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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> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: B204A100009 X-Rspam-User: X-Stat-Signature: pegg3t6q3u76yp1mfim86xq6ke8sxdg7 X-HE-Tag: 1747106037-960732 X-HE-Meta: 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 VEx73Iuv 30DK841THWWlbEroGX9fzqw8yV/LfBsQHGtwS62sh/Jkb5qllwDoTcHC1HFP1n3FJyLHyXFd1GFCLV77JtJJPPRf/zX1q9p0tzJRsF1g3F+3ZVmIgA1zhGSBP3quieTmhkQmRYkV6ZxJEfu9WmGJMYbf97k2m7ODGnyBkhG9aD3RUDY6Q7WJulXcQ74v710u/AlSQu4CDCthdx8HhNLYGQtwT9odnncComwYD X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 --- 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); } -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); 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, enum node_stat_item idx, } 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 = -nr_pages; /* for event */ } @@ -689,7 +689,7 @@ void memcg1_uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout, unsigned long flags; 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) } /** - * __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 = memcg_events_index(idx); @@ -846,9 +846,13 @@ void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx, if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx)) return; + if (WARN_ONCE(in_nmi(), "%s: called in nmi context for stat item %d\n", + __func__, idx)) + return; + cpu = get_cpu(); - __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); 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); __count_vm_events(PGACTIVATE, nr_pages); - __count_memcg_events(lruvec_memcg(lruvec), PGACTIVATE, nr_pages); + count_memcg_events(lruvec_memcg(lruvec), PGACTIVATE, nr_pages); } #ifdef CONFIG_SMP @@ -581,7 +581,7 @@ static void lru_deactivate_file(struct lruvec *lruvec, struct folio *folio) 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, struct folio *folio) lruvec_add_folio(lruvec, folio); __count_vm_events(PGDEACTIVATE, nr_pages); - __count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_pages); + count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_pages); } 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); __count_vm_events(PGLAZYFREE, nr_pages); - __count_memcg_events(lruvec_memcg(lruvec), PGLAZYFREE, nr_pages); + count_memcg_events(lruvec_memcg(lruvec), PGLAZYFREE, nr_pages); } /* 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 long nr_to_scan, item = 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); spin_unlock_irq(&lruvec->lru_lock); @@ -2048,7 +2048,7 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan, item = 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); @@ -2138,7 +2138,7 @@ static void shrink_active_list(unsigned long nr_to_scan, 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); spin_unlock_irq(&lruvec->lru_lock); @@ -2195,7 +2195,7 @@ static void shrink_active_list(unsigned long nr_to_scan, nr_deactivate = move_folios_to_lru(lruvec, &l_inactive); __count_vm_events(PGDEACTIVATE, nr_deactivate); - __count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate); + count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate); __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, struct 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, struct lruvec *lruvec, item = 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); spin_unlock_irq(&lruvec->lru_lock); -- 2.47.1