From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752403AbcEMIbT (ORCPT ); Fri, 13 May 2016 04:31:19 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:33192 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751709AbcEMIbO (ORCPT ); Fri, 13 May 2016 04:31:14 -0400 Date: Fri, 13 May 2016 10:31:11 +0200 From: Michal Hocko To: Vlastimil Babka Cc: linux-mm@kvack.org, Andrew Morton , Joonsoo Kim , Rik van Riel , David Rientjes , Mel Gorman , Johannes Weiner , Tetsuo Handa , linux-kernel@vger.kernel.org, Linus Torvalds , Hugh Dickins Subject: Re: [RFC 04/13] mm, page_alloc: restructure direct compaction handling in slowpath Message-ID: <20160513083110.GG20141@dhcp22.suse.cz> References: <1462865763-22084-1-git-send-email-vbabka@suse.cz> <1462865763-22084-5-git-send-email-vbabka@suse.cz> <20160512132918.GJ4200@dhcp22.suse.cz> <57358C0A.4020002@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <57358C0A.4020002@suse.cz> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 13-05-16 10:10:50, Vlastimil Babka wrote: > On 05/12/2016 03:29 PM, Michal Hocko wrote: > > On Tue 10-05-16 09:35:54, Vlastimil Babka wrote: > > > This patch attempts to restructure the code with only minimal functional > > > changes. The call to the first compaction and THP-specific checks are now > > > placed above the retry loop, and the "noretry" direct compaction is removed. > > > > > > The initial compaction is additionally restricted only to costly orders, as we > > > can expect smaller orders to be held back by watermarks, and only larger orders > > > to suffer primarily from fragmentation. This better matches the checks in > > > reclaim's shrink_zones(). > > > > > > There are two other smaller functional changes. One is that the upgrade from > > > async migration to light sync migration will always occur after the initial > > > compaction. > > > > I do not think this belongs to the patch. There are two reasons. First > > we do not need to do potentially more expensive sync mode when async is > > able to make some progress and the second > > My concern was that __GFP_NORETRY non-costly allocations wouldn't otherwise > get a MIGRATE_SYNC_LIGHT pass at all. Previously they would get it in the > noretry: label. OK, I haven't considered this. So scratch this then. -- Michal Hocko SUSE Labs