Commit e34e0131 authored by Michal Koutný's avatar Michal Koutný Committed by Peter Zijlstra
Browse files

sched: Add commadline option for RT_GROUP_SCHED toggling 



Only simple implementation with a static key wrapper, it will be wired
in later.

Signed-off-by: default avatarMichal Koutný <mkoutny@suse.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20250310170442.504716-5-mkoutny@suse.com
parent a5a25b32

Documentation/admin-guide/kernel-parameters.txt

+5 −0
Original line number Diff line number Diff line
@@ -6280,6 +6280,11 @@ 
			Memory area to be used by remote processor image,

			managed by CMA.



	rt_group_sched=	[KNL] Enable or disable SCHED_RR/FIFO group scheduling

			when CONFIG_RT_GROUP_SCHED=y. Defaults to

			!CONFIG_RT_GROUP_SCHED_DEFAULT_DISABLED.

			Format: <bool>



	rw		[KNL] Mount root device read-write on boot



	S		[KNL] Run init in single mode

init/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -1082,6 +1082,17 @@ config RT_GROUP_SCHED 
	  realtime bandwidth for them.

	  See Documentation/scheduler/sched-rt-group.rst for more information.



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

kernel/sched/core.c

+25 −0
Original line number Diff line number Diff line
@@ -9892,6 +9892,31 @@ static struct cftype cpu_legacy_files[] = { 
	{ }	/* Terminate */

};



#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=", setup_rt_group_sched);

#endif /* CONFIG_RT_GROUP_SCHED */



static int cpu_extra_stat_show(struct seq_file *sf,

			       struct cgroup_subsys_state *css)

{

kernel/sched/sched.h

+17 −0
Original line number Diff line number Diff line
@@ -1500,6 +1500,23 @@ static inline bool sched_group_cookie_match(struct rq *rq, 
}



#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 */



static inline void lockdep_assert_rq_held(struct rq *rq)

{