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 6489DC433EF for ; Thu, 7 Jul 2022 15:05:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230262AbiGGPFh (ORCPT ); Thu, 7 Jul 2022 11:05:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34986 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229926AbiGGPFf (ORCPT ); Thu, 7 Jul 2022 11:05:35 -0400 Received: from mail-pg1-x52f.google.com (mail-pg1-x52f.google.com [IPv6:2607:f8b0:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7BEC326AC3 for ; Thu, 7 Jul 2022 08:05:34 -0700 (PDT) Received: by mail-pg1-x52f.google.com with SMTP id 145so19006072pga.12 for ; Thu, 07 Jul 2022 08:05:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=Le4AocDuW7VdQISs6Wd4Al83WpJ581AYhtnychAKbhI=; b=GdY1GcMwpWH+ETieCrzFKA7KDi5SkWAc/vhSYHQTIaUfYCto4lOdplCE/XYwm3PBfP IdDgsYubOWdtH7e/jae2R7LqSISla4wuA7X21LfHa0wrrIS/tKCiYmfWV5r6S97FO4sW IVTJf18uefSG/mLQHHL1v6LgMR9U9YPdajkI9YlD9rpJ9Gi5bplVPO/0wZBGLNpSafSP o5iL4rDHEcvWjVdRXZLMoJtL5OrSaVPC3tAm8GT/ITGxL/wUHeEhSl3/4HuFu4EtWA/8 5MKUmUUk7VTHqjlHvwkQmUVEMcohIac8sfZnVflInFZ+HiPUWfJInfJlzuazSbfurPPP RYlg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=Le4AocDuW7VdQISs6Wd4Al83WpJ581AYhtnychAKbhI=; b=Yz5Ql7FVt0n/Gvb8/70TcxA52gLVmdpIMBjCL5js2AxjLuOVQdwu4ejIw4NC+LtJyJ xzdwsnxFDtD2/ATnyjM4sDikrouaCrC4YSv4BSQ7OVBjOhhcodReq0xta1iAXnol5dAn QIM2A4lzEh+VmSEUeF3uPLk8LRt5wqygcd8ax4GKIrNKLgbBzBOPdyDBXLsbHXM68SiS 7n06KqC4qiq51IIea4g6nJ6ikXCZMaF8dv+TgFNjiuN+soI+ILduN/oHFVYYA+4Cck1M CI9zAR2Da0/m6jC9p8wc/NRgsqx+xX/rMXOxVE2aj5ImL0oEK4+IvDhnuh/kciAEZuMS ly2A== X-Gm-Message-State: AJIora8h3v+n2f6IJvy30oHeVHmloqihAJO1aL2LlHBb0qOk9kz+U2Ho UK1RDQnW95Rb5FyNrDeJwcNR1w== X-Google-Smtp-Source: AGRyM1uY0mRO9OJRzfDP0AUAxaAAfJF9CNs/HhFSvvf5KV2IjYdHVA9LDJIgzZhiRel4jJkoDKpQCA== X-Received: by 2002:a17:90a:6383:b0:1ef:c181:3777 with SMTP id f3-20020a17090a638300b001efc1813777mr5821829pjj.50.1657206333976; Thu, 07 Jul 2022 08:05:33 -0700 (PDT) Received: from [10.4.255.21] ([139.177.225.235]) by smtp.gmail.com with ESMTPSA id h17-20020a170902f7d100b0016be6a554b5sm8718761plw.233.2022.07.07.08.05.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 07 Jul 2022 08:05:30 -0700 (PDT) Message-ID: Date: Thu, 7 Jul 2022 23:05:21 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.0 Subject: Re: [RFC PATCH 1/2] arm64: run softirqs on the per-CPU IRQ stack Content-Language: en-US To: Arnd Bergmann Cc: Catalin Marinas , Will Deacon , Linux ARM , Linux Kernel Mailing List , Sebastian Andrzej Siewior References: <20220707110511.52129-1-zhengqi.arch@bytedance.com> <20220707110511.52129-2-zhengqi.arch@bytedance.com> <6802d78e-5aeb-6115-a4ec-73be78ccc577@bytedance.com> From: Qi Zheng In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/7/7 21:53, Arnd Bergmann wrote: > On Thu, Jul 7, 2022 at 3:43 PM Qi Zheng wrote: >> On 2022/7/7 20:58, Arnd Bergmann wrote: >>> On Thu, Jul 7, 2022 at 1:05 PM Qi Zheng wrote: >>> Are there any architectures left that use IRQ stacks but don't >>> set HAVE_SOFTIRQ_ON_OWN_STACK? If not, we could >>> also consider removing the Kconfig symbol and just requiring >>> it to be done this way (for non-PREEMPT_RT). >> >> I haven't taken a close look at other architectures than x86 and arm, >> but I think it's a good idea. > > I had another look in the meantime, and I think it's only mips and loongarch > now that don't use HAVE_SOFTIRQ_ON_OWN_STACK. Not sure about > arch/um/, which is a bit different from the rest. I just glanced at arch/um/, and it's really different from the rest: * Unlike i386, UML doesn't receive IRQs on the normal kernel stack * and switch over to the IRQ stack after some preparation. > > Arnd -- Thanks, Qi