From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 84DE9900001 for ; Fri, 29 Apr 2011 11:15:04 -0400 (EDT) Received: by qwa26 with SMTP id 26so2613900qwa.14 for ; Fri, 29 Apr 2011 08:15:01 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110428084820.GH12437@cmpxchg.org> References: <4dc5e63cfc8672426336e43dea29057d5bb6e863.1303833417.git.minchan.kim@gmail.com> <20110428084820.GH12437@cmpxchg.org> Date: Sat, 30 Apr 2011 00:15:01 +0900 Message-ID: Subject: Re: [RFC 2/8] compaction: make isolate_lru_page with filter aware From: Minchan Kim Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Andrew Morton , linux-mm , LKML , Christoph Lameter , Johannes Weiner , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Mel Gorman , Rik van Riel , Andrea Arcangeli Hi Hannes, On Thu, Apr 28, 2011 at 5:48 PM, Johannes Weiner wrote= : > On Wed, Apr 27, 2011 at 01:25:19AM +0900, Minchan Kim wrote: >> In async mode, compaction doesn't migrate dirty or writeback pages. >> So, it's meaningless to pick the page and re-add it to lru list. >> >> Of course, when we isolate the page in compaction, the page might >> be dirty or writeback but when we try to migrate the page, the page >> would be not dirty, writeback. So it could be migrated. But it's >> very unlikely as isolate and migration cycle is much faster than >> writeout. >> >> So, this patch helps cpu and prevent unnecessary LRU churning. >> >> Cc: KOSAKI Motohiro >> Cc: Mel Gorman >> Cc: Rik van Riel >> Cc: Andrea Arcangeli >> Signed-off-by: Minchan Kim >> --- >> =C2=A0mm/compaction.c | =C2=A0 =C2=A02 +- >> =C2=A01 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/mm/compaction.c b/mm/compaction.c >> index dea32e3..9f80b5a 100644 >> --- a/mm/compaction.c >> +++ b/mm/compaction.c >> @@ -335,7 +335,7 @@ static unsigned long isolate_migratepages(struct zon= e *zone, >> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 } >> >> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 /* Try isolate the page= */ >> - =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 if (__isolate_lru_page(page,= ISOLATE_BOTH, 0, 0, 0) !=3D 0) >> + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 if (__isolate_lru_page(page,= ISOLATE_BOTH, 0, !cc->sync, 0) !=3D 0) >> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 continue; > > With the suggested flags argument from 1/8, this would look like: > > =C2=A0 =C2=A0 =C2=A0 =C2=A0flags =3D ISOLATE_BOTH; > =C2=A0 =C2=A0 =C2=A0 =C2=A0if (!cc->sync) > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0flags |=3D ISOLATE= _CLEAN; > > ? Yes. I will change it. > > Anyway, nice change indeed! Thanks! --=20 Kind regards, Minchan Kim -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org