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Date: Thu, 21 Dec 2000 18:46:33 -0200 (BRDT)
From: Rik van Riel <riel@conectiva.com.br>
To: Sourav Sen <sourav@csa.iisc.ernet.in>
cc: linux-kernel@vger.kernel.org
Subject: Re: Wiring down Pages
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On Fri, 22 Dec 2000, Sourav Sen wrote:

> 	Suppose I want to wire-down( as they call in BSD ) a page
> in memory, how I go about doing that? (I guess by setting the
> PG_locked bit of the flags field in the struct page, I can do
> it, am I right?)

Linux simply uses page->count for this. By using the page->count,
multiple parts of the kernel can pin the same page in memory at
different times and unlock them at different times without any
locking/unlocking conflicts...

page_cache_get(page);  <= increases page->count

<your critical stuff here>

page_cache_drop(page); <= removes your extra count

regards,

Rik
--
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