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sched/fair: Simplify the continue_balancing logic in sched_balance_newidle()

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newidle(CPU_NEWLY_IDLE) balancing doesn't stop the load-balancing if the
continue_balancing flag is reset, but the other two balancing (IDLE, BUSY)
cases do that.

newidle balance stops the load balancing if rq has a task or there
is wakeup pending. The same checks are present in should_we_balance for
newidle. Hence use the return value and simplify continue_balancing
mechanism for newidle. Update the comment surrounding it as well.

No change in functionality intended.

Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/20240325153926.274284-1-sshegde@linux.ibm.com
This commit is contained in:
Shrikanth Hegde 2024-03-25 21:09:26 +05:30 committed by Ingo Molnar
parent d0f5d3cefc
commit c829d6818b
1 changed files with 5 additions and 5 deletions
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10
kernel/sched/fair.c
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@ -12358,6 +12358,7 @@ static int sched_balance_newidle(struct rq *this_rq, struct rq_flags *rf)
{
unsigned long next_balance = jiffies + HZ;
int this_cpu = this_rq->cpu;
int continue_balancing = 1;
u64 t0, t1, curr_cost = 0;
struct sched_domain *sd;
int pulled_task = 0;
@ -12372,8 +12373,9 @@ static int sched_balance_newidle(struct rq *this_rq, struct rq_flags *rf)
return 0;
/*
* We must set idle_stamp _before_ calling idle_balance(), such that we
* measure the duration of idle_balance() as idle time.
* We must set idle_stamp _before_ calling sched_balance_rq()
* for CPU_NEWLY_IDLE, such that we measure the this duration
* as idle time.
*/
this_rq->idle_stamp = rq_clock(this_rq);
@ -12412,7 +12414,6 @@ static int sched_balance_newidle(struct rq *this_rq, struct rq_flags *rf)
rcu_read_lock();
for_each_domain(this_cpu, sd) {
int continue_balancing = 1;
u64 domain_cost;
update_next_balance(sd, &next_balance);
@ -12438,8 +12439,7 @@ static int sched_balance_newidle(struct rq *this_rq, struct rq_flags *rf)
* Stop searching for tasks to pull if there are
* now runnable tasks on this rq.
*/
if (pulled_task || this_rq->nr_running > 0 ||
this_rq->ttwu_pending)
if (pulled_task || !continue_balancing)
break;
}
rcu_read_unlock();