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

Pull RCU updates from Ingo Molnar:
 "The sole purpose of these changes is to shrink and simplify the RCU
  code base, which has suffered from creeping bloat over the past couple
  of years. The end result is a net removal of ~2700 lines of code:

     79 files changed, 1496 insertions(+), 4211 deletions(-)

  Plus there's a marked reduction in the Kconfig space complexity as
  well, here's the number of matches on 'grep RCU' in the .config:

                               before       after

     x86-defconfig                 17          15
     x86-allmodconfig              33          20"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (86 commits)
  rcu: Remove RCU CPU stall warnings from Tiny RCU
  rcu: Remove event tracing from Tiny RCU
  rcu: Move RCU debug Kconfig options to kernel/rcu
  rcu: Move RCU non-debug Kconfig options to kernel/rcu
  rcu: Eliminate NOCBs CPU-state Kconfig options
  rcu: Remove debugfs tracing
  srcu: Remove Classic SRCU
  srcu: Fix rcutorture-statistics typo
  rcu: Remove SPARSE_RCU_POINTER Kconfig option
  rcu: Remove the now-obsolete PROVE_RCU_REPEATEDLY Kconfig option
  rcu: Remove typecheck() from RCU locking wrapper functions
  rcu: Remove #ifdef moving rcu_end_inkernel_boot from rcupdate.h
  rcu: Remove nohz_full full-system-idle state machine
  rcu: Remove the RCU_KTHREAD_PRIO Kconfig option
  rcu: Remove *_SLOW_* Kconfig options
  srcu: Use rnp->lock wrappers to replace explicit memory barriers
  rcu: Move rnp->lock wrappers for SRCU use
  rcu: Convert rnp->lock wrappers to macros for SRCU use
  rcu: Refactor #includes from include/linux/rcupdate.h
  bcm47xx: Fix build regression
  ...

Documentation/admin-guide/kernel-parameters.txt

@@ -3238,21 +3238,17 @@
 
 	rcutree.gp_cleanup_delay=	[KNL]
 			Set the number of jiffies to delay each step of
-			RCU grace-period cleanup.  This only has effect
-			when CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP is set.
+			RCU grace-period cleanup.
 
 	rcutree.gp_init_delay=	[KNL]
 			Set the number of jiffies to delay each step of
-			RCU grace-period initialization.  This only has
-			effect when CONFIG_RCU_TORTURE_TEST_SLOW_INIT
-			is set.
+			RCU grace-period initialization.
 
 	rcutree.gp_preinit_delay=	[KNL]
 			Set the number of jiffies to delay each step of
 			RCU grace-period pre-initialization, that is,
 			the propagation of recent CPU-hotplug changes up
-			the rcu_node combining tree.  This only has effect
-			when CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT is set.
+			the rcu_node combining tree.
 
 	rcutree.rcu_fanout_exact= [KNL]
 			Disable autobalancing of the rcu_node combining
@@ -3328,6 +3324,17 @@
 			This wake_up() will be accompanied by a
 			WARN_ONCE() splat and an ftrace_dump().
 
+	rcuperf.gp_async= [KNL]
+			Measure performance of asynchronous
+			grace-period primitives such as call_rcu().
+
+	rcuperf.gp_async_max= [KNL]
+			Specify the maximum number of outstanding
+			callbacks per writer thread.  When a writer
+			thread exceeds this limit, it invokes the
+			corresponding flavor of rcu_barrier() to allow
+			previously posted callbacks to drain.
+
 	rcuperf.gp_exp= [KNL]
 			Measure performance of expedited synchronous
 			grace-period primitives.
@@ -3355,17 +3362,22 @@
 	rcuperf.perf_runnable= [BOOT]
 			Start rcuperf running at boot time.
 
+	rcuperf.perf_type= [KNL]
+			Specify the RCU implementation to test.
+
 	rcuperf.shutdown= [KNL]
 			Shut the system down after performance tests
 			complete.  This is useful for hands-off automated
 			testing.
 
-	rcuperf.perf_type= [KNL]
-			Specify the RCU implementation to test.
-
 	rcuperf.verbose= [KNL]
 			Enable additional printk() statements.
 
+	rcuperf.writer_holdoff= [KNL]
+			Write-side holdoff between grace periods,
+			in microseconds.  The default of zero says
+			no holdoff.
+
 	rcutorture.cbflood_inter_holdoff= [KNL]
 			Set holdoff time (jiffies) between successive
 			callback-flood tests.
@@ -3803,6 +3815,15 @@
 	spia_pedr=
 	spia_peddr=
 
+	srcutree.counter_wrap_check [KNL]
+			Specifies how frequently to check for
+			grace-period sequence counter wrap for the
+			srcu_data structure's ->srcu_gp_seq_needed field.
+			The greater the number of bits set in this kernel
+			parameter, the less frequently counter wrap will
+			be checked for.  Note that the bottom two bits
+			are ignored.
+
 	srcutree.exp_holdoff [KNL]
 			Specifies how many nanoseconds must elapse
 			since the end of the last SRCU grace period for