Re: [PATCH] mm: disallow direct reclaim page writeback

From: James Bottomley
Date: Sun Apr 18 2010 - 17:31:06 EST


On Sun, 2010-04-18 at 15:10 -0400, Sorin Faibish wrote:
> On Sat, 17 Apr 2010 20:32:39 -0400, Andrew Morton
> <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> >
> > There are two issues here: stack utilisation and poor IO patterns in
> > direct reclaim. They are different.
> >
> > The poor IO patterns thing is a regression. Some time several years
> > ago (around 2.6.16, perhaps), page reclaim started to do a LOT more
> > dirty-page writeback than it used to. AFAIK nobody attempted to work
> > out why, nor attempted to try to fix it.

> I for one am looking very seriously at this problem together with Bruce.
> We plan to have a discussion on this topic at the next LSF meeting
> in Boston.

As luck would have it, the Memory Management summit is co-located with
the Storage and Filesystem workshop ... how about just planning to lock
all the protagonists in a room if it's not solved by August. The less
extreme might even like to propose topics for the plenary sessions ...

James


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