From: Ric Mason <ric.masonn@gmail.com>
To: Michal Hocko <mhocko@suse.cz>
Cc: Simon Jeons <simon.jeons@gmail.com>, 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: Wed, 10 Apr 2013 13:15:42 +0800 [thread overview]
Message-ID: <5164F57E.3030106@gmail.com> (raw)
In-Reply-To: <20130409101437.GE29860@dhcp22.suse.cz>
Hi Michal,
On 04/09/2013 06:14 PM, Michal Hocko wrote:
> On Tue 09-04-13 18:05:30, Simon Jeons wrote:
> [...]
>>> 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?
>>>
>> Sorry for waste your time, but the test result is weird, is it?
> I am not sure which values you have been watching but you have to
> realize that you are reading a _partition_ not a file and those pages
> go into buffers rather than the page chache.
Interesting. ;-)
What's the difference between buffers and page cache? Why buffers don't
grow?
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prev parent reply other threads:[~2013-04-10 5:15 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
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 [this message]
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