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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1747636346; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=pscW8GSmC5MxHSwlI+8ZvdnC6pDSuCRMn1j4o1jkTeU=; b=GazpB2DyXf7pkV95zXT85Qot5wdAGwWb5fmoJfvHAKhuPf1Mi88qIW7KeYwqNtGNT9iuwW vvFcRUIhOafzKpskuI7M0726f4rNVrkZevT3uDX6wv48SRJTPywIPh+OWI58fPslTRrMM6 aV22pxwrCOClRMk0jCKTEeB3+pgeZ44= From: Shakeel Butt To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Vlastimil Babka , Alexei Starovoitov , Sebastian Andrzej Siewior , Harry Yoo , Yosry Ahmed , Peter Zijlstra , Mathieu Desnoyers , Tejun Heo , bpf@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Meta kernel team Subject: [PATCH v4 3/5] memcg: add nmi-safe update for MEMCG_KMEM Date: Sun, 18 May 2025 23:31:40 -0700 Message-ID: <20250519063142.111219-4-shakeel.butt@linux.dev> In-Reply-To: <20250519063142.111219-1-shakeel.butt@linux.dev> References: <20250519063142.111219-1-shakeel.butt@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam10 X-Stat-Signature: bp7ek47gj3bgh18hq6nmkynqm9657545 X-Rspamd-Queue-Id: 7716240002 X-Rspam-User: X-HE-Tag: 1747636348-977499 X-HE-Meta: U2FsdGVkX1+nJs2Ch9hV5X2idcetWxXW9c4VQzZdvmjL92xNr+TPyVocJ3RKHpsJpIX9MxYjPbk/+Pn7wKaFrcbLumYduUVoq0Gk+v7SnlEQjoh+mYBlTwAwEgyJfiv8d6bZnbNiDkidHthh06SLpngqxit77pTb+JhPAeUYeZbfvqNAsW05PvIQVuXs2sy33CxP9MfsZlp12+Ey6A1xpykfhDcOEzK+b69yT+Sul04b0f/7SW3WYNXVeWm6XQQmXa/lYDjlhtGJgq02Gpsfo1H/HKWn4sOKsa3OwZJgdnY1KrIuzBArDiqLU3LYwKgQgFFAYiKeMAzkO47jBLeo2xxvcOGE7CLPmB6p29+oUby2fv1109Z9upHyDo4ki1Y7SMe5csYD5w5FYN5S5vTvm7rv8r5G2q7eDOTLLvBAJdldVLDDw+cC9UiPYZK62MLaZxUaH648EisX8MvIFJsBRLyayx+RVzlJZi4VDM/piU+HOe8No4X8GDm9dAC5OpAPhON40K644FNKYHCG0ryY92ScYxDtKahBPZqGHZvGhCBFQsFGk9kL//MMXJXnn3HTgwv11IV5eIr3HnCoQOxZdAcZdazE4PHD4Khj5YxRu+pwJ5Ae9kDHkzY6OJn6YIziOqiro/pQY8iLxEiIhlW3E4aKjrmWmucXuVXeKGWGT7NAeOp7KJVgWdG75sTdksjyd4QDulzytDzLHQ585i/QAs60AL0ijl7SFlOu/RrWGv2EWg8KFLP359oFPZycB5E/+uxD9vraIyafnVp3zQj8+V1dTIxWON3g/6+CFtWmzGZdl9nvv0u11RckxFqAhgiItU7EOoYQecg1VDwMQK9/XXjRGlW+rODcciN63J9sr7Os+NYMxr1KNXabkJaKmYoY/wZwaweZTMUBWBuU0MGO4owLg+7mjqVfa/5gDBH0Av+greFMAL9DNsYmydLUVsEfZgvdozTPMyGsTEzv0mW C9W/BDSz qTm8a3A31rgqkwzpPlVgOwdlXoyEALva8polTJRhNBB29UEk3phWa1g/qyuO9YyxHRZA7xOX8RBxJCG4zCY9MwxNu2vR0dcVbZXGdSoS8NE9TuLfZ9BQZQlaaT42XpZdxYLSbQN9v3pcOuxcjoa+HnYEZAEx2xNxXqs7NWA+IahYfenfi7ISfPrxPfCOs+OhaipnPwbmIiWtkMq35ncO219JR8iSJi4Bg7QY2 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 objcg based kmem charging and uncharging code path needs to update MEMCG_KMEM appropriately. Let's add support to update MEMCG_KMEM in nmi-safe way for those code paths. Signed-off-by: Shakeel Butt Acked-by: Vlastimil Babka --- mm/memcontrol.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e3f0b298308a..62d7997640db 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2717,6 +2717,23 @@ struct obj_cgroup *get_obj_cgroup_from_folio(struct folio *folio) return objcg; } +#ifdef CONFIG_MEMCG_NMI_SAFETY_REQUIRES_ATOMIC +static inline void account_kmem_nmi_safe(struct mem_cgroup *memcg, int val) +{ + if (likely(!in_nmi())) { + mod_memcg_state(memcg, MEMCG_KMEM, val); + } else { + /* TODO: add to cgroup update tree once it is nmi-safe. */ + atomic_add(val, &memcg->kmem_stat); + } +} +#else +static inline void account_kmem_nmi_safe(struct mem_cgroup *memcg, int val) +{ + mod_memcg_state(memcg, MEMCG_KMEM, val); +} +#endif + /* * obj_cgroup_uncharge_pages: uncharge a number of kernel pages from a objcg * @objcg: object cgroup to uncharge @@ -2729,7 +2746,7 @@ static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg, memcg = get_mem_cgroup_from_objcg(objcg); - mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages); + account_kmem_nmi_safe(memcg, -nr_pages); memcg1_account_kmem(memcg, -nr_pages); if (!mem_cgroup_is_root(memcg)) refill_stock(memcg, nr_pages); @@ -2757,7 +2774,7 @@ static int obj_cgroup_charge_pages(struct obj_cgroup *objcg, gfp_t gfp, if (ret) goto out; - mod_memcg_state(memcg, MEMCG_KMEM, nr_pages); + account_kmem_nmi_safe(memcg, nr_pages); memcg1_account_kmem(memcg, nr_pages); out: css_put(&memcg->css); -- 2.47.1