Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161498Ab3DEGbj (ORCPT ); Fri, 5 Apr 2013 02:31:39 -0400 Received: from mail-ie0-f177.google.com ([209.85.223.177]:52101 "EHLO mail-ie0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161148Ab3DEGbi (ORCPT ); Fri, 5 Apr 2013 02:31:38 -0400 Message-ID: <515E6FC4.5000202@gmail.com> Date: Fri, 05 Apr 2013 14:31:32 +0800 From: Simon Jeons User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130308 Thunderbird/17.0.4 MIME-Version: 1.0 To: Michal Hocko CC: Mel Gorman , Andrew Morton , Hedi Berriche , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: page_alloc: Avoid marking zones full prematurely after zone_reclaim() References: <20130320181957.GA1878@suse.de> <514A7163.5070700@gmail.com> <20130321081902.GD6094@dhcp22.suse.cz> In-Reply-To: <20130321081902.GD6094@dhcp22.suse.cz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1596 Lines: 39 Hi Michal, On 03/21/2013 04:19 PM, Michal Hocko wrote: > On Thu 21-03-13 10:33:07, Simon Jeons wrote: >> Hi Mel, >> On 03/21/2013 02:19 AM, Mel Gorman wrote: >>> The following problem was reported against a distribution kernel when >>> zone_reclaim was enabled but the same problem applies to the mainline >>> kernel. The reproduction case was as follows >>> >>> 1. Run numactl -m +0 dd if=largefile of=/dev/null >>> This allocates a large number of clean pages in node 0 >> I confuse why this need allocate a large number of clean pages? > It reads from file and puts pages into the page cache. The pages are not > modified so they are clean. Output file is /dev/null so no pages are > written. dd doesn't call fadvise(POSIX_FADV_DONTNEED) on the input file > by default so pages from the file stay in the page cache I try this in v3.9-rc5: dd if=/dev/sda of=/dev/null bs=1MB 14813+0 records in 14812+0 records out 14812000000 bytes (15 GB) copied, 105.988 s, 140 MB/s free -m -s 1 total used free shared buffers cached Mem: 7912 1181 6731 0 663 239 -/+ buffers/cache: 277 7634 Swap: 8011 0 8011 It seems that almost 15GB copied before I stop dd, but the used pages which I monitor during dd always around 1200MB. Weird, why? -- 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/