rd->overload is accessed at multiple places. Instead it could use helper
get/set functions. This would make the code more readable and easy to
maintain.

No change in functionality intended.

Suggested-by: Qais Yousef <qyousef@layalina.io>
Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
---
 kernel/sched/fair.c  |  7 ++++---
 kernel/sched/sched.h | 14 ++++++++++++--
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index eeebadd7d9ae..cee99c93e6a4 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -10621,8 +10621,9 @@ 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);
+		if (is_rd_overloaded(env->dst_rq->rd) != (sg_status & SG_OVERLOAD))
+			set_rd_overload_status(env->dst_rq->rd,
+					       sg_status & SG_OVERLOAD);

 		/* Update over-utilization (tipping point, U >= 0) indicator */
 		set_rd_overutilized_status(env->dst_rq->rd,
@@ -12344,7 +12345,7 @@ 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 (!is_rd_overloaded(this_rq->rd) ||
 	    (sd && this_rq->avg_idle < sd->max_newidle_lb_cost)) {

 		if (sd)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 41024c1c49b4..c91eb8811bef 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -918,6 +918,16 @@ 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 is_rd_overloaded(struct root_domain *rd)
+{
+	return READ_ONCE(rd->overload);
+}
+
+static inline void set_rd_overload_status(struct root_domain *rd, int status)
+{
+	WRITE_ONCE(rd->overload, status);
+}
+
 #ifdef HAVE_RT_PUSH_IPI
 extern void rto_push_irq_work_func(struct irq_work *work);
 #endif
@@ -2518,8 +2528,8 @@ 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);
+		if (!is_rd_overloaded(rq->rd))
+			set_rd_overload_status(rq->rd, 1);
 	}
 #endif

--
2.39.3

On Wed, 13 Mar 2024 at 16:02, Shrikanth Hegde <sshegde@linux.ibm.com> wrote:
>
> rd->overload is accessed at multiple places. Instead it could use helper
> get/set functions. This would make the code more readable and easy to
> maintain.
>
> No change in functionality intended.
>
> Suggested-by: Qais Yousef <qyousef@layalina.io>
> Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>

Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>

> ---
>  kernel/sched/fair.c  |  7 ++++---
>  kernel/sched/sched.h | 14 ++++++++++++--
>  2 files changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index eeebadd7d9ae..cee99c93e6a4 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -10621,8 +10621,9 @@ 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);
> +               if (is_rd_overloaded(env->dst_rq->rd) != (sg_status & SG_OVERLOAD))
> +                       set_rd_overload_status(env->dst_rq->rd,
> +                                              sg_status & SG_OVERLOAD);
>
>                 /* Update over-utilization (tipping point, U >= 0) indicator */
>                 set_rd_overutilized_status(env->dst_rq->rd,
> @@ -12344,7 +12345,7 @@ 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 (!is_rd_overloaded(this_rq->rd) ||
>             (sd && this_rq->avg_idle < sd->max_newidle_lb_cost)) {
>
>                 if (sd)
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index 41024c1c49b4..c91eb8811bef 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -918,6 +918,16 @@ 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 is_rd_overloaded(struct root_domain *rd)
> +{
> +       return READ_ONCE(rd->overload);
> +}
> +
> +static inline void set_rd_overload_status(struct root_domain *rd, int status)
> +{
> +       WRITE_ONCE(rd->overload, status);
> +}
> +
>  #ifdef HAVE_RT_PUSH_IPI
>  extern void rto_push_irq_work_func(struct irq_work *work);
>  #endif
> @@ -2518,8 +2528,8 @@ 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);
> +               if (!is_rd_overloaded(rq->rd))
> +                       set_rd_overload_status(rq->rd, 1);
>         }
>  #endif
>
> --
> 2.39.3
>