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

Nick Piggin
2007-08-03T00:57:00Z

On Thu, Aug 02, 2007 at 05:52:28PM -0700, Christoph Lameter wrote:
> On Fri, 3 Aug 2007, Nick Piggin wrote:
>
> > > Add a (slow) kmalloc_policy? Strict Object round robin for interleave
> > > right? It probably needs its own RR counter otherwise it disturbs the per
> > > task page RR.
> >
> > I guess interleave could be nice for other things, but for this, I
> > just want MPOL_BIND to work. The problem is that the pagetable copying
> > etc codepaths cover a lot of code and some of it (eg pagetable allocation)
> > is used for other paths as well.. so I was just hoping to do something
> > less intrusive for now if possible.
>
> Ok. So MPOL_BIND on a single node. We would have to save the current
> memory policy on the stack and then restore it later. Then you would need
> a special call anyways.

Well the memory policy will already be set to MPOL_BIND at this point.
The slab allocator I think would just have to honour the node at the
object level.

> Or is there some way to execute the code on the target cpu? That may be
> the easiest solution.

It isn't so easy... we'd have to migrate the parent process to the new
node to perform the setup, and then migrate it back again afterwards.