Re: Possible Idea with filesystem buffering.

Rik van Riel
2002-01-20T15:14:25Z

On Sun, 20 Jan 2002, Hans Reiser wrote:

> Write clustering is one thing it achieves.
>
> Flushing everything involved in a transaction ... is another thing.

Agreed on these points, but you really HAVE TO work towards
flushing the page ->writepage() gets called for.

Think about your typical PC, with memory in ZONE_DMA,
ZONE_NORMAL and ZONE_HIGHMEM. If we are short on DMA pages
we will end up calling ->writepage() on a DMA page.

If the filesystem ends up writing completely unrelated pages
and marking the DMA page in question referenced the VM will
go in a loop until the filesystem finally gets around to
making a page in the (small) DMA zone freeable ...

regards,

Rik
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