[RFC -v7 PATCH 1/7] sched: check the right ->nr_running in yield_task_fair

Rik van Riel
2011-01-26T22:27:03Z

With CONFIG_FAIR_GROUP_SCHED, each task_group has its own cfs_rq.
Yielding to a task from another cfs_rq may be worthwhile, since
a process calling yield typically cannot use the CPU right now.

Therefor, we want to check the per-cpu nr_running, not the
cgroup local one.

Signed-off-by: Rik van Riel <riel@redhat.com>
---
kernel/sched_fair.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index c62ebae..7b338ac 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1304,7 +1304,7 @@ static void yield_task_fair(struct rq *rq)
/*
* Are we the only task in the tree?
*/
- if (unlikely(cfs_rq->nr_running == 1))
+ if (unlikely(rq->nr_running == 1))
return;

clear_buddies(cfs_rq, se);