sched: fix sched_slice()
Mike Galbraith [Fri, 2 Jan 2009 11:16:42 +0000 (12:16 +0100)]
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(-)

kernel/sched_fair.c

index 5ad4440..b808563 100644 (file)
@@ -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;
 }
 
 /*