From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 34D7B84A52; Tue, 2 Apr 2024 13:11:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712063487; cv=none; b=Ab+4DOG88HjoOiv4xBM47NxBmgiUFTY3Hy9u7A04HCzOSu5NaXU36utXhJrr9XqYteA58Vepp88PWfxm6gwz+AkPWWY6MSEYgos95d9h2owMCb5CDLtcG02ywQd3NJT2J8z8KmBjuZNtjiGNR8lguydLm74MZtOuQ/1o9cukWos= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712063487; c=relaxed/simple; bh=9zAsnZKUtdaB+0oUBoSFWoiBkfOWRDSb/L5GPa9FOno=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YxBMH/vw9BRleuY+Tgiarjh9bwd72GPxFeu0mmPcJREbnWAJBZN/yKpfG4Kaaw+TbuiZXI9i0CP5GUV3A+mByQFFdOpijlcJdW5RjXrn4OVvBEWp4ZFd+dDZ7/Uk5W0BYB24fbqwaTmKHhiEhGZq2SnC/vrbfUdgjDel2Xq/w7M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pLBmLWbF; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="pLBmLWbF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ECE50C433F1; Tue, 2 Apr 2024 13:11:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712063486; bh=9zAsnZKUtdaB+0oUBoSFWoiBkfOWRDSb/L5GPa9FOno=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pLBmLWbFq8b7R4iZ1CSvRnROpQc318dtdynLw3zTplx/2SSnxsPhnBaGB0KWLxJLw gtTVGsvy4tfXtBGJpBXwq9+p3MCPwkvK/hDkMvCwjFUh5usnZu6XFTibfhvcKn+2H6 bNq+gdNLc+F4UpxqMWgGKmEwi+KPVyCSJwAIqsT2U4GGmN/LnMTaAplp/AjMnXlBu3 Ft/ordeAQQOyjQYy8NAB2+7Nq/5pKWCsboYnCGnNR1VKTyBFWEf/lcch7254rsWnWE MLVvNT3x0cyP38rdvhtkwlombEcbUi6JLHcn3CjFq0MSnQTG+8Cf+UPPNEYFD7jwHP CjyG1mwKRgoUQ== Date: Tue, 2 Apr 2024 18:41:22 +0530 From: Vinod Koul To: Linus Walleij Cc: Allen Pais , linux-kernel@vger.kernel.org, tj@kernel.org, keescook@chromium.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, 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, ulf.hansson@linaro.org, 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 2/9] dma: Convert from tasklet to BH workqueue Message-ID: References: <20240327160314.9982-1-apais@linux.microsoft.com> <20240327160314.9982-3-apais@linux.microsoft.com> Precedence: bulk X-Mailing-List: asahi@lists.linux.dev 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: On 02-04-24, 14:25, Linus Walleij wrote: > Hi Allen, > > thanks for your patch! > > On Wed, Mar 27, 2024 at 5:03 PM Allen Pais wrote: > > > The only generic interface to execute asynchronously in the BH context is > > tasklet; however, it's marked deprecated and has some design flaws. To > > replace tasklets, BH workqueue support was recently added. A BH workqueue > > behaves similarly to regular workqueues except that the queued work items > > are executed in the BH context. > > > > This patch converts drivers/dma/* from tasklet to BH workqueue. > > > > Based on the work done by Tejun Heo > > Branch: git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-6.10 > > > > Signed-off-by: Allen Pais > (...) > > diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c > (...) > > if (d40c->pending_tx) > > - tasklet_schedule(&d40c->tasklet); > > + queue_work(system_bh_wq, &d40c->work); > > Why is "my" driver not allowed to use system_bh_highpri_wq? > > I can't see the reasoning between some drivers using system_bh_wq > and others being highpri? > > Given the DMA usecase I would expect them all to be high prio. It didnt use tasklet_hi_schedule(), I guess Allen has done the conversion of tasklet_schedule -> system_bh_wq and tasklet_hi_schedule -> system_bh_highpri_wq Anyway, we are going to use a dma queue so should be better performance -- ~Vinod From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 86EBECD1284 for ; Tue, 2 Apr 2024 13:11:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; 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Tue, 2 Apr 2024 13:11:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712063486; bh=9zAsnZKUtdaB+0oUBoSFWoiBkfOWRDSb/L5GPa9FOno=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pLBmLWbFq8b7R4iZ1CSvRnROpQc318dtdynLw3zTplx/2SSnxsPhnBaGB0KWLxJLw gtTVGsvy4tfXtBGJpBXwq9+p3MCPwkvK/hDkMvCwjFUh5usnZu6XFTibfhvcKn+2H6 bNq+gdNLc+F4UpxqMWgGKmEwi+KPVyCSJwAIqsT2U4GGmN/LnMTaAplp/AjMnXlBu3 Ft/ordeAQQOyjQYy8NAB2+7Nq/5pKWCsboYnCGnNR1VKTyBFWEf/lcch7254rsWnWE MLVvNT3x0cyP38rdvhtkwlombEcbUi6JLHcn3CjFq0MSnQTG+8Cf+UPPNEYFD7jwHP CjyG1mwKRgoUQ== Date: Tue, 2 Apr 2024 18:41:22 +0530 From: Vinod Koul To: Linus Walleij Cc: Allen Pais , linux-kernel@vger.kernel.org, tj@kernel.org, keescook@chromium.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, 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, ulf.hansson@linaro.org, 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 2/9] dma: Convert from tasklet to BH workqueue Message-ID: References: <20240327160314.9982-1-apais@linux.microsoft.com> <20240327160314.9982-3-apais@linux.microsoft.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240402_061136_004961_9C8FDAE9 X-CRM114-Status: GOOD ( 17.64 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; 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charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Mailman-Approved-At: Wed, 03 Apr 2024 07:17:02 +1100 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: imx@lists.linux.dev, ulf.hansson@linaro.org, oneukum@suse.com, duncan.sands@free.fr, hayashi.kunihiko@socionext.com, linux-mmc@vger.kernel.org, aubin.constans@microchip.com, Frank.Li@nxp.com, linux-hyperv@vger.kernel.org, linux-mips@vger.kernel.org, paul@crapouillou.net, linux-tegra@vger.kernel.org, netdev@vger.kernel.org, maintainers@bluecherrydvr.com, peter.ujfalusi@gmail.com, manivannan.sadhasivam@linaro.org, linux-riscv@lists.infradead.org, kys@microsoft.com, robert.jarzmik@free.fr, haijie1@huawei.com, linux-renesas-soc@vger.kernel.org, wei.liu@kernel.org, linux-omap@vger.kernel.org, florian.fainelli@broadcom.com, linux-rdma@vger.kernel.org, vireshk@kernel.org, jassisinghbrar@gmail.com, decui@microsoft.com, HaraldWelte@viatech.com, jernej.skrabec@gmail.com, jh80.chung@samsung.com, zw@zh-kernel.org, wens@csie.org, stern@rowland.harvard.edu, linux-arm-msm@vger.kernel.org, orsonzhai@gmail.com, pierre@ossman.eu, linux-usb@vger.kernel.org, Eugeniy.Paltsev@synopsys.com, patrice.cho tard@foss.st.com, asahi@lists.linux.dev, brucechang@via.com.tw, keescook@chromium.org, oakad@yahoo.com, sven@svenpeter.dev, rjui@broadcom.com, s.hauer@pengutronix.de, sean.wang@mediatek.com, linux-actions@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, haojian.zhuang@gmail.com, mirq-linux@rere.qmqm.pl, dmaengine@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, baolin.wang@linux.alibaba.com, matthias.bgg@gmail.com, openipmi-developer@lists.sourceforge.net, mchehab@kernel.org, Allen Pais , linux-arm-kernel@lists.infradead.org, angelogioacchino.delregno@collabora.com, sbranden@broadcom.com, logang@deltatee.com, andersson@kernel.org, marcan@marcan.st, haiyangz@microsoft.com, linux-kernel@vger.kernel.org, leoyang.li@nxp.com, konrad.dybcio@linaro.org, linux-sunxi@lists.linux.dev, wangzhou1@hisilicon.com, linux-s390@vger.kernel.org, mhiramat@kernel.org, zhang.lyra@gmail.com, tj@kernel.org, manuel.lauss@gmail.com, linu x-media@vger.kernel.org, shawnguo@kernel.org, afaerber@suse.de, daniel@zonque.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 02-04-24, 14:25, Linus Walleij wrote: > Hi Allen, > > thanks for your patch! > > On Wed, Mar 27, 2024 at 5:03 PM Allen Pais wrote: > > > The only generic interface to execute asynchronously in the BH context is > > tasklet; however, it's marked deprecated and has some design flaws. To > > replace tasklets, BH workqueue support was recently added. A BH workqueue > > behaves similarly to regular workqueues except that the queued work items > > are executed in the BH context. > > > > This patch converts drivers/dma/* from tasklet to BH workqueue. > > > > Based on the work done by Tejun Heo > > Branch: git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-6.10 > > > > Signed-off-by: Allen Pais > (...) > > diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c > (...) > > if (d40c->pending_tx) > > - tasklet_schedule(&d40c->tasklet); > > + queue_work(system_bh_wq, &d40c->work); > > Why is "my" driver not allowed to use system_bh_highpri_wq? > > I can't see the reasoning between some drivers using system_bh_wq > and others being highpri? > > Given the DMA usecase I would expect them all to be high prio. It didnt use tasklet_hi_schedule(), I guess Allen has done the conversion of tasklet_schedule -> system_bh_wq and tasklet_hi_schedule -> system_bh_highpri_wq Anyway, we are going to use a dma queue so should be better performance -- ~Vinod