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Date: Sun, 20 Jan 2002 22:47:39 -0200 (BRST)
From: Rik van Riel <riel@conectiva.com.br>
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To: Hans Reiser <reiser@namesys.com>
Cc: Shawn Starr <spstarr@sh0n.net>, <linux-kernel@vger.kernel.org>
Subject: Re: Possible Idea with filesystem buffering.
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On Mon, 21 Jan 2002, Hans Reiser wrote:

> Suppose we do what you ask, and always write the page (as well as some
> other pages) to disk.  This will result in the filesystem cache as a
> whole receiving more pressure than other caches that only write one
> page in response to pressure.  This is unbalanced, leads to some
> caches having shorter average page lifetimes than others, and it is
> therefor suboptimal.  Yes?

If your ->writepage() writes pages to disk it just means
that reiserfs will be able to clean its pages faster than
the other filesystems.

This means the VM will not call reiserfs ->writepage() as
often as for the other filesystems, since more of the
pages it finds will already be clean and freeable.

I guess the only way to unbalance the caches is by actually
freeing pages in ->writepage, but I don't see any real reason
why you'd want to do that...

regards,

Rik
-- 
"Linux holds advantages over the single-vendor commercial OS"
    -- Microsoft's "Competing with Linux" document

http://www.surriel.com/		http://distro.conectiva.com/

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