From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f44.google.com (mail-wm0-f44.google.com [74.125.82.44]) by kanga.kvack.org (Postfix) with ESMTP id A50BC6B0038 for ; Tue, 8 Dec 2015 04:45:52 -0500 (EST) Received: by wmvv187 with SMTP id v187so205314047wmv.1 for ; Tue, 08 Dec 2015 01:45:52 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id uq9si3312237wjc.17.2015.12.08.01.45.51 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 08 Dec 2015 01:45:51 -0800 (PST) Date: Tue, 8 Dec 2015 09:45:46 +0000 From: Mel Gorman Subject: Re: [PATCH] mm/compaction: restore COMPACT_CLUSTER_MAX to 32 Message-ID: <20151208094546.GD19677@suse.de> References: <1449115900-20112-1-git-send-email-iamjoonsoo.kim@lge.com> <20151207170041.c470d362915ae1b42a8a4ef8@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20151207170041.c470d362915ae1b42a8a4ef8@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Joonsoo Kim , Vlastimil Babka , David Rientjes , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Joonsoo Kim On Mon, Dec 07, 2015 at 05:00:41PM -0800, Andrew Morton wrote: > On Thu, 3 Dec 2015 13:11:40 +0900 Joonsoo Kim wrote: > > > Until now, COMPACT_CLUSTER_MAX is defined as SWAP_CLUSTER_MAX. > > Commit ("mm: increase SWAP_CLUSTER_MAX to batch TLB flushes") > > changes SWAP_CLUSTER_MAX from 32 to 256 to improve tlb flush performance > > so COMPACT_CLUSTER_MAX is also changed to 256. > > "mm: increase SWAP_CLUSTER_MAX to batch TLB flushes" has been in limbo > for quite a while. Because it has been unclear whether the patch's > benefits exceed its costs+risks. > > We should make a decision here - either do the appropriate testing or > drop the patch. > At this point, drop it. The benefits that apply to some corner cases are marginal but the concerns about potentially isolating and reclaiming too much persist. -- Mel Gorman SUSE Labs -- 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