Re: [PATCH] Improve buffered streaming write ordering

From: Andrew Morton
Date: Thu Oct 02 2008 - 00:53:36 EST


On Wed, 01 Oct 2008 14:40:51 -0400 Chris Mason <chris.mason@xxxxxxxxxx> wrote:

> The patch below changes write_cache_pages to only use writeback_index
> when current_is_pdflush(). The basic idea is that pdflush is the only
> one who has concurrency control against the bdi, so it is the only one
> who can safely use and update writeback_index.

Another approach would be to only update mapping->writeback_index if
nobody else altered it meanwhile.

That being said, I don't really see why we get lots of seekiness when
two threads start their writing the file from the same offset.
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