The 'back' member in struct sched_rt_entity only related to RT_GROUP_SCHED,
it should not place out of RT_GROUP_SCHED, move 'back' to RT_GROUP_SCHED.
It will save a few bytes.

v1 -> v2:
 - introduce rt_se_back() helper function.

Yajun Deng (2):
  sched/rt: Use 'back' only if CONFIG_RT_GROUP_SCHED is enabled
  sched/headers: Move sched_rt_entity::back to under the
    CONFIG_RT_GROUP_SCHED block

 include/linux/sched.h |  2 +-
 kernel/sched/rt.c     | 22 ++++++++++++++++------
 2 files changed, 17 insertions(+), 7 deletions(-)

-- 
2.25.1