Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

Pull RCU updates from Paul E. McKenney:

 - Miscellaneous fixes, perhaps most notably removing obsolete
   code whose only purpose in life was to gather information for
   the now-removed RCU debugfs facility.  Other notable changes
   include removing NO_HZ_FULL_ALL in favor of the nohz_full kernel
   boot parameter, minor optimizations for expedited grace periods,
   some added tracing, creating an RCU-specific workqueue using Tejun's
   new WQ_MEM_RECLAIM flag, and several cleanups to code and comments.

 - SRCU cleanups and optimizations.

 - Torture-test updates, perhaps most notably the adding of ARMv8
   support, but also including numerous cleanups and usability fixes.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

3 files changed, 11 insertions, 5 deletions

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 043d04784675..36360d07f25b 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -214,10 +214,12 @@ do { \
 #endif
 
 /*
- * init_rcu_head_on_stack()/destroy_rcu_head_on_stack() are needed for dynamic
- * initialization and destruction of rcu_head on the stack. rcu_head structures
- * allocated dynamically in the heap or defined statically don't need any
- * initialization.
+ * The init_rcu_head_on_stack() and destroy_rcu_head_on_stack() calls
+ * are needed for dynamic initialization and destruction of rcu_head
+ * on the stack, and init_rcu_head()/destroy_rcu_head() are needed for
+ * dynamic initialization and destruction of statically allocated rcu_head
+ * structures.  However, rcu_head structures allocated dynamically in the
+ * heap don't need any initialization.
  */
 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
 void init_rcu_head(struct rcu_head *head);
diff --git a/include/linux/types.h b/include/linux/types.h
index c94d59ef96cc..ec13d02b3481 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -217,7 +217,7 @@ struct ustat {
  *
  * This guarantee is important for few reasons:
  *  - future call_rcu_lazy() will make use of lower bits in the pointer;
- *  - the structure shares storage spacer in struct page with @compound_head,
+ *  - the structure shares storage space in struct page with @compound_head,
  *    which encode PageTail() in bit 0. The guarantee is needed to avoid
  *    false-positive PageTail().
  */
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index 0b50fda80db0..d8c33298c153 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -179,6 +179,10 @@ TRACE_EVENT(rcu_grace_period_init,
  *
  *	"snap": Captured snapshot of expedited grace period sequence number.
  *	"start": Started a real expedited grace period.
+ *	"reset": Started resetting the tree
+ *	"select": Started selecting the CPUs to wait on.
+ *	"selectofl": Selected CPU partially offline.
+ *	"startwait": Started waiting on selected CPUs.
  *	"end": Ended a real expedited grace period.
  *	"endwake": Woke piggybackers up.
  *	"done": Someone else did the expedited grace period for us.