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 biggest change in this cycle is the conclusion of the big
  'simplify RCU to two primary flavors' consolidation work - i.e.
  there's a single RCU flavor for any kernel variant (PREEMPT and
  !PREEMPT):

    - Consolidate the RCU-bh, RCU-preempt, and RCU-sched flavors into a
      single flavor similar to RCU-sched in !PREEMPT kernels and into a
      single flavor similar to RCU-preempt (but also waiting on
      preempt-disabled sequences of code) in PREEMPT kernels.

      This branch also includes a refactoring of
      rcu_{nmi,irq}_{enter,exit}() from Byungchul Park.

    - Now that there is only one RCU flavor in any given running kernel,
      the many "rsp" pointers are no longer required, and this cleanup
      series removes them.

    - This branch carries out additional cleanups made possible by the
      RCU flavor consolidation, including inlining now-trivial
      functions, updating comments and definitions, and removing
      now-unneeded rcutorture scenarios.

    - Now that there is only one flavor of RCU in any running kernel,
      there is also only on rcu_data structure per CPU. This means that
      the rcu_dynticks structure can be merged into the rcu_data
      structure, a task taken on by this branch. This branch also
      contains a -rt-related fix from Mike Galbraith.

  There were also other updates:

    - Documentation updates, including some good-eye catches from Joel
      Fernandes.

    - SRCU updates, most notably changes enabling call_srcu() to be
      invoked very early in the boot sequence.

    - Torture-test updates, including some preliminary work towards
      making rcutorture better able to find problems that result in
      insufficient grace-period forward progress.

    - Initial changes to RCU to better promote forward progress of grace
      periods, including fixing a bug found by Marius Hillenbrand and
      David Woodhouse, with the fix suggested by Peter Zijlstra"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (140 commits)
  srcu: Make early-boot call_srcu() reuse workqueue lists
  rcutorture: Test early boot call_srcu()
  srcu: Make call_srcu() available during very early boot
  rcu: Convert rcu_state.ofl_lock to raw_spinlock_t
  rcu: Remove obsolete ->dynticks_fqs and ->cond_resched_completed
  rcu: Switch ->dynticks to rcu_data structure, remove rcu_dynticks
  rcu: Switch dyntick nesting counters to rcu_data structure
  rcu: Switch urgent quiescent-state requests to rcu_data structure
  rcu: Switch lazy counts to rcu_data structure
  rcu: Switch last accelerate/advance to rcu_data structure
  rcu: Switch ->tick_nohz_enabled_snap to rcu_data structure
  rcu: Merge rcu_dynticks structure into rcu_data structure
  rcu: Remove unused rcu_dynticks_snap() from Tiny RCU
  rcu: Convert "1UL << x" to "BIT(x)"
  rcu: Avoid resched_cpu() when rescheduling the current CPU
  rcu: More aggressively enlist scheduler aid for nohz_full CPUs
  rcu: Compute jiffies_till_sched_qs from other kernel parameters
  rcu: Provide functions for determining if call_rcu() has been invoked
  rcu: Eliminate ->rcu_qs_ctr from the rcu_dynticks structure
  rcu: Motivate Tiny RCU forward progress
  ...

1 files changed, 12 insertions, 19 deletions

diff --git a/Documentation/RCU/Design/Data-Structures/Data-Structures.html b/Documentation/RCU/Design/Data-Structures/Data-Structures.html
index f5120a00f511..1d2051c0c3fc 100644
--- a/Documentation/RCU/Design/Data-Structures/Data-Structures.html
+++ b/Documentation/RCU/Design/Data-Structures/Data-Structures.html
@@ -1227,9 +1227,11 @@ to overflow the counter, this approach corrects the
 CPU enters the idle loop from process context.
 
 </p><p>The <tt>-&gt;dynticks</tt> field counts the corresponding
-CPU's transitions to and from dyntick-idle mode, so that this counter
-has an even value when the CPU is in dyntick-idle mode and an odd
-value otherwise.
+CPU's transitions to and from either dyntick-idle or user mode, so
+that this counter has an even value when the CPU is in dyntick-idle
+mode or user mode and an odd value otherwise. The transitions to/from
+user mode need to be counted for user mode adaptive-ticks support
+(see timers/NO_HZ.txt).
 
 </p><p>The <tt>-&gt;rcu_need_heavy_qs</tt> field is used
 to record the fact that the RCU core code would really like to
@@ -1372,8 +1374,7 @@ that is, if the CPU is currently idle.
 Accessor Functions</a></h3>
 
 <p>The following listing shows the
-<tt>rcu_get_root()</tt>, <tt>rcu_for_each_node_breadth_first</tt>,
-<tt>rcu_for_each_nonleaf_node_breadth_first()</tt>, and
+<tt>rcu_get_root()</tt>, <tt>rcu_for_each_node_breadth_first</tt> and
 <tt>rcu_for_each_leaf_node()</tt> function and macros:
 
 <pre>
@@ -1386,13 +1387,9 @@ Accessor Functions</a></h3>
   7   for ((rnp) = &amp;(rsp)-&gt;node[0]; \
   8        (rnp) &lt; &amp;(rsp)-&gt;node[NUM_RCU_NODES]; (rnp)++)
   9
- 10 #define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \
- 11   for ((rnp) = &amp;(rsp)-&gt;node[0]; \
- 12        (rnp) &lt; (rsp)-&gt;level[NUM_RCU_LVLS - 1]; (rnp)++)
- 13
- 14 #define rcu_for_each_leaf_node(rsp, rnp) \
- 15   for ((rnp) = (rsp)-&gt;level[NUM_RCU_LVLS - 1]; \
- 16        (rnp) &lt; &amp;(rsp)-&gt;node[NUM_RCU_NODES]; (rnp)++)
+ 10 #define rcu_for_each_leaf_node(rsp, rnp) \
+ 11   for ((rnp) = (rsp)-&gt;level[NUM_RCU_LVLS - 1]; \
+ 12        (rnp) &lt; &amp;(rsp)-&gt;node[NUM_RCU_NODES]; (rnp)++)
 </pre>
 
 <p>The <tt>rcu_get_root()</tt> simply returns a pointer to the
@@ -1405,10 +1402,7 @@ macro takes advantage of the layout of the <tt>rcu_node</tt>
 structures in the <tt>rcu_state</tt> structure's
 <tt>-&gt;node[]</tt> array, performing a breadth-first traversal by
 simply traversing the array in order.
-The <tt>rcu_for_each_nonleaf_node_breadth_first()</tt> macro operates
-similarly, but traverses only the first part of the array, thus excluding
-the leaf <tt>rcu_node</tt> structures.
-Finally, the <tt>rcu_for_each_leaf_node()</tt> macro traverses only
+Similarly, the <tt>rcu_for_each_leaf_node()</tt> macro traverses only
 the last part of the array, thus traversing only the leaf
 <tt>rcu_node</tt> structures.
 
@@ -1416,15 +1410,14 @@ the last part of the array, thus traversing only the leaf
 <tr><th>&nbsp;</th></tr>
 <tr><th align="left">Quick Quiz:</th></tr>
 <tr><td>
-	What do <tt>rcu_for_each_nonleaf_node_breadth_first()</tt> and
+	What does
 	<tt>rcu_for_each_leaf_node()</tt> do if the <tt>rcu_node</tt> tree
 	contains only a single node?
 </td></tr>
 <tr><th align="left">Answer:</th></tr>
 <tr><td bgcolor="#ffffff"><font color="ffffff">
 	In the single-node case,
-	<tt>rcu_for_each_nonleaf_node_breadth_first()</tt> is a no-op
-	and <tt>rcu_for_each_leaf_node()</tt> traverses the single node.
+	<tt>rcu_for_each_leaf_node()</tt> traverses the single node.
 </font></td></tr>
 <tr><td>&nbsp;</td></tr>
 </table>