The patch titled
Subject: mm: memcg/slab: fix root memcg vmstats
has been added to the -mm tree. Its filename is
mm-memcg-slab-fix-root-memcg-vmstats.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-memcg-slab-fix-root-memcg-vmstats.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-memcg-slab-fix-root-memcg-vmstats.patch
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From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Subject: 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.
Link: https://lkml.kernel.org/r/20201110031015.15715-1-songmuchun@xxxxxxxxxxxxx
Fixes: ec9f02384f60 ("mm: workingset: fix vmstat counters for shadow nodes")
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Acked-by: Roman Gushchin <guro@xxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: Christopher Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Yafang Shao <laoar.shao@xxxxxxxxx>
Cc: Chris Down <chris@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
--- a/mm/memcontrol.c~mm-memcg-slab-fix-root-memcg-vmstats
+++ a/mm/memcontrol.c
@@ -853,8 +853,13 @@ void __mod_lruvec_slab_state(void *p, en
rcu_read_lock();
memcg = mem_cgroup_from_obj(p);
- /* Untracked pages have no memcg, no lruvec. Update only the node */
- if (!memcg || memcg == root_mem_cgroup) {
+ /*
+ * Untracked pages have no memcg, no lruvec. Update only the
+ * node. 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.
+ */
+ if (!memcg) {
__mod_node_page_state(pgdat, idx, val);
} else {
lruvec = mem_cgroup_lruvec(memcg, pgdat);
_
Patches currently in -mm which might be from songmuchun@xxxxxxxxxxxxx are
mm-memcontrol-fix-missing-wakeup-polling-thread.patch
mm-memcontrol-remove-unused-mod_memcg_obj_state.patch
mm-memcg-slab-fix-return-child-memcg-objcg-for-root-memcg.patch
mm-memcg-slab-fix-use-after-free-in-obj_cgroup_charge.patch
mm-memcg-slab-fix-root-memcg-vmstats.patch
