mm: fix remote numa hits statistics

Jia He has noticed that commit b9f00e147f27 ("mm, page_alloc: reduce
branches in zone_statistics") has an unintentional side effect that
remote node allocation requests are accounted as NUMA_MISS rathat than
NUMA_HIT and NUMA_OTHER if such a request doesn't use __GFP_OTHER_NODE.

There are many of these potentially because the flag is used very rarely
while we have many users of __alloc_pages_node.

Fix this by simply ignoring __GFP_OTHER_NODE (it can be removed in a
follow up patch) and treat all allocations that were satisfied from the
preferred zone's node as NUMA_HITS because this is the same node we
requested the allocation from in most cases.  If this is not the local
node then we just account it as NUMA_OTHER rather than NUMA_LOCAL.

One downsize would be that an allocation request for a node which is
outside of the mempolicy nodemask would be reported as a hit which is a
bit weird but that was the case before b9f00e147f27 already.

Fixes: b9f00e147f27 ("mm, page_alloc: reduce branches in zone_statistics")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Michal Hocko <[email protected]>
Reported-by: Jia He <[email protected]>
Reviewed-by: Vlastimil Babka <[email protected]> # with cbmc[1] superpowers
Acked-by: Mel Gorman <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Taku Izumi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions