Commit 67bb6c03 authored by Gautham R Shenoy's avatar Gautham R Shenoy Committed by Ingo Molnar
Browse files

sched: Simple helper functions for find_busiest_group() 



Impact: cleanup

Currently the load idx calculation code is in find_busiest_group().
Move that to a static inline helper function.

Similary, to find the first cpu of a sched_group we use
cpumask_first(sched_group_cpus(group))

Use a helper to that. It improves readability in some cases.

Signed-off-by: default avatarGautham R Shenoy <ego@in.ibm.com>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Balbir Singh" <balbir@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Dhaval Giani" <dhaval@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: "Vaidyanathan Srinivasan" <svaidy@linux.vnet.ibm.com>
LKML-Reference: <20090325091335.13992.55424.stgit@sofia.in.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent b6d98422

kernel/sched.c

+43 −12
Original line number Diff line number Diff line
@@ -3189,6 +3189,43 @@ static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, 


	return 0;

}

/********** Helpers for find_busiest_group ************************/



/**

 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.

 * @group: The group whose first cpu is to be returned.

 */

static inline unsigned int group_first_cpu(struct sched_group *group)

{

	return cpumask_first(sched_group_cpus(group));

}



/**

 * get_sd_load_idx - Obtain the load index for a given sched domain.

 * @sd: The sched_domain whose load_idx is to be obtained.

 * @idle: The Idle status of the CPU for whose sd load_icx is obtained.

 */

static inline int get_sd_load_idx(struct sched_domain *sd,

					enum cpu_idle_type idle)

{

	int load_idx;



	switch (idle) {

	case CPU_NOT_IDLE:

		load_idx = sd->busy_idx;

		break;



	case CPU_NEWLY_IDLE:

		load_idx = sd->newidle_idx;

		break;

	default:

		load_idx = sd->idle_idx;

		break;

	}



	return load_idx;

}

/******* find_busiest_group() helpers end here *********************/



/*

 * find_busiest_group finds and returns the busiest CPU group within the
@@ -3217,12 +3254,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, 
	busiest_load_per_task = busiest_nr_running = 0;

	this_load_per_task = this_nr_running = 0;



	if (idle == CPU_NOT_IDLE)

		load_idx = sd->busy_idx;

	else if (idle == CPU_NEWLY_IDLE)

		load_idx = sd->newidle_idx;

	else

		load_idx = sd->idle_idx;

	load_idx = get_sd_load_idx(sd, idle);



	do {

		unsigned long load, group_capacity, max_cpu_load, min_cpu_load;
@@ -3238,7 +3270,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, 
					       sched_group_cpus(group));



		if (local_group)

			balance_cpu = cpumask_first(sched_group_cpus(group));

			balance_cpu = group_first_cpu(group);



		/* Tally up the load of all CPUs in the group */

		sum_weighted_load = sum_nr_running = avg_load = 0;
@@ -3359,8 +3391,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, 
		 */

		if ((sum_nr_running < min_nr_running) ||

		    (sum_nr_running == min_nr_running &&

		     cpumask_first(sched_group_cpus(group)) >

		     cpumask_first(sched_group_cpus(group_min)))) {

		     group_first_cpu(group) > group_first_cpu(group_min))) {

			group_min = group;

			min_nr_running = sum_nr_running;

			min_load_per_task = sum_weighted_load /
@@ -3375,8 +3406,8 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, 
		if (sum_nr_running <= group_capacity - 1) {

			if (sum_nr_running > leader_nr_running ||

			    (sum_nr_running == leader_nr_running &&

			     cpumask_first(sched_group_cpus(group)) <

			     cpumask_first(sched_group_cpus(group_leader)))) {

			     group_first_cpu(group) <

			     group_first_cpu(group_leader))) {

				group_leader = group;

				leader_nr_running = sum_nr_running;

			}
@@ -3504,7 +3535,7 @@ out_balanced: 
		*imbalance = min_load_per_task;

		if (sched_mc_power_savings >= POWERSAVINGS_BALANCE_WAKEUP) {

			cpu_rq(this_cpu)->rd->sched_mc_preferred_wakeup_cpu =

				cpumask_first(sched_group_cpus(group_leader));

				group_first_cpu(group_leader);

		}

		return group_min;

	}

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