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 950F4C433F5 for ; Wed, 25 May 2022 17:49:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242275AbiEYRs7 convert rfc822-to-8bit (ORCPT ); Wed, 25 May 2022 13:48:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52714 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245754AbiEYRs6 (ORCPT ); Wed, 25 May 2022 13:48:58 -0400 Received: from mout.kundenserver.de (mout.kundenserver.de [217.72.192.74]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CED4743EDE; Wed, 25 May 2022 10:48:56 -0700 (PDT) Received: from mail-yb1-f171.google.com ([209.85.219.171]) by mrelayeu.kundenserver.de (mreue107 [213.165.67.113]) with ESMTPSA (Nemesis) id 1M2fM1-1nqKtN3I7j-004Dtu; Wed, 25 May 2022 19:48:55 +0200 Received: by mail-yb1-f171.google.com with SMTP id x2so37194248ybi.8; Wed, 25 May 2022 10:48:54 -0700 (PDT) X-Gm-Message-State: AOAM532z4B2YsGkU8NqMTxoEHFwQiwnHVwNZYXi3Ob308zaQ5j+FnF0w jni83HTZDNvGbs4RAq2ICINuaLpPa14NdBma8vI= X-Google-Smtp-Source: ABdhPJzuiHSmZ8nVYKAXx5dLxFxpNAHZXgLqBiamodT4boGdrCuJxzCCcnQVNo+mB/7OjTNGg0DOAvLa5X1IWqszNVY= X-Received: by 2002:a25:31c2:0:b0:641:660f:230f with SMTP id x185-20020a2531c2000000b00641660f230fmr32038430ybx.472.1653500933346; Wed, 25 May 2022 10:48:53 -0700 (PDT) MIME-Version: 1.0 References: <20220419211658.11403-1-apais@linux.microsoft.com> <20220419211658.11403-2-apais@linux.microsoft.com> <9947cfa64667406996de191f07b9e8b9@AcuMS.aculab.com> <6E248F41-6687-4F2B-B847-DB5459BA1344@linux.microsoft.com> In-Reply-To: <6E248F41-6687-4F2B-B847-DB5459BA1344@linux.microsoft.com> From: Arnd Bergmann Date: Wed, 25 May 2022 19:48:36 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC 1/1] drivers/dma/*: replace tasklets with workqueue To: Allen Pais Cc: David Laight , Arnd Bergmann , Linus Walleij , Vincent Guittot , "olivier.dautricourt@orolia.com" , Stefan Roese , Vinod Koul , Kees Cook , "linux-hardening@vger.kernel.org" , Ludovic Desroches , Tudor Ambarus , Florian Fainelli , Ray Jui , Scott Branden , bcm-kernel-feedback-list , Nicolas Saenz Julienne , Paul Cercueil , "Eugeniy.Paltsev@synopsys.com" , Gustavo Pimentel , Viresh Kumar , Andy Shevchenko , Leo Li , "zw@zh-kernel.org" , Zhou Wang , Shawn Guo , Sascha Hauer , Sean Wang , Matthias Brugger , =?UTF-8?Q?Andreas_F=C3=A4rber?= , Manivannan Sadhasivam , Logan Gunthorpe , Sanjay R Mehta , Daniel Mack , Haojian Zhuang , Robert Jarzmik , Andy Gross , Bjorn Andersson , Krzysztof Kozlowski , "green.wan@sifive.com" , Orson Zhai , Baolin Wang , Lyra Zhang , Patrice CHOTARD , Chen-Yu Tsai , =?UTF-8?Q?Jernej_=C5=A0krabec?= , Samuel Holland , "dmaengine@vger.kernel.org" , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Provags-ID: V03:K1:0oNKE+aYHXzvIhZnI05JLdbh19bMeWgQr7g/ZSVtzRDQ0Xy/8ho UrKFc8cz+xgeYHXnF1gl1iiybnsWi0QqL/iQBfx7lhklR1sawXLchnDW+IMAnSffs4gBf3o Uo6FCKD5LxF3o9guwwJ2lgZrkJMQcw2+hD/Y+EpCyymeLzupaaEdOmH2B/q7mf6ixsOsmtA +vD8UYwxw9lqQe/GqUIKg== X-UI-Out-Filterresults: notjunk:1;V03:K0:rmvH/JoWJlA=:kUTYk+HrtMJMhbxax9LfL4 R4J+6jT3qQGVQRXv8YhKYIFA/pIfPn80fhaxobBKSKJtsCyunsNESdo+P0plc0e8Yp7zmctTf QY3xVFRPOAb6jL09p5vOxZAMF0gXsm/Pg+Y5tfhn0lHvWDgLAtMcW2Gc4RvAKrtaaoNaZQ2wq Sm0O+NSbO/uEfjRsBM06JxeFWehWXRylGD7MGF6+9OJDxg94C548F2F9EcVsO+yaPwEpdwa73 S/C99mW0h9Slaa/aDosOhWFBX/G1WpHuvV4Pg5jRe08UOmgC9eI6bf/ryE164p5SFtlU/hnIX VwCP85wPNyMArDO50QYOsZR/wyU8jIOhoLkCys0VVNkVmMOBiRL3Um0aVs2vzAuj5JxLlvHJo NxVbkdp1kcv2wy1niWJrMLX0E8otYhhpXmo3DD2LV+8vjK8hlV7dCkCHQi2ByOk3dD2c/RaK7 XinJkm61E5JNPpBs1lKmpaCEUfX6dVsoRLia3KSpMMtyEZkXH+uKmST7ywyxVtngIOHT3YLvo 26PWqxyzPGlGqhhtG/XpmG1nXNE5HoD/rNSkRZF0Ibd+yCyR93rcBbtuqF43iMsG1a366LMAd qRlyY66mmhdXvd2h2dWuj8kgDaUmyC3VjVJac6QaOL61MzSCSpD1KPvVeIz6+xKE6ma35O6z1 iTUGHkNIxw8TanpGDxbv6RwPyopwX0Rp6EsAwybTRgqWUOZyF5W9RWmfzpsDjeynB9NEyrmVz 8Ir77Lg3Hh0oArE/epwry+GI3bDWl4rFtGzm4uNy7NQbwgxr5wcnd1+RNgkBO4ZMcNgq7HOTx Gp/a84DbgEMF/TRGogdido+ObB6tSesdcyYLUBa4VW+lGUtvtjGqLBAmLoAW9lPdLXhgPho+Z v4rP1Jf+ynDUBxrD5BRQ== Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On Wed, May 25, 2022 at 6:56 PM Allen Pais wrote: > > Thank you Linus, Arnd, Vincent and David for the feedback. > > This is a lot more than a just conversion of API’s. I am in the process > Of replacing tasklets with threaded irq’s and hopefully that should be > A better solution than using workqueues. I don't think that is much better for the case of the DMA engine callbacks than the work queue, the problem I pointed out here is scheduling into task context, which may be too expensive in some cases, but whether it is or not depends on the slave driver, not the dmaengine driver. Even if all the slave drivers are better off using task context (threaded irq or workqueue), you need to look at the slave drivers first before you can convert the dmaengine drivers. Arnd