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[141.239.149.160]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-70803ecf9d0sm6802977b3a.115.2024.07.01.10.19.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Jul 2024 10:19:08 -0700 (PDT) Sender: Tejun Heo Date: Mon, 1 Jul 2024 07:19:06 -1000 From: Tejun Heo To: Xiu Jianfeng Cc: lizefan.x@bytedance.com, hannes@cmpxchg.org, corbet@lwn.net, kamalesh.babulal@oracle.com, haitao.huang@linux.intel.com, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH -next] cgroup/misc: Introduce misc.peak Message-ID: References: <20240701125259.2611466-1-xiujianfeng@huawei.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240701125259.2611466-1-xiujianfeng@huawei.com> On Mon, Jul 01, 2024 at 12:52:59PM +0000, Xiu Jianfeng wrote: > + if (new_usage > READ_ONCE(res->watermark)) > + WRITE_ONCE(res->watermark, new_usage); It'd be better to do cmpxchg loop on update. That doesn't make it noticeably more expensive and the peak tracking would actually be accurate. Thanks. -- tejun