Re: [PATCH] mm: use pagevec to rotate reclaimable page

Nick Piggin
2007-09-18T17:55:54Z

On Wednesday 19 September 2007 03:44, Andrew Morton wrote:
> On Tue, 18 Sep 2007 11:29:50 +1000 Nick Piggin <nickpiggin@yahoo.com.au>
wrote:
> > It would be interesting to test -mm kernels. They have a patch which
> > reduces zone lock contention quite a lot.
>
> They do? Which patch?

Hmm... mm-buffered-write-cleanup.patch.

> > I think your patch is a nice idea, and with less zone lock contention in
> > other areas, it is possible that it might produce a relatively larger
> > improvement.
>
> I'm a bit wobbly about this patch - it adds additional single-cpu overhead
> to reduce multiple-cpu overhead and latency.

Yeah, that's true. Although maybe it gets significantly more after the
patch in -mm.

Possibly other page batching sites have similar issues on UP... I wonder
if a type of pagevec that turns into a noop on UP would be interesting...
probably totally unmeasurable and not worth the cost of code
maintenance ;)