From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-182.mta1.migadu.com (out-182.mta1.migadu.com [95.215.58.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 282A81A5B95 for ; Fri, 16 May 2025 06:49:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747378200; cv=none; b=YEgFD84HsNlBxGv73ZoJ18NQDfmIGx+MyL7OyjzOkttVlgi62CdH5Ef0F/9LW58GLd1+gP/nkpo4lTSWeA+Egs6nzSTwwnqg9fAJQxoCu5i7dS1wXICVsMQiboF2LuTRcavH1OlAhxxcjN5srQqpuCaChmCbetG5VyhowZ4LXYo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747378200; c=relaxed/simple; bh=/T3ZsKT8VNYbD3xOoG59SO/PpCy0LoJnigPxVN5Air4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gQccbAEItCkd9F6p8S5qUczZDltq0qzedjGV4Ow6CwcYI4p2OPSuFUB5Ryg7HGlkEh/ju+n8ZupZDXmgS+1WxJIz0WdIttH8feClNUZd5gOx2GPgo6b4cOGYiubeva1HujCQYtII8xydpBDz1SWApo3Xsv0yzwP4cTtPcKigyg0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=eUrZE+qT; arc=none smtp.client-ip=95.215.58.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="eUrZE+qT" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. 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> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 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