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b=C8AXhZl+gXT7Wn4j0WTzrl75mnwgtlWombLUDLZsESBSf1B1sbjpjnwfsvn+zVGE4 1k31OZAdZNpqkhpeMU6kbL3YO//pWMNEdGM8v6qGjRlUGQZPtmhefUAyVD4Lgo9eBo SUAto569iRvjZecY1rEQI8w4bgovBDYW2mx70TPBAXYobui3Ew/e+7B2uWGQfU7BaW 8g2hpGYcq0tOuirdQu+z+nu0gLWlISIEIXTakrbzjAWze60tmue26KzabRJhD0F5eR 7yHNlS+5eup2c/DeXHLgHzG510t+Bj7V1AqmDMon7edVCGP2bG18HSD5dICpyTBGCg XLCm26U0+Wz+A== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Andrew Morton , Ingo Molnar , Johannes Weiner , Marco Crivellari , Michal Hocko , Muchun Song , Peter Zijlstra , Roman Gushchin , Shakeel Butt , Tejun Heo , Thomas Gleixner , Vlastimil Babka , Waiman Long , cgroups@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 15/33] sched/isolation: Flush memcg workqueues on cpuset isolated partition change Date: Fri, 29 Aug 2025 17:47:56 +0200 Message-ID: <20250829154814.47015-16-frederic@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250829154814.47015-1-frederic@kernel.org> References: <20250829154814.47015-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 4180218000E X-Stat-Signature: 48fzosrh5bqjxam6n481moi9wmpu6ahh X-Rspam-User: X-HE-Tag: 1756482544-258756 X-HE-Meta: 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 gg/IxKhx NCYTOlVUG85eI5XRjUC0GamN0kK0atwz8Lza8DzYSThPkfxO/ztqT6Dj5B1Q2Tw9i0VRHRxWNJivOUIGLrvw/EPVjQsxcT3KhsKAlFKC42FyGfiBwo8d80WmFNZlB8i5DgXB/ZnwyUs/HZyJUBaZro9bO5Bd3rlKghHguKHiB+6Ua+unsGliWz8vcc2dVSxRKMz73MnvZP8tPTRWLM0X3zNTPSt7QFkSZCTkh8O0ORMcaUgkS5hOKwxcsQlhfPHm3kio5AW83ET3mstQ44GK2bbrOmYcNuKD0999PQ87i7DK8Mgc= 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 modifyable 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 785173aa0739..8b23ff000473 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1048,6 +1048,8 @@ 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 */ @@ -1453,6 +1455,8 @@ 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 48f3b6b20604..e85f402b103a 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -124,6 +124,8 @@ 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 d3512138027b..1dad1ac7fc61 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 2649d6c09160..1aa2dfa32ccd 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; @@ -1974,7 +1976,7 @@ 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); } /* @@ -5071,6 +5073,11 @@ void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, 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; @@ -5113,6 +5120,9 @@ 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", 0, 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