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Miller" , Eric Dumazet , Gabriele Monaco , Greg Kroah-Hartman , Ingo Molnar , Jakub Kicinski , Jens Axboe , Johannes Weiner , Lai Jiangshan , Marco Crivellari , Michal Hocko , Muchun Song , Paolo Abeni , Peter Zijlstra , Phil Auld , "Rafael J . Wysocki" , Roman Gushchin , Shakeel Butt , Simon Horman , Tejun Heo , Thomas Gleixner , Vlastimil Babka , Waiman Long , Will Deacon , cgroups@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH 15/33] sched/isolation: Flush memcg workqueues on cpuset isolated partition change Date: Sun, 25 Jan 2026 23:45:22 +0100 Message-ID: <20260125224541.50226-16-frederic@kernel.org> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20260125224541.50226-1-frederic@kernel.org> References: <20260125224541.50226-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 321A480002 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: ntskymqeupoiwgywscpbrs5brp1bskfg X-HE-Tag: 1769381275-397797 X-HE-Meta: U2FsdGVkX1+F+o+I1tPLLaZUIPiGSXC8wKfLjEsePzcGy4E37gXaZPl6imJvymhXpIB2AUag4iFQOpxsEMQQabmzMhY64ilKs/RBQ+Ceo28ZWB+Vg8e5+gMJWHOHoDCkGwzaO33lwUTrqdLjImmWwJBjSL435gw/N+EcLq4dfvKkGSEbxsZ7MZbF6WKA2NWSUxMrCkzlE5qautcXwMwArzPpMesLM8zZe/Mpc7Fngv0k4Ep5aI01SZZ9xGviVtipO9SVCC75Kouonz7HUrZRix/AzmOodnByzwfYidB5W1sPWJ9M99pV8AQe/5Cyw8S+JEPcQ9ubIGw1Lm/Zx5bT4YCevQ/N3g04Ydq0woavVNFagEQwMnNCwy9y2CUEoxvLg9mrHZ6Sa34RtwutiMrb/r9vNpT/lK2xcjifJzalaHTVDAPI1h5oy1b5DwwMDw7i6zne8kPIDqO5B0PYVD/+txCl0BHXvfWYq1Lhv0RvFaEmQ/TCqqiSx3QrzpltnyeNpbyWA29AQk6r1CNhuA6SBOO7Cc3Qb0KCPn8+iB4O/o+MXtjZhfcoAqm1n3PvUwrRiYzKacSuQXSqWimCnfZiG+nsGAiUAg2GD790h9HVr6JqklUw1BGqYuA8AZrd6uXAdwwXsfVPcaiYPUl30cHZGJHXhTeUSor8H7HUvJHsTpSOfeUh2T/UGUrNjNT/DmZIIZuPOn9CtuzNOllwrdCyFiAwssnSEOEkluOcoyC+pm5f27QCWN9I9PTCN356Y3JSklwYBYSQk5LHo3f/c7vhclmVnO8CHwH2425ghX+4nbnrBCFyCc6joK/ZscD+ElDlNx3t3PzqOPk4gBO3YsJWK4HeYMJxPHT9j2rDrz4btIvDTu4JPNYxd6QGZT335JCqkiPWhmnZ12hsi1JiCrkQGjQNZ1tuMNJJMobOHfSDFXYhcK4bG3HVyhJcimAPtXNDPu2OjhddVNDMmi+yMQC l9A== 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: The HK_TYPE_DOMAIN housekeeping cpumask is now modifiable at runtime. In order to synchronize against memcg workqueue to make sure that no asynchronous draining is still pending or executing on a newly made isolated CPU, the housekeeping susbsystem must flush the memcg workqueues. However the memcg workqueues can't be flushed easily since they are queued to the main per-CPU workqueue pool. Solve this with creating a memcg specific pool and provide and use the appropriate flushing API. Acked-by: Shakeel Butt Signed-off-by: Frederic Weisbecker --- include/linux/memcontrol.h | 4 ++++ kernel/sched/isolation.c | 2 ++ kernel/sched/sched.h | 1 + mm/memcontrol.c | 12 +++++++++++- 4 files changed, 18 insertions(+), 1 deletion(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 0651865a4564..5b004b95648b 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1037,6 +1037,8 @@ static inline u64 cgroup_id_from_mm(struct mm_struct *mm) return id; } +void mem_cgroup_flush_workqueue(void); + extern int mem_cgroup_init(void); #else /* CONFIG_MEMCG */ @@ -1436,6 +1438,8 @@ static inline u64 cgroup_id_from_mm(struct mm_struct *mm) return 0; } +static inline void mem_cgroup_flush_workqueue(void) { } + static inline int mem_cgroup_init(void) { return 0; } #endif /* CONFIG_MEMCG */ diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c index 674a02891b38..f4053ebf4027 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -144,6 +144,8 @@ int housekeeping_update(struct cpumask *isol_mask) synchronize_rcu(); + mem_cgroup_flush_workqueue(); + kfree(old); return 0; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 653e898a996a..65dfa48e54b7 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -44,6 +44,7 @@ #include #include #include +#include #include #include #include diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 2289a0299331..b3ca241bb1d6 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -96,6 +96,8 @@ static bool cgroup_memory_nokmem __ro_after_init; /* BPF memory accounting disabled? */ static bool cgroup_memory_nobpf __ro_after_init; +static struct workqueue_struct *memcg_wq __ro_after_init; + static struct kmem_cache *memcg_cachep; static struct kmem_cache *memcg_pn_cachep; @@ -2013,7 +2015,7 @@ static void schedule_drain_work(int cpu, struct work_struct *work) */ guard(rcu)(); if (!cpu_is_isolated(cpu)) - schedule_work_on(cpu, work); + queue_work_on(cpu, memcg_wq, work); } /* @@ -5125,6 +5127,11 @@ void mem_cgroup_sk_uncharge(const struct sock *sk, unsigned int nr_pages) refill_stock(memcg, nr_pages); } +void mem_cgroup_flush_workqueue(void) +{ + flush_workqueue(memcg_wq); +} + static int __init cgroup_memory(char *s) { char *token; @@ -5167,6 +5174,9 @@ int __init mem_cgroup_init(void) cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL, memcg_hotplug_cpu_dead); + memcg_wq = alloc_workqueue("memcg", WQ_PERCPU, 0); + WARN_ON(!memcg_wq); + for_each_possible_cpu(cpu) { INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work, drain_local_memcg_stock); -- 2.51.1