From: Simon Jeons <simon.jeons@gmail.com>
To: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
Hedi Berriche <hedi@sgi.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: page_alloc: Avoid marking zones full prematurely after zone_reclaim()
Date: Fri, 05 Apr 2013 14:31:32 +0800 [thread overview]
Message-ID: <515E6FC4.5000202@gmail.com> (raw)
In-Reply-To: <20130321081902.GD6094@dhcp22.suse.cz>
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?
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next prev parent reply other threads:[~2013-04-05 6:31 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-20 18:19 [PATCH] mm: page_alloc: Avoid marking zones full prematurely after zone_reclaim() Mel Gorman
2013-03-20 18:45 ` Michal Hocko
2013-03-21 2:32 ` Wanpeng Li
2013-03-21 2:32 ` Wanpeng Li
2013-03-21 2:33 ` Simon Jeons
2013-03-21 8:19 ` Michal Hocko
2013-03-21 8:32 ` Simon Jeons
2013-03-21 8:44 ` Michal Hocko
2013-03-21 8:59 ` Wanpeng Li
2013-03-21 8:59 ` Wanpeng Li
2013-04-05 6:31 ` Simon Jeons [this message]
2013-04-07 6:37 ` Simon Jeons
2013-04-09 10:05 ` Simon Jeons
2013-04-09 10:14 ` Michal Hocko
2013-04-09 10:20 ` Simon Jeons
2013-04-10 5:15 ` Ric Mason
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