From: Kevin Hilman <khilman@kernel•org>
To: "Celeste Liu" <coelacanthushex@gmail•com>,
"Heinrich Schuchardt" <heinrich.schuchardt@canonical•com>,
"Anup Patel" <anup@brainfault•org>, "Guo Ren" <guoren@kernel•org>,
"Palmer Dabbelt" <palmer@rivosinc•com>,
"Paul Walmsley" <paul.walmsley@sifive•com>,
"Huacai Chen" <chenhuacai@kernel•org>,
"WANG Xuerui" <kernel@xen0n•name>,
"Thomas Bogendoerfer" <tsbogend@alpha•franken.de>,
"Vladimir Kondratiev" <vladimir.kondratiev@mobileye•com>,
"Gregory CLEMENT" <gregory.clement@bootlin•com>,
"Théo Lebrun" <theo.lebrun@bootlin•com>,
"Michael Ellerman" <mpe@ellerman•id.au>,
"Nicholas Piggin" <npiggin@gmail•com>,
"Christophe Leroy" <christophe.leroy@csgroup•eu>,
"Naveen N . Rao" <naveen.n.rao@linux•ibm.com>,
"Sven Joachim" <svenjoac@gmx•de>,
"Yoshinori Sato" <ysato@users•sourceforge.jp>,
"Rich Felker" <dalias@libc•org>,
"John Paul Adrian Glaubitz" <glaubitz@physik•fu-berlin.de>,
"Russell King" <linux@armlinux•org.uk>,
"Florian Fainelli" <florian.fainelli@broadcom•com>,
"Ray Jui" <rjui@broadcom•com>,
"Scott Branden" <sbranden@broadcom•com>,
"Broadcom internal kernel review list"
<bcm-kernel-feedback-list@broadcom•com>,
"Tony Lindgren" <tony@atomide•com>,
"Thierry Reding" <thierry.reding@gmail•com>,
"Jonathan Hunter" <jonathanh@nvidia•com>,
"Arnd Bergmann" <arnd@arndb•de>,
"Mykola Lysenko" <mykolal@fb•com>,
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, linux-kernel@vger•kernel.org,
Celeste Liu <CoelacanthusHex@gmail•com>,
Lennart Poettering <lennart@poettering•net>,
bpf@vger•kernel.org, Icenowy Zheng <uwu@icenowy•me>
Subject: Re: [PATCH 6/6] arm: defconfig: drop RT_GROUP_SCHED=y from bcm2855/tegra/omap2plus
Date: Mon, 08 Jul 2024 16:49:01 -0700 [thread overview]
Message-ID: <7hv81f78cy.fsf@baylibre.com> (raw)
In-Reply-To: <20240530111947.549474-14-CoelacanthusHex@gmail.com>
Celeste Liu <coelacanthushex@gmail•com> 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 <CoelacanthusHex@gmail•com>
> ---
> 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 <khilman@baylibre•com>
next prev parent reply other threads:[~2024-07-08 23:49 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-30 11:19 [PATCH 0/6] defconfig: drop RT_GROUP_SCHED=y Celeste Liu
2024-05-30 11:19 ` [PATCH 1/6] riscv: " Celeste Liu
2024-05-30 11:19 ` [PATCH 2/6] loongarch: " Celeste Liu
2024-05-30 11:27 ` Xi Ruoyao
2024-05-30 11:19 ` [PATCH 3/6] mips: defconfig: drop RT_GROUP_SCHED=y from generic/db1xxx/eyeq5 Celeste Liu
2024-06-11 8:41 ` Thomas Bogendoerfer
2024-05-30 11:19 ` [PATCH 4/6] powerpc: defconfig: drop RT_GROUP_SCHED=y from ppc6xx_defconfig Celeste Liu
2024-05-30 11:19 ` [PATCH 5/6] sh: defconfig: drop RT_GROUP_SCHED=y from sdk7786/urquell Celeste Liu
2024-05-30 11:19 ` [PATCH 6/6] arm: defconfig: drop RT_GROUP_SCHED=y from bcm2855/tegra/omap2plus Celeste Liu
2024-07-08 23:49 ` Kevin Hilman [this message]
2024-07-09 12:26 ` Stefan Wahren
2024-07-09 12:45 ` Celeste Liu
2024-06-20 12:49 ` (subset) [PATCH 0/6] defconfig: drop RT_GROUP_SCHED=y Michael Ellerman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7hv81f78cy.fsf@baylibre.com \
--to=khilman@kernel$(echo .)org \
--cc=anup@brainfault$(echo .)org \
--cc=arnd@arndb$(echo .)de \
--cc=bcm-kernel-feedback-list@broadcom$(echo .)com \
--cc=bpf@vger$(echo .)kernel.org \
--cc=chenhuacai@kernel$(echo .)org \
--cc=christophe.leroy@csgroup$(echo .)eu \
--cc=coelacanthushex@gmail$(echo .)com \
--cc=dalias@libc$(echo .)org \
--cc=florian.fainelli@broadcom$(echo .)com \
--cc=glaubitz@physik$(echo .)fu-berlin.de \
--cc=gregory.clement@bootlin$(echo .)com \
--cc=guoren@kernel$(echo .)org \
--cc=heinrich.schuchardt@canonical$(echo .)com \
--cc=jonathanh@nvidia$(echo .)com \
--cc=kernel@xen0n$(echo .)name \
--cc=lennart@poettering$(echo .)net \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=linux-kselftest@vger$(echo .)kernel.org \
--cc=linux-mips@vger$(echo .)kernel.org \
--cc=linux-omap@vger$(echo .)kernel.org \
--cc=linux-riscv@lists$(echo .)infradead.org \
--cc=linux-rpi-kernel@lists$(echo .)infradead.org \
--cc=linux-sh@vger$(echo .)kernel.org \
--cc=linux-tegra@vger$(echo .)kernel.org \
--cc=linux@armlinux$(echo .)org.uk \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
--cc=loongarch@lists$(echo .)linux.dev \
--cc=mpe@ellerman$(echo .)id.au \
--cc=mykolal@fb$(echo .)com \
--cc=naveen.n.rao@linux$(echo .)ibm.com \
--cc=npiggin@gmail$(echo .)com \
--cc=palmer@rivosinc$(echo .)com \
--cc=paul.walmsley@sifive$(echo .)com \
--cc=rjui@broadcom$(echo .)com \
--cc=sbranden@broadcom$(echo .)com \
--cc=svenjoac@gmx$(echo .)de \
--cc=theo.lebrun@bootlin$(echo .)com \
--cc=thierry.reding@gmail$(echo .)com \
--cc=tony@atomide$(echo .)com \
--cc=tsbogend@alpha$(echo .)franken.de \
--cc=uwu@icenowy$(echo .)me \
--cc=vladimir.kondratiev@mobileye$(echo .)com \
--cc=ysato@users$(echo .)sourceforge.jp \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox