Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar:

 - Apply a number of membarrier related fixes and cleanups, which fixes
   a use-after-free race in the membarrier code

 - Introduce proper RCU protection for tasks on the runqueue - to get
   rid of the subtle task_rcu_dereference() interface that was easy to
   get wrong

 - Misc fixes, but also an EAS speedup

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Avoid redundant EAS calculation
  sched/core: Remove double update_max_interval() call on CPU startup
  sched/core: Fix preempt_schedule() interrupt return comment
  sched/fair: Fix -Wunused-but-set-variable warnings
  sched/core: Fix migration to invalid CPU in __set_cpus_allowed_ptr()
  sched/membarrier: Return -ENOMEM to userspace on memory allocation failure
  sched/membarrier: Skip IPIs when mm->mm_users == 1
  selftests, sched/membarrier: Add multi-threaded test
  sched/membarrier: Fix p->mm->membarrier_state racy load
  sched/membarrier: Call sync_core only before usermode for same mm
  sched/membarrier: Remove redundant check
  sched/membarrier: Fix private expedited registration check
  tasks, sched/core: RCUify the assignment of rq->curr
  tasks, sched/core: With a grace period after finish_task_switch(), remove unnecessary code
  tasks, sched/core: Ensure tasks are available for a grace period after leaving the runqueue
  tasks: Add a count of task RCU users
  sched/core: Convert vcpu_is_preempted() from macro to an inline function
  sched/fair: Remove unused cfs_rq_clock_task() function

1 files changed, 11 insertions, 3 deletions

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 5183e0d77dfa..2222fa795284 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -383,6 +383,16 @@ struct mm_struct {
 		unsigned long highest_vm_end;	/* highest vma end address */
 		pgd_t * pgd;
 
+#ifdef CONFIG_MEMBARRIER
+		/**
+		 * @membarrier_state: Flags controlling membarrier behavior.
+		 *
+		 * This field is close to @pgd to hopefully fit in the same
+		 * cache-line, which needs to be touched by switch_mm().
+		 */
+		atomic_t membarrier_state;
+#endif
+
 		/**
 		 * @mm_users: The number of users including userspace.
 		 *
@@ -452,9 +462,7 @@ struct mm_struct {
 		unsigned long flags; /* Must use atomic bitops to access */
 
 		struct core_state *core_state; /* coredumping support */
-#ifdef CONFIG_MEMBARRIER
-		atomic_t membarrier_state;
-#endif
+
 #ifdef CONFIG_AIO
 		spinlock_t			ioctx_lock;
 		struct kioctx_table __rcu	*ioctx_table;