From nobody Fri Dec 19 16:01:39 2025 Received: from out-183.mta0.migadu.com (out-183.mta0.migadu.com [91.218.175.183]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 30B7F1DF27D for ; Tue, 13 May 2025 03:13:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.183 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747106041; cv=none; b=r8NAsmooVeeqKe0DiQz2qTErtivYvm3F6UQSnnIWNCO/QTQkfZZARl5cAPKkYrEu3UGpOU3Tg1RyDAW8c6zSmhBHeG6fQIuut+v+7oLOEXO3ckGrXWQ3worpOX9Snlc6I5sZ3p5OQGGj2H/nLOPFX8UnwmcZ7MaEOf7zW47gxqo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747106041; c=relaxed/simple; bh=1mm3f0O5Be2EnsuG7OBgfK2sWYAOIWscnoGZnAsBQqQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kj0XHr8GzrQo8umdL1caPY+GsHZyY8GGxDnvQOPT6PV01E9DoFSKzPkyznonAoJKf49whuzWr1KWYbaBrk1co02CitGmQypD1CBPovdBHcjBpc4GOYkbGxFgrBLpDZMBQiSgQ/v6gK6glxvwNEtcdQ1GpIuCu+clSbkzxWLZblo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=DaZOypgB; arc=none smtp.client-ip=91.218.175.183 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="DaZOypgB" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1747106035; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=klyfdgosczkIxLXzuA4t2pqJ0LtQH1VmXZPt0a+K7m8=; b=DaZOypgBkXrwAwUvrSfjv5WH82ml+vBvH8L/+D6GSCzgZWyHydlEIwz6ulgSdtD/+bgZSD Rtimfu6vTpmLLDhniHQ6m5qYv+DCrfFLtQDKTsju/rtv+3aGwkjkxgxHj8HSWwXyvB+MHm pN7O+/sWU0gSH5MVWZ/R9Qv+0ZnaXqE= From: Shakeel Butt To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Vlastimil Babka , Alexei Starovoitov , Sebastian Andrzej Siewior , Harry Yoo , Yosry Ahmed , bpf@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Meta kernel team Subject: [RFC PATCH 4/7] memcg: make count_memcg_events re-entrant safe against irqs Date: Mon, 12 May 2025 20:13:13 -0700 Message-ID: <20250513031316.2147548-5-shakeel.butt@linux.dev> In-Reply-To: <20250513031316.2147548-1-shakeel.butt@linux.dev> References: <20250513031316.2147548-1-shakeel.butt@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" Let's make count_memcg_events re-entrant safe against irqs. The only thing needed is to convert the usage of __this_cpu_add() to this_cpu_add(). In addition, with re-entrant safety, there is no need to disable irqs. Also add warnings for in_nmi() as it is not safe against nmi context. Signed-off-by: Shakeel Butt Acked-by: Vlastimil Babka --- include/linux/memcontrol.h | 21 ++------------------- mm/memcontrol-v1.c | 6 +++--- mm/memcontrol.c | 10 +++++++--- mm/swap.c | 8 ++++---- mm/vmscan.c | 14 +++++++------- 5 files changed, 23 insertions(+), 36 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 84e2cea7e666..31b9ab93d4e1 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -952,19 +952,8 @@ static inline void mod_lruvec_kmem_state(void *p, enum= node_stat_item idx, local_irq_restore(flags); } =20 -void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx, - unsigned long count); - -static inline void count_memcg_events(struct mem_cgroup *memcg, - enum vm_event_item idx, - unsigned long count) -{ - unsigned long flags; - - local_irq_save(flags); - __count_memcg_events(memcg, idx, count); - local_irq_restore(flags); -} +void count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx, + unsigned long count); =20 static inline void count_memcg_folio_events(struct folio *folio, enum vm_event_item idx, unsigned long nr) @@ -1438,12 +1427,6 @@ static inline void mod_lruvec_kmem_state(void *p, en= um node_stat_item idx, } =20 static inline void count_memcg_events(struct mem_cgroup *memcg, - enum vm_event_item idx, - unsigned long count) -{ -} - -static inline void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx, unsigned long count) { diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index 3852f0713ad2..581c960ba19b 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -512,9 +512,9 @@ static void memcg1_charge_statistics(struct mem_cgroup = *memcg, int nr_pages) { /* pagein of a big page is an event. So, ignore page size */ if (nr_pages > 0) - __count_memcg_events(memcg, PGPGIN, 1); + count_memcg_events(memcg, PGPGIN, 1); else { - __count_memcg_events(memcg, PGPGOUT, 1); + count_memcg_events(memcg, PGPGOUT, 1); nr_pages =3D -nr_pages; /* for event */ } =20 @@ -689,7 +689,7 @@ void memcg1_uncharge_batch(struct mem_cgroup *memcg, un= signed long pgpgout, unsigned long flags; =20 local_irq_save(flags); - __count_memcg_events(memcg, PGPGOUT, pgpgout); + count_memcg_events(memcg, PGPGOUT, pgpgout); __this_cpu_add(memcg->events_percpu->nr_page_events, nr_memory); memcg1_check_events(memcg, nid); local_irq_restore(flags); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 373d36cae069..9e7dc90cc460 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -829,12 +829,12 @@ void __mod_lruvec_kmem_state(void *p, enum node_stat_= item idx, int val) } =20 /** - * __count_memcg_events - account VM events in a cgroup + * count_memcg_events - account VM events in a cgroup * @memcg: the memory cgroup * @idx: the event item * @count: the number of events that occurred */ -void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx, +void count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx, unsigned long count) { int i =3D memcg_events_index(idx); @@ -846,9 +846,13 @@ void __count_memcg_events(struct mem_cgroup *memcg, en= um vm_event_item idx, if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, id= x)) return; =20 + if (WARN_ONCE(in_nmi(), "%s: called in nmi context for stat item %d\n", + __func__, idx)) + return; + cpu =3D get_cpu(); =20 - __this_cpu_add(memcg->vmstats_percpu->events[i], count); + this_cpu_add(memcg->vmstats_percpu->events[i], count); memcg_rstat_updated(memcg, count, cpu); trace_count_memcg_events(memcg, idx, count); =20 diff --git a/mm/swap.c b/mm/swap.c index 77b2d5997873..4fc322f7111a 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -309,7 +309,7 @@ static void lru_activate(struct lruvec *lruvec, struct = folio *folio) trace_mm_lru_activate(folio); =20 __count_vm_events(PGACTIVATE, nr_pages); - __count_memcg_events(lruvec_memcg(lruvec), PGACTIVATE, nr_pages); + count_memcg_events(lruvec_memcg(lruvec), PGACTIVATE, nr_pages); } =20 #ifdef CONFIG_SMP @@ -581,7 +581,7 @@ static void lru_deactivate_file(struct lruvec *lruvec, = struct folio *folio) =20 if (active) { __count_vm_events(PGDEACTIVATE, nr_pages); - __count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, + count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_pages); } } @@ -599,7 +599,7 @@ static void lru_deactivate(struct lruvec *lruvec, struc= t folio *folio) lruvec_add_folio(lruvec, folio); =20 __count_vm_events(PGDEACTIVATE, nr_pages); - __count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_pages); + count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_pages); } =20 static void lru_lazyfree(struct lruvec *lruvec, struct folio *folio) @@ -625,7 +625,7 @@ static void lru_lazyfree(struct lruvec *lruvec, struct = folio *folio) lruvec_add_folio(lruvec, folio); =20 __count_vm_events(PGLAZYFREE, nr_pages); - __count_memcg_events(lruvec_memcg(lruvec), PGLAZYFREE, nr_pages); + count_memcg_events(lruvec_memcg(lruvec), PGLAZYFREE, nr_pages); } =20 /* diff --git a/mm/vmscan.c b/mm/vmscan.c index 5efd939d8c76..f86d264558f5 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2028,7 +2028,7 @@ static unsigned long shrink_inactive_list(unsigned lo= ng nr_to_scan, item =3D PGSCAN_KSWAPD + reclaimer_offset(sc); if (!cgroup_reclaim(sc)) __count_vm_events(item, nr_scanned); - __count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned); + count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned); __count_vm_events(PGSCAN_ANON + file, nr_scanned); =20 spin_unlock_irq(&lruvec->lru_lock); @@ -2048,7 +2048,7 @@ static unsigned long shrink_inactive_list(unsigned lo= ng nr_to_scan, item =3D PGSTEAL_KSWAPD + reclaimer_offset(sc); if (!cgroup_reclaim(sc)) __count_vm_events(item, nr_reclaimed); - __count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); + count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); __count_vm_events(PGSTEAL_ANON + file, nr_reclaimed); spin_unlock_irq(&lruvec->lru_lock); =20 @@ -2138,7 +2138,7 @@ static void shrink_active_list(unsigned long nr_to_sc= an, =20 if (!cgroup_reclaim(sc)) __count_vm_events(PGREFILL, nr_scanned); - __count_memcg_events(lruvec_memcg(lruvec), PGREFILL, nr_scanned); + count_memcg_events(lruvec_memcg(lruvec), PGREFILL, nr_scanned); =20 spin_unlock_irq(&lruvec->lru_lock); =20 @@ -2195,7 +2195,7 @@ static void shrink_active_list(unsigned long nr_to_sc= an, nr_deactivate =3D move_folios_to_lru(lruvec, &l_inactive); =20 __count_vm_events(PGDEACTIVATE, nr_deactivate); - __count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate); + count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate); =20 __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken); spin_unlock_irq(&lruvec->lru_lock); @@ -4616,8 +4616,8 @@ static int scan_folios(unsigned long nr_to_scan, stru= ct lruvec *lruvec, __count_vm_events(item, isolated); __count_vm_events(PGREFILL, sorted); } - __count_memcg_events(memcg, item, isolated); - __count_memcg_events(memcg, PGREFILL, sorted); + count_memcg_events(memcg, item, isolated); + count_memcg_events(memcg, PGREFILL, sorted); __count_vm_events(PGSCAN_ANON + type, isolated); trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, MAX_LRU_BATCH, scanned, skipped, isolated, @@ -4769,7 +4769,7 @@ static int evict_folios(unsigned long nr_to_scan, str= uct lruvec *lruvec, item =3D PGSTEAL_KSWAPD + reclaimer_offset(sc); if (!cgroup_reclaim(sc)) __count_vm_events(item, reclaimed); - __count_memcg_events(memcg, item, reclaimed); + count_memcg_events(memcg, item, reclaimed); __count_vm_events(PGSTEAL_ANON + type, reclaimed); =20 spin_unlock_irq(&lruvec->lru_lock); --=20 2.47.1