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From: mulyadi.santosa@gmail.com (Mulyadi Santosa)
To: kernelnewbies@lists.kernelnewbies.org
Subject: Question about page count
Date: Tue, 21 Jun 2011 12:15:00 +0700	[thread overview]
Message-ID: <BANLkTi=NqaNz-2uEPduwgidcm2bDEZeyMQ@mail.gmail.com> (raw)
In-Reply-To: <BANLkTimjXCij_vf-vPgB26Gt93bMwD5zkg@mail.gmail.com>

Hi...

On 20/06/2011, Jui-Hao Chiang <windtracekimo@gmail.com> wrote:
> Hi,
>
> I am currently analyzing the memory pages footprint in 2.6.18.8 kernel (1GB
> ram,
> 32-bit, Flat model, no NUMA), and got a question. Does page_count(page)==0
> really means the page is free because the source code says so?

looking at how page_count implemented, it checks whether the related
page is gonna be reclaimed or a compound page (not sure what it is).
If so, returns the first page of that "page".

by comparing the definition of free page as "really free, not being
used for any purpose" versus the above perception, I guess it's not
surprising to see the difference

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

  parent reply	other threads:[~2011-06-21  5:15 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-20 13:10 Question about page count Jui-Hao Chiang
2011-06-21  1:46 ` Wick
2011-06-21  5:15 ` Mulyadi Santosa [this message]
2011-06-21 13:23   ` Dave Hylands
2011-06-21 16:34     ` Mulyadi Santosa
2011-06-21 14:25   ` Jui-Hao Chiang

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