linux-kernel - [PATCH v2 4/4] memcg: cgroup: call css_rstat_updated irrespective of in

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Message-ID: <20250611221532.2513772-5-shakeel.butt@linux.dev>
Date: Wed, 11 Jun 2025 15:15:32 -0700
From: Shakeel Butt <shakeel.butt@...ux.dev>
To: Tejun Heo <tj@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Cc: JP Kobryn <inwardvessel@...il.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Michal Hocko <mhocko@...nel.org>,
	Roman Gushchin <roman.gushchin@...ux.dev>,
	Muchun Song <muchun.song@...ux.dev>,
	Vlastimil Babka <vbabka@...e.cz>,
	Alexei Starovoitov <ast@...nel.org>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	Michal Koutný <mkoutny@...e.com>,
	Harry Yoo <harry.yoo@...cle.com>,
	Yosry Ahmed <yosry.ahmed@...ux.dev>,
	bpf@...r.kernel.org,
	linux-mm@...ck.org,
	cgroups@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Meta kernel team <kernel-team@...a.com>
Subject: [PATCH v2 4/4] memcg: cgroup: call css_rstat_updated irrespective of in_nmi()

css_rstat_updated() is nmi safe, so there is no need to avoid it in
in_nmi(), so remove the check.

Signed-off-by: Shakeel Butt <shakeel.butt@...ux.dev>
---
 mm/memcontrol.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 902da8a9c643..d122bfe33e98 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -573,9 +573,7 @@ static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val,
 	if (!val)
 		return;
 
-	/* TODO: add to cgroup update tree once it is nmi-safe. */
-	if (!in_nmi())
-		css_rstat_updated(&memcg->css, cpu);
+	css_rstat_updated(&memcg->css, cpu);
 	statc_pcpu = memcg->vmstats_percpu;
 	for (; statc_pcpu; statc_pcpu = statc->parent_pcpu) {
 		statc = this_cpu_ptr(statc_pcpu);
@@ -2530,7 +2528,8 @@ static inline void account_slab_nmi_safe(struct mem_cgroup *memcg,
 	} else {
 		struct mem_cgroup_per_node *pn = memcg->nodeinfo[pgdat->node_id];
 
-		/* TODO: add to cgroup update tree once it is nmi-safe. */
+		/* preemption is disabled in_nmi(). */
+		css_rstat_updated(&memcg->css, smp_processor_id());
 		if (idx == NR_SLAB_RECLAIMABLE_B)
 			atomic_add(nr, &pn->slab_reclaimable);
 		else
@@ -2753,7 +2752,8 @@ static inline void account_kmem_nmi_safe(struct mem_cgroup *memcg, int val)
 	if (likely(!in_nmi())) {
 		mod_memcg_state(memcg, MEMCG_KMEM, val);
 	} else {
-		/* TODO: add to cgroup update tree once it is nmi-safe. */
+		/* preemption is disabled in_nmi(). */
+		css_rstat_updated(&memcg->css, smp_processor_id());
 		atomic_add(val, &memcg->kmem_stat);
 	}
 }
-- 
2.47.1