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AJvYcCUYKjCIoKWOipRhCL3aalrXlxnJyCe4mdL0JNjiGJb0HeFFWqcdovENdbmN62ZoWozlqAtwtT53gdLU@vger.kernel.org X-Gm-Message-State: AOJu0YzJhEdAW3lRLgrGyl08HVY2dF0H5NRudwQSBE2INRz4BtENBtW9 dKqaykI3DoZJMzgPfmQ+XsQbe3xy3sEb1n608DQm+Xo2eQ3TRZ3YkLYGr6o22EQ= X-Google-Smtp-Source: AGHT+IFNbFNRlMUVnmzvIAqMYOHLNoYiu39w2cW+++5PhbuKhP72IpMktdJxCrIrvKb5Z0jSCotKrw== X-Received: by 2002:a17:902:f60e:b0:205:809c:d490 with SMTP id d9443c01a7336-20781d61d67mr8439965ad.16.1726174689001; Thu, 12 Sep 2024 13:58:09 -0700 (PDT) Received: from ghost ([50.145.13.30]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2076b0097desm18030445ad.247.2024.09.12.13.58.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Sep 2024 13:58:08 -0700 (PDT) Date: Thu, 12 Sep 2024 13:58:05 -0700 From: Charlie Jenkins To: Celeste Liu Cc: 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 , 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 Subject: Re: [PATCH v3 1/4] riscv: defconfig: drop RT_GROUP_SCHED=y Message-ID: References: <20240910-fix-riscv-rt_group_sched-v3-0-486e75e5ae6d@gmail.com> <20240910-fix-riscv-rt_group_sched-v3-1-486e75e5ae6d@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: <20240910-fix-riscv-rt_group_sched-v3-1-486e75e5ae6d@gmail.com> On Tue, Sep 10, 2024 at 08:51:07PM +0800, Celeste Liu wrote: > 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 > > Acked-by: Heinrich Schuchardt > Signed-off-by: Celeste Liu Acked-by: Charlie Jenkins > --- > arch/riscv/configs/defconfig | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig > index 12dc8c73a8acfaa5c8f442968a807de303428d9e..de85c3ab261e6d62b2089a3c89bdc9d1b34fa792 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 > > -- > 2.46.0 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv