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Commit 5f3edc1b authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
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sched: Hook sched_balance_self() into sched_class::select_task_rq() 



Rather ugly patch to fully place the sched_balance_self() code
inside the fair class.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent aaee1203

include/linux/sched.h

+2 −1
Original line number Diff line number Diff line
@@ -811,6 +811,7 @@ enum cpu_idle_type { 
#define SD_SERIALIZE		0x0400	/* Only a single load balancing instance */

#define SD_WAKE_IDLE_FAR	0x0800	/* Gain latency sacrificing cache hit */

#define SD_PREFER_SIBLING	0x1000	/* Prefer to place tasks in a sibling domain */

#define SD_BALANCE_WAKE		0x2000  /* Balance on wakeup */



enum powersavings_balance_level {

	POWERSAVINGS_BALANCE_NONE = 0,  /* No power saving load balance */
@@ -1032,7 +1033,7 @@ struct sched_class { 
	void (*put_prev_task) (struct rq *rq, struct task_struct *p);



#ifdef CONFIG_SMP

	int  (*select_task_rq)(struct task_struct *p, int sync);

	int  (*select_task_rq)(struct task_struct *p, int flag, int sync);



	unsigned long (*load_balance) (struct rq *this_rq, int this_cpu,

			struct rq *busiest, unsigned long max_load_move,

kernel/sched.c

+7 −7
Original line number Diff line number Diff line
@@ -2350,7 +2350,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) 
	if (unlikely(task_running(rq, p)))

		goto out_activate;



	cpu = p->sched_class->select_task_rq(p, sync);

	cpu = p->sched_class->select_task_rq(p, SD_BALANCE_WAKE, sync);

	if (cpu != orig_cpu) {

		set_task_cpu(p, cpu);

		task_rq_unlock(rq, &flags);
@@ -2525,11 +2525,6 @@ void sched_fork(struct task_struct *p, int clone_flags) 


	__sched_fork(p);



#ifdef CONFIG_SMP

	cpu = sched_balance_self(cpu, SD_BALANCE_FORK);

#endif

	set_task_cpu(p, cpu);



	/*

	 * Make sure we do not leak PI boosting priority to the child.

	 */
@@ -2560,6 +2555,11 @@ void sched_fork(struct task_struct *p, int clone_flags) 
	if (!rt_prio(p->prio))

		p->sched_class = &fair_sched_class;



#ifdef CONFIG_SMP

	cpu = p->sched_class->select_task_rq(p, SD_BALANCE_FORK, 0);

#endif

	set_task_cpu(p, cpu);



#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)

	if (likely(sched_info_on()))

		memset(&p->sched_info, 0, sizeof(p->sched_info));
@@ -3114,7 +3114,7 @@ static void sched_migrate_task(struct task_struct *p, int dest_cpu) 
void sched_exec(void)

{

	int new_cpu, this_cpu = get_cpu();

	new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC);

	new_cpu = current->sched_class->select_task_rq(current, SD_BALANCE_EXEC, 0);

	put_cpu();

	if (new_cpu != this_cpu)

		sched_migrate_task(current, new_cpu);

kernel/sched_fair.c

+6 −1
Original line number Diff line number Diff line
@@ -1300,7 +1300,9 @@ wake_affine(struct sched_domain *this_sd, struct rq *this_rq, 
	return 0;

}



static int select_task_rq_fair(struct task_struct *p, int sync)

static int sched_balance_self(int cpu, int flag);



static int select_task_rq_fair(struct task_struct *p, int flag, int sync)

{

	struct sched_domain *sd, *this_sd = NULL;

	int prev_cpu, this_cpu, new_cpu;
@@ -1314,6 +1316,9 @@ static int select_task_rq_fair(struct task_struct *p, int sync) 
	this_rq		= cpu_rq(this_cpu);

	new_cpu		= prev_cpu;



	if (flag != SD_BALANCE_WAKE)

		return sched_balance_self(this_cpu, flag);



	/*

	 * 'this_sd' is the first domain that both

	 * this_cpu and prev_cpu are present in:

kernel/sched_idletask.c

+1 −1
Original line number Diff line number Diff line
@@ -6,7 +6,7 @@ 
 */



#ifdef CONFIG_SMP

static int select_task_rq_idle(struct task_struct *p, int sync)

static int select_task_rq_idle(struct task_struct *p, int flag, int sync)

{

	return task_cpu(p); /* IDLE tasks as never migrated */

}

kernel/sched_rt.c

+4 −1
Original line number Diff line number Diff line
@@ -938,10 +938,13 @@ static void yield_task_rt(struct rq *rq) 
#ifdef CONFIG_SMP

static int find_lowest_rq(struct task_struct *task);



static int select_task_rq_rt(struct task_struct *p, int sync)

static int select_task_rq_rt(struct task_struct *p, int flag, int sync)

{

	struct rq *rq = task_rq(p);



	if (flag != SD_BALANCE_WAKE)

		return smp_processor_id();



	/*

	 * If the current task is an RT task, then

	 * try to see if we can wake this RT task up on another