[PATCH 2/6 v3] sched/eevdf: Take into account current's lag when updating slice protection

[Vincent Guittot]

Take into account the lag of current task when updating the slice
protection in order to ensure that the absolute value of lags will remain
in the range [0 : slice+tick]
A task that already has a negative lag will see its protection reduced
whereas a task with positive lag will keep a full slice protection.

Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Tested-by: K Prateek Nayak <kprateek.nayak@xxxxxxx>
---
 kernel/sched/fair.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 83bce5a04f3d..8639086e5d9e 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1099,8 +1099,9 @@ static inline void set_protect_slice(struct cfs_rq *cfs_rq, struct sched_entity
 static inline void update_protect_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
 	u64 slice = cfs_rq_min_slice(cfs_rq);
+	u64 vruntime = min_vruntime(se->vruntime, avg_vruntime(cfs_rq));
 
-	se->vprot = min_vruntime(se->vprot, se->vruntime + calc_delta_fair(slice, se));
+	se->vprot = min_vruntime(se->vprot, vruntime + calc_delta_fair(slice, se));
 }
 
 static inline bool protect_slice(struct sched_entity *se)
-- 
2.43.0