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sched: Remove load_balance_newidle()

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The two functions: load_balance{,_newidle}() are very similar, with the
following differences:

 - rq->lock usage
 - sb->balance_interval updates
 - *balance check

So remove the load_balance_newidle() call with load_balance(.idle =
CPU_NEWLY_IDLE), explicitly unlock the rq->lock before calling (would be
done by double_lock_balance() anyway), and ignore the other differences
for now.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-12-23 15:29:42 +01:00 committed by Ingo Molnar
parent 1af3ed3ddf
commit f492e12ef0
1 changed files with 13 additions and 122 deletions
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135
kernel/sched_fair.c
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@ -3009,125 +3009,6 @@ static int load_balance(int this_cpu, struct rq *this_rq,
return ld_moved;
}
/*
* Check this_cpu to ensure it is balanced within domain. Attempt to move
* tasks if there is an imbalance.
*
* Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
* this_rq is locked.
*/
static int
load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd)
{
struct sched_group *group;
struct rq *busiest = NULL;
unsigned long imbalance;
int ld_moved = 0;
int sd_idle = 0;
int all_pinned = 0;
struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
cpumask_copy(cpus, cpu_active_mask);
/*
* When power savings policy is enabled for the parent domain, idle
* sibling can pick up load irrespective of busy siblings. In this case,
* let the state of idle sibling percolate up as IDLE, instead of
* portraying it as CPU_NOT_IDLE.
*/
if (sd->flags & SD_SHARE_CPUPOWER &&
!test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
sd_idle = 1;
schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]);
redo:
update_shares_locked(this_rq, sd);
group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE,
&sd_idle, cpus, NULL);
if (!group) {
schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]);
goto out_balanced;
}
busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus);
if (!busiest) {
schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]);
goto out_balanced;
}
BUG_ON(busiest == this_rq);
schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
ld_moved = 0;
if (busiest->nr_running > 1) {
/* Attempt to move tasks */
double_lock_balance(this_rq, busiest);
/* this_rq->clock is already updated */
update_rq_clock(busiest);
ld_moved = move_tasks(this_rq, this_cpu, busiest,
imbalance, sd, CPU_NEWLY_IDLE,
&all_pinned);
double_unlock_balance(this_rq, busiest);
if (unlikely(all_pinned)) {
cpumask_clear_cpu(cpu_of(busiest), cpus);
if (!cpumask_empty(cpus))
goto redo;
}
}
if (!ld_moved) {
int active_balance = 0;
schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
sd->nr_balance_failed++;
if (need_active_balance(sd, sd_idle, CPU_NEWLY_IDLE)) {
double_lock_balance(this_rq, busiest);
/*
* don't kick the migration_thread, if the curr
* task on busiest cpu can't be moved to this_cpu
*/
if (!cpumask_test_cpu(this_cpu,
&busiest->curr->cpus_allowed)) {
double_unlock_balance(this_rq, busiest);
all_pinned = 1;
return ld_moved;
}
if (!busiest->active_balance) {
busiest->active_balance = 1;
busiest->push_cpu = this_cpu;
active_balance = 1;
}
double_unlock_balance(this_rq, busiest);
/*
* Should not call ttwu while holding a rq->lock
*/
raw_spin_unlock(&this_rq->lock);
if (active_balance)
wake_up_process(busiest->migration_thread);
raw_spin_lock(&this_rq->lock);
}
} else
sd->nr_balance_failed = 0;
update_shares_locked(this_rq, sd);
return ld_moved;
out_balanced:
schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
!test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
return -1;
sd->nr_balance_failed = 0;
return 0;
}
/*
* idle_balance is called by schedule() if this_cpu is about to become
* idle. Attempts to pull tasks from other CPUs.
@ -3143,16 +3024,23 @@ static void idle_balance(int this_cpu, struct rq *this_rq)
if (this_rq->avg_idle < sysctl_sched_migration_cost)
return;
/*
* Drop the rq->lock, but keep IRQ/preempt disabled.
*/
raw_spin_unlock(&this_rq->lock);
for_each_domain(this_cpu, sd) {
unsigned long interval;
int balance = 1;
if (!(sd->flags & SD_LOAD_BALANCE))
continue;
if (sd->flags & SD_BALANCE_NEWIDLE)
if (sd->flags & SD_BALANCE_NEWIDLE) {
/* If we've pulled tasks over stop searching: */
pulled_task = load_balance_newidle(this_cpu, this_rq,
sd);
pulled_task = load_balance(this_cpu, this_rq,
sd, CPU_NEWLY_IDLE, &balance);
}
interval = msecs_to_jiffies(sd->balance_interval);
if (time_after(next_balance, sd->last_balance + interval))
@ -3162,6 +3050,9 @@ static void idle_balance(int this_cpu, struct rq *this_rq)
break;
}
}
raw_spin_lock(&this_rq->lock);
if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
/*
* We are going idle. next_balance may be set based on