From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BFBE3109C032 for ; Wed, 25 Mar 2026 15:29:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 270256B0096; Wed, 25 Mar 2026 11:29:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 246AC6B0098; Wed, 25 Mar 2026 11:29:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 183AE6B0099; Wed, 25 Mar 2026 11:29:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 0B4D66B0096 for ; Wed, 25 Mar 2026 11:29:05 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id B2E21140951 for ; Wed, 25 Mar 2026 15:29:04 +0000 (UTC) X-FDA: 84584968608.14.7163311 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf23.hostedemail.com (Postfix) with ESMTP id EC615140011 for ; Wed, 25 Mar 2026 15:29:02 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=CsU1vZ+n; spf=pass (imf23.hostedemail.com: domain of ljs@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=ljs@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1774452543; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=GZoG/KtFMymaV5jHuhCZ7WF+MbGglZumYUi+g7zM6MI=; b=eFp7e1i24Q7qJ62t4zBpxq2cu0XF5L/whQSbAntuHlVBPjh64WDuM5GDHeqWfm3V74xwKn QssuZEqlxI4mqhWRfN2PnPbAl7Ng2j6MeWtNKXI2kOPJWjS3oXDE9oPn4enTgwc13Y4Hy4 PQi8SLtkEQnkkKn/ubqKlyV9HwdE82M= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1774452543; a=rsa-sha256; cv=none; b=kENbJXFEX9qvuRTFrSy4y5wOY/stsz8OtY7Z+9wa1QIQzC2FlnYgXjGKY++Jwyi/F3xjh+ aurc4DgeNYTj4FYt/Pit5eQqH22orUSmYaRIHuSwI5e4JwhO72eBdKSv9hDsHdx20TOE96 KzspsG216kZ442wvY+we8eTQQBpX2U8= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=CsU1vZ+n; spf=pass (imf23.hostedemail.com: domain of ljs@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=ljs@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id F363A41ACA; Wed, 25 Mar 2026 15:29:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2560C4CEF7; Wed, 25 Mar 2026 15:28:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774452541; bh=S+gB9lXh3YOTsDeZFSd4g0zO49rKXLKXwGpvrhbPAu8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CsU1vZ+neeDNy1FrFSsnvYWLJC+Y5AbizxD9JdhZhz5TLzWJXU8AeQ3/KAJVp9MJx nOnwLgRcxQq9RfFkwfFk5uupxbbMwYYlGjMjdxWQpMAMjmrn9JmWZc0AQnNfWLu/Rf 4Shltt28OwDtEK6WwAPksJHzbrjfupQIkuYDawBFDDct8c8wSAwHLyF+ypUqBVmAji hiATEKCQbMcNYZWKj0qzZWHrWjfnEN3hKeLKYbMauPawZHgMiqCm/oKaSc2WjpwFQo spyzsqqnWDx97KRa0TK60JZpbHBH8qbORj5iWLnp/C95Fm9oYth+ZOZkLciVq8wk+w He9oxW9vKHw9Q== Date: Wed, 25 Mar 2026 15:28:53 +0000 From: "Lorenzo Stoakes (Oracle)" To: Qi Zheng Cc: hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@kernel.org, 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, bhe@redhat.com, usamaarif642@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qi Zheng Subject: Re: [PATCH v2 1/4] mm: memcontrol: correct the type of stats_updates to unsigned long Message-ID: References: <158fa0b1296168047342f02050e9d2bda6888d27.1774447069.git.zhengqi.arch@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <158fa0b1296168047342f02050e9d2bda6888d27.1774447069.git.zhengqi.arch@bytedance.com> X-Rspamd-Server: rspam12 X-Stat-Signature: mmero3imaiud6q48go1gjhopa44denww X-Rspamd-Queue-Id: EC615140011 X-Rspam-User: X-HE-Tag: 1774452542-852125 X-HE-Meta: U2FsdGVkX18ZwMwa42Szhlbry3vqa2YLdl7NzLchrpjMjsgL7fG+UOe6+es/UGZ8CF190MM6zsi5iHdigZMkT4jT1hwq7lOkMBNNrR1dwglNLtDharv8++jMgwkQfZGDcDVD9HctkebtjxwfsPr8hU+iqEUqvPsMkzCuQybCzfTJgTIw+uBwqF5VAQ9zqW27Ci0BTdcWIolDsZrAKwvgc+K5XXMyZ4iGvnaIVtUlkvzQD+eVdozQ0QDZIK50UQvhpzZh+g5LL/qN6e6CyQBbbWRkiwiW5vLtozK2kTfs9//fF4CrsIGA/oB3VF8w2/sgHUHDOaTuzEdciurrOkIopJa/PuS5prnqBFPgBCd6L5D3yHa8Z2H002qeHcauYNwDlksVGqLS18WwjIp/3OpXnU1LLaZ/vfZxvIS86hZ8vssAcXxN4OuPmZxmmM7/PSSIXBbTNFH+WtG3EeSNTiipMKUw1NYINKxwidHvNjExElXT1lhESSvAoYPgEMNW7aRKpJOhcmiICzqZVHxRBPlqnfUpptuzsyaE59VxZOPgBHTQFujquJ2oOqwdJclcISageGsjmV8c4zZfsBs3HuD0jyfDZHuclLxODrU56qYf+c7qbh8JxhqKGzsLveCtbWTfKpzAWMLuIG7CMOKpiq2PV2zzzjfbUY6kbCSEHo2cOEeKUJy0b1DizE+wK5tY6pmrVbc6SRQ16UYNTCWXMtyE6eyTOvAMRv5B7lyaLKqsVNlCgEyUSx0bBUYJ+IrWSVzPQRRHcsK/+IvbAQgRLUFSy9v/dg2ZXkXSWSDUqVPK4Y8z7ouLCoqeAcWd3hwgQ1KO4/vKJ16wxwlyr5dBAkSUOatTCzCyoZtfzNNIjmu0AyZE5slcJNLpCSK/ouKB/Xxk8ZFt7RwJ3JH8EJ5oT7enUBVkuiJJufkxGuH3DGG8p6+oLOqtTFiqgSQZFPD5DZyq0kkEMNVy/02iPgz79bv UPWWs2VY LqYEXLPDuezM8kBNFU3VTcbI23i+DqTLimNVJW/745z2OtiJwZDAUA7C+JYgWdlugK7taFVFXxeq0N8slD563lG6JYFsPMXQal1GeDvdqZv3/hYc6yXNmkC13kziMjuvJMWkUETpzKFHnVz81KEz9M8JDIjSNAYruddcqgSouuEuT0XYWNxrmeUhkSj7rIh0V/7lQnNR9rhCyLIKlMZFvEuYREMg7wPR8wdmSlPdoyC3Ea0PxFzHcHRiLX4ESIqongmddvaQ8KDVmU7VeDauoN0VQGC0iWJfIOxbpSiZzUrmdMsL+BVR+9uobBA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Mar 25, 2026 at 10:13:22PM +0800, Qi Zheng wrote: > From: Qi Zheng > > The memcg_rstat_updated() tracks updates for vmstats_percpu->state > and lruvec_stats_percpu->state. Since these state values are of type long, > change the val parameter passed to memcg_rstat_updated() to long as well. > > Correspondingly, change the type of stats_updates in struct > memcg_vmstats_percpu and struct memcg_vmstats from unsigned int and > atomic_t to unsigned long and atomic_long_t respectively to prevent > potential overflow when handling large state updates during the > reparenting of LRU folios. Do we need a Fixes, possibly cc: stable for that? Apologies if already asked + answered. > > Signed-off-by: Qi Zheng Anyway logic seems fine to me, so: Reviewed-by: Lorenzo Stoakes (Oracle) > --- > mm/memcontrol.c | 18 +++++++++--------- > 1 file changed, 9 insertions(+), 9 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index a47fb68dd65f1..7fb9cbc10dfbb 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -608,7 +608,7 @@ static inline int memcg_events_index(enum vm_event_item idx) > > struct memcg_vmstats_percpu { > /* Stats updates since the last flush */ > - unsigned int stats_updates; > + unsigned long stats_updates; > > /* Cached pointers for fast iteration in memcg_rstat_updated() */ > struct memcg_vmstats_percpu __percpu *parent_pcpu; > @@ -639,7 +639,7 @@ struct memcg_vmstats { > unsigned long events_pending[NR_MEMCG_EVENTS]; > > /* Stats updates since the last flush */ > - atomic_t stats_updates; > + atomic_long_t stats_updates; > }; > > /* > @@ -665,16 +665,16 @@ static u64 flush_last_time; > > static bool memcg_vmstats_needs_flush(struct memcg_vmstats *vmstats) > { > - return atomic_read(&vmstats->stats_updates) > > + return atomic_long_read(&vmstats->stats_updates) > > MEMCG_CHARGE_BATCH * num_online_cpus(); > } > > -static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val, > +static inline void memcg_rstat_updated(struct mem_cgroup *memcg, long val, > int cpu) > { > struct memcg_vmstats_percpu __percpu *statc_pcpu; > struct memcg_vmstats_percpu *statc; > - unsigned int stats_updates; > + unsigned long stats_updates; > > if (!val) > return; > @@ -697,7 +697,7 @@ static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val, > continue; > > stats_updates = this_cpu_xchg(statc_pcpu->stats_updates, 0); > - atomic_add(stats_updates, &statc->vmstats->stats_updates); > + atomic_long_add(stats_updates, &statc->vmstats->stats_updates); > } > } > > @@ -705,7 +705,7 @@ static void __mem_cgroup_flush_stats(struct mem_cgroup *memcg, bool force) > { > bool needs_flush = memcg_vmstats_needs_flush(memcg->vmstats); > > - trace_memcg_flush_stats(memcg, atomic_read(&memcg->vmstats->stats_updates), > + trace_memcg_flush_stats(memcg, atomic_long_read(&memcg->vmstats->stats_updates), > force, needs_flush); > > if (!force && !needs_flush) > @@ -4406,8 +4406,8 @@ static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu) > } > WRITE_ONCE(statc->stats_updates, 0); > /* We are in a per-cpu loop here, only do the atomic write once */ > - if (atomic_read(&memcg->vmstats->stats_updates)) > - atomic_set(&memcg->vmstats->stats_updates, 0); > + if (atomic_long_read(&memcg->vmstats->stats_updates)) > + atomic_long_set(&memcg->vmstats->stats_updates, 0); > } > > static void mem_cgroup_fork(struct task_struct *task) > -- > 2.20.1 >