On Fri, Mar 06, 2026 at 08:55:20PM -0800, JP Kobryn (Meta) wrote: > When investigating pressure on a NUMA node, there is no straightforward way > to determine which policies are driving allocations to it. > > Add per-policy page allocation counters as new node stat items. These > counters track allocations to nodes and also whether the allocations were > intentional or fallbacks. > > The new stats follow the existing numa hit/miss/foreign style and have the > following meanings: > > hit > - for BIND and PREFERRED_MANY, allocation succeeded on node in nodemask > - for other policies, allocation succeeded on intended node > - counted on the node of the allocation > miss > - allocation intended for other node, but happened on this one > - counted on other node > foreign > - allocation intended on this node, but happened on other node > - counted on this node > > Counters are exposed per-memcg, per-node in memory.numa_stat and globally > in /proc/vmstat. > > Signed-off-by: JP Kobryn (Meta) <[email protected]> > --- > v2: > - Replaced single per-policy total counter (PGALLOC_MPOL_*) with > hit/miss/foreign triplet per policy > - Changed from global node stats to per-memcg per-node tracking > > v1: > https://lore.kernel.org/linux-mm/[email protected]/ > > include/linux/mmzone.h | 20 ++++++++++ > mm/memcontrol.c | 60 ++++++++++++++++++++++++++++ > mm/mempolicy.c | 90 ++++++++++++++++++++++++++++++++++++++++-- > mm/vmstat.c | 20 ++++++++++ > 4 files changed, 187 insertions(+), 3 deletions(-) > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index 7bd0134c241c..c0517cbcb0e2 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -323,6 +323,26 @@ enum node_stat_item { > PGSCAN_ANON, > PGSCAN_FILE, > PGREFILL, > +#ifdef CONFIG_NUMA > + NUMA_MPOL_LOCAL_HIT, > + NUMA_MPOL_LOCAL_MISS, > + NUMA_MPOL_LOCAL_FOREIGN, > + NUMA_MPOL_PREFERRED_HIT, > + NUMA_MPOL_PREFERRED_MISS, > + NUMA_MPOL_PREFERRED_FOREIGN, > + NUMA_MPOL_PREFERRED_MANY_HIT, > + NUMA_MPOL_PREFERRED_MANY_MISS, > + NUMA_MPOL_PREFERRED_MANY_FOREIGN, > + NUMA_MPOL_BIND_HIT, > + NUMA_MPOL_BIND_MISS, > + NUMA_MPOL_BIND_FOREIGN, > + NUMA_MPOL_INTERLEAVE_HIT, > + NUMA_MPOL_INTERLEAVE_MISS, > + NUMA_MPOL_INTERLEAVE_FOREIGN, > + NUMA_MPOL_WEIGHTED_INTERLEAVE_HIT, > + NUMA_MPOL_WEIGHTED_INTERLEAVE_MISS, > + NUMA_MPOL_WEIGHTED_INTERLEAVE_FOREIGN, > +#endif
I have not looked into what these metrics mean but these are too many, at least for the memcg. For the memcg, there is significant memory cost for each metric added to memcg.
