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Thu, 28 Mar 2024 09:21:36 -0700 (PDT) Received: from localhost ([2620:10d:c090:400::5:4d4e]) by smtp.gmail.com with ESMTPSA id fd37-20020a056a002ea500b006eab6ac1f83sm1576815pfb.0.2024.03.28.09.21.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Mar 2024 09:21:35 -0700 (PDT) Date: Thu, 28 Mar 2024 06:21:34 -1000 From: Tejun Heo To: Ulf Hansson Cc: Allen Pais , linux-kernel@vger.kernel.org, keescook@chromium.org, vkoul@kernel.org, marcan@marcan.st, sven@svenpeter.dev, florian.fainelli@broadcom.com, rjui@broadcom.com, sbranden@broadcom.com, paul@crapouillou.net, Eugeniy.Paltsev@synopsys.com, manivannan.sadhasivam@linaro.org, vireshk@kernel.org, Frank.Li@nxp.com, leoyang.li@nxp.com, zw@zh-kernel.org, wangzhou1@hisilicon.com, haijie1@huawei.com, shawnguo@kernel.org, s.hauer@pengutronix.de, sean.wang@mediatek.com, matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com, afaerber@suse.de, logang@deltatee.com, daniel@zonque.org, haojian.zhuang@gmail.com, robert.jarzmik@free.fr, andersson@kernel.org, konrad.dybcio@linaro.org, orsonzhai@gmail.com, baolin.wang@linux.alibaba.com, zhang.lyra@gmail.com, patrice.chotard@foss.st.com, linus.walleij@linaro.org, wens@csie.org, jernej.skrabec@gmail.com, peter.ujfalusi@gmail.com, kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, jassisinghbrar@gmail.com, mchehab@kernel.org, maintainers@bluecherrydvr.com, aubin.constans@microchip.com, manuel.lauss@gmail.com, mirq-linux@rere.qmqm.pl, jh80.chung@samsung.com, oakad@yahoo.com, hayashi.kunihiko@socionext.com, mhiramat@kernel.org, brucechang@via.com.tw, HaraldWelte@viatech.com, pierre@ossman.eu, duncan.sands@free.fr, stern@rowland.harvard.edu, oneukum@suse.com, openipmi-developer@lists.sourceforge.net, dmaengine@vger.kernel.org, asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, linux-mips@vger.kernel.org, imx@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-mediatek@lists.infradead.org, linux-actions@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-riscv@lists.infradead.org, linux-sunxi@lists.linux.dev, linux-tegra@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, linux-mmc@vger.kernel.org, linux-omap@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-usb@vger.kernel.org Subject: Re: [PATCH 9/9] mmc: Convert from tasklet to BH workqueue Message-ID: References: <20240327160314.9982-1-apais@linux.microsoft.com> <20240327160314.9982-10-apais@linux.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240328_092137_830801_AD3E69B7 X-CRM114-Status: GOOD ( 10.13 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org Hello, On Thu, Mar 28, 2024 at 01:53:25PM +0100, Ulf Hansson wrote: > At this point we have suggested to drivers to switch to use threaded > irq handlers (and regular work queues if needed too). That said, > what's the benefit of using the BH work queue? BH workqueues should behave about the same as tasklets which have more limited interface and is subtly broken in an expensive-to-fix way (around freeing in-flight work item), so the plan is to replace tasklets with BH workqueues and remove tasklets from the kernel. The [dis]advantages of BH workqueues over threaded IRQs or regular threaded workqueues are the same as when you compare them to tasklets. No thread switching overhead, so latencies will be a bit tighter. Wheteher that actually matters really depends on the use case. Here, the biggest advantage is that it's mostly interchangeable with tasklets and can thus be swapped easily. Thanks. -- tejun