From: Alexandre Ghiti <alex@ghiti.fr>
Date: Mon, 18 May 2026 08:28:19 +0000 (+0200)
Subject: mm: memcontrol: propagate NMI slab stats to memcg vmstats
X-Git-Tag: v7.1-rc6~32^2~5
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e16f17a9c5af50221184d1ef4be4056bf3c4209e;p=thirdparty%2Flinux.git

mm: memcontrol: propagate NMI slab stats to memcg vmstats

flush_nmi_stats() drains per-node NMI slab atomics into the per-node
lruvec_stats, but does not propagate them to the memcg-level vmstats.

For non NMI case, account_slab_nmi_safe() calls mod_memcg_lruvec_state()
which updates both per-node lruvec_stats and memcg-level vmstats, so
flush_nmi_stats() needs to flush to per-node lruvec_stats as well as
memcg-level vmstats.

So fix this by flushing to the memcg-level vmstats for NMI too.

Link: https://lore.kernel.org/20260518082830.599102-1-alex@ghiti.fr
Fixes: 940b01fc8dc1 ("memcg: nmi safe memcg stats for specific archs")
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Harry Yoo (Oracle) <harry@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c03d4787d4668..507be1cca3923 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4352,6 +4352,9 @@ static void flush_nmi_stats(struct mem_cgroup *memcg, struct mem_cgroup *parent,
 			lstats->state[index] += slab;
 			if (plstats)
 				plstats->state_pending[index] += slab;
+			memcg->vmstats->state[index] += slab;
+			if (parent)
+				parent->vmstats->state_pending[index] += slab;
 		}
 		if (atomic_read(&pn->slab_unreclaimable)) {
 			int slab = atomic_xchg(&pn->slab_unreclaimable, 0);
@@ -4360,6 +4363,9 @@ static void flush_nmi_stats(struct mem_cgroup *memcg, struct mem_cgroup *parent,
 			lstats->state[index] += slab;
 			if (plstats)
 				plstats->state_pending[index] += slab;
+			memcg->vmstats->state[index] += slab;
+			if (parent)
+				parent->vmstats->state_pending[index] += slab;
 		}
 	}
 }