sched: re-do "sched: fix fair sleepers"

re-apply:

| commit e22ecef1d2658ba54ed7d3fdb5d60829fb434c23
| Author: Ingo Molnar <mingo@elte.hu>
| Date:   Fri Mar 14 22:16:08 2008 +0100
|
|     sched: fix fair sleepers
|
|     Fair sleepers need to scale their latency target down by runqueue
|     weight. Otherwise busy systems will gain ever larger sleep bonus.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 0080968..86a9337 100644 (file)
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -510,8 +510,10 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
 
        if (!initial) {
                /* sleeps upto a single latency don't count. */
-               if (sched_feat(NEW_FAIR_SLEEPERS))
-                       vruntime -= sysctl_sched_latency;
+               if (sched_feat(NEW_FAIR_SLEEPERS)) {
+                       vruntime -= calc_delta_fair(sysctl_sched_latency,
+                                                   &cfs_rq->load);
+               }
 
                /* ensure we never gain time by being placed backwards. */
                vruntime = max_vruntime(se->vruntime, vruntime);