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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 Cc: linux-kselftest@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Lennart Poettering , Icenowy Zheng , Celeste Liu Subject: [PATCH 5/6] sh: defconfig: drop RT_GROUP_SCHED=y from sdk7786/urquell Date: Thu, 30 May 2024 19:19:53 +0800 Message-ID: <20240530111947.549474-13-CoelacanthusHex@gmail.com> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240530111947.549474-8-CoelacanthusHex@gmail.com> References: <20240530111947.549474-8-CoelacanthusHex@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2029; i=CoelacanthusHex@gmail.com; h=from:subject; bh=kOqrnzdbmJCW+4DZmJVchuzFR6LT5fL9WaReqTWmC8g=; b=owJ4nJvAy8zAJfY4pvNJRPo6U8bTakkMaREJNwub0yXLjr83sFl6+r9m9kR/++RbfTfmNMpv7 my3dmlavLujlIVBjItBVkyRRWzn09fLSh99WMZrMgNmDisTyBAGLk4BmAiHHSPDiWeRLf+fbOwM 1WVrORm/XDDz8bQ1DJ+etga9dN23//qBHoY/HAcKm/+7fhPVYMsRuzTfViI8IXPz8oWr86eHXVw Sp9rHBgChF03a X-Developer-Key: i=CoelacanthusHex@gmail.com; a=openpgp; fpr=892EBC7DC392DFF9C9C03F1D15F4180E73787863 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 ne= ed to be sum up to < 1 for each individal cgroup. That means we cannot really com= e up with values that would work by default in the general case.[1] For cgroup v2, it's almost unusable as well. If it turned on, the cpu contr= oller can only be enabled when all RT processes are in the root cgroup. But it wi= ll lose the benefits of cgroup v2 if all RT process were placed in the same cg= roup. Red Hat, Gentoo, Arch Linux and Debian all disable it. systemd also doesn't support it.[2] [1]: https://bugzilla.redhat.com/show_bug.cgi?id=3D1229700 [2]: https://github.com/systemd/systemd/issues/13781#issuecomment-549164383 Signed-off-by: Celeste Liu --- arch/sh/configs/sdk7786_defconfig | 1 - arch/sh/configs/urquell_defconfig | 1 - 2 files changed, 2 deletions(-) diff --git a/arch/sh/configs/sdk7786_defconfig b/arch/sh/configs/sdk7786_de= fconfig index 7b427c17fbfe..3599b1683593 100644 --- a/arch/sh/configs/sdk7786_defconfig +++ b/arch/sh/configs/sdk7786_defconfig @@ -17,7 +17,6 @@ CONFIG_CPUSETS=3Dy CONFIG_CGROUP_CPUACCT=3Dy CONFIG_CGROUP_MEMCG=3Dy CONFIG_CGROUP_SCHED=3Dy -CONFIG_RT_GROUP_SCHED=3Dy CONFIG_BLK_CGROUP=3Dy CONFIG_RELAY=3Dy CONFIG_NAMESPACES=3Dy diff --git a/arch/sh/configs/urquell_defconfig b/arch/sh/configs/urquell_de= fconfig index 00ef62133b04..9cf4a719001e 100644 --- a/arch/sh/configs/urquell_defconfig +++ b/arch/sh/configs/urquell_defconfig @@ -15,7 +15,6 @@ CONFIG_CPUSETS=3Dy CONFIG_CGROUP_CPUACCT=3Dy CONFIG_CGROUP_MEMCG=3Dy CONFIG_CGROUP_SCHED=3Dy -CONFIG_RT_GROUP_SCHED=3Dy CONFIG_BLK_DEV_INITRD=3Dy CONFIG_PROFILING=3Dy CONFIG_MODULES=3Dy --=20 2.45.1