Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753287AbaG2JQm (ORCPT ); Tue, 29 Jul 2014 05:16:42 -0400 Received: from mail-ig0-f180.google.com ([209.85.213.180]:60629 "EHLO mail-ig0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753068AbaG2JQk (ORCPT ); Tue, 29 Jul 2014 05:16:40 -0400 Date: Tue, 29 Jul 2014 02:16:37 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Joonsoo Kim cc: Vlastimil Babka , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@vger.kernel.org, Minchan Kim , Michal Nazarewicz , Naoya Horiguchi , Christoph Lameter , Rik van Riel , Mel Gorman , Zhang Yanfei Subject: Re: [PATCH v5 07/14] mm, compaction: khugepaged should not give up due to need_resched() In-Reply-To: <20140729082714.GD1610@js1304-P5Q-DELUXE> Message-ID: References: <1406553101-29326-1-git-send-email-vbabka@suse.cz> <1406553101-29326-8-git-send-email-vbabka@suse.cz> <20140729065327.GB1610@js1304-P5Q-DELUXE> <20140729082714.GD1610@js1304-P5Q-DELUXE> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 29 Jul 2014, Joonsoo Kim wrote: > Hmm, if thp faults want to pay cost as least as possible, how about > making thp faults skip async/sync compaction at all? > You can certainly do that with /sys/kernel/mm/transparent_hugepage/defrag. Without doing memory compaction, though, at least one of my customers will have their thp ratio drop significantly and for the vast majority of our machines minimal compaction is all that is needed to allocate a hugepage. I'm concerned primarily about the straggler that has very lengthy fault times for even single hugepages. This patchset will address some of those concerns, but I agree with you that we should be terminating async compaction with another heuristic rather than need_resched(). -- 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/