Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753855AbZGMDIX (ORCPT ); Sun, 12 Jul 2009 23:08:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753299AbZGMDIV (ORCPT ); Sun, 12 Jul 2009 23:08:21 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:48250 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753057AbZGMDIU (ORCPT ); Sun, 12 Jul 2009 23:08:20 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Shaohua Li Subject: Re: [PATCH] switch free memory back to MIGRATE_MOVABLE Cc: kosaki.motohiro@jp.fujitsu.com, KAMEZAWA Hiroyuki , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "mel@csn.ul.ie" , "akpm@linux-foundation.org" In-Reply-To: <20090713030444.GA2582@sli10-desk.sh.intel.com> References: <20090713115803.b78a4f4f.kamezawa.hiroyu@jp.fujitsu.com> <20090713030444.GA2582@sli10-desk.sh.intel.com> Message-Id: <20090713120549.6252.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Mon, 13 Jul 2009 12:08:14 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1436 Lines: 33 > 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. This answer is not actual answer. Why do you think __rmqueue_fallback() doesn't works well? Do you have any test-case or found a bug by review? -- 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/