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Mon, 10 Mar 2025 10:05:01 -0700 (PDT) From: =?UTF-8?q?Michal=20Koutn=C3=BD?= To: Peter Zijlstra , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Frederic Weisbecker , =?UTF-8?q?Michal=20Koutn=C3=BD?= Subject: [PATCH v2 04/10] sched: Add commadline option for RT_GROUP_SCHED toggling Date: Mon, 10 Mar 2025 18:04:36 +0100 Message-ID: <20250310170442.504716-5-mkoutny@suse.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250310170442.504716-1-mkoutny@suse.com> References: <20250310170442.504716-1-mkoutny@suse.com> 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 Only simple implementation with a static key wrapper, it will be wired in later. Signed-off-by: Michal Koutn=C3=BD --- .../admin-guide/kernel-parameters.txt | 5 ++++ init/Kconfig | 11 ++++++++ kernel/sched/core.c | 25 +++++++++++++++++++ kernel/sched/sched.h | 17 +++++++++++++ 4 files changed, 58 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentatio= n/admin-guide/kernel-parameters.txt index fb8752b42ec85..6f734c57e6ce2 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -6235,6 +6235,11 @@ Memory area to be used by remote processor image, managed by CMA. =20 + rt_group_sched=3D [KNL] Enable or disable SCHED_RR/FIFO group scheduling + when CONFIG_RT_GROUP_SCHED=3Dy. Defaults to + !CONFIG_RT_GROUP_SCHED_DEFAULT_DISABLED. + Format: + rw [KNL] Mount root device read-write on boot =20 S [KNL] Run init in single mode diff --git a/init/Kconfig b/init/Kconfig index 4dbc059d2de5c..5461e232d325a 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1079,6 +1079,17 @@ config RT_GROUP_SCHED realtime bandwidth for them. See Documentation/scheduler/sched-rt-group.rst for more information. =20 +config RT_GROUP_SCHED_DEFAULT_DISABLED + bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO" + depends on RT_GROUP_SCHED + default n + help + When set, the RT group scheduling is disabled by default. The option + is in inverted form so that mere RT_GROUP_SCHED enables the group + scheduling. + + Say N if unsure. + config EXT_GROUP_SCHED bool depends on SCHED_CLASS_EXT && CGROUP_SCHED diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 165c90ba64ea9..e6e072e618a00 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -9852,6 +9852,31 @@ static struct cftype cpu_legacy_files[] =3D { { } /* Terminate */ }; =20 +#ifdef CONFIG_RT_GROUP_SCHED +# ifdef CONFIG_RT_GROUP_SCHED_DEFAULT_DISABLED +DEFINE_STATIC_KEY_FALSE(rt_group_sched); +# else +DEFINE_STATIC_KEY_TRUE(rt_group_sched); +# endif + +static int __init setup_rt_group_sched(char *str) +{ + long val; + + if (kstrtol(str, 0, &val) || val < 0 || val > 1) { + pr_warn("Unable to set rt_group_sched\n"); + return 1; + } + if (val) + static_branch_enable(&rt_group_sched); + else + static_branch_disable(&rt_group_sched); + + return 1; +} +__setup("rt_group_sched=3D", setup_rt_group_sched); +#endif /* CONFIG_RT_GROUP_SCHED */ + static int cpu_extra_stat_show(struct seq_file *sf, struct cgroup_subsys_state *css) { diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 4453e79ff65a3..e4f6c0b1a3163 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1508,6 +1508,23 @@ static inline bool sched_group_cookie_match(struct r= q *rq, } =20 #endif /* !CONFIG_SCHED_CORE */ +#ifdef CONFIG_RT_GROUP_SCHED +# ifdef CONFIG_RT_GROUP_SCHED_DEFAULT_DISABLED +DECLARE_STATIC_KEY_FALSE(rt_group_sched); +static inline bool rt_group_sched_enabled(void) +{ + return static_branch_unlikely(&rt_group_sched); +} +# else +DECLARE_STATIC_KEY_TRUE(rt_group_sched); +static inline bool rt_group_sched_enabled(void) +{ + return static_branch_likely(&rt_group_sched); +} +# endif /* CONFIG_RT_GROUP_SCHED_DEFAULT_DISABLED */ +#else +# define rt_group_sched_enabled() false +#endif /* CONFIG_RT_GROUP_SCHED */ =20 static inline void lockdep_assert_rq_held(struct rq *rq) { --=20 2.48.1