From: Shrikanth Hegde <sshegde@linux.ibm.com>
To: mingo@kernel.org, peterz@infradead.org, vincent.guittot@linaro.org
Cc: sshegde@linux.ibm.com, dietmar.eggemann@arm.com,
qyousef@layalina.io, linux-kernel@vger.kernel.org,
vschneid@redhat.com, joshdon@google.com, riel@surriel.com
Subject: [PATCH] sched/fair: Simplify continue_balancing for newidle
Date: Mon, 25 Mar 2024 21:09:26 +0530 [thread overview]
Message-ID: <20240325153926.274284-1-sshegde@linux.ibm.com> (raw)
newidle(CPU_NEWLY_IDLE) balancing doesn't stop the load balancing if the
continue_balancing flag is reset. Other two balancing (IDLE, BUSY) 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>
---
kernel/sched/fair.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index f00cb66cc479..d80535df8f03 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -12307,6 +12307,7 @@ 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;
@@ -12321,8 +12322,9 @@ 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);
@@ -12361,7 +12363,6 @@ 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);
@@ -12387,8 +12388,7 @@ 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();
--
2.39.3
next reply other threads:[~2024-03-25 15:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-25 15:39 Shrikanth Hegde [this message]
2024-03-26 8:07 ` [PATCH] sched/fair: Simplify continue_balancing for newidle Ingo Molnar
2024-03-26 9:00 ` Shrikanth Hegde
2024-03-26 15:11 ` Dietmar Eggemann
2024-03-26 19:15 ` Ingo Molnar
2024-03-26 19:24 ` [tip: sched/core] sched/fair: Simplify the continue_balancing logic in sched_balance_newidle() tip-bot2 for Shrikanth Hegde
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