Re: [rfc] balance-on-fork NUMA placement

Nick Piggin
2007-08-02T03:42:01Z

On Tue, Jul 31, 2007 at 04:40:18PM -0700, Christoph Lameter wrote:
> On Tue, 31 Jul 2007, Andi Kleen wrote:
>
> > On Tuesday 31 July 2007 07:41, Nick Piggin wrote:
> >
> > > I haven't given this idea testing yet, but I just wanted to get some
> > > opinions on it first. NUMA placement still isn't ideal (eg. tasks with
> > > a memory policy will not do any placement, and process migrations of
> > > course will leave the memory behind...), but it does give a bit more
> > > chance for the memory controllers and interconnects to get evenly
> > > loaded.
> >
> > I didn't think slab honored mempolicies by default?
> > At least you seem to need to set special process flags.
>
> It does in the sense that slabs are allocated following policies. If you
> want to place individual objects then you need to use kmalloc_node().

Is there no way to place objects via policy? At least kernel stack and page
tables on x86-64 should be covered by page allocator policy, so the patch
will still be useful.