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Wed, 23 Sep 2026 02:40:30 +0000 X-Mizu-Trace-ID: 41c7d1fbf26606a1 X-Migadu-Flow: FLOW_OUT Message-ID: <15ac7069-d687-4985-90bd-25bc900b4bdd@linux.dev> Date: Wed, 23 Sep 2026 10:40:22 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/2] mm/memcg: migrate per-node hugetlb lruvec stat together with hugetlb folio To: Hongfu Li Cc: Chris Down , linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, stable@vger.kernel.org, Hongfu Li , Oscar Salvador , David Hildenbrand , Andrew Morton , Shakeel Butt , Michal Hocko , Johannes Weiner , Joshua Hahn , Nhat Pham , Michal Hocko , Roman Gushchin References: <20260923-for-hugetlb_state3-v2-0-e8a36245bfab@kylinos.cn> <20260923-for-hugetlb_state3-v2-2-e8a36245bfab@kylinos.cn> Content-Language: en-US From: Muchun Song In-Reply-To: <20260923-for-hugetlb_state3-v2-2-e8a36245bfab@kylinos.cn> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 7045F100003 X-Stat-Signature: zcxw31h1siqef9bp9psqqge65y7y9qjn X-Rspam-User: X-HE-Tag: 1790131233-701848 X-HE-Meta: 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 ARhYEZWC 6uPjdzn1P72zq/bIePrpvTOrp9AwOpytNxaV/6bQw4sR6cQnkRpPZ496F7v0fE+8ukaZimG9NEHeaCzuzgguV+Zw5dZ+dJLx0pSP2bK3ZqM1T4lf4oRB9aS7pnuf8SmIWtn5c883zNO1LPRfchdBjtj4lvc9dDbEjEvJZxNUJlk2i9jAQx2Q7j9uD37vbMUSu2rh+RNhTK2SIRHCfUDBShIjgRNmcZ7oC/XlbWiPVDUUAgSMa1DRZCVyeqbQbsknI8tCIIr7ajA4ClUumvgZBMn5f5S8QE7y2cmfwTv2OllTUQUzVbvzNKKBFaKvU28xOfnjidyrIA/8lQd7vB507newE0QvoRHqj1bc+6eCilSRY5BvTA+lBu87Bmn7WIMBhHYWT8bupez1DSrETrMFtYvMUlg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2026/9/23 10:05, Hongfu Li wrote: > From: Hongfu Li > > memory.numa_stat exposes per-node hugetlb counters from per-node lruvec > stats. These stats are accounted against folio_nid(): incremented on > the folio's node when handed to a user, decremented when the folio is > returned to the pool. > > During hugetlb folio migration, mem_cgroup_migrate() moves the charge > to the new folio and drops the memcg data of the old one, so the free > of the old folio right after the migration skips the memcg per-node > lruvec decrement. The hugetlb count stays attributed to the old node > for the rest of the life of the charge, while the target folio gets no > increment on the new node; its later free decrements a counter that > was never incremented. > > Migrate the per-node lruvec accounting alongside migration. Global > memcg totals remain balanced because they track resource consumption, > not node placement. > > Fixes: 05d4532b60e3 ("memcg/hugetlb: add hugeTLB counters to memcg") > Cc: stable@vger.kernel.org > Signed-off-by: Hongfu Li > Tested-by: Joshua Hahn > Reviewed-by: Joshua Hahn > Reviewed-by: Oscar Salvador > --- > include/linux/memcontrol.h | 8 ++++++++ > mm/hugetlb.c | 25 +++++++++++++++++++++++++ > mm/memcontrol.c | 5 ++--- > 3 files changed, 35 insertions(+), 3 deletions(-) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index a8358f297b65..74110a324f9e 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -984,6 +984,9 @@ unsigned long lruvec_page_state_monotonic(const struct lruvec *lruvec, > unsigned long lruvec_page_state_local(const struct lruvec *lruvec, > enum node_stat_item idx); > > +void mod_memcg_lruvec_state(struct lruvec *lruvec, > + enum node_stat_item idx, int val); > + > void mem_cgroup_flush_stats(struct mem_cgroup *memcg); > void mem_cgroup_flush_stats_ratelimited(struct mem_cgroup *memcg); > > @@ -1452,6 +1455,11 @@ static inline unsigned long lruvec_page_state_local(const struct lruvec *lruvec, > return node_page_state(lruvec_pgdat(lruvec), idx); > } > > +static inline void mod_memcg_lruvec_state(struct lruvec *lruvec, > + enum node_stat_item idx, int val) > +{ > +} > + > static inline void mem_cgroup_flush_stats(struct mem_cgroup *memcg) > { > } > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 519c30b338a8..76d019594b39 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -23,6 +23,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -7378,12 +7379,36 @@ void folio_putback_hugetlb(struct folio *folio) > folio_put(folio); > } > > +static void move_hugetlb_lruvec_stat(struct folio *old_folio, > + struct folio *new_folio) > +{ > + struct mem_cgroup *memcg; > + long nr_pages = folio_nr_pages(old_folio); > + int old_nid = folio_nid(old_folio); > + int new_nid = folio_nid(new_folio); > + > + if (old_nid == new_nid) > + return; > + > + guard(rcu)(); > + > + memcg = folio_memcg(new_folio); > + if (!memcg) > + return; > + > + mod_memcg_lruvec_state(mem_cgroup_lruvec(memcg, NODE_DATA(old_nid)), > + NR_HUGETLB, -nr_pages); Why not use mod_lruvec_state? mod_memcg_lruvec_state is an internal API for memcg, I don't want it to be exported. Thanks. > + mod_memcg_lruvec_state(mem_cgroup_lruvec(memcg, NODE_DATA(new_nid)), > + NR_HUGETLB, nr_pages); > +} > + > void move_hugetlb_state(struct folio *old_folio, struct folio *new_folio, > enum migrate_reason reason) > { > struct hstate *h = folio_hstate(old_folio); > > hugetlb_cgroup_migrate(old_folio, new_folio); > + move_hugetlb_lruvec_stat(old_folio, new_folio); > folio_set_owner_migrate_reason(new_folio, reason); > > /* > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 88824f783571..a5335da5d425 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1015,9 +1015,8 @@ static void __mod_memcg_lruvec_state(struct mem_cgroup_per_node *pn, > put_cpu(); > } > > -static void mod_memcg_lruvec_state(struct lruvec *lruvec, > - enum node_stat_item idx, > - int val) > +void mod_memcg_lruvec_state(struct lruvec *lruvec, > + enum node_stat_item idx, int val) > { > struct pglist_data *pgdat = lruvec_pgdat(lruvec); > struct mem_cgroup_per_node *pn; >