mm: memcg/slab: fix root memcg vmstats

If we reparent the slab objects to the root memcg, when we free the slab
object, we need to update the per-memcg vmstats to keep it correct for
the root memcg.  Now this at least affects the vmstat of
NR_KERNEL_STACK_KB for !CONFIG_VMAP_STACK when the thread stack size is
smaller than the PAGE_SIZE.

David said:
 "I assume that without this fix that the root memcg's vmstat would
  always be inflated if we reparented"

Fixes: ec9f02384f60 ("mm: workingset: fix vmstat counters for shadow nodes")
Signed-off-by: Muchun Song <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Shakeel Butt <[email protected]>
Acked-by: Roman Gushchin <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Acked-by: David Rientjes <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Vladimir Davydov <[email protected]>
Cc: Christopher Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Roman Gushchin <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Yafang Shao <[email protected]>
Cc: Chris Down <[email protected]>
Cc: <[email protected]>	[5.3+]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions