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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 C4B5EC6FD1F for ; Tue, 2 Apr 2024 20:20:27 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=pLBmLWbF; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4V8K4p26WZz3c9y for ; Wed, 3 Apr 2024 07:20:26 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=pLBmLWbF; 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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 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-Type: text/plain; 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