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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 14/33] sched/isolation: Flush memcg workqueues on cpuset isolated partition change Date: Mon, 13 Oct 2025 22:31:27 +0200 Message-ID: <20251013203146.10162-15-frederic@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251013203146.10162-1-frederic@kernel.org> References: <20251013203146.10162-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 8C2E140012 X-Stat-Signature: b1z64ppknaffcy7ksq66uaj8ie9bkuco X-HE-Tag: 1760387630-841170 X-HE-Meta: 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 WnyoOQoM dVqOPfJMVikQVroNUHWsxdktg/8l2QSJsKYdlHlgdpSUzT7yKuovw9SYhkRAVpO7BYEyrzslwZcDtiI54TKsRzfeTaCPPSubUHMuBqnNTErNKXFHOCV1ulCrdJNgiZD+nJir0BHLMjulLZIELce4XE8A9oeFL3MY3PW1SmwaVFs/gJGh70UguGtbWYiChaEbQTkcnPSjbZEpg5BwR8zlPnOon2He1IIuumfqjVer2UMROafsWKp6QpSyiub6shMifsdxTf4ALjVJn5B1YAEInjumyKlb80wwl99qpHaxMN2t2as4= 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 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 95d69c2102f6..9ec365dea921 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -144,6 +144,8 @@ 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 8fac8aa451c6..8bfc0b4b133f 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..1aa14e543f35 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", 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