Re: The performance and behaviour of the anti-fragmentation related patches

Andrew Morton
2007-03-02T16:59:18Z

On Fri, 02 Mar 2007 10:29:58 -0500 Rik van Riel <riel@redhat.com> wrote:

> Andrew Morton wrote:
>
> > And I'd judge that per-container RSS limits are of considerably more value
> > than antifrag (in fact per-container RSS might be a superset of antifrag,
> > in the sense that per-container RSS and containers could be abused to fix
> > the i-cant-get-any-hugepages problem, dunno).
>
> The RSS bits really worry me, since it looks like they could
> exacerbate the scalability problems that we are already running
> into on very large memory systems.

Using a zone-per-container or N-64MB-zones-per-container should actually
move us in the direction of *fixing* any such problems. Because, to a
first-order, the scanning of such a zone has the same behaviour as a 64MB
machine.

(We'd run into a few other problems, some related to the globalness of the
dirty-memory management, but that's fixable).

> Linux is *not* happy on 256GB systems. Even on some 32GB systems
> the swappiness setting *needs* to be tweaked before Linux will even
> run in a reasonable way.

Please send testcases.