3C.A69D9226@jp.fujitsu.com> <20090611173819.0f76e431.kamezawa.hiroyu@jp.fujitsu.com> <28c262360906110237u1f3d1877hae54a51575955549@mail.gmail.com> Date: Thu, 11 Jun 2009 18:39:01 +0900 Message-ID: <28c262360906110239g1e4d0fabg15dc33111014e96a@mail.gmail.com> Subject: Re: [PATCH 2/3] check unevictable flag in lumy reclaim v2 From: Minchan Kim To: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "nishimura@mxp.nes.nec.co.jp" , "balbir@linux.vnet.ibm.com" , "akpm@linux-foundation.org" , apw@canonical.com, riel@redhat.com, mel@csn.ul.ie Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 11, 2009 at 6:37 PM, Minchan Kim wrote: > On Thu, Jun 11, 2009 at 5:38 PM, KAMEZAWA > Hiroyuki wrote: >> How about this ? >> >> From: KAMEZAWA Hiroyuki >> >> Lumpy reclaim check pages from their pfn. Then, it can find unevictable pages >> in its loop. >> Abort lumpy reclaim when we find Unevictable page, we never get a lump >> of pages for requested order. >> >> Changelog: v1->v2 >>  - rewrote commet. >> >> Signed-off-by: KAMEZAWA Hiroyuki >> --- >>  mm/vmscan.c |    9 +++++++++ >>  1 file changed, 9 insertions(+) >> >> Index: lumpy-reclaim-trial/mm/vmscan.c >> =================================================================== >> --- lumpy-reclaim-trial.orig/mm/vmscan.c >> +++ lumpy-reclaim-trial/mm/vmscan.c >> @@ -936,6 +936,15 @@ static unsigned long isolate_lru_pages(u >>                        /* Check that we have not crossed a zone boundary. */ >>                        if (unlikely(page_zone_id(cursor_page) != zone_id)) >>                                continue; >> +                       /* >> +                        * We tries to free all pages in this range to create >> +                        * a free large page. Then, if the range includes a page >> +                        * never be reclaimed, we have no reason to do more. >> +                        * PageUnevictable page is not a page which can be >> +                        * easily freed. Abort this scan now. >> +                        */ >> +                       if (unlikely(PageUnevictable(cursor_page))) >> +                               break; > > __isolate_lru_pages already checked PageUnevictable to return error. > I want to remove repeated check although it is trivial. > > By your patch, It seems to remove PageUnevictable check in __isolate_lru_pages. typo. It seems we can remove PageUnevictable check in __isolate_lru_pages. Sorry for noise. > But I know that. If we remove PageUnevictable check in > __isolate_lru_pages, it can't go into BUG in non-lumpy case. ( I > mentioned following as code) > >                case -EBUSY: >                        /* else it is being freed elsewhere */ >                        list_move(&page->lru, src); >                        continue; > >                default: >                        BUG(); >                } > > > It means we can remove BUG in non-lumpy case and then add BUG into > __isolate_lru_pages directly. > > If we can do it, we can remove unnecessary PageUnevictable check in > __isolate_lru_page. > > I am not sure this is right in case of memcg. > > -- > Kinds regards, > Minchan Kim > -- Kinds regards, Minchan Kim