From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 508776B00B8 for ; Fri, 2 Jan 2009 06:18:59 -0500 (EST) Received: by yx-out-1718.google.com with SMTP id 36so1817000yxh.26 for ; Fri, 02 Jan 2009 03:18:57 -0800 (PST) Message-ID: <28c262360901020318n189cf48bl4081d15adc99e3d9@mail.gmail.com> Date: Fri, 2 Jan 2009 20:18:57 +0900 From: "MinChan Kim" Subject: Re: [PATCH] mm: stop kswapd's infinite loop at high order allocation take2 In-Reply-To: <2f11576a0901020254h13d43d2difa340aa1c40a0dbf@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20081231115332.GB20534@csn.ul.ie> <20081231215934.1296.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20090101021240.A057.KOSAKI.MOTOHIRO@jp.fujitsu.com> <28c262360901020155l3a9260b5h3c79d4b23a213825@mail.gmail.com> <2f11576a0901020200t3a6dadf5qa944432cd9fd8873@mail.gmail.com> <28c262360901020229k55d47445yc9a6c9c7aa3e9c66@mail.gmail.com> <2f11576a0901020254h13d43d2difa340aa1c40a0dbf@mail.gmail.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Mel Gorman , LKML , linux-mm , Andrew Morton , Nick Piggin , wassim dagash List-ID: On Fri, Jan 2, 2009 at 7:54 PM, KOSAKI Motohiro wrote: >>>> So I want to balance zone's proportional free page. >>>> How about following ? >>>> >>>> if (nr_reclaimed < SWAP_CLUSTER_MAX) { >>>> if (order != 0) { >>>> order -=1; >>>> sc.order -=1; >>>> } >>>> } >>>> >>>> It prevents infinite loop and do best effort to make zone's >>>> proportional free page per order size good. >>>> >>>> It's just my opinion within my knowledge. >>>> If it have a problem, pz, explain me :) >>> >>> Please read Nick's expalin. it explain very kindly :) >> >> Hm. I read Nick's explain. >> I understand his point. >> >> Nick said, >> "A higher kswapd reclaim order shouldn't weaken kswapd >> postcondition for order-0 memory." >> >> My patch don't prevent order-0 memory reclaim. After all, it will do it. >> It also can do best effort to reclaim other order size. >> >> In this case, others order size reclaim is needless ? > > Yes, needless. > > wakeup_kswapd() function mean > - please make free memory until pages_high > - and, I want to "order argument" conteniously pages. > > then, shorter conteniously pages than "order argumet" pages aren't needed > by caller. > > Unfortunately, your patch has more bad side effect. > high order shrink_zone() cause lumpy reclaim. > lumpy reclaim cause reclaim neighbor pages although it is active page. > > needlessly active page reclaiming decrease system performance. > I agree. It can reclaim active pages. Thanks for kind explain. :) -- Kinds 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/ . Don't email: email@kvack.org