sched/balancing: Standardize the naming of scheduler load-balancing functions

[PATCH 12/13] sched/balancing: Rename find_idlest_group() => sched_balance_find_dst_group()

Posted by Ingo Molnar 1 year, 11 months ago

Standardize scheduler load-balancing function names on the
sched_balance_() prefix.

Also use 'dst' instead of 'idlest', because it's not really
true that we return the 'idlest' group or CPU, we sort by
idle-exit latency and only return the idlest CPUs from the
lowest-latency set of CPUs.

The true 'idlest' CPUs often remain idle for a long time
and are never returned as long as the system is under-loaded.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shrikanth Hegde <sshegde@linux.ibm.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
---
 kernel/sched/fair.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 02ff0272b2e4..d0c3a091d7d1 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7098,7 +7098,7 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p,
 }
 
 static struct sched_group *
-find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu);
+sched_balance_find_dst_group(struct sched_domain *sd, struct task_struct *p, int this_cpu);
 
 /*
  * sched_balance_find_dst_group_cpu - find the idlest CPU among the CPUs in the group.
@@ -7185,7 +7185,7 @@ static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p
 			continue;
 		}
 
-		group = find_idlest_group(sd, p, cpu);
+		group = sched_balance_find_dst_group(sd, p, cpu);
 		if (!group) {
 			sd = sd->child;
 			continue;
@@ -10296,13 +10296,13 @@ static bool update_pick_idlest(struct sched_group *idlest,
 }
 
 /*
- * find_idlest_group() finds and returns the least busy CPU group within the
+ * sched_balance_find_dst_group() finds and returns the least busy CPU group within the
  * domain.
  *
  * Assumes p is allowed on at least one CPU in sd.
  */
 static struct sched_group *
-find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
+sched_balance_find_dst_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
 {
 	struct sched_group *idlest = NULL, *local = NULL, *group = sd->groups;
 	struct sg_lb_stats local_sgs, tmp_sgs;
-- 
2.40.1

[tip: sched/core] sched/balancing: Rename find_idlest_group() => sched_balance_find_dst_group()

Posted by tip-bot2 for Ingo Molnar 1 year, 11 months ago

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     a88b17080294f735c4124acccfa2d803a6a7d46f
Gitweb:        https://git.kernel.org/tip/a88b17080294f735c4124acccfa2d803a6a7d46f
Author:        Ingo Molnar <mingo@kernel.org>
AuthorDate:    Fri, 08 Mar 2024 12:18:18 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 12 Mar 2024 12:00:00 +01:00

sched/balancing: Rename find_idlest_group() => sched_balance_find_dst_group()

Standardize scheduler load-balancing function names on the
sched_balance_() prefix.

Also use 'dst' instead of 'idlest', because it's not really
true that we return the 'idlest' group or CPU, we sort by
idle-exit latency and only return the idlest CPUs from the
lowest-latency set of CPUs.

The true 'idlest' CPUs often remain idle for a long time
and are never returned as long as the system is under-loaded.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://lore.kernel.org/r/20240308111819.1101550-13-mingo@kernel.org
---
 kernel/sched/fair.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 02ff027..d0c3a09 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7098,7 +7098,7 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p,
 }
 
 static struct sched_group *
-find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu);
+sched_balance_find_dst_group(struct sched_domain *sd, struct task_struct *p, int this_cpu);
 
 /*
  * sched_balance_find_dst_group_cpu - find the idlest CPU among the CPUs in the group.
@@ -7185,7 +7185,7 @@ static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p
 			continue;
 		}
 
-		group = find_idlest_group(sd, p, cpu);
+		group = sched_balance_find_dst_group(sd, p, cpu);
 		if (!group) {
 			sd = sd->child;
 			continue;
@@ -10296,13 +10296,13 @@ static bool update_pick_idlest(struct sched_group *idlest,
 }
 
 /*
- * find_idlest_group() finds and returns the least busy CPU group within the
+ * sched_balance_find_dst_group() finds and returns the least busy CPU group within the
  * domain.
  *
  * Assumes p is allowed on at least one CPU in sd.
  */
 static struct sched_group *
-find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
+sched_balance_find_dst_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
 {
 	struct sched_group *idlest = NULL, *local = NULL, *group = sd->groups;
 	struct sg_lb_stats local_sgs, tmp_sgs;