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 0ED89ECE57A for ; Mon, 9 Sep 2024 13:16:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:References:Cc:To:Subject:MIME-Version:Date: Message-ID:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=R6Cd5fhD8ici5afX6+xiG5utNAqtTvz1M5Dqy2BN2P8=; b=cyCuqY1+yne8NFOP4zUw0TknUZ 0tALr3XnAq/Cju3b9BO/lRjE/QaCLNLPSTK8eVMZN6vHcwq3aRaEjwkIjBfW2bbTu1cu4GWE0f9Mg CxJsWNtk++ZPNrOqbfnfdq1U1u2xrp4+z+he1Yevo8PQz+9toum9vC3ogWISvPavkMSKcSiUgoHoe xEovHQ1ZGRoRJMR0xNvV1DJmscgJB34qktkJc9idl10ClTXjAcmBQOO7cXSHW3BaqSzNdrah5VlF7 edsSH3zQRosKbusonlgfgFNG9i+GWDSIoi7UqAg4Qgpo8oMKx4HWoV13ZQEw3AGoS5yt3ijc35QWj DBLziGzg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sneFJ-000000021Z2-3LAb; Mon, 09 Sep 2024 13:15:57 +0000 Received: from mail-pf1-x443.google.com ([2607:f8b0:4864:20::443]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sneEG-000000021HR-3SzV; Mon, 09 Sep 2024 13:14:54 +0000 Received: by mail-pf1-x443.google.com with SMTP id d2e1a72fcca58-71798a15ce5so2650824b3a.0; Mon, 09 Sep 2024 06:14:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1725887692; x=1726492492; darn=lists.infradead.org; h=content-transfer-encoding:in-reply-to:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:from:to:cc:subject:date:message-id:reply-to; bh=R6Cd5fhD8ici5afX6+xiG5utNAqtTvz1M5Dqy2BN2P8=; b=IInlvcdrbzEeLU+TxWVePQfiawa7r1grXkI0QSMJ37AUAwJDXAiZRmbjooZanlCSVK fgHkEh3+hOfDUIBge9x9LT1jfMOGQBzlVwaSHYlj7wCgWUt/lO1eS6lPFGMeYrzfXDKf 9Ae16lAc82e+9ZgIvoyygzWcjYsfc47sOXu++H7v4YXAancKgrDX/m8YzZZzqhFjts/2 k+yVRqosEUqKZAfNvejF3+lHE+VCmN/s91pvVo2nVSruSDTDUS6o+AogwSECWt1pcu+5 7tfX5p0iQi/hGHX2vNUuoDVV73fX/kRJZSd601ED729djOk5nLV+5I0PimJ4fIqg6pul f5ZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1725887692; x=1726492492; h=content-transfer-encoding:in-reply-to:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=R6Cd5fhD8ici5afX6+xiG5utNAqtTvz1M5Dqy2BN2P8=; b=tHTop5hXn/mTuShZ5Caw5dIto//vnKoi8oPfPnN8iAmIFSgwpYwAOzYOuMoIGxvz7a UsuX3zGLpPQ61bO/DtuZRSNGDlPmvtzmhUpBAL51c6BBD1lQA6Tnwk3aDxpwIgiZif/y SJsS5dRlYcNF1IZemQ0AoruNB1kXwK6906Un8tQENU/ji6byrlT7HH7PuN7vVJRufC7f jTdtdSvfpS8YtI2qooNemgwWIFkf/tSk0vNA9SkOZtweUHmsURM1bUOQhxWAEQqGwkE7 x1e/EQHp17K98TNM26QkbADIeIdIfa4Yz9c25IvFmPrjgx7nmZhlqnHBM64/FDxGYsm8 vrGg== X-Forwarded-Encrypted: i=1; AJvYcCVa2Z2WU/NQm2clxjdxKTxY9Irryt07ieK3iMrO50QD/Ha1mAysWEaMQpnKcezjFT+UZuohtqei9SNMR+/2Iyro6w==@lists.infradead.org, AJvYcCW1aNGuu5wNueiBnhiDF14bL5hy8TNJXbOVjGEkLiBXd5kQst8oC1etanjAQYIxe6wdlnp/TU2f8q8zg/V7i9AS@lists.infradead.org, AJvYcCWTclSWlH5zgLfbWP74wLTJ1/hcpbm27ZTvosVOQgtWFpVgEL/myEojcurg/ex9yEjac/k/Fv16eurHHY8=@lists.infradead.org X-Gm-Message-State: AOJu0YydEOHEgguFKSXEn/tpw/F10ZIokvg2Q/0PiTAEaZV92Ys4piJY OMDJN2M48qv7lgMIzt3fSjoU5Pb/7JG6CTD0N11UHFfzjWHqWer/ X-Google-Smtp-Source: AGHT+IGnhYZgwGNXFcQ7s7STKWrNIO2hqlAK0VnpZ8PE0GryIBXkZ1t9udpbTlWICo5af882CgWSiQ== X-Received: by 2002:a05:6a00:6f0e:b0:712:7512:add9 with SMTP id d2e1a72fcca58-718d560bb37mr13347863b3a.13.1725887691912; Mon, 09 Sep 2024 06:14:51 -0700 (PDT) Received: from [127.0.0.1] ([212.107.28.55]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-718e5897d43sm3496400b3a.28.2024.09.09.06.14.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Sep 2024 06:14:51 -0700 (PDT) From: Celeste Liu X-Google-Original-From: Celeste Liu Message-ID: Date: Mon, 9 Sep 2024 21:14:43 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/4] riscv: defconfig: drop RT_GROUP_SCHED=y Content-Language: en-GB-large To: Conor Dooley Cc: Paul Walmsley , Palmer Dabbelt , Albert Ou , Guo Ren , Anup Patel , Heinrich Schuchardt , Huacai Chen , WANG Xuerui , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , Russell King , Florian Fainelli , Broadcom internal kernel review list , Ray Jui , Scott Branden , Tony Lindgren , Thierry Reding , Jonathan Hunter , Palmer Dabbelt , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-sh@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, linux-omap@vger.kernel.org, linux-tegra@vger.kernel.org References: <20240823-fix-riscv-rt_group_sched-v2-0-e4dbae24f7e1@gmail.com> <20240823-fix-riscv-rt_group_sched-v2-1-e4dbae24f7e1@gmail.com> <20240909-gave-celtic-af2ea8bc38d5@wendy> <9e364ae4-dc2c-4efa-8611-462218402a5d@gmail.com> <20240909-arguable-detection-02445bd1cc89@wendy> In-Reply-To: <20240909-arguable-detection-02445bd1cc89@wendy> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240909_061452_922628_3055E8F2 X-CRM114-Status: GOOD ( 18.78 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2024-09-09 21:06, Conor Dooley wrote: > On Mon, Sep 09, 2024 at 08:14:16PM +0800, Celeste Liu wrote: >> On 2024-09-09 19:53, Conor Dooley wrote: >> >>> On Fri, Aug 23, 2024 at 01:43:26AM +0800, Celeste Liu wrote: >>>> Commit ba6cfef057e1 ("riscv: enable Docker requirements in defconfig") >>>> introduced it because of Docker, but Docker has removed this requirement >>>> since [1] (2023-04-19). >>>> >>>> For cgroup v1, if turned on, and there's any cgroup in the "cpu" hierarchy it >>>> needs an RT budget assigned, otherwise the processes in it will not be able to >>>> get RT at all. The problem with RT group scheduling is that it requires the >>>> budget assigned but there's no way we could assign a default budget, since the >>>> values to assign are both upper and lower time limits, are absolute, and need to >>>> be sum up to < 1 for each individal cgroup. That means we cannot really come up >>>> with values that would work by default in the general case.[2] >>>> >>>> For cgroup v2, it's almost unusable as well. If it turned on, the cpu controller >>>> can only be enabled when all RT processes are in the root cgroup. But it will >>>> lose the benefits of cgroup v2 if all RT process were placed in the same cgroup. >>>> >>>> Red Hat, Gentoo, Arch Linux and Debian all disable it. systemd also doesn't >>>> support it.[3] >>>> >>>> [1]: https://github.com/moby/moby/commit/005150ed69c540fb0b5323e0f2208608c1204536 >>>> [2]: https://bugzilla.redhat.com/show_bug.cgi?id=1229700 >>>> [3]: https://github.com/systemd/systemd/issues/13781#issuecomment-549164383 >>>> >>>> Fixes: ba6cfef057e1 ("riscv: enable Docker requirements in defconfig") >>> >>> I don't think this fixes tag is suitable, the commit you cite in >>> moby/docker is a year younger than the one in the fixes tag, so it was >>> correct at the time it was written. I think the fixes tag should just be >>> removed, since that commit was not wrong. Or am I missing something? >> >> The Docker commit I cited introduce the fix, not the bug. So it should be later >> than commit in fixes tag, otherwise Heinrich Schuchardt won't pick the wrong >> config from upstream. >> >> Timeline is: >> 1) 2015-06-19 Qiang Huang introduce RT_GROUP_SCHED check in Docker.[1] >> 2) 2022-06-08 Heinrich Schuchardt pick this to defconfig in commit >> in fixes tag. >> 3) 2023-04-19 Florian Schmaus remove this requirement from Docker in >> commit I cited. > > Yes, this is the way I understood things to be. IOW, when Heinrich wrote > ba6cfef057e1 ("riscv: enable Docker requirements in defconfig"), it was > a requirement for docker. The requirement later being removed doesn't > make his patch incorrect, which is why I don't think this is a fix. Oh, you are right. I will send v3 later.