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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: Mon, 13 Oct 2025 22:31:16 +0200 Message-ID: <20251013203146.10162-4-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-Stat-Signature: spsfj4prs5pyznrzpt5suxb9dgcbwxra X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 92CEA120004 X-HE-Tag: 1760387542-101980 X-HE-Meta: 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 FOazJ79Z ahTmKRfbK46s4Bzz+1f6NwkfgbGevQxrGNnt1DcULCpFzQKeZABNpYm77oUl833b55FsMrP0pQJkXXUVybrvTRrLEBkB3kgZM9Go0oOvMFGvYw2xYotQukj1ZP0WHuAshrmU+0VW2SpbjPOhWUpmIkx5n6S1VBcWBnVLuxYW1GDXG8t0hYx6Q6cjbGNTZGSruJiszrjX6QRNz0/e0r3Q2ZFEGH64laeLcTaVqSZpSPmkvxcRdfH3C5TpNt/Jr/rb8H1zFXu1dLlmWWRY= 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 modifyable 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 4deda33625f4..1033e52ab6cf 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1971,6 +1971,13 @@ 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. @@ -2000,8 +2007,8 @@ 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) && @@ -2010,8 +2017,8 @@ 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(); -- 2.51.0