[PATCH] sched/fair: Fix stale comments referring to removed CFS concepts

[Zhan Xusheng]

A few comments still describe the pre-EEVDF CFS world:

 - sysctl_sched_base_slice is documented as "Minimal preemption
   granularity for CPU-bound tasks".  That was the wording of the old
   sysctl_sched_min_granularity, renamed in commit e4ec3318a17f
   ("sched/debug: Rename sysctl_sched_min_granularity to
   sysctl_sched_base_slice").  Under EEVDF it is the default base time
   slice / request size (r_i) used to compute the virtual deadline, as
   documented in update_deadline().

 - Two comments still mention sched_slice(), which was removed when the
   fair class committed to EEVDF in commit 5e963f2bd465 ("sched/fair:
   Commit to EEVDF").  The dequeue-path comment should simply refer to
   the task's slice (se->slice); the forced-idle comment describes the
   slice accounting now performed by __entity_slice_used(), which is the
   function actually used right below it.

No functional change.

Signed-off-by: Zhan Xusheng <zhanxusheng@xxxxxxxxxx>
---
 kernel/sched/fair.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d78467ec6ee1..599ff23f52d3 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -72,7 +72,10 @@
 unsigned int sysctl_sched_tunable_scaling = SCHED_TUNABLESCALING_LOG;
 
 /*
- * Minimal preemption granularity for CPU-bound tasks:
+ * Default base time slice (request size r_i) for SCHED_NORMAL/SCHED_BATCH:
+ *
+ * Under EEVDF this is the request size used to compute the virtual
+ * deadline; see update_deadline().
  *
  * (default: 0.70 msec * (1 + ilog(ncpus)), units: nanoseconds)
  */
@@ -7974,7 +7977,7 @@ static int dequeue_entities(struct rq *rq, struct sched_entity *se, int flags)
 			se = parent_entity(se);
 			/*
 			 * Bias pick_next to pick a task from this cfs_rq, as
-			 * p is sleeping when it is within its sched_slice.
+			 * p is sleeping when it is within its slice.
 			 */
 			if (task_sleep && se)
 				set_next_buddy(se);
@@ -14571,7 +14574,7 @@ static inline void task_tick_core(struct rq *rq, struct task_struct *curr)
 	 * if the sibling is forced idle, then trigger schedule to
 	 * give forced idle task a chance.
 	 *
-	 * sched_slice() considers only this active rq and it gets the
+	 * __entity_slice_used() considers only this active rq and it gets the
 	 * whole slice. But during force idle, we have siblings acting
 	 * like a single runqueue and hence we need to consider runnable
 	 * tasks on this CPU and the forced idle CPU. Ideally, we should
-- 
2.43.0