sched: optimize vruntime based scheduling

optimize vruntime based scheduling.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 6 insertions, 2 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index a5dd03522e32..5594e65166fc 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -732,13 +732,14 @@ calc_delta_fair(unsigned long delta_exec, struct load_weight *lw)
 static inline void update_load_add(struct load_weight *lw, unsigned long inc)
 {
         lw->weight += inc;
-        lw->inv_weight = WMULT_CONST / lw->weight;
+        if (sched_feat(FAIR_SLEEPERS))
+                lw->inv_weight = WMULT_CONST / lw->weight;
 }
 
 static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
 {
         lw->weight -= dec;
-        if (likely(lw->weight))
+        if (sched_feat(FAIR_SLEEPERS) && likely(lw->weight))
                 lw->inv_weight = WMULT_CONST / lw->weight;
 }
 
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index a566a4558167..7041dc697855 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -336,6 +336,9 @@ __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr,
         }
         curr->vruntime += delta_exec_weighted;
 
+        if (!sched_feat(FAIR_SLEEPERS))
+                return;
+
         if (unlikely(!load))
                 return;