Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753798AbZGMDEt (ORCPT ); Sun, 12 Jul 2009 23:04:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753299AbZGMDEq (ORCPT ); Sun, 12 Jul 2009 23:04:46 -0400 Received: from mga01.intel.com ([192.55.52.88]:52622 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753253AbZGMDEq (ORCPT ); Sun, 12 Jul 2009 23:04:46 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.42,388,1243839600"; d="scan'208";a="707203632" Date: Mon, 13 Jul 2009 11:04:44 +0800 From: Shaohua Li To: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "mel@csn.ul.ie" , "akpm@linux-foundation.org" Subject: Re: [PATCH] switch free memory back to MIGRATE_MOVABLE Message-ID: <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090713115803.b78a4f4f.kamezawa.hiroyu@jp.fujitsu.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1265 Lines: 27 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. Thanks, Shaohua -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/