[Patch 2/5] sched: minor fixes for group scheduler

Minor bug fixes for group scheduler: - Use a mutex to serialize add/remove of task groups and also when changing shares of a task group. Use the same mutex when printing cfs_rq stats for various task groups. - Use list_for_each_entry_rcu in for_each_leaf_cfs_rq macro (when walking task

[Patch 2/5] sched: minor fixes for group scheduler

Minor bug fixes for group scheduler: - Use a mutex to serialize add/remove of task groups and also when changing shares of a task group. Use the same mutex when printing cfs_rq stats for various task groups. - Use list_for_each_entry_rcu in for_each_leaf_cfs_rq macro (when walking task