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AHgh+RqKSnxaTyFo/J2z8rvTO6GtadtE0lLGbO1piMhI5dHcVvngKGlH1Cc5g7yNa8Bj+QoU9p8IJaI0GQ==@kvack.org X-Gm-Message-State: AFuF++nT0HRnHBBC/rV0aF5jPY4gr4GrUbYDI4sJmE5jcP+f1+y22H0h Uv1k4DJm/OweQqj2YAJTLzBRRJ77Bpr5h24gkfzeru+slWOu5ttMln3bnSc8tAgMQpup+XJguz6 AisesZIMzOn3gRA== X-Received: from dlbts8-n1.prod.google.com ([2002:a05:7022:b048:10b0:142:e77e:11fa]) (user=stevensd job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:3a87:b0:3d3:af86:fb94 with SMTP id adf61e73a8af0-3d3af87e902mr34342527637.26.1788219871732; Mon, 31 Aug 2026 16:44:31 -0700 (PDT) Date: Mon, 31 Aug 2026 16:43:39 -0700 Mime-Version: 1.0 X-Mailer: git-send-email 2.55.0.897.gb25b4bd76c-goog Message-ID: <20260831234339.280376-1-stevensd@google.com> Subject: [PATCH] memcg: Don't call schedule_work when no spinning is allowed From: David Stevens To: Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Stevens Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: yhrjzusjsmupangnk8w1p79s7ji3fsu9 X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 4E730140003 X-Rspam-User: X-HE-Tag: 1788219873-404157 X-HE-Meta: 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 JO1QV3yk 1z8oxLW4MkGmmfzAYZMWN5dyKdbpmBYX9e1QUrE0pioK3rbVzmH6Qr+nZW4isygKmuIfwqo4WFIRo4apXO2MCq1wPqpl3RNhIuz8lOSkMqgHE1FIjEHfU4HpBYjqDy0gk373xEGWEywuV4iHEvBs6Ho27DK+oGh8db5X3DfIagqHcRZh6iByfgJdWgx+7vNYpqZ7Vw7PqyFDNSgaoUySK3qSawHQ3MTWjuoinwllVZSQYumb8lUlSTp+8UOSfNe+fbb4hkCVzoGKmKzzvnlHKRd2PpSvvStHqGikLsOApu887ucLzlMOImycRabhrQwgd3n5k7NwF7OrWspXnM5+vMkKsv9cQJ85EEyGMr/DX0ivPij8yzoRcHbzxd28DUJwDf4jrBv7RpXTjYmJ0apZl1ks3NNH7ycLV/nTpWVfZsc1iMZLa/FofS8nBvAouYK7wJyP0l6HK5kgUm7GHw0IGV5pgyc0WY78aw5ggoEvwY9wKuPI4NVstmJAfDWzq94O+/j8tzRjYgCizeaJJIm6Jv7eDBN1Bw1LpPCr9PeCL5jyrqLPNdZXG7FuzYswpxugEZ/ZBfjs2OWhMC7aWAIF6r51ElvXgBhAkRyziXVxTj/kmG+NZIO2Vlk/Mq6wC7oh/dvuVBvExGAJKxZ4= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Memcg charging can be done from any context, but calling schedule_work() isn't safe from an NMI. If memory.high is breached from a context where spinning isn't allowed, use irq_work to schedule the reclaim work. Fixes: 3ac4638a734a ("memcg: make memcg_rstat_updated nmi safe") Signed-off-by: David Stevens --- include/linux/memcontrol.h | 1 + mm/memcontrol.c | 12 +++++++++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 8170bb8066a2..036d973ceca6 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -219,6 +219,7 @@ struct mem_cgroup { spinlock_t peaks_lock; /* Range enforcement for interrupt charges */ + struct irq_work high_irq_work; struct work_struct high_work; #ifdef CONFIG_ZSWAP diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 6dc4888a90f3..5e2f749067cb 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2360,6 +2360,11 @@ static void high_work_func(struct work_struct *work) reclaim_high(memcg, MEMCG_CHARGE_BATCH, GFP_KERNEL); } +static void high_irq_work_func(struct irq_work *work) +{ + schedule_work(&container_of(work, struct mem_cgroup, high_irq_work)->high_work); +} + /* * Clamp the maximum sleep time per allocation batch to 2 seconds. This is * enough to still cause a significant slowdown in most cases, while still @@ -2752,7 +2757,10 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask, /* Don't bother a random interrupted task */ if (!in_task()) { if (mem_high) { - schedule_work(&memcg->high_work); + if (allow_spinning) + schedule_work(&memcg->high_work); + else + irq_work_queue(&memcg->high_irq_work); break; } continue; @@ -4129,6 +4137,7 @@ static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent) goto fail; INIT_WORK(&memcg->high_work, high_work_func); + init_irq_work(&memcg->high_irq_work, high_irq_work_func); vmpressure_init(&memcg->vmpressure); INIT_LIST_HEAD(&memcg->memory_peaks); INIT_LIST_HEAD(&memcg->swap_peaks); @@ -4337,6 +4346,7 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css) static_branch_dec(&memcg_bpf_enabled_key); vmpressure_cleanup(&memcg->vmpressure); + irq_work_sync(&memcg->high_irq_work); cancel_work_sync(&memcg->high_work); memcg1_remove_from_trees(memcg); free_shrinker_info(memcg); base-commit: 8d3ae59288f1e7d58d76558a6ee96d533bc5019f -- 2.55.0.897.gb25b4bd76c-goog