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Commit 58e2d4ca authored by Srivatsa Vaddagiri's avatar Srivatsa Vaddagiri Committed by Ingo Molnar
Browse files

sched: group scheduling, change how cpu load is calculated 



This patch changes how the cpu load exerted by fair_sched_class tasks
is calculated. Load exerted by fair_sched_class tasks on a cpu is now
a summation of the group weights, rather than summation of task weights.
Weight exerted by a group on a cpu is dependent on the shares allocated
to it.

This version of patch has a minor impact on code size, but should have
no runtime/functional impact for !CONFIG_FAIR_GROUP_SCHED.

Signed-off-by: default avatarSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent ec2c507f

kernel/sched.c

+11 −16
Original line number Diff line number Diff line
@@ -886,6 +886,16 @@ static void cpuacct_charge(struct task_struct *tsk, u64 cputime); 
static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}

#endif



static inline void inc_cpu_load(struct rq *rq, unsigned long load)

{

	update_load_add(&rq->load, load);

}



static inline void dec_cpu_load(struct rq *rq, unsigned long load)

{

	update_load_sub(&rq->load, load);

}



#include "sched_stats.h"

#include "sched_idletask.c"

#include "sched_fair.c"
@@ -896,26 +906,14 @@ static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {} 


#define sched_class_highest (&rt_sched_class)



static inline void inc_load(struct rq *rq, const struct task_struct *p)

{

	update_load_add(&rq->load, p->se.load.weight);

}



static inline void dec_load(struct rq *rq, const struct task_struct *p)

{

	update_load_sub(&rq->load, p->se.load.weight);

}



static void inc_nr_running(struct task_struct *p, struct rq *rq)

{

	rq->nr_running++;

	inc_load(rq, p);

}



static void dec_nr_running(struct task_struct *p, struct rq *rq)

{

	rq->nr_running--;

	dec_load(rq, p);

}



static void set_load_weight(struct task_struct *p)
@@ -4087,10 +4085,8 @@ void set_user_nice(struct task_struct *p, long nice) 
		goto out_unlock;

	}

	on_rq = p->se.on_rq;

	if (on_rq) {

	if (on_rq)

		dequeue_task(rq, p, 0);

		dec_load(rq, p);

	}



	p->static_prio = NICE_TO_PRIO(nice);

	set_load_weight(p);
@@ -4100,7 +4096,6 @@ void set_user_nice(struct task_struct *p, long nice) 


	if (on_rq) {

		enqueue_task(rq, p, 0);

		inc_load(rq, p);

		/*

		 * If the task increased its priority or is running and

		 * lowered its priority, then reschedule its CPU:

kernel/sched_fair.c

+27 −4
Original line number Diff line number Diff line
@@ -760,15 +760,26 @@ static inline struct sched_entity *parent_entity(struct sched_entity *se) 
static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup)

{

	struct cfs_rq *cfs_rq;

	struct sched_entity *se = &p->se;

	struct sched_entity *se = &p->se,

			    *topse = NULL;	/* Highest schedulable entity */

	int incload = 1;



	for_each_sched_entity(se) {

		if (se->on_rq)

		topse = se;

		if (se->on_rq) {

			incload = 0;

			break;

		}

		cfs_rq = cfs_rq_of(se);

		enqueue_entity(cfs_rq, se, wakeup);

		wakeup = 1;

	}

	/* Increment cpu load if we just enqueued the first task of a group on

	 * 'rq->cpu'. 'topse' represents the group to which task 'p' belongs

	 * at the highest grouping level.

	 */

	if (incload)

		inc_cpu_load(rq, topse->load.weight);

}



/*
@@ -779,16 +790,28 @@ static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup) 
static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep)

{

	struct cfs_rq *cfs_rq;

	struct sched_entity *se = &p->se;

	struct sched_entity *se = &p->se,

			    *topse = NULL; 	/* Highest schedulable entity */

	int decload = 1;



	for_each_sched_entity(se) {

		topse = se;

		cfs_rq = cfs_rq_of(se);

		dequeue_entity(cfs_rq, se, sleep);

		/* Don't dequeue parent if it has other entities besides us */

		if (cfs_rq->load.weight)

		if (cfs_rq->load.weight) {

			if (parent_entity(se))

				decload = 0;

			break;

		}

		sleep = 1;

	}

	/* Decrement cpu load if we just dequeued the last task of a group on

	 * 'rq->cpu'. 'topse' represents the group to which task 'p' belongs

	 * at the highest grouping level.

	 */

	if (decload)

		dec_cpu_load(rq, topse->load.weight);

}



/*

kernel/sched_rt.c

+2 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup) 


	list_add_tail(&p->run_list, array->queue + p->prio);

	__set_bit(p->prio, array->bitmap);

	inc_cpu_load(rq, p->se.load.weight);

}



/*
@@ -46,6 +47,7 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep) 
	list_del(&p->run_list);

	if (list_empty(array->queue + p->prio))

		__clear_bit(p->prio, array->bitmap);

	dec_cpu_load(rq, p->se.load.weight);

}



/*