On Wed, 19 Jan 2011, Minchan Kim wrote:
> >
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -2034,6 +2034,18 @@ restart:
> > */
> > alloc_flags = gfp_to_alloc_flags(gfp_mask);
> >
> > + /*
> > + * If preferred_zone cannot be allocated from in this context, find the
> > + * first allowable zone instead.
> > + */
> > + if ((alloc_flags & ALLOC_CPUSET) &&
> > + !cpuset_zone_allowed_softwall(preferred_zone, gfp_mask)) {
> > + first_zones_zonelist(zonelist, high_zoneidx,
> > + &cpuset_current_mems_allowed, &preferred_zone);
>
> This patch is one we need. but I have a nitpick.
> I am not familiar with CPUSET so I might be wrong.
>
> I think it could make side effect of statistics of ZVM on
> buffered_rmqueue since you intercept and change preferred_zone.
> It could make NUMA_HIT instead of NUMA_MISS.
> Is it your intention?
>
It depends on the semantics of NUMA_MISS: if no local nodes are allowed by
current's cpuset (a pretty poor cpuset config :), then it seems logical
that all allocations would be a miss.