From nobody Mon Feb 9 18:45:18 2026 Received: from out-185.mta0.migadu.com (out-185.mta0.migadu.com [91.218.175.185]) (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 54882393DC0 for ; Wed, 14 Jan 2026 11:36:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.185 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768390587; cv=none; b=OMdPHeYPw4z4JSrzSIsO8kvGpzrI77xANctxpNqSqhotrSSnpASUypwnqh3blrHcW608/B17wtXk09HLXLupwAJ8zVKVVlMGOnkzYJvRkvneRddeP6FuxRYgf2/+4DxZsWyli7vfG88DYufIGjbXviUPM/ABe04knzTjP60F0GI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768390587; c=relaxed/simple; bh=p9Vglr5K1UPYxrr6EUmCRtY2AADI8eJzvA6GbDKoW7E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CEMOXUUqGhiM+GZKdY8qp9S6lV0uK9qtJOnXcjMw6vLtDyPEgKjtxpbsJbT8HI9hbk9OoEka88MDXy2+gVsKyTLVnCmBvlGIhCxZ5DIJvpLXnIEU4eMEH6ZocpH/YyKaxCigmnoLqvTlfa66QZVzLwL2fL3cxP/iCLwUWgAlrnk= 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=hP2Zk2ST; arc=none smtp.client-ip=91.218.175.185 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="hP2Zk2ST" 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=1768390584; 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=qPjfXOeLD3JqDz3IDoD+k8CQ2UhiNCnYJI1wQcwmWYE=; b=hP2Zk2ST5tXGQJs5jKumpXbTNEQa6cSN/QefSYfwvZwTZLcduImseVBv4ckkJPsodJ4g7m 6lzvZCv7rw8zQHewhdAtzt+yN2TQdS1KXkKxaIdyajvzKgAvJA4AkBi8RnfsO+xbt9Jtnv CekD4YJFeHRZG9Mh3bbOdcqJngsDuaY= From: Qi Zheng To: hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@kernel.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, harry.yoo@oracle.com, yosry.ahmed@linux.dev, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, chenridong@huaweicloud.com, mkoutny@suse.com, akpm@linux-foundation.org, hamzamahfooz@linux.microsoft.com, apais@linux.microsoft.com, lance.yang@linux.dev Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Qi Zheng Subject: [PATCH v3 28/30] mm: memcontrol: prepare for reparenting state_local Date: Wed, 14 Jan 2026 19:32:55 +0800 Message-ID: In-Reply-To: References: 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" From: Qi Zheng To resolve the dying memcg issue, we need to reparent LRU folios of child memcg to its parent memcg. The following counts are all non-hierarchical and need to be reparented to prevent the counts of parent memcg overflow. 1. memcg->vmstats->state_local[i] 2. pn->lruvec_stats->state_local[i] This commit implements the specific function, which will be used during the reparenting process. Signed-off-by: Qi Zheng --- include/linux/memcontrol.h | 4 +++ mm/memcontrol-v1.c | 16 +++++++++++ mm/memcontrol-v1.h | 3 ++ mm/memcontrol.c | 56 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 79 insertions(+) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 26c3c0e375f58..f84a23f13ffb4 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -963,12 +963,16 @@ static inline void mod_memcg_page_state(struct page *= page, =20 unsigned long memcg_events(struct mem_cgroup *memcg, int event); unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx); +void reparent_memcg_state_local(struct mem_cgroup *memcg, + struct mem_cgroup *parent, int idx); unsigned long memcg_page_state_output(struct mem_cgroup *memcg, int item); bool memcg_stat_item_valid(int idx); bool memcg_vm_event_item_valid(enum vm_event_item idx); unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item= idx); unsigned long lruvec_page_state_local(struct lruvec *lruvec, enum node_stat_item idx); +void reparent_memcg_lruvec_state_local(struct mem_cgroup *memcg, + struct mem_cgroup *parent, int idx); =20 void mem_cgroup_flush_stats(struct mem_cgroup *memcg); void mem_cgroup_flush_stats_ratelimited(struct mem_cgroup *memcg); diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index f0ef650d2317b..800606135e7ba 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -1898,6 +1898,22 @@ static const unsigned int memcg1_events[] =3D { PGMAJFAULT, }; =20 +void reparent_memcg1_state_local(struct mem_cgroup *memcg, struct mem_cgro= up *parent) +{ + int i; + + for (i =3D 0; i < ARRAY_SIZE(memcg1_stats); i++) + reparent_memcg_state_local(memcg, parent, memcg1_stats[i]); +} + +void reparent_memcg1_lruvec_state_local(struct mem_cgroup *memcg, struct m= em_cgroup *parent) +{ + int i; + + for (i =3D 0; i < ARRAY_SIZE(memcg1_stats); i++) + reparent_memcg_lruvec_state_local(memcg, parent, memcg1_stats[i]); +} + void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) { unsigned long memory, memsw; diff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h index eb3c3c1056574..45528195d3578 100644 --- a/mm/memcontrol-v1.h +++ b/mm/memcontrol-v1.h @@ -41,6 +41,7 @@ static inline bool do_memsw_account(void) =20 unsigned long memcg_events_local(struct mem_cgroup *memcg, int event); unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx); +void mod_memcg_page_state_local(struct mem_cgroup *memcg, int idx, unsigne= d long val); unsigned long memcg_page_state_local_output(struct mem_cgroup *memcg, int = item); bool memcg1_alloc_events(struct mem_cgroup *memcg); void memcg1_free_events(struct mem_cgroup *memcg); @@ -73,6 +74,8 @@ void memcg1_uncharge_batch(struct mem_cgroup *memcg, unsi= gned long pgpgout, unsigned long nr_memory, int nid); =20 void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s); +void reparent_memcg1_state_local(struct mem_cgroup *memcg, struct mem_cgro= up *parent); +void reparent_memcg1_lruvec_state_local(struct mem_cgroup *memcg, struct m= em_cgroup *parent); =20 void memcg1_account_kmem(struct mem_cgroup *memcg, int nr_pages); static inline bool memcg1_tcpmem_active(struct mem_cgroup *memcg) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 70583394f421f..7aa32b97c9f17 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -225,6 +225,28 @@ static inline struct obj_cgroup *__memcg_reparent_objc= gs(struct mem_cgroup *memc return objcg; } =20 +#ifdef CONFIG_MEMCG_V1 +static void __mem_cgroup_flush_stats(struct mem_cgroup *memcg, bool force); + +static inline void reparent_state_local(struct mem_cgroup *memcg, struct m= em_cgroup *parent) +{ + if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) + return; + + synchronize_rcu(); + + __mem_cgroup_flush_stats(memcg, true); + + /* The following counts are all non-hierarchical and need to be reparente= d. */ + reparent_memcg1_state_local(memcg, parent); + reparent_memcg1_lruvec_state_local(memcg, parent); +} +#else +static inline void reparent_state_local(struct mem_cgroup *memcg, struct m= em_cgroup *parent) +{ +} +#endif + static inline void reparent_locks(struct mem_cgroup *memcg, struct mem_cgr= oup *parent) { spin_lock_irq(&objcg_lock); @@ -458,6 +480,28 @@ unsigned long lruvec_page_state_local(struct lruvec *l= ruvec, return x; } =20 +void reparent_memcg_lruvec_state_local(struct mem_cgroup *memcg, + struct mem_cgroup *parent, int idx) +{ + int i =3D memcg_stats_index(idx); + int nid; + + if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, id= x)) + return; + + for_each_node(nid) { + struct lruvec *child_lruvec =3D mem_cgroup_lruvec(memcg, NODE_DATA(nid)); + struct lruvec *parent_lruvec =3D mem_cgroup_lruvec(parent, NODE_DATA(nid= )); + struct mem_cgroup_per_node *parent_pn; + unsigned long value =3D lruvec_page_state_local(child_lruvec, idx); + + parent_pn =3D container_of(parent_lruvec, struct mem_cgroup_per_node, lr= uvec); + + WRITE_ONCE(parent_pn->lruvec_stats->state_local[i], + parent_pn->lruvec_stats->state_local[i] + value); + } +} + /* Subset of vm_event_item to report for memcg event stats */ static const unsigned int memcg_vm_event_stat[] =3D { #ifdef CONFIG_MEMCG_V1 @@ -757,6 +801,18 @@ unsigned long memcg_page_state_local(struct mem_cgroup= *memcg, int idx) #endif return x; } + +void reparent_memcg_state_local(struct mem_cgroup *memcg, + struct mem_cgroup *parent, int idx) +{ + int i =3D memcg_stats_index(idx); + unsigned long value =3D memcg_page_state_local(memcg, idx); + + if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, id= x)) + return; + + WRITE_ONCE(parent->vmstats->state_local[i], parent->vmstats->state_local[= i] + value); +} #endif =20 static void mod_memcg_lruvec_state(struct lruvec *lruvec, --=20 2.20.1