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

Andi Kleen
2007-07-31T09:14:08Z

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.

> NUMA balance-on-fork code is in a good position to allocate all of a new
> process's memory on a chosen node. However, it really only starts
> allocating on the correct node after the process starts running.
>
> task and thread structures, stack, mm_struct, vmas, page tables etc. are
> all allocated on the parent's node.

The page tables should be only allocated when the process runs; except
for the PGD.

-Andi