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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B8B5C433F5 for ; Wed, 27 Apr 2022 16:00:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241370AbiD0QDj (ORCPT ); Wed, 27 Apr 2022 12:03:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241571AbiD0QDX (ORCPT ); Wed, 27 Apr 2022 12:03:23 -0400 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 44635170E33; Wed, 27 Apr 2022 08:59:35 -0700 (PDT) Received: from smtpclient.apple (d66-183-91-182.bchsia.telus.net [66.183.91.182]) by linux.microsoft.com (Postfix) with ESMTPSA id 6DA7720E97CA; Wed, 27 Apr 2022 08:58:53 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 6DA7720E97CA DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1651075134; bh=LOLk8KFWAb5rXU/Jm0ZFnROrkWq5xdzno1Ze707Mg8Q=; h=Subject:From:In-Reply-To:Date:Cc:References:To:From; b=lCin7lh3eOWoC8NOgWTsOU0C03Zh/WxRxATeRAsLc9arDLmXdbC8Xz3cFZXKGqkcf DfBeM6nu6FeQm0CloG/1lp+Jr4MIPORFywV2OmiQ61fJFZoc5aJpPjVsFbvFPSlF4R uU8SBBkMZMrfVfX7uVGZLvABbGZFb3L5JMNn+Qfs= Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.80.82.1.1\)) Subject: Re: [RFC 1/1] drivers/dma/*: replace tasklets with workqueue From: Allen Pais In-Reply-To: Date: Wed, 27 Apr 2022 08:58:52 -0700 Cc: Vinod Koul , olivier.dautricourt@orolia.com, sr@denx.de, Kees Cook , linux-hardening@vger.kernel.org, ludovic.desroches@microchip.com, tudor.ambarus@microchip.com, f.fainelli@gmail.com, rjui@broadcom.com, sbranden@broadcom.com, bcm-kernel-feedback-list@broadcom.com, nsaenz@kernel.org, paul@crapouillou.net, Eugeniy.Paltsev@synopsys.com, gustavo.pimentel@synopsys.com, vireshk@kernel.org, andriy.shevchenko@linux.intel.com, leoyang.li@nxp.com, zw@zh-kernel.org, wangzhou1@hisilicon.com, shawnguo@kernel.org, s.hauer@pengutronix.de, sean.wang@mediatek.com, matthias.bgg@gmail.com, afaerber@suse.de, mani@kernel.org, logang@deltatee.com, sanju.mehta@amd.com, daniel@zonque.org, haojian.zhuang@gmail.com, robert.jarzmik@free.fr, agross@kernel.org, bjorn.andersson@linaro.org, krzysztof.kozlowski@linaro.org, green.wan@sifive.com, orsonzhai@gmail.com, baolin.wang7@gmail.com, zhang.lyra@gmail.com, patrice.chotard@foss.st.com, linus.walleij@linaro.org, wens@csie.org, jernej.skrabec@gmail.com, samuel@sholland.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: <27B51CB8-FCC0-49FB-AA28-93594943423E@linux.microsoft.com> References: <20220419211658.11403-1-apais@linux.microsoft.com> <20220419211658.11403-2-apais@linux.microsoft.com> To: Dave Jiang X-Mailer: Apple Mail (2.3696.80.82.1.1) Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org >> On 19-04-22, 21:16, Allen Pais wrote: >>> The tasklet is an old API which will be deprecated, workqueue API >>> cab be used instead of them. >> What is the reason for tasklet removal, I am not sure old is a reason = to >> remove an API... >>=20 >>> This patch replaces the tasklet usage in drivers/dma/* with a >>> simple work. >> Dmaengines need very high throughput, one of the reasons in dmaengine >> API design to use tasklet was higher priority given to them. Will the >> workqueue allow that...? >=20 > Wouldn't the logical move be to convert threaded irq IF tasklets are = being deprecated rather than using workqueue as replacement? Logically yes. Would all tasklets need to be moved to threaded irq, = that I am not sure. I think Workqueues does the job. >=20 > Also, wouldn't all the spin_lock_bh() calls need to be changed to = spin_lock_irqsave() now? Probably not as simple as just replace tasklet = with workqueue. >=20 Yes, this was carefully looked at as we have moved from the = interrupt/softirq context to process context. Thanks.