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

Pull RCU changes from Ingo Molar:
 "The main changes:

   - torture-test updates
   - callback-offloading changes
   - maintainership changes
   - update RCU documentation
   - miscellaneous fixes"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
  rcu: Allow for NULL tick_nohz_full_mask when nohz_full= missing
  rcu: Fix a sparse warning in rcu_report_unblock_qs_rnp()
  rcu: Fix a sparse warning in rcu_initiate_boost()
  rcu: Fix __rcu_reclaim() to use true/false for bool
  rcu: Remove CONFIG_PROVE_RCU_DELAY
  rcu: Use __this_cpu_read() instead of per_cpu_ptr()
  rcu: Don't use NMIs to dump other CPUs' stacks
  rcu: Bind grace-period kthreads to non-NO_HZ_FULL CPUs
  rcu: Simplify priority boosting by putting rt_mutex in rcu_node
  rcu: Check both root and current rcu_node when setting up future grace period
  rcu: Allow post-unlock reference for rt_mutex
  rcu: Loosen __call_rcu()'s rcu_head alignment constraint
  rcu: Eliminate read-modify-write ACCESS_ONCE() calls
  rcu: Remove redundant ACCESS_ONCE() from tick_do_timer_cpu
  rcu: Make rcu node arrays static const char * const
  signal: Explain local_irq_save() call
  rcu: Handle obsolete references to TINY_PREEMPT_RCU
  rcu: Document deadlock-avoidance information for rcu_read_unlock()
  scripts: Teach get_maintainer.pl about the new "R:" tag
  rcu: Update rcu torture maintainership filename patterns
  ...

1 files changed, 7 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 45fbea7c329b..90f6139608ff 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2813,6 +2813,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         quiescent states.  Units are jiffies, minimum
                         value is one, and maximum value is HZ.
 
+        rcutree.rcu_nocb_leader_stride= [KNL]
+                        Set the number of NOCB kthread groups, which
+                        defaults to the square root of the number of
+                        CPUs.  Larger numbers reduces the wakeup overhead
+                        on the per-CPU grace-period kthreads, but increases
+                        that same overhead on each group's leader.
+
         rcutree.qhimark= [KNL]
                         Set threshold of queued RCU callbacks beyond which
                         batch limiting is disabled.