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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 03/33] memcg: Prepare to protect against concurrent isolated cpuset change Date: Wed, 24 Dec 2025 14:44:50 +0100 Message-ID: <20251224134520.33231-4-frederic@kernel.org> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251224134520.33231-1-frederic@kernel.org> References: <20251224134520.33231-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 8988140002 X-Stat-Signature: ufqcg9idbu45z4xwbyyoshten6c9nui7 X-HE-Tag: 1766583958-718126 X-HE-Meta: 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 GAbWGRWk rtczcLTN2AlPxNs8pj4ztEjS18OjMuwQNI9wd/hp7T/qFsWeqdH/cLlHMwdGOFCi6YfTgRg8qxT2lNQjkTRzHHqKyYia7oMBTZfow27sYpRwiTz6iRPIy2U8nrKQPF/+Yt7s2k5QEBK7AUxPsRv8HwXAbWLPB+BeKS/AsPjIFJEF/P/9hNwaFMqBATEFuVhlyXMyazD7MQtqiII7IM7K852q7jDA6joSmrQ8LDPXCxubMs+PedHpJ9xfDMOBqc1WGzfbomSkV/JGmcZk= 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 will soon be made modifiable at runtime. In order to synchronize against memcg workqueue to make sure that no asynchronous draining is pending or executing on a newly made isolated CPU, target and queue a drain work under the same RCU critical section. Whenever housekeeping will update the HK_TYPE_DOMAIN cpumask, a memcg workqueue flush will also be issued in a further change to make sure that no work remains pending after a CPU has been made isolated. Signed-off-by: Frederic Weisbecker --- mm/memcontrol.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index be810c1fbfc3..c3c473c3dfca 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2003,6 +2003,13 @@ static bool is_memcg_drain_needed(struct memcg_stock_pcp *stock, return flush; } +static void schedule_drain_work(int cpu, struct work_struct *work) +{ + guard(rcu)(); + if (!cpu_is_isolated(cpu)) + schedule_work_on(cpu, work); +} + /* * Drains all per-CPU charge caches for given root_memcg resp. subtree * of the hierarchy under it. @@ -2032,8 +2039,8 @@ void drain_all_stock(struct mem_cgroup *root_memcg) &memcg_st->flags)) { if (cpu == curcpu) drain_local_memcg_stock(&memcg_st->work); - else if (!cpu_is_isolated(cpu)) - schedule_work_on(cpu, &memcg_st->work); + else + schedule_drain_work(cpu, &memcg_st->work); } if (!test_bit(FLUSHING_CACHED_CHARGE, &obj_st->flags) && @@ -2042,8 +2049,8 @@ void drain_all_stock(struct mem_cgroup *root_memcg) &obj_st->flags)) { if (cpu == curcpu) drain_local_obj_stock(&obj_st->work); - else if (!cpu_is_isolated(cpu)) - schedule_work_on(cpu, &obj_st->work); + else + schedule_drain_work(cpu, &obj_st->work); } } migrate_enable(); -- 2.51.1