Commit caac6291 authored by Shrikanth Hegde's avatar Shrikanth Hegde Committed by Ingo Molnar
Browse files

sched/fair: Use helper functions to access root_domain::overload 



Introduce two helper functions to access & set the root_domain::overload flag:

  get_rd_overload()
  set_rd_overload()

To make sure code is always following READ_ONCE()/WRITE_ONCE() access methods.

No change in functionality intended.

[ mingo: Renamed the accessors to get_/set_rd_overload(), tidied up the changelog. ]

Suggested-by: default avatarQais Yousef <qyousef@layalina.io>
Signed-off-by: default avatarShrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Reviewed-by: default avatarQais Yousef <qyousef@layalina.io>
Reviewed-by: default avatarVincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20240325054505.201995-3-sshegde@linux.ibm.com
parent c628db0a

kernel/sched/fair.c

+2 −3
Original line number Diff line number Diff line
@@ -10657,8 +10657,7 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd 


	if (!env->sd->parent) {

		/* update overload indicator if we are at root domain */

		if (READ_ONCE(env->dst_rq->rd->overload) != (sg_status & SG_OVERLOAD))

			WRITE_ONCE(env->dst_rq->rd->overload, sg_status & SG_OVERLOAD);

		set_rd_overload(env->dst_rq->rd, sg_status & SG_OVERLOAD);



		/* Update over-utilization (tipping point, U >= 0) indicator */

		set_rd_overutilized_status(env->dst_rq->rd,
@@ -12391,7 +12390,7 @@ static int sched_balance_newidle(struct rq *this_rq, struct rq_flags *rf) 
	rcu_read_lock();

	sd = rcu_dereference_check_sched_domain(this_rq->sd);



	if (!READ_ONCE(this_rq->rd->overload) ||

	if (!get_rd_overload(this_rq->rd) ||

	    (sd && this_rq->avg_idle < sd->max_newidle_lb_cost)) {



		if (sd)

kernel/sched/sched.h

+12 −2
Original line number Diff line number Diff line
@@ -930,6 +930,17 @@ extern void rq_attach_root(struct rq *rq, struct root_domain *rd); 
extern void sched_get_rd(struct root_domain *rd);

extern void sched_put_rd(struct root_domain *rd);



static inline int get_rd_overload(struct root_domain *rd)

{

	return READ_ONCE(rd->overload);

}



static inline void set_rd_overload(struct root_domain *rd, int status)

{

	if (get_rd_overload(rd) != status)

		WRITE_ONCE(rd->overload, status);

}



#ifdef HAVE_RT_PUSH_IPI

extern void rto_push_irq_work_func(struct irq_work *work);

#endif
@@ -2530,8 +2541,7 @@ static inline void add_nr_running(struct rq *rq, unsigned count) 


#ifdef CONFIG_SMP

	if (prev_nr < 2 && rq->nr_running >= 2) {

		if (!READ_ONCE(rq->rd->overload))

			WRITE_ONCE(rq->rd->overload, 1);

		set_rd_overload(rq->rd, SG_OVERLOAD);

	}

#endif