Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f4e26b12 authored by Paul Turner's avatar Paul Turner Committed by Ingo Molnar
Browse files

sched: Introduce temporary FAIR_GROUP_SCHED dependency for load-tracking 



While per-entity load-tracking is generally useful, beyond computing shares
distribution, e.g. runnable based load-balance (in progress), governors,
power-management, etc.

These facilities are not yet consumers of this data.  This may be trivially
reverted when the information is required; but avoid paying the overhead for
calculations we will not use until then.

Signed-off-by: default avatarPaul Turner <pjt@google.com>
Reviewed-by: default avatarBen Segall <bsegall@google.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141507.422162369@google.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 5b51f2f8

include/linux/sched.h

+7 −1
Original line number Diff line number Diff line
@@ -1168,7 +1168,13 @@ struct sched_entity { 
	/* rq "owned" by this entity/group: */

	struct cfs_rq		*my_q;

#endif

#ifdef CONFIG_SMP

/*

 * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be

 * removed when useful for applications beyond shares distribution (e.g.

 * load-balance).

 */

#if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)

	/* Per-entity load-tracking */

	struct sched_avg	avg;

#endif

};

kernel/sched/core.c

+6 −1
Original line number Diff line number Diff line
@@ -1526,7 +1526,12 @@ static void __sched_fork(struct task_struct *p) 
	p->se.vruntime			= 0;

	INIT_LIST_HEAD(&p->se.group_node);



#ifdef CONFIG_SMP

/*

 * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be

 * removed when useful for applications beyond shares distribution (e.g.

 * load-balance).

 */

#if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)

	p->se.avg.runnable_avg_period = 0;

	p->se.avg.runnable_avg_sum = 0;

#endif

kernel/sched/fair.c

+11 −2
Original line number Diff line number Diff line
@@ -882,7 +882,8 @@ static inline void update_cfs_shares(struct cfs_rq *cfs_rq) 
}

#endif /* CONFIG_FAIR_GROUP_SCHED */



#ifdef CONFIG_SMP

/* Only depends on SMP, FAIR_GROUP_SCHED may be removed when useful in lb */

#if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)

/*

 * We choose a half-life close to 1 scheduling period.

 * Note: The tables below are dependent on this value.
@@ -3173,6 +3174,12 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags) 
	return new_cpu;

}



/*

 * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be

 * removed when useful for applications beyond shares distribution (e.g.

 * load-balance).

 */

#ifdef CONFIG_FAIR_GROUP_SCHED

/*

 * Called immediately before a task is migrated to a new cpu; task_cpu(p) and

 * cfs_rq_of(p) references at time of call are still valid and identify the
@@ -3196,6 +3203,7 @@ migrate_task_rq_fair(struct task_struct *p, int next_cpu) 
		atomic64_add(se->avg.load_avg_contrib, &cfs_rq->removed_load);

	}

}

#endif

#endif /* CONFIG_SMP */



static unsigned long
@@ -5773,8 +5781,9 @@ const struct sched_class fair_sched_class = { 


#ifdef CONFIG_SMP

	.select_task_rq		= select_task_rq_fair,

#ifdef CONFIG_FAIR_GROUP_SCHED

	.migrate_task_rq	= migrate_task_rq_fair,



#endif

	.rq_online		= rq_online_fair,

	.rq_offline		= rq_offline_fair,

kernel/sched/sched.h

+8 −1
Original line number Diff line number Diff line
@@ -225,6 +225,12 @@ struct cfs_rq { 
#endif



#ifdef CONFIG_SMP

/*

 * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be

 * removed when useful for applications beyond shares distribution (e.g.

 * load-balance).

 */

#ifdef CONFIG_FAIR_GROUP_SCHED

	/*

	 * CFS Load tracking

	 * Under CFS, load is tracked on a per-entity basis and aggregated up.
@@ -234,7 +240,8 @@ struct cfs_rq { 
	u64 runnable_load_avg, blocked_load_avg;

	atomic64_t decay_counter, removed_load;

	u64 last_decay;



#endif /* CONFIG_FAIR_GROUP_SCHED */

/* These always depend on CONFIG_FAIR_GROUP_SCHED */

#ifdef CONFIG_FAIR_GROUP_SCHED

	u32 tg_runnable_contrib;

	u64 tg_load_contrib;