sched/fair: Track cgroup depth

Track depth in cgroup tree, this is useful for things like
find_matching_se() where you need to get to a common parent of two
sched entities.

Keeping the depth avoids having to calculate it on the spot, which
saves a number of possible cache-misses.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1328936700.2476.17.camel@laptop
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index e3d556427b2e..555e27d717c0 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1078,6 +1078,7 @@ struct sched_entity {
 #endif
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
+        int                     depth;
         struct sched_entity     *parent;
         /* rq on which this entity is (to be) queued: */
         struct cfs_rq           *cfs_rq;