sched: fix sched_slice()

Impact: fix bad-interactivity buglet

Fix sched_slice() to emit a sane result whether a task is currently
enqueued or not.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Tested-by: Jayson King <dev@jaysonking.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

 kernel/sched_fair.c |   30 ++++++++++++------------------
 1 file changed, 12 insertions(+), 18 deletions(-)

1 files changed, 12 insertions, 18 deletions

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 5ad4440f0fc..b808563f4f1 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -386,20 +386,6 @@ int sched_nr_latency_handler(struct ctl_table *table, int write,
 #endif
 
 /*
- * delta *= P[w / rw]
- */
-static inline unsigned long
-calc_delta_weight(unsigned long delta, struct sched_entity *se)
-{
-        for_each_sched_entity(se) {
-                delta = calc_delta_mine(delta,
-                                se->load.weight, &cfs_rq_of(se)->load);
-        }
-
-        return delta;
-}
-
-/*
  * delta /= w
  */
 static inline unsigned long
@@ -440,12 +426,20 @@ static u64 __sched_period(unsigned long nr_running)
  */
 static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
-        unsigned long nr_running = cfs_rq->nr_running;
+        u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq);
 
-        if (unlikely(!se->on_rq))
-                nr_running++;
+        for_each_sched_entity(se) {
+                struct load_weight *load = &cfs_rq->load;
 
-        return calc_delta_weight(__sched_period(nr_running), se);
+                if (unlikely(!se->on_rq)) {
+                        struct load_weight lw = cfs_rq->load;
+
+                        update_load_add(&lw, se->load.weight);
+                        load = &lw;
+                }
+                slice = calc_delta_mine(slice, se->load.weight, load);
+        }
+        return slice;
 }
 
 /*