[PATCH v2 2/2] sched/fair: Use helper function to access rd->overutilized

Shrikanth Hegde
2024-02-28T07:18:29Z

Overutilized field is accessed directly in multiple places.
So it could use a helper function. That way one might be more
informed that it needs to be used only in case of EAS.

No change in functionality intended.

Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
---
kernel/sched/fair.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 3105fb08b87e..c085fe8421b8 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6670,6 +6670,15 @@ static inline bool cpu_overutilized(int cpu)
return !util_fits_cpu(cpu_util_cfs(cpu), rq_util_min, rq_util_max, cpu);
}

+/*
+ * Ensure that caller can do EAS. overutilized value
+ * make sense only if EAS is enabled
+ */
+static inline int is_rd_overutilized(struct root_domain *rd)
+{
+ return READ_ONCE(rd->overutilized);
+}
+
static inline void update_rd_overutilized_status(struct root_domain *rd,
int status)
{
@@ -6686,7 +6695,7 @@ static inline void check_update_overutilized_status(struct rq *rq)
* if energy aware scheduler is being used
*/
if (sched_energy_enabled()) {
- if (!READ_ONCE(rq->rd->overutilized) && cpu_overutilized(rq->cpu))
+ if (!is_rd_overutilized(rq->rd) && cpu_overutilized(rq->cpu))
update_rd_overutilized_status(rq->rd, SG_OVERUTILIZED);
}
}
@@ -6694,6 +6703,7 @@ static inline void check_update_overutilized_status(struct rq *rq)
static inline void check_update_overutilized_status(struct rq *rq) { }
static inline void update_rd_overutilized_status(struct root_domain *rd,
bool status) { }
+static inline int is_rd_overutilized(struct root_domain *rd) { }
#endif

/* Runqueue only has SCHED_IDLE tasks enqueued */
@@ -7969,7 +7979,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)

rcu_read_lock();
pd = rcu_dereference(rd->pd);
- if (!pd || READ_ONCE(rd->overutilized))
+ if (!pd || is_rd_overutilized(rd))
goto unlock;

/*
@@ -10872,7 +10882,7 @@ static struct sched_group *find_busiest_group(struct lb_env *env)
if (sched_energy_enabled()) {
struct root_domain *rd = env->dst_rq->rd;

- if (rcu_dereference(rd->pd) && !READ_ONCE(rd->overutilized))
+ if (rcu_dereference(rd->pd) && !is_rd_overutilized(rd))
goto out_balanced;
}

--
2.39.3