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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 1/6] riscv: defconfig: drop RT_GROUP_SCHED=y Date: Thu, 30 May 2024 19:19:49 +0800 Message-ID: <20240530111947.549474-9-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> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1883; i=CoelacanthusHex@gmail.com; h=from:subject; bh=FEk4ZichD7CqTRAppezRH+4H9dhTF4GYT9EUDpibpAE=; b=owJ4nJvAy8zAJfY4pvNJRPo6U8bTakkMaREJ16rP/zv78xijc+SbFuluq7KoDVxfdGb3ntmwV 4b5b/rJ87kdpSwMYlwMsmKKLGI7n75eVvrowzJekxkwc1iZQIYwcHEKwERiuRj+FyWbH5kg7nGC bXudX8b5SVrfDn7ffNohZmU9l4bwcat4U4b/tfNS9VctvP7+NI+h5NrpGpcrHCr9as+x9XPYVM9 LOc3JBwDwgkw9 X-Developer-Key: i=CoelacanthusHex@gmail.com; a=openpgp; fpr=892EBC7DC392DFF9C9C03F1D15F4180E73787863 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240530_042013_472151_18E54E46 X-CRM114-Status: GOOD ( 12.46 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Commit ba6cfef057e1 ("riscv: enable Docker requirements in defconfig") introduced it because of Docker, but Docker has removed this requirement since [1] (2023-04-19). 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.[3] [1]: https://github.com/moby/moby/commit/005150ed69c540fb0b5323e0f2208608c1204536 [2]: https://bugzilla.redhat.com/show_bug.cgi?id=1229700 [3]: https://github.com/systemd/systemd/issues/13781#issuecomment-549164383 Fixes: ba6cfef057e1 ("riscv: enable Docker requirements in defconfig") Signed-off-by: Celeste Liu --- arch/riscv/configs/defconfig | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig index 12dc8c73a8ac..de85c3ab261e 100644 --- a/arch/riscv/configs/defconfig +++ b/arch/riscv/configs/defconfig @@ -9,7 +9,6 @@ CONFIG_CGROUPS=y CONFIG_MEMCG=y CONFIG_CGROUP_SCHED=y CONFIG_CFS_BANDWIDTH=y -CONFIG_RT_GROUP_SCHED=y CONFIG_CGROUP_PIDS=y CONFIG_CGROUP_FREEZER=y CONFIG_CGROUP_HUGETLB=y From patchwork Thu May 30 11:19:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Celeste Liu X-Patchwork-Id: 13680293 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 075D0C25B74 for ; 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Thu, 30 May 2024 04:20:09 -0700 (PDT) From: Celeste Liu X-Google-Original-From: Celeste Liu To: Heinrich Schuchardt , Anup Patel , Guo Ren , Palmer Dabbelt , Paul Walmsley , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Vladimir Kondratiev , Gregory CLEMENT , =?utf-8?q?Th=C3=A9o_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 Cc: linux-kselftest@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Lennart Poettering , Icenowy Zheng , Celeste Liu Subject: [PATCH 2/6] loongarch: defconfig: drop RT_GROUP_SCHED=y Date: Thu, 30 May 2024 19:19:50 +0800 Message-ID: <20240530111947.549474-10-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> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1629; i=CoelacanthusHex@gmail.com; h=from:subject; bh=h4glHeoHIj1lCrO/9cfcaGCSQbc7rI3O4B300cL/OlA=; b=owJ4nJvAy8zAJfY4pvNJRPo6U8bTakkMaREJ1/n69Xxaeu7NP36NP963pkB213cGx83nk+e+3 76w6tID+4kdpSwMYlwMsmKKLGI7n75eVvrowzJekxkwc1iZQIYwcHEKwESKNRn+WU/3fra1weNu krm/TiCjVtvfa8brLyYvXBxW9+bE9hjTBwx/hWUiri0SdmdLcHzGfvl11UovoVVOsWVy29fF/F/ 2874CBwCfBE2n X-Developer-Key: i=CoelacanthusHex@gmail.com; a=openpgp; fpr=892EBC7DC392DFF9C9C03F1D15F4180E73787863 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240530_122357_043654_C33B97FC X-CRM114-Status: GOOD ( 11.99 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 Reviewed-by: Xi Ruoyao --- arch/loongarch/configs/loongson3_defconfig | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/loongarch/configs/loongson3_defconfig b/arch/loongarch/configs/loongson3_defconfig index b4252c357c8e..4d93adb3f1a2 100644 --- a/arch/loongarch/configs/loongson3_defconfig +++ b/arch/loongarch/configs/loongson3_defconfig @@ -23,7 +23,6 @@ CONFIG_NUMA_BALANCING=y CONFIG_MEMCG=y CONFIG_BLK_CGROUP=y CONFIG_CFS_BANDWIDTH=y -CONFIG_RT_GROUP_SCHED=y CONFIG_CGROUP_PIDS=y CONFIG_CGROUP_RDMA=y CONFIG_CGROUP_FREEZER=y From patchwork Thu May 30 11:19:51 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Celeste Liu X-Patchwork-Id: 13680292 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3017AC25B74 for ; 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Thu, 30 May 2024 04:20:12 -0700 (PDT) From: Celeste Liu X-Google-Original-From: Celeste Liu To: Heinrich Schuchardt , Anup Patel , Guo Ren , Palmer Dabbelt , Paul Walmsley , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Vladimir Kondratiev , Gregory CLEMENT , =?utf-8?q?Th=C3=A9o_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 Cc: linux-kselftest@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Lennart Poettering , Icenowy Zheng , Celeste Liu Subject: [PATCH 3/6] mips: defconfig: drop RT_GROUP_SCHED=y from generic/db1xxx/eyeq5 Date: Thu, 30 May 2024 19:19:51 +0800 Message-ID: <20240530111947.549474-11-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> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2501; i=CoelacanthusHex@gmail.com; h=from:subject; bh=iuzxupRQlKvaCQIBiZ4xlf2r612WVp0v0y+1iZrYbx8=; b=owJ4nJvAy8zAJfY4pvNJRPo6U8bTakkMaREJN5aHbSvetGXDI9/Lgg/2RZ0Pr9tZ2Zeh8l34s JFf/NkbX3s7SlkYxLgYZMUUWcR2Pn29rPTRh2W8JjNg5rAygQxh4OIUgIkc2cnw3+dB99H+ecua Oiy0mLQjDFasNi7dvfTwkdv38ytDfrqaLGRkOOx28cCrP0VHmn/UfmB7LhiTWCzOvmna5ka3YIu yCes1WADtNVCT X-Developer-Key: i=CoelacanthusHex@gmail.com; a=openpgp; fpr=892EBC7DC392DFF9C9C03F1D15F4180E73787863 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240530_122357_710139_AFE0F14C X-CRM114-Status: GOOD ( 11.30 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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(-) diff --git a/arch/mips/configs/db1xxx_defconfig b/arch/mips/configs/db1xxx_defconfig index b2d9253ff786..6eff21ff15d5 100644 --- a/arch/mips/configs/db1xxx_defconfig +++ b/arch/mips/configs/db1xxx_defconfig @@ -12,7 +12,6 @@ CONFIG_MEMCG=y CONFIG_BLK_CGROUP=y CONFIG_CGROUP_SCHED=y CONFIG_CFS_BANDWIDTH=y -CONFIG_RT_GROUP_SCHED=y CONFIG_CGROUP_FREEZER=y CONFIG_CGROUP_DEVICE=y CONFIG_CGROUP_CPUACCT=y diff --git a/arch/mips/configs/eyeq5_defconfig b/arch/mips/configs/eyeq5_defconfig index c35c29a4d479..3794707c9522 100644 --- a/arch/mips/configs/eyeq5_defconfig +++ b/arch/mips/configs/eyeq5_defconfig @@ -8,7 +8,6 @@ CONFIG_IKCONFIG_PROC=y CONFIG_MEMCG=y CONFIG_BLK_CGROUP=y CONFIG_CFS_BANDWIDTH=y -CONFIG_RT_GROUP_SCHED=y CONFIG_CGROUP_PIDS=y CONFIG_CGROUP_FREEZER=y CONFIG_CPUSETS=y diff --git a/arch/mips/configs/generic_defconfig b/arch/mips/configs/generic_defconfig index 071e2205c7ed..fa916407bdd4 100644 --- a/arch/mips/configs/generic_defconfig +++ b/arch/mips/configs/generic_defconfig @@ -5,7 +5,6 @@ CONFIG_IKCONFIG_PROC=y CONFIG_MEMCG=y CONFIG_BLK_CGROUP=y CONFIG_CFS_BANDWIDTH=y -CONFIG_RT_GROUP_SCHED=y CONFIG_CGROUP_PIDS=y CONFIG_CGROUP_FREEZER=y CONFIG_CPUSETS=y From patchwork Thu May 30 11:19:52 2024 Content-Type: text/plain; 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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 4/6] powerpc: defconfig: drop RT_GROUP_SCHED=y from ppc6xx_defconfig Date: Thu, 30 May 2024 19:19:52 +0800 Message-ID: <20240530111947.549474-12-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> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1725; i=CoelacanthusHex@gmail.com; h=from:subject; bh=Y154zJjweZqXiEFejTlLKuxlmlIxiSlX1+quATRaPS0=; b=owJ4nJvAy8zAJfY4pvNJRPo6U8bTakkMaREJNwz83B+K5vRMSbg2N3g2v23ulidmG/9Zikz5N r1Q2vnFpk0dpSwMYlwMsmKKLGI7n75eVvrowzJekxkwc1iZQIYwcHEKwES4nzD89/SoEmo8dO8G n0eO7Aw1cZt90Zb+dnteRPD1pkVFLBEsZmT4umrj9jtvzS78ub1pD3/1w7Mzvl6+8T9jVc6dBXm cuVf72AEUHU7d X-Developer-Key: i=CoelacanthusHex@gmail.com; a=openpgp; fpr=892EBC7DC392DFF9C9C03F1D15F4180E73787863 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240530_042018_053637_47E70143 X-CRM114-Status: GOOD ( 12.46 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Commit 6e5f1537833a ("powerpc: Add a 6xx defconfig") said it was copied from fedore's ppc32 defconfig, but at least since 2015-06-10, Fedora has dropped this option.[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.[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. 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/powerpc/configs/ppc6xx_defconfig | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/powerpc/configs/ppc6xx_defconfig b/arch/powerpc/configs/ppc6xx_defconfig index 66c7b28d7450..c06344db0eb3 100644 --- a/arch/powerpc/configs/ppc6xx_defconfig +++ b/arch/powerpc/configs/ppc6xx_defconfig @@ -12,7 +12,6 @@ CONFIG_TASK_XACCT=y CONFIG_TASK_IO_ACCOUNTING=y CONFIG_CGROUPS=y CONFIG_CGROUP_SCHED=y -CONFIG_RT_GROUP_SCHED=y CONFIG_CGROUP_DEVICE=y CONFIG_CGROUP_CPUACCT=y CONFIG_USER_NS=y From patchwork Thu May 30 11:19:53 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Celeste Liu X-Patchwork-Id: 13680253 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A0565C25B74 for ; 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Thu, 30 May 2024 04:20:17 -0700 (PDT) Received: from localhost ([212.107.28.52]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1f62218d9e6sm9517475ad.117.2024.05.30.04.20.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 May 2024 04:20:17 -0700 (PDT) From: Celeste Liu X-Google-Original-From: Celeste Liu To: Heinrich Schuchardt , Anup Patel , Guo Ren , Palmer Dabbelt , Paul Walmsley , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Vladimir Kondratiev , Gregory CLEMENT , =?utf-8?q?Th=C3=A9o_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 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> 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240530_042021_323285_DDA68F02 X-CRM114-Status: GOOD ( 11.83 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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/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_defconfig index 7b427c17fbfe..3599b1683593 100644 --- a/arch/sh/configs/sdk7786_defconfig +++ b/arch/sh/configs/sdk7786_defconfig @@ -17,7 +17,6 @@ CONFIG_CPUSETS=y CONFIG_CGROUP_CPUACCT=y CONFIG_CGROUP_MEMCG=y CONFIG_CGROUP_SCHED=y -CONFIG_RT_GROUP_SCHED=y CONFIG_BLK_CGROUP=y CONFIG_RELAY=y CONFIG_NAMESPACES=y diff --git a/arch/sh/configs/urquell_defconfig b/arch/sh/configs/urquell_defconfig index 00ef62133b04..9cf4a719001e 100644 --- a/arch/sh/configs/urquell_defconfig +++ b/arch/sh/configs/urquell_defconfig @@ -15,7 +15,6 @@ CONFIG_CPUSETS=y CONFIG_CGROUP_CPUACCT=y CONFIG_CGROUP_MEMCG=y CONFIG_CGROUP_SCHED=y -CONFIG_RT_GROUP_SCHED=y CONFIG_BLK_DEV_INITRD=y CONFIG_PROFILING=y CONFIG_MODULES=y From patchwork Thu May 30 11:19:54 2024 Content-Type: text/plain; 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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 6/6] arm: defconfig: drop RT_GROUP_SCHED=y from bcm2855/tegra/omap2plus Date: Thu, 30 May 2024 19:19:54 +0800 Message-ID: <20240530111947.549474-14-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> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2729; i=CoelacanthusHex@gmail.com; h=from:subject; bh=z/Xh6Oh4/edMyA0oTGEdVRRBweOMR/LS4ucNKKx8jxk=; b=owJ4nJvAy8zAJfY4pvNJRPo6U8bTakkMaREJt//Jpz1/9vq+ftrjnHPOdUJ7Zl16y3oqfNMJ2 c4TmxeuZVnZUcrCIMbFICumyCK28+nrZaWPPizjNZkBM4eVCWQIAxenAExEIJzhf8HRRdu8P/5W lRSfdEtSzuIjW+AJrhe/BHfb27mxp8vLBjP8D+rcabfgddQ8Botz1wy6Gi5ev2tY0Ppvy/7rzt8 y5t8MZQUAhClPwQ== X-Developer-Key: i=CoelacanthusHex@gmail.com; a=openpgp; fpr=892EBC7DC392DFF9C9C03F1D15F4180E73787863 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240530_042021_446674_11C961DF X-CRM114-Status: GOOD ( 12.13 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 Acked-by: Kevin Hilman Tested-by: Stefan Wahren --- 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=y CONFIG_BSD_PROCESS_ACCT_V3=y CONFIG_LOG_BUF_SHIFT=18 CONFIG_CFS_BANDWIDTH=y -CONFIG_RT_GROUP_SCHED=y CONFIG_CGROUP_FREEZER=y CONFIG_CPUSETS=y CONFIG_CGROUP_DEVICE=y diff --git a/arch/arm/configs/omap2plus_defconfig b/arch/arm/configs/omap2plus_defconfig index 3a166c2f02bd..9cb265c8d414 100644 --- a/arch/arm/configs/omap2plus_defconfig +++ b/arch/arm/configs/omap2plus_defconfig @@ -13,7 +13,6 @@ CONFIG_MEMCG=y CONFIG_BLK_CGROUP=y CONFIG_CGROUP_SCHED=y CONFIG_CFS_BANDWIDTH=y -CONFIG_RT_GROUP_SCHED=y CONFIG_CGROUP_FREEZER=y CONFIG_CPUSETS=y CONFIG_CGROUP_DEVICE=y diff --git a/arch/arm/configs/tegra_defconfig b/arch/arm/configs/tegra_defconfig index d2a094ad360c..3a9bda2bf422 100644 --- a/arch/arm/configs/tegra_defconfig +++ b/arch/arm/configs/tegra_defconfig @@ -6,7 +6,6 @@ CONFIG_IKCONFIG=y CONFIG_IKCONFIG_PROC=y CONFIG_CGROUPS=y CONFIG_CGROUP_SCHED=y -CONFIG_RT_GROUP_SCHED=y CONFIG_CGROUP_FREEZER=y CONFIG_CGROUP_CPUACCT=y CONFIG_CGROUP_DEBUG=y