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Rao" , Sven Joachim , Huacai Chen , Heinrich Schuchardt , Anup Patel , Nicholas Piggin , Thomas Bogendoerfer , Jonathan Hunter , Christophe Leroy , Broadcom internal kernel review list , Rich Felker , Russell King , Tony Lindgren , Guo Ren , linux-tegra@vger.kernel.org, Thierry Reding , linux-riscv@lists.infradead.org, Arnd Bergmann , linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, Palmer Dabbelt , linux-sh@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mips@vger.kernel.org, loongarch@lists.linux.dev, Mykola Lysenko , Yoshinori Sato , Paul Walmsley , John Paul Adrian Glaubitz , linux-rpi-kernel@lists.infradead.org, WANG Xuerui References: <20240530111947.549474-8-CoelacanthusHex@gmail.com> <20240530111947.549474-14-CoelacanthusHex@gmail.com> <7hv81f78cy.fsf@baylibre.com> <6b7cfe69-4f72-490f-8e86-5343bd244a2d@gmx.net> Content-Language: en-GB-large In-Reply-To: <6b7cfe69-4f72-490f-8e86-5343bd244a2d@gmx.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 2024-07-09 20:26, Stefan Wahren wrote: > Hi Celeste, > > there is a typo in the subject line > > s/bcm2855/bcm2835 Will be included in next version. > > Am 09.07.24 um 01:49 schrieb Kevin Hilman: >> 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 >> >> > For bcm2835_defconfig: > > Tested-by: Stefan Wahren