Re: [PATCH] mm: page_alloc: Avoid marking zones full prematurelyafter zone_reclaim()

From: Simon Jeons
Date: Tue Apr 09 2013 - 06:20:22 EST

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
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.

buffer cache are contained in page cache, is it? Which value I should watch?

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