Commit 681f3e68 authored by Peter Williams's avatar Peter Williams Committed by Ingo Molnar
Browse files

sched: isolate SMP balancing code a bit more 



At the moment, a lot of load balancing code that is irrelevant to non
SMP systems gets included during non SMP builds.

This patch addresses this issue and reduces the binary size on non
SMP systems:

   text    data     bss     dec     hex filename
  10983      28    1192   12203    2fab sched.o.before
  10739      28    1192   11959    2eb7 sched.o.after

Signed-off-by: default avatarPeter Williams <pwil3058@bigpond.net.au>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent e1d1484f

include/linux/sched.h

+2 −0
Original line number Diff line number Diff line
@@ -828,6 +828,7 @@ struct sched_class { 
	struct task_struct * (*pick_next_task) (struct rq *rq);

	void (*put_prev_task) (struct rq *rq, struct task_struct *p);



#ifdef CONFIG_SMP

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

			struct rq *busiest, unsigned long max_load_move,

			struct sched_domain *sd, enum cpu_idle_type idle,
@@ -836,6 +837,7 @@ struct sched_class { 
	int (*move_one_task) (struct rq *this_rq, int this_cpu,

			      struct rq *busiest, struct sched_domain *sd,

			      enum cpu_idle_type idle);

#endif



	void (*set_curr_task) (struct rq *rq);

	void (*task_tick) (struct rq *rq, struct task_struct *p);

kernel/sched.c

+0 −17
Original line number Diff line number Diff line
@@ -849,23 +849,6 @@ static int 
iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,

		   struct sched_domain *sd, enum cpu_idle_type idle,

		   struct rq_iterator *iterator);

#else

static inline unsigned long

balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,

	      unsigned long max_load_move, struct sched_domain *sd,

	      enum cpu_idle_type idle, int *all_pinned,

	      int *this_best_prio, struct rq_iterator *iterator)

{

	return 0;

}



static inline int

iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,

		   struct sched_domain *sd, enum cpu_idle_type idle,

		   struct rq_iterator *iterator)

{

	return 0;

}

#endif



#include "sched_stats.h"

kernel/sched_fair.c

+4 −0
Original line number Diff line number Diff line
@@ -876,6 +876,7 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev) 
	}

}



#ifdef CONFIG_SMP

/**************************************************

 * Fair scheduling class load-balancing methods:

 */
@@ -1008,6 +1009,7 @@ move_one_task_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, 


	return 0;

}

#endif



/*

 * scheduler tick hitting a task of our scheduling class:
@@ -1084,8 +1086,10 @@ static const struct sched_class fair_sched_class = { 
	.pick_next_task		= pick_next_task_fair,

	.put_prev_task		= put_prev_task_fair,



#ifdef CONFIG_SMP

	.load_balance		= load_balance_fair,

	.move_one_task		= move_one_task_fair,

#endif



	.set_curr_task          = set_curr_task_fair,

	.task_tick		= task_tick_fair,

kernel/sched_idletask.c

+4 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ static void put_prev_task_idle(struct rq *rq, struct task_struct *prev) 
{

}



#ifdef CONFIG_SMP

static unsigned long

load_balance_idle(struct rq *this_rq, int this_cpu, struct rq *busiest,

		  unsigned long max_load_move,
@@ -52,6 +53,7 @@ move_one_task_idle(struct rq *this_rq, int this_cpu, struct rq *busiest, 
{

	return 0;

}

#endif



static void task_tick_idle(struct rq *rq, struct task_struct *curr)

{
@@ -76,8 +78,10 @@ const struct sched_class idle_sched_class = { 
	.pick_next_task		= pick_next_task_idle,

	.put_prev_task		= put_prev_task_idle,



#ifdef CONFIG_SMP

	.load_balance		= load_balance_idle,

	.move_one_task		= move_one_task_idle,

#endif



	.set_curr_task          = set_curr_task_idle,

	.task_tick		= task_tick_idle,

kernel/sched_rt.c

+4 −0
Original line number Diff line number Diff line
@@ -98,6 +98,7 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p) 
	p->se.exec_start = 0;

}



#ifdef CONFIG_SMP

/*

 * Load-balancing iterator. Note: while the runqueue stays locked

 * during the whole iteration, the current task might be
@@ -202,6 +203,7 @@ move_one_task_rt(struct rq *this_rq, int this_cpu, struct rq *busiest, 
	return iter_move_one_task(this_rq, this_cpu, busiest, sd, idle,

				  &rt_rq_iterator);

}

#endif



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

{
@@ -245,8 +247,10 @@ const struct sched_class rt_sched_class = { 
	.pick_next_task		= pick_next_task_rt,

	.put_prev_task		= put_prev_task_rt,



#ifdef CONFIG_SMP

	.load_balance		= load_balance_rt,

	.move_one_task		= move_one_task_rt,

#endif



	.set_curr_task          = set_curr_task_rt,

	.task_tick		= task_tick_rt,

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