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 67682C3DA45 for ; Mon, 8 Jul 2024 23:49:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:References :In-Reply-To:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=4nEVAlst6mEAsGybdhJsftlF/Okg7ADGluZE4qO4fVI=; b=EfiOEyAQzw3mRJ HlYC7TdQ5JjVJHHI+371jIp6OT0SQM0xx8a1rGAZMBbkSeMkhjfhw+gByJD8QrSNvFsE8y+8WWFI4 reXEWcRBqpluwFxl2e0mX7MOxFkDD58PU0WynBnKTeC4uboUPsNX38UTQJV31jd+Xce5e1ljgFjp9 WdiHZgedGssC56jMEjRBYEXQcm4VVRIX4yGXUvLbkDrvhbLiCr5urLmAe/oFcHv4hK7EreyfmS7Li 1HwD0lAHZmWH1SfdZJB+E5msZ7xAoDYHJodvrHhIlv4r0lDxQvfjGmDQs4kf7cl0l4pyZLEFBW3Re kXlucU0zmXXVSAQW5qSQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sQy6j-00000005MG3-22sz; Mon, 08 Jul 2024 23:49:21 +0000 Received: from mail-pj1-f52.google.com ([209.85.216.52]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sQy6S-00000005MBU-2uoo for linux-riscv@lists.infradead.org; Mon, 08 Jul 2024 23:49:07 +0000 Received: by mail-pj1-f52.google.com with SMTP id 98e67ed59e1d1-2c9a10728abso2433414a91.0 for ; Mon, 08 Jul 2024 16:49:03 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1720482543; x=1721087343; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=KTCvURDHt1Ehhy2ogJ4G2eNRAbN+TU2XGb1d5J/SBYc=; b=VB3PdnO376faD2zhG0kIa4UdXhYRaNdRenR6dv/CprJ9nwQnBo/3Wi+nIDUGltGwuj d4ePHBkv459gOuZownaUSmqAjKhfg+AFKDIjR3+YHDcsYUvVzJzzV5IZ7T+HDCinNdtH dT+uJfY+i9035kc2mZeI87fBwEMruJaRcun7q/LB9V8BH8zSL+w1MMZjGwV4PBQ8+zCQ omz96NyoCVhDWYxa14mPXNvEJaRR7qDTnVzjbpCqgKN3j6EUYUAuMjrZ6oMrlZbS1DKQ +r+VOdUXozryBYTEBfV/hV2P9oUFtl+ltgz9Thsp2bIhByfyeGgEvnZAyqns/Qr5Af20 9ENA== X-Forwarded-Encrypted: i=1; AJvYcCV+2fHaxxJqXL6pl34hQAtue+5d81AKhCmu4LpkZqcgDVemRadVJu2PtFURlvHUsuSEf2TnTzTV0kRniQO5Dme7R1uLzSmz0wlF1Hp0PiK0 X-Gm-Message-State: AOJu0YyU6YQWxrIGOhFZmu5LyHl3dQORhem+szUYiDIjH2WdtaYVpk1z IY7Z2VKPGvfr8PYtPPYzvWkxWXeH30bs5wI+rZ+jWh5pz1eNOcQro5NZDgpK/n4= X-Google-Smtp-Source: AGHT+IF2sRCcp1Qt2ncA7/dcBS7eQVYhbuVP4CESqTDlDqz8AWSIBYQ0ftySS6HXoODFEfyN2bXeTQ== X-Received: by 2002:a17:90a:a10d:b0:2c4:dfa6:df00 with SMTP id 98e67ed59e1d1-2ca35be0661mr981011a91.8.1720482542878; Mon, 08 Jul 2024 16:49:02 -0700 (PDT) Received: from localhost (97-126-77-189.tukw.qwest.net. [97.126.77.189]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2ca344c399csm596679a91.5.2024.07.08.16.49.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Jul 2024 16:49:02 -0700 (PDT) From: Kevin Hilman To: Celeste Liu , Heinrich Schuchardt , Anup Patel , Guo Ren , Palmer Dabbelt , Paul Walmsley , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Vladimir Kondratiev , Gregory CLEMENT , =?utf-8?Q?Th=C3=A9o?= Lebrun , Michael Ellerman , Nicholas Piggin , Christophe Leroy , "Naveen N . Rao" , Sven Joachim , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , Russell King , Florian Fainelli , Ray Jui , Scott Branden , Broadcom internal kernel review list , Tony Lindgren , Thierry Reding , Jonathan Hunter , Arnd Bergmann , Mykola Lysenko , linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, linux-omap@vger.kernel.org, linux-tegra@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-sh@vger.kernel.org Subject: Re: [PATCH 6/6] arm: defconfig: drop RT_GROUP_SCHED=y from bcm2855/tegra/omap2plus In-Reply-To: <20240530111947.549474-14-CoelacanthusHex@gmail.com> References: <20240530111947.549474-8-CoelacanthusHex@gmail.com> <20240530111947.549474-14-CoelacanthusHex@gmail.com> Date: Mon, 08 Jul 2024 16:49:01 -0700 Message-ID: <7hv81f78cy.fsf@baylibre.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240708_164904_747457_37A27A6C X-CRM114-Status: GOOD ( 14.60 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Celeste Liu , Lennart Poettering , bpf@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Celeste Liu writes: > Commit 673ce00c5d6c ("ARM: omap2plus_defconfig: Add support for distros > with systemd") said it's because of recommendation from systemd. But > systemd changed their recommendation later.[1] > > 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. > > [1]: https://github.com/systemd/systemd/commit/f4e74be1856b3ac058acbf1be321c31d5299f69f > [2]: https://bugzilla.redhat.com/show_bug.cgi?id=1229700 > > Signed-off-by: Celeste Liu > --- > arch/arm/configs/bcm2835_defconfig | 1 - > arch/arm/configs/omap2plus_defconfig | 1 - > arch/arm/configs/tegra_defconfig | 1 - For omap2plus_defconfig: Acked-by: Kevin Hilman _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv