From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 283276B0055 for ; Sun, 12 Jul 2009 22:49:12 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp ([10.0.50.72]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n6D3920w009772 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Mon, 13 Jul 2009 12:09:03 +0900 Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id BD74345DD75 for ; Mon, 13 Jul 2009 12:09:02 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 9C9F045DE5D for ; Mon, 13 Jul 2009 12:09:02 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 78FF2E38002 for ; Mon, 13 Jul 2009 12:09:02 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.249.87.106]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id F1032E38004 for ; Mon, 13 Jul 2009 12:09:01 +0900 (JST) Date: Mon, 13 Jul 2009 12:07:16 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH] switch free memory back to MIGRATE_MOVABLE Message-Id: <20090713120716.cd58a9f7.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090713030444.GA2582@sli10-desk.sh.intel.com> References: <20090713023030.GA27269@sli10-desk.sh.intel.com> <20090713113326.624F.A69D9226@jp.fujitsu.com> <20090713115803.b78a4f4f.kamezawa.hiroyu@jp.fujitsu.com> <20090713030444.GA2582@sli10-desk.sh.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Shaohua Li Cc: KOSAKI Motohiro , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "mel@csn.ul.ie" , "akpm@linux-foundation.org" List-ID: On Mon, 13 Jul 2009 11:04:44 +0800 Shaohua Li wrote: > On Mon, Jul 13, 2009 at 10:58:03AM +0800, KAMEZAWA Hiroyuki wrote: > > On Mon, 13 Jul 2009 11:47:46 +0900 (JST) > > KOSAKI Motohiro wrote: > > > > > > When page is back to buddy and its order is bigger than pageblock_order, we can > > > > switch its type to MIGRATE_MOVABLE. This can reduce fragmentation. The patch > > > > has obvious effect when read a block device and then drop caches. > > > > > > > > Signed-off-by: Shaohua Li > > > > > > This patch change hot path, but there is no performance mesurement description. > > > Also, I don't like modification buddy core for only drop caches. > > > > > Li, does this patch imply fallback of migration type doesn't work well ? > > What is the bad case ? > The page is initialized as migrate_movable, and then switch to reclaimable or > something else when fallback occurs, but its type remains even the page gets > freed. When the page gets freed, its type actually can be switch back to movable, > this is what the patch does. > Then, what is the benefits ? Changing this Movable here is better than fallback and find this chunk again in lazy way ? Thanks, -Kame -- 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