From nobody Mon Feb 9 14:33:26 2026 Received: from mail-pf1-f195.google.com (mail-pf1-f195.google.com [209.85.210.195]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BED151CF2A1; Thu, 22 Aug 2024 17:43:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.195 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724348626; cv=none; b=of0fP+0729CBTwgXJ+G6wV1I0CXLh/4xAQ3Qs1ywN/mGiz+KbslY6u9hnixrLVJkGRMWkfxg0agCaH8MrtoaNqQPcQuML54WHP3ssH67YkIGymfR8eFt9enK70UB5+L5OnVGWwVNB47MhfyKlWUbrsn9YqN7l796PApTYkVUkCA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724348626; c=relaxed/simple; bh=NFJyZNClpVUHx0Z3NXNiq6kpWDX+CueV3L4clx5uBrg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=pYhcCsEfcISmHVbpSJdZtoCNuzfBA/cHiKHRYHGLucKP8ud37S1rq4ekevIvpRzGbWjRtuoR8nzaoLmS7uO4/d/vURIwxgmpw2LBvMEPkurOmqJ7n53OpG/WAv7bxKqb5BqvP96xvW2yUfc6hAJlgAGFcGf09r5OZUg9JEeM5zQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=dSOWVQZw; arc=none smtp.client-ip=209.85.210.195 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="dSOWVQZw" Received: by mail-pf1-f195.google.com with SMTP id d2e1a72fcca58-7141b04e7b5so726464b3a.2; Thu, 22 Aug 2024 10:43:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1724348624; x=1724953424; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=flQt4FT94ocjxfYVsDsgAIXjhRxl01ohtqmqMtZp6jc=; b=dSOWVQZwhOcxjVN5NhMtpWMc0b4V2cUbWjyNtqKKOSKnkmYyO6Vj43Frn4EyO3C9PA lgVmN0XYJRCg6keRGP1QEj36Tw7oyhhhpRBSbsJ9qoKpXKO9Bcft9R6RPPmGOa2ktSy1 KHikYBdIuAOYe5BL4JggNPW0R6KRpKc2ILlupWu1E6I4dixdJv/4N0Tkgi5ZiMQZJfeX st609SF7ifqipGGesTl3QVHbRaq2CiffN10cs+Fp/SmggfhTRDgTDYCRJAjVKo5jNq62 EY9gc9bvEbZP9LULIER18n9V6fCGCfNKl+FfOZczz+zme/eBKct68wn7KR1FJL2qPpkl xZMg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724348624; x=1724953424; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=flQt4FT94ocjxfYVsDsgAIXjhRxl01ohtqmqMtZp6jc=; b=mXeWGN0phtdJj+9RzgU3jxZFXCq7XCDM+ywV5h4Tl0dww3tjhvT9GFU1WsU2i48HqN 8jezbm93jrieXu4SDprYOcHfNxeMGBu1N6FiQZrWS+pNoLkAmOoXG9W8RYDKxAvQ304P gE7sSeWvWazUcBCSB5eJRSgSBy03Hlp4fnEkycNNt5A1tGt2nPPx2luwJ3CVONtk9q14 Z/95GRa7MySPXg40glNYzjTvjdSvWY/mqilx4cgPMmIqwwS3hD5iquLk3h05U8cJUw65 nMrQ3KdWxBJleu3z91/YP22HtE9eBEWvbyyiypEKZWJSbV/vcNrYA+0v6E0sUXyVTD6K Ga6A== X-Forwarded-Encrypted: i=1; AJvYcCVCDbTORMXC3NYrfyvkY6IzP32VoXBuxjEMj9uivGyuvO5byyeEpsq074dUCzBIwuINBBiuae/+630=@vger.kernel.org, AJvYcCVVHajNRqg8yddsy3nZPkHvKWmdI00xSXzoGJIiXeUkw02eT/CyiFu/mawPfgIlQ+dNIDKI1bMl7d4DiJI=@vger.kernel.org, AJvYcCX1YHG6vS72A55wZmw0qs3+jwQOaOwwbaJT5guVVJj2c+a86/pxjH6Wt4HugmpUlAmRwxJknDlcdgTZZ/0=@vger.kernel.org, AJvYcCXsso/i4PhipK/btJL3okGONJleKufxokeRYkXEQQif3epVKpY/HeP8zqiJZetld2w4KPfAV1EKPI78JA==@vger.kernel.org X-Gm-Message-State: AOJu0Yx+8aQULUBd70iuyfT3f1SRCEh56/uUBQMuTuWSa3DTpuo2dy1R NG2/19n+WLkFHmV/d4dzAFlHRmxBreBaRiSuxk16c9d8W6RC6RJ0 X-Google-Smtp-Source: AGHT+IFGkELVvNa0lI1frVFe6EWSijWeT2NndQtVRkhY3tXIvi6/Nr7KdOgUntuymQnVsLZZV1NHsQ== X-Received: by 2002:a05:6a20:cfa4:b0:1c4:9c27:77a5 with SMTP id adf61e73a8af0-1cad7fb3fd0mr7479354637.31.1724348623824; Thu, 22 Aug 2024 10:43:43 -0700 (PDT) Received: from localhost ([103.156.242.194]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-71434af17ebsm1583180b3a.3.2024.08.22.10.43.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Aug 2024 10:43:43 -0700 (PDT) From: Celeste Liu X-Google-Original-From: Celeste Liu Date: Fri, 23 Aug 2024 01:43:29 +0800 Subject: [PATCH v2 4/4] arm: defconfig: drop RT_GROUP_SCHED=y from bcm2835/tegra/omap2plus Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20240823-fix-riscv-rt_group_sched-v2-4-e4dbae24f7e1@gmail.com> References: <20240823-fix-riscv-rt_group_sched-v2-0-e4dbae24f7e1@gmail.com> In-Reply-To: <20240823-fix-riscv-rt_group_sched-v2-0-e4dbae24f7e1@gmail.com> To: Paul Walmsley , Palmer Dabbelt , Albert Ou , Guo Ren , Anup Patel , Heinrich Schuchardt , Huacai Chen , WANG Xuerui , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , Russell King , Florian Fainelli , Broadcom internal kernel review list , Ray Jui , Scott Branden , Tony Lindgren , Thierry Reding , Jonathan Hunter Cc: Palmer Dabbelt , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-sh@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, linux-omap@vger.kernel.org, linux-tegra@vger.kernel.org, Stefan Wahren , Kevin Hilman , Celeste Liu X-Mailer: b4 0.14.1 X-Developer-Signature: v=1; a=openpgp-sha256; l=2823; i=CoelacanthusHex@gmail.com; h=from:subject:message-id; bh=NFJyZNClpVUHx0Z3NXNiq6kpWDX+CueV3L4clx5uBrg=; b=owJ4nJvAy8zAJfY4pvNJRPo6U8bTakkMaccrDivyM1yYePqvmKhQXbdc0o4/M99VH9rqbjfrd C2704FIwfKOUhYGMS4GWTFFFrGdT18vK330YRmvyQyYOaxMIEMYuDgF4CKcjAwdc84dWeL8XvrP oXWq2Tvq7x9Qlrtz8PpheXWhu2maxd+PMfyvY/2cPcnsqtDXK2v61hZlLJVe4rPDPnSvlHrjhGk +FpHMAC41TKg= X-Developer-Key: i=CoelacanthusHex@gmail.com; a=openpgp; fpr=892EBC7DC392DFF9C9C03F1D15F4180E73787863 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 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.[2] 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. [1]: https://github.com/systemd/systemd/commit/f4e74be1856b3ac058acbf1be321= c31d5299f69f [2]: https://bugzilla.redhat.com/show_bug.cgi?id=3D1229700 Tested-by: Stefan Wahren Acked-by: Kevin Hilman Signed-off-by: Celeste Liu --- arch/arm/configs/bcm2835_defconfig | 1 - arch/arm/configs/omap2plus_defconfig | 1 - arch/arm/configs/tegra_defconfig | 1 - 3 files changed, 3 deletions(-) diff --git a/arch/arm/configs/bcm2835_defconfig b/arch/arm/configs/bcm2835_= defconfig index b5f0bd8dd536..27dc3bf6b124 100644 --- a/arch/arm/configs/bcm2835_defconfig +++ b/arch/arm/configs/bcm2835_defconfig @@ -7,7 +7,6 @@ CONFIG_BSD_PROCESS_ACCT=3Dy CONFIG_BSD_PROCESS_ACCT_V3=3Dy CONFIG_LOG_BUF_SHIFT=3D18 CONFIG_CFS_BANDWIDTH=3Dy -CONFIG_RT_GROUP_SCHED=3Dy CONFIG_CGROUP_FREEZER=3Dy CONFIG_CPUSETS=3Dy CONFIG_CGROUP_DEVICE=3Dy diff --git a/arch/arm/configs/omap2plus_defconfig b/arch/arm/configs/omap2p= lus_defconfig index 3a166c2f02bd..9cb265c8d414 100644 --- a/arch/arm/configs/omap2plus_defconfig +++ b/arch/arm/configs/omap2plus_defconfig @@ -13,7 +13,6 @@ CONFIG_MEMCG=3Dy CONFIG_BLK_CGROUP=3Dy CONFIG_CGROUP_SCHED=3Dy CONFIG_CFS_BANDWIDTH=3Dy -CONFIG_RT_GROUP_SCHED=3Dy CONFIG_CGROUP_FREEZER=3Dy CONFIG_CPUSETS=3Dy CONFIG_CGROUP_DEVICE=3Dy diff --git a/arch/arm/configs/tegra_defconfig b/arch/arm/configs/tegra_defc= onfig index d2a094ad360c..3a9bda2bf422 100644 --- a/arch/arm/configs/tegra_defconfig +++ b/arch/arm/configs/tegra_defconfig @@ -6,7 +6,6 @@ CONFIG_IKCONFIG=3Dy CONFIG_IKCONFIG_PROC=3Dy CONFIG_CGROUPS=3Dy CONFIG_CGROUP_SCHED=3Dy -CONFIG_RT_GROUP_SCHED=3Dy CONFIG_CGROUP_FREEZER=3Dy CONFIG_CGROUP_CPUACCT=3Dy CONFIG_CGROUP_DEBUG=3Dy --=20 2.46.0