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From: dhylands@gmail.com (Dave Hylands)
To: kernelnewbies@lists.kernelnewbies.org
Subject: Question about page count
Date: Tue, 21 Jun 2011 06:23:34 -0700	[thread overview]
Message-ID: <BANLkTi=diyfECSXUqFNxEKwy9Efh89EcDw@mail.gmail.com> (raw)
In-Reply-To: <BANLkTi=NqaNz-2uEPduwgidcm2bDEZeyMQ@mail.gmail.com>

Hey Mulyadi,

On Mon, Jun 20, 2011 at 10:15 PM, Mulyadi Santosa
<mulyadi.santosa@gmail.com> wrote:
...snip...
> 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".

On the ARM, you can setup the MMU to map 1Mb regions or 4Kb regions. A
1 Mb region only goes through the top level of the MMU, whereas a 4K
page has to go through 2 levesl, so accessing pages through the 1 Mb
mapping is faster.

I believe (I'm not 100% sure) that the 256 x 4K pages that make up the
1Mb region are a compound page.

-- 
Dave Hylands
Shuswap, BC, Canada
http://www.davehylands.com

  reply	other threads:[~2011-06-21 13:23 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
2011-06-21 13:23   ` Dave Hylands [this message]
2011-06-21 16:34     ` Mulyadi Santosa
2011-06-21 14:25   ` Jui-Hao Chiang

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