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

Pull RCU fixes from Thomas Gleixner:
 "Two RCU patches:
   - Address a serious performance regression on open/close caused by
     commit ac1bea85781e ("Make cond_resched() report RCU quiescent
     states")
   - Export RCU debug functions.  Not a regression, but enablement to
     address a serious recursion bug in the sl*b allocators in 3.17"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rcu: Reduce overhead of cond_resched() checks for RCU
  rcu: Export debug_init_rcu_head() and and debug_init_rcu_head()

1 files changed, 6 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e332e718cad6..b7fa2f599459 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2790,6 +2790,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         leaf rcu_node structure.  Useful for very large
                         systems.
 
+        rcutree.jiffies_till_sched_qs= [KNL]
+                        Set required age in jiffies for a
+                        given grace period before RCU starts
+                        soliciting quiescent-state help from
+                        rcu_note_context_switch().
+
         rcutree.jiffies_till_first_fqs= [KNL]
                         Set delay from grace-period initialization to
                         first attempt to force quiescent states.