On Thu, Sep 03 2009, Theodore Tso wrote:

On Thu, Sep 03, 2009 at 12:42:09PM -0400, Christoph Hellwig wrote:

quoted

quoted

Careful:

-	tloff = min(tlast, startpage->index + 64);
+	tloff = min(tlast, startpage->index + 8192);

That will cause 64k page machines to try to write back 512MB at a
time. This will re-introduce similar to the behaviour in sles9 where
writeback would only terminate at the end of an extent (because the
mapping end wasn't capped like above).

Pretty good point, any applies to all the different things we discussed
recently.  Ted, should be maybe introduce a max_writeback_mb instead of
the max_writeback_pages in the VM, too?

Good point.

Jens, maybe we should replace my patch with this one, which makes the
tunable in terms of megabytes instead of pages?

That is probably a better metric than 'pages', lets update it.

-- 
Jens Axboe