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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1747378196; 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=CI0Bp2IqmZG3mdccHhETvzHB03Kjr+cVmvCiU8mxhk8=; b=eUrZE+qTBmqtnw5qgpMu5Xy5nqqfp4nL5OQwO/cMx1nhkP5cl2G1N0FzLVHsYX+AHOAX0R 6r+IDuqrlnNMWzF5B7mNhK+NW7AjBBMC6xFKS6uO7B3olBoUWEoUYgewvnNkpuTfE3GGub 1Bvoop0NQFZkgT+rvHVR4ZkpVSP33pk= 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 , bpf@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Meta kernel team Subject: [PATCH 3/5] memcg: add nmi-safe update for MEMCG_KMEM Date: Thu, 15 May 2025 23:49:10 -0700 Message-ID: <20250516064912.1515065-4-shakeel.butt@linux.dev> In-Reply-To: <20250516064912.1515065-1-shakeel.butt@linux.dev> References: <20250516064912.1515065-1-shakeel.butt@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam10 X-Stat-Signature: k6yy336e8wgojnhji59coq7gsowr5otk X-Rspamd-Queue-Id: AE14718000A X-Rspam-User: X-HE-Tag: 1747378197-960946 X-HE-Meta: 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 HEDe2fxJ ROGlUYu1k+f30LiFI33BtvBVVcMXuyWW2xeJQ6PlRiQuj/6FmAr0K5txttBQBbvLU8V7Tp3stRflGfLxpN+uFhgpFDHcZMdMmgbrOlMhQckTCn3XkMN3OlVSt2lDp4u4jY22T/eBJ2sXaQ21iCr93qbw+ovAJQRfY7YNuwcOFKKvV0IgwChNLYuiXBgezwLNH3LPLChs6VeDtwsWjaaIhYnbss79qg2Wu1LB+ 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 --- mm/memcontrol.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 102fdec3f49e..899a31e6b087 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2729,6 +2729,23 @@ struct obj_cgroup *get_obj_cgroup_from_folio(struct folio *folio) return objcg; } +#ifdef MEMCG_NMI_NEED_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 @@ -2741,7 +2758,7 @@ 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); @@ -2769,7 +2786,7 @@ 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