sched: Factor out update_other_load_avgs() from __update_blocked_others()

RT, DL, thermal and irq load and utilization metrics need to be decayed and
updated periodically and before consumption to keep the numbers reasonable.
This is currently done from __update_blocked_others() as a part of the fair
class load balance path. Let's factor it out to update_other_load_avgs().
Pure refactor. No functional changes.

This will be used by the new BPF extensible scheduling class to ensure that
the above metrics are properly maintained.

v2: Refreshed on top of tip:sched/core.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: David Vernet <dvernet@meta.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/kernel/sched/syscalls.c b/kernel/sched/syscalls.c
index cf189bc3dd18..050215ef8fa4 100644
--- a/kernel/sched/syscalls.c
+++ b/kernel/sched/syscalls.c
@@ -260,6 +260,25 @@ int sched_core_idle_cpu(int cpu)
 
 #ifdef CONFIG_SMP
 /*
+ * Load avg and utiliztion metrics need to be updated periodically and before
+ * consumption. This function updates the metrics for all subsystems except for
+ * the fair class. @rq must be locked and have its clock updated.
+ */
+bool update_other_load_avgs(struct rq *rq)
+{
+	u64 now = rq_clock_pelt(rq);
+	const struct sched_class *curr_class = rq->curr->sched_class;
+	unsigned long hw_pressure = arch_scale_hw_pressure(cpu_of(rq));
+
+	lockdep_assert_rq_held(rq);
+
+	return update_rt_rq_load_avg(now, rq, curr_class == &rt_sched_class) |
+		update_dl_rq_load_avg(now, rq, curr_class == &dl_sched_class) |
+		update_hw_load_avg(now, rq, hw_pressure) |
+		update_irq_load_avg(rq, 0);
+}
+
+/*
  * This function computes an effective utilization for the given CPU, to be
  * used for frequency selection given the linear relation: f = u * f_max.
  *