Re: Possible Idea with filesystem buffering.

Hans Reiser
2002-01-21T01:05:45Z

Rik van Riel wrote:

>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.
>
the logical extreme of this is that no write caching should be done at
all, only read caching?

>
>
>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
>
It would unbalance the write cache, not the read cache.

Hans