From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yh0-f54.google.com (mail-yh0-f54.google.com [209.85.213.54]) by kanga.kvack.org (Postfix) with ESMTP id A33D66B00AC for ; Fri, 6 Dec 2013 17:51:42 -0500 (EST) Received: by mail-yh0-f54.google.com with SMTP id z12so1016126yhz.13 for ; Fri, 06 Dec 2013 14:51:42 -0800 (PST) Received: from mail-pb0-x22f.google.com (mail-pb0-x22f.google.com [2607:f8b0:400e:c01::22f]) by mx.google.com with ESMTPS id r46si56671920yhm.122.2013.12.06.14.51.40 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 06 Dec 2013 14:51:41 -0800 (PST) Received: by mail-pb0-f47.google.com with SMTP id um1so1873450pbc.34 for ; Fri, 06 Dec 2013 14:51:40 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20131204130038.GY11295@suse.de> References: <20131204130038.GY11295@suse.de> From: Florian Fainelli Date: Fri, 6 Dec 2013 14:51:00 -0800 Message-ID: Subject: Re: high kswapd CPU usage when executing binaries from NFS w/ CMA and COMPACTION Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: "linux-kernel@vger.kernel.org" , mhocko , hannes , riel , linux-mm , "m.szyprowski" , "marc.ceeeee" 2013/12/4 Mel Gorman : > On Tue, Dec 03, 2013 at 06:30:28PM -0800, Florian Fainelli wrote: >> Hi all, >> >> I am experiencing high kswapd CPU usage on an ARMv7 system running >> 3.8.13 when executing relatively large binaries from NFS. When this >> happens kswapd consumes around 55-60% CPU usage and the applications >> takes a huge time to load. >> > > There were a number of changes made related to how and when kswapd > stalls, particularly when pages are dirty. Brief check confirms that > > git log v3.8..v3.12 --pretty=one --author "Mel Gorman" mm/vmscan.c > > NFS dirty pages are problematic for compaction as dirty pages cannot be > migrated until cleaned. I'd suggest checking if current mainline suffers > the same problem and if not, focus on patches related to dirty page > handling and kswapd throttling in mm/vmscan.c as backport candidates. I have just backported these patches to 3.8.13 and am still seeing the problem, although kswapd usage dropped considerably (by half approximately). Will keep you updated once I have properly tested current mainline on my platform. Thanks! -- Florian -- 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