Re: [PATCH 0/4] mm/mempolicy: introduce package-aware weighted interleave

[Gregory Price <gourry@gourry.net>]

On Thu, Aug 06, 2026 at 05:09:31PM +0900, Rakie Kim wrote:
> Package-aware weighted interleave places a task's weighted-interleave
> pages on the NUMA nodes of its local package, so that interleave traffic
> does not have to cross the interconnect to another package. This keeps
> each node's weight aligned with the bandwidth the task actually gets
> from it, so effective bandwidth holds up on a system that has more than
> one package. (A package is a CPU socket together with the memory
> attached to it.)
>

The only major question I have before I dig into the actual patches is
whether you actually need this on a *per-task* basis, rather than simply
a *per-process* basis - because that's all this really buys you.

You can already do what is described here by simply using a combination
of cpuset and mempolicy

cpuset.mems = 0,2
mempolicy = weighted interleave --all

If this is actually required on a per-task basis, then I agree this
concept is reasonable.  I just want to make we're grounded on a real
use case before we go adding this complexity.

~Gregory