From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from elvis.franken.de (elvis.franken.de [193.175.24.41]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 0A1FA174EEB; Tue, 11 Jun 2024 08:50:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.175.24.41 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718095831; cv=none; b=hftt5o8OoXxG0wRv+b4a2GsF8RMjDSgffuOyscDRNOrUGtLBm30S80K26QiLZjxKcIFTcOCs5+tuRWvRFCmxpMfJlmcmteY0noWb82bpOg05qAMzhGe/VdV2tLS3IyS89CPmOUmsHeS0+yZWNbmevkns0tPIVXlSjYFrhW1osz0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718095831; c=relaxed/simple; bh=Tz0c5VcTfHJlV2uX+Q+nERoAMIrZpPDtHjcTjqCCVNo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NQRRWfFz6L6s0kLyXKc9BmOMdc47vbR+qybGa8fJTsQbdvLRzy7RxSXmVwswpODEt94iXHqHqRFdD2IOd+00usbny3R70LO5Gflv8ldR2vzTLN5QMj63v563YOSiO3dlfi8CdqENGjh0e5ir2xN/b8/j24WvDh7M6brRmsT2CLg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=alpha.franken.de; spf=pass smtp.mailfrom=alpha.franken.de; arc=none smtp.client-ip=193.175.24.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=alpha.franken.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alpha.franken.de Received: from uucp by elvis.franken.de with local-rmail (Exim 3.36 #1) id 1sGxBT-0000Ne-00; Tue, 11 Jun 2024 10:48:51 +0200 Received: by alpha.franken.de (Postfix, from userid 1000) id 023C9C0120; Tue, 11 Jun 2024 10:41:16 +0200 (CEST) Date: Tue, 11 Jun 2024 10:41:16 +0200 From: Thomas Bogendoerfer To: Celeste Liu Cc: Heinrich Schuchardt , Anup Patel , Guo Ren , Palmer Dabbelt , Paul Walmsley , Huacai Chen , WANG Xuerui , Vladimir Kondratiev , Gregory CLEMENT , =?iso-8859-1?Q?Th=E9o?= 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, linux-kselftest@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Lennart Poettering , Icenowy Zheng Subject: Re: [PATCH 3/6] mips: defconfig: drop RT_GROUP_SCHED=y from generic/db1xxx/eyeq5 Message-ID: References: <20240530111947.549474-8-CoelacanthusHex@gmail.com> <20240530111947.549474-11-CoelacanthusHex@gmail.com> Precedence: bulk X-Mailing-List: linux-omap@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240530111947.549474-11-CoelacanthusHex@gmail.com> On Thu, May 30, 2024 at 07:19:51PM +0800, Celeste Liu wrote: > 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.[1] > > 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.[2] > > [1]: https://bugzilla.redhat.com/show_bug.cgi?id=1229700 > [2]: https://github.com/systemd/systemd/issues/13781#issuecomment-549164383 > > Signed-off-by: Celeste Liu > --- > arch/mips/configs/db1xxx_defconfig | 1 - > arch/mips/configs/eyeq5_defconfig | 1 - > arch/mips/configs/generic_defconfig | 1 - > 3 files changed, 3 deletions(-) applied to mips-next. Thomas. -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea. [ RFC1925, 2.3 ]