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[141.239.149.160]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2cacd6da7b4sm6688202a91.46.2024.07.15.10.21.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Jul 2024 10:21:27 -0700 (PDT) Sender: Tejun Heo Date: Mon, 15 Jul 2024 07:21:26 -1000 From: "tj@kernel.org" To: Boy Wu =?utf-8?B?KOWQs+WLg+iqvCk=?= Cc: "linux-kernel@vger.kernel.org" , "boris@bur.io" , "linux-block@vger.kernel.org" , "linux-mediatek@lists.infradead.org" , "cgroups@vger.kernel.org" , "axboe@kernel.dk" , Iverlin Wang =?utf-8?B?KOeOi+iLs+mclik=?= , "josef@toxicpanda.com" , "linux-arm-kernel@lists.infradead.org" , "matthias.bgg@gmail.com" , "angelogioacchino.delregno@collabora.com" Subject: Re: [PATCH v2] blk-cgroup: Replace u64_sync with blkg_stat_lock for stats update Message-ID: References: <20240710061334.1888-1-boy.wu@mediatek.com> <6114fbad7bce9b15806bb9fee25a1075ecb53dd1.camel@mediatek.com> <70c37035f006de3a4fde895ceeee92826cd280e0.camel@mediatek.com> <5a1e1bd5168696a0857b62572336c5e598cb5493.camel@mediatek.com> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5a1e1bd5168696a0857b62572336c5e598cb5493.camel@mediatek.com> Hello, On Mon, Jul 15, 2024 at 07:15:24AM +0000, Boy Wu (吳勃誼) wrote: > I think I get your idea. You want to replace all the u64 sync for > iostat. However, I have one question: why use blkg_stat_lock instead of > adding a spin lock for each iostat like iostat.spinlock? We don't need > to lock between updating different iostats, but only lock when updating > the same iostat. Oh yeah, that'd be even better. Thanks. -- tejun