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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 14/31] sched/isolation: Flush memcg workqueues on cpuset isolated partition change Date: Wed, 5 Nov 2025 22:03:30 +0100 Message-ID: <20251105210348.35256-15-frederic@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251105210348.35256-1-frederic@kernel.org> References: <20251105210348.35256-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 1388340007 X-Stat-Signature: 7xi9e8mtxkm4q4sk7ebozhgrkqqajr7g X-Rspam-User: X-HE-Tag: 1762376752-104666 X-HE-Meta: U2FsdGVkX1+7QkYT+KLvyEUzAFbi+SnLm1jFoYwwYiuom9anQcKuGZpHTu2XuPVsLaj+7+0ZalncOf8tPNnJ0/gdpegLbu1vtMJkpL/y/yDbARMwyFjoPwTDG40sAGiWTJO8RmmTtD2woXJ+KqziheZYANALl9x6HZoyS6V/E9St8UD9oXVS+yT4xYsrE3NQ1U04Olv579FScu0/nn5ZOAA9B1QEGZWSE7AVVC4/nT4pyW7hFkBF97XM1OOgNx2pRxYiTn5Zc5f4lvAhzFUifvcNJKXC2dpFyqUwpcI+tyE8mgxU5ffDg391QbF4pf3I1o1agARngGKAEokbqgOgsFcSSAw7noivveDYjlXi09DWAfGcLivDXawHm0uBEIwJToc+APRV0LsYy/f+Z0E6aaL7uf3eOLOV8HTbodsJI3tQyxXLeXJbTyVwNu4xKcZkAerHf3VAiMOMRMMAdLtbtf3ve4FDuPisyzgaVgh682as2o9KjMXq04NrbLb+GOO1qygQRiKHFb4bYhXCp4K+owb9qHNxCF99ZQHds7nmEXgL0LgI1gUDyh8ZtnKzN7P2rt2/LZxIL/6WrmkW9BU5dhU4zqk7eEXANxuydyH05+3vg/JsDGzRCZ+Hx8PCvaLHqsiFtyVYu/DLbOvXvCD+l/QrYKTQEwM9rgPWijO6+r18dR+Dl8dQ4pAtpvbwplkbtYnB4BziixKqEGX4AWh+RdeAUZ8tTym970QEkpc9bbSVsbYXFkUAk+pJOOJP1PlCAhY4J8bk65sbRdkXw8laDOkRvbFYvVRSHoZ7cIcPghO7sLR9k6JiPn3Oj4ifhKqztnTFtCtlHozffc35uVoqQQau5BpAPmeeg3GjY2msO5Rl6EQkb/AWeg/envoj99B3XlsdSEHpjW0ECW00Jgg4D09d4s2q4DjkbA9Z8hQoWDq0nKSikzR+98r0wW9+OnK/mkz6iLTVxZ2/ThXbHKB GC6ELcrK bw5+ge8ZveZb9M0w39oHiQ3dcS3yR4JhrsrYFGok+z8YNvNQOiBpp0RyVAs2uk3Jb0gTXzF5NSU7WuFSqEO0lBy2dHc5OK/t5LLIUhgwC5FncHr+dYDxmxQc8DNEQNmtdz3jdkldG3ArZ5gt+jBY/S+7kq9Vsg2EjL+yPXDRGw6ccFJ0D9uXXlG3pcLawmcV1KF57LxPvBZIcJwH4LC05YXurVaFjc9+eyHZNTaluBuSgurRu2Pf4mISeIe7MsafVzwV3xyLDmEGuB8+sXsc7yU7B+UyoInUl/DMNlqI7OO6buJ4= 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 873e510d6f8d..001200df63cf 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1074,6 +1074,8 @@ 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 */ @@ -1481,6 +1483,8 @@ 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 80a5b7c6400c..16c912dd91d2 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -145,6 +145,8 @@ int housekeeping_update(struct cpumask *mask, enum hk_type type) synchronize_rcu(); + mem_cgroup_flush_workqueue(); + kfree(old); return 0; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 5a44e85d4864..77034d20b4e8 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 1033e52ab6cf..4d1f680a4bb0 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -95,6 +95,8 @@ 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; @@ -1975,7 +1977,7 @@ 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); } /* @@ -5092,6 +5094,11 @@ 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; @@ -5134,6 +5141,9 @@ 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); -- 2.51.0