Merge git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched (3174ffaa) · Commits · 戴 / test

Documentation/sched-rt-group.txt

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		Real-Time group scheduling.

		The problem space:

		In order to schedule multiple groups of realtime tasks each group must
		be assigned a fixed portion of the CPU time available. Without a minimum
		guarantee a realtime group can obviously fall short. A fuzzy upper limit
		is of no use since it cannot be relied upon. Which leaves us with just
		the single fixed portion.

		CPU time is divided by means of specifying how much time can be spent
		running in a given period. Say a frame fixed realtime renderer must
		deliver 25 frames a second, which yields a period of 0.04s. Now say
		it will also have to play some music and respond to input, leaving it
		with around 80% for the graphics. We can then give this group a runtime
		of 0.8 * 0.04s = 0.032s.

		This way the graphics group will have a 0.04s period with a 0.032s runtime
		limit.

		Now if the audio thread needs to refill the DMA buffer every 0.005s, but
		needs only about 3% CPU time to do so, it can do with a 0.03 * 0.005s
		= 0.00015s.


		The Interface:

		system wide:

		/proc/sys/kernel/sched_rt_period_ms
		/proc/sys/kernel/sched_rt_runtime_us

		CONFIG_FAIR_USER_SCHED

		/sys/kernel/uids/<uid>/cpu_rt_runtime_us

		or

		CONFIG_FAIR_CGROUP_SCHED

		/cgroup/<cgroup>/cpu.rt_runtime_us

		[ time is specified in us because the interface is s32; this gives an
		operating range of ~35m to 1us ]

		The period takes values in [ 1, INT_MAX ], runtime in [ -1, INT_MAX - 1 ].

		A runtime of -1 specifies runtime == period, ie. no limit.

		New groups get the period from /proc/sys/kernel/sched_rt_period_us and
		a runtime of 0.

		Settings are constrained to:

		\Sum_{i} runtime_{i} / global_period <= global_runtime / global_period

		in order to keep the configuration schedulable.

include/linux/cgroup_subsys.h

+1 −1

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		@@ -25,7 +25,7 @@ SUBSYS(ns)

		/* */

		#ifdef CONFIG_FAIR_CGROUP_SCHED
		#ifdef CONFIG_CGROUP_SCHED
		SUBSYS(cpu_cgroup)
		#endif

include/linux/sched.h

+12 −6

Original line number	Diff line number	Diff line
		@@ -590,7 +590,7 @@ struct user_struct {
		struct hlist_node uidhash_node;
		uid_t uid;

		#ifdef CONFIG_FAIR_USER_SCHED
		#ifdef CONFIG_USER_SCHED
		struct task_group *tg;
		#ifdef CONFIG_SYSFS
		struct kobject kobj;
		@@ -973,7 +973,7 @@ struct sched_rt_entity {
		unsigned long timeout;
		int nr_cpus_allowed;

		#ifdef CONFIG_FAIR_GROUP_SCHED
		#ifdef CONFIG_RT_GROUP_SCHED
		struct sched_rt_entity *parent;
		/* rq on which this entity is (to be) queued: */
		struct rt_rq *rt_rq;
		@@ -1541,8 +1541,6 @@ extern unsigned int sysctl_sched_child_runs_first;
		extern unsigned int sysctl_sched_features;
		extern unsigned int sysctl_sched_migration_cost;
		extern unsigned int sysctl_sched_nr_migrate;
		extern unsigned int sysctl_sched_rt_period;
		extern unsigned int sysctl_sched_rt_ratio;
		#if defined(CONFIG_FAIR_GROUP_SCHED) && defined(CONFIG_SMP)
		extern unsigned int sysctl_sched_min_bal_int_shares;
		extern unsigned int sysctl_sched_max_bal_int_shares;
		@@ -1552,6 +1550,8 @@ int sched_nr_latency_handler(struct ctl_table *table, int write,
		struct file file, void __user buffer, size_t *length,
		loff_t *ppos);
		#endif
		extern unsigned int sysctl_sched_rt_period;
		extern int sysctl_sched_rt_runtime;

		extern unsigned int sysctl_sched_compat_yield;

		@@ -2027,16 +2027,22 @@ extern int sched_mc_power_savings, sched_smt_power_savings;

		extern void normalize_rt_tasks(void);

		#ifdef CONFIG_FAIR_GROUP_SCHED
		#ifdef CONFIG_GROUP_SCHED

		extern struct task_group init_task_group;

		extern struct task_group *sched_create_group(void);
		extern void sched_destroy_group(struct task_group *tg);
		extern void sched_move_task(struct task_struct *tsk);
		#ifdef CONFIG_FAIR_GROUP_SCHED
		extern int sched_group_set_shares(struct task_group *tg, unsigned long shares);
		extern unsigned long sched_group_shares(struct task_group *tg);

		#endif
		#ifdef CONFIG_RT_GROUP_SCHED
		extern int sched_group_set_rt_runtime(struct task_group *tg,
		long rt_runtime_us);
		extern long sched_group_rt_runtime(struct task_group *tg);
		#endif
		#endif

		#ifdef CONFIG_TASK_XACCT

init/Kconfig

+17 −6

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		@@ -311,25 +311,36 @@ config CPUSETS

		Say N if unsure.

		config FAIR_GROUP_SCHED
		bool "Fair group CPU scheduler"
		config GROUP_SCHED
		bool "Group CPU scheduler"
		default y
		help
		This feature lets CPU scheduler recognize task groups and control CPU
		bandwidth allocation to such task groups.

		config FAIR_GROUP_SCHED
		bool "Group scheduling for SCHED_OTHER"
		depends on GROUP_SCHED
		default y

		config RT_GROUP_SCHED
		bool "Group scheduling for SCHED_RR/FIFO"
		depends on EXPERIMENTAL
		depends on GROUP_SCHED
		default n

		choice
		depends on FAIR_GROUP_SCHED
		depends on GROUP_SCHED
		prompt "Basis for grouping tasks"
		default FAIR_USER_SCHED
		default USER_SCHED

		config FAIR_USER_SCHED
		config USER_SCHED
		bool "user id"
		help
		This option will choose userid as the basis for grouping
		tasks, thus providing equal CPU bandwidth to each user.

		config FAIR_CGROUP_SCHED
		config CGROUP_SCHED
		bool "Control groups"
		depends on CGROUPS
		help

kernel/rtmutex.c

+4 −1

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		@@ -630,9 +630,12 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
		set_current_state(state);

		/* Setup the timer, when timeout != NULL */
		if (unlikely(timeout))
		if (unlikely(timeout)) {
		hrtimer_start(&timeout->timer, timeout->timer.expires,
		HRTIMER_MODE_ABS);
		if (!hrtimer_active(&timeout->timer))
		timeout->task = NULL;
		}

		for (;;) {
		/* Try to acquire the lock: */

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