From patchwork Thu Nov 30 19:40:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nhat Pham X-Patchwork-Id: 749945 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YmkUr7hK" Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B73493; Thu, 30 Nov 2023 11:40:26 -0800 (PST) Received: by mail-pf1-x42b.google.com with SMTP id d2e1a72fcca58-6cde4aeea29so1115887b3a.2; Thu, 30 Nov 2023 11:40:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1701373226; x=1701978026; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=wu5h2uK3efWNzQSn40V3SLhhxDZPSFSFXXaEbLeDNVU=; b=YmkUr7hK8s3vKG4KyUdq9tGqrt46SJDxlPgYzC+2ms5s2fZF9FWemm9CzMAtnpLXoj mSwp9VE+vdUXycehX5skKznJpO4laRlGBOqbinPTZsvLNUFu1yZc8wF8kAyk9Bq1yZrQ TTxItInlzYR8UYV+FX+RC9ocTSt0pFzhotTI8ZS83uyATDdcGciJf0AdBHshk/IVqltY OqbE2S87hUTyTkc5Rhldg47vOrr+wC0geKef0VY2nL0d8hLTGR2y3HeCJ3RcZliugPPt 9hXbqRZGekh90PpyRYLwNk2Z/kHzUq+ocpF5wshETJXuxACdGRkb0S6f0mSZdQPWyw6Z yCtg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701373226; x=1701978026; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=wu5h2uK3efWNzQSn40V3SLhhxDZPSFSFXXaEbLeDNVU=; b=mar4BOaKoN/HTjRRQqjI1q+81QdsCvVk1FBWDZ/vx0ue44OxKyiVDgZFA/3A6YtwcR 4XxV+X+2hn2xijht/8psoHN5XGSwAq6WI6OGUomBOydGG5JKxG3nwXTMMC0VE5JHX7r/ sr0UcCq41U1xCbfR0r/qJGB4NPKDYEThSsGlSmOLJkQrjCxH4MOkScMXKhvhsuekEYEW NWece3HhA66MOj/ggmeNa+D6z1hOOmUUnXChxffhFJz3DCe50F2fnL/4eHh7aySgvj0p eJ5/MpsXEut7I2IMaD7w0IVAJ+V0moXsr1nkSbpqBizCifombBiKxX4wmd74+xPoxIsh cDYw== X-Gm-Message-State: AOJu0Yz0QLF0WL7Zu7dAkpB20JT6LBAmULUUCoiIX3eseay2p5oNP1LR q+4b0Hq/cSAJVk5DldG3od0= X-Google-Smtp-Source: AGHT+IHAYv2QywW+kJu67uQmw9fkTUq5k9I3OqO0/TQg0O7WFleUTQj+azK6qIpJqRZiFpj/7FBacg== X-Received: by 2002:a05:6a00:1894:b0:6cd:eb43:f1cd with SMTP id x20-20020a056a00189400b006cdeb43f1cdmr2816622pfh.9.1701373225625; Thu, 30 Nov 2023 11:40:25 -0800 (PST) Received: from localhost (fwdproxy-prn-005.fbsv.net. [2a03:2880:ff:5::face:b00c]) by smtp.gmail.com with ESMTPSA id g2-20020aa78742000000b006cda62f118bsm1593501pfo.60.2023.11.30.11.40.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Nov 2023 11:40:25 -0800 (PST) From: Nhat Pham To: akpm@linux-foundation.org Cc: hannes@cmpxchg.org, cerasuolodomenico@gmail.com, yosryahmed@google.com, sjenning@redhat.com, ddstreet@ieee.org, vitaly.wool@konsulko.com, mhocko@kernel.org, roman.gushchin@linux.dev, shakeelb@google.com, muchun.song@linux.dev, chrisl@kernel.org, linux-mm@kvack.org, kernel-team@meta.com, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, shuah@kernel.org Subject: [PATCH v8 2/6] memcontrol: implement mem_cgroup_tryget_online() Date: Thu, 30 Nov 2023 11:40:19 -0800 Message-Id: <20231130194023.4102148-3-nphamcs@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231130194023.4102148-1-nphamcs@gmail.com> References: <20231130194023.4102148-1-nphamcs@gmail.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This patch implements a helper function that try to get a reference to an memcg's css, as well as checking if it is online. This new function is almost exactly the same as the existing mem_cgroup_tryget(), except for the onlineness check. In the !CONFIG_MEMCG case, it always returns true, analogous to mem_cgroup_tryget(). This is useful for e.g to the new zswap writeback scheme, where we need to select the next online memcg as a candidate for the global limit reclaim. Signed-off-by: Nhat Pham Reviewed-by: Yosry Ahmed --- include/linux/memcontrol.h | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 7bdcf3020d7a..2bd7d14ace78 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -821,6 +821,11 @@ static inline bool mem_cgroup_tryget(struct mem_cgroup *memcg) return !memcg || css_tryget(&memcg->css); } +static inline bool mem_cgroup_tryget_online(struct mem_cgroup *memcg) +{ + return !memcg || css_tryget_online(&memcg->css); +} + static inline void mem_cgroup_put(struct mem_cgroup *memcg) { if (memcg) @@ -1349,6 +1354,11 @@ static inline bool mem_cgroup_tryget(struct mem_cgroup *memcg) return true; } +static inline bool mem_cgroup_tryget_online(struct mem_cgroup *memcg) +{ + return true; +} + static inline void mem_cgroup_put(struct mem_cgroup *memcg) { }