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authorMuchun Song <songmuchun@bytedance.com>2020-11-21 22:17:12 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-11-22 10:48:22 -0800
commit8faeb1ffd79593c9cd8a2a80ecdda371e3b826cb (patch)
treec3cae3af7158190642fbbac5b98fa368074266de
parent4349a83a3190c1d4414371161b0f4a4c3ccd3f9d (diff)
downloadlinux-stericsson-8faeb1ffd79593c9cd8a2a80ecdda371e3b826cb.tar.gz
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 <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Christopher Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Roman Gushchin <guro@fb.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yafang Shao <laoar.shao@gmail.com> Cc: Chris Down <chris@chrisdown.name> Cc: <stable@vger.kernel.org> [5.3+] Link: https://lkml.kernel.org/r/20201110031015.15715-1-songmuchun@bytedance.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memcontrol.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3dcbf24d2227..29459a6ce1c7 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -867,8 +867,13 @@ void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val)
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);