Commit 3229adbe authored by K Prateek Nayak's avatar K Prateek Nayak Committed by Peter Zijlstra
Browse files

sched/fair: Do not compute overloaded status unnecessarily during lb 



Only set sg_overloaded when computing sg_lb_stats() at the highest sched
domain since rd->overloaded status is updated only when load balancing
at the highest domain. While at it, move setting of sg_overloaded below
idle_cpu() check since an idle CPU can never be overloaded.

Signed-off-by: default avatarK Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarVincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: default avatarShrikanth Hegde <sshegde@linux.ibm.com>
Link: https://lore.kernel.org/r/20241223043407.1611-8-kprateek.nayak@amd.com
parent 0ac1ee9e

kernel/sched/fair.c

+5 −3
Original line number Diff line number Diff line
@@ -10410,6 +10410,7 @@ static inline void update_sg_lb_stats(struct lb_env *env, 
				      bool *sg_overutilized)

{

	int i, nr_running, local_group, sd_flags = env->sd->flags;

	bool balancing_at_rd = !env->sd->parent;



	memset(sgs, 0, sizeof(*sgs));
@@ -10427,9 +10428,6 @@ static inline void update_sg_lb_stats(struct lb_env *env, 
		nr_running = rq->nr_running;

		sgs->sum_nr_running += nr_running;



		if (nr_running > 1)

			*sg_overloaded = 1;



		if (cpu_overutilized(i))

			*sg_overutilized = 1;
@@ -10442,6 +10440,10 @@ static inline void update_sg_lb_stats(struct lb_env *env, 
			continue;

		}



		/* Overload indicator is only updated at root domain */

		if (balancing_at_rd && nr_running > 1)

			*sg_overloaded = 1;



#ifdef CONFIG_NUMA_BALANCING

		/* Only fbq_classify_group() uses this to classify NUMA groups */

		if (sd_flags & SD_NUMA) {