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 main changes in this cycle are mostly related to preparatory work
  for the full-dynticks work:

   - Remove restrictions on no-CBs CPUs, make RCU_FAST_NO_HZ take
     advantage of numbered callbacks, do callback accelerations based on
     numbered callbacks.  Posted to LKML at
        https://lkml.org/lkml/2013/3/18/960

   - RCU documentation updates.  Posted to LKML at
        https://lkml.org/lkml/2013/3/18/570

   - Miscellaneous fixes.  Posted to LKML at
        https://lkml.org/lkml/2013/3/18/594"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  rcu: Make rcu_accelerate_cbs() note need for future grace periods
  rcu: Abstract rcu_start_future_gp() from rcu_nocb_wait_gp()
  rcu: Rename n_nocb_gp_requests to need_future_gp
  rcu: Push lock release to rcu_start_gp()'s callers
  rcu: Repurpose no-CBs event tracing to future-GP events
  rcu: Rearrange locking in rcu_start_gp()
  rcu: Make RCU_FAST_NO_HZ take advantage of numbered callbacks
  rcu: Accelerate RCU callbacks at grace-period end
  rcu: Export RCU_FAST_NO_HZ parameters to sysfs
  rcu: Distinguish "rcuo" kthreads by RCU flavor
  rcu: Add event tracing for no-CBs CPUs' grace periods
  rcu: Add event tracing for no-CBs CPUs' callback registration
  rcu: Introduce proper blocking to no-CBs kthreads GP waits
  rcu: Provide compile-time control for no-CBs CPUs
  rcu: Tone down debugging during boot-up and shutdown.
  rcu: Add softirq-stall indications to stall-warning messages
  rcu: Documentation update
  rcu: Make bugginess of code sample more evident
  rcu: Fix hlist_bl_set_first_rcu() annotation
  rcu: Delete unused rcu_node "wakemask" field
  ...

1 files changed, 55 insertions, 0 deletions

diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index 1918e832da4f..59ebcc89f148 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -72,6 +72,58 @@ TRACE_EVENT(rcu_grace_period,
 );
 
 /*
+ * Tracepoint for future grace-period events, including those for no-callbacks
+ * CPUs.  The caller should pull the data from the rcu_node structure,
+ * other than rcuname, which comes from the rcu_state structure, and event,
+ * which is one of the following:
+ *
+ * "Startleaf": Request a nocb grace period based on leaf-node data.
+ * "Startedleaf": Leaf-node start proved sufficient.
+ * "Startedleafroot": Leaf-node start proved sufficient after checking root.
+ * "Startedroot": Requested a nocb grace period based on root-node data.
+ * "StartWait": Start waiting for the requested grace period.
+ * "ResumeWait": Resume waiting after signal.
+ * "EndWait": Complete wait.
+ * "Cleanup": Clean up rcu_node structure after previous GP.
+ * "CleanupMore": Clean up, and another no-CB GP is needed.
+ */
+TRACE_EVENT(rcu_future_grace_period,
+
+        TP_PROTO(char *rcuname, unsigned long gpnum, unsigned long completed,
+                 unsigned long c, u8 level, int grplo, int grphi,
+                 char *gpevent),
+
+        TP_ARGS(rcuname, gpnum, completed, c, level, grplo, grphi, gpevent),
+
+        TP_STRUCT__entry(
+                __field(char *, rcuname)
+                __field(unsigned long, gpnum)
+                __field(unsigned long, completed)
+                __field(unsigned long, c)
+                __field(u8, level)
+                __field(int, grplo)
+                __field(int, grphi)
+                __field(char *, gpevent)
+        ),
+
+        TP_fast_assign(
+                __entry->rcuname = rcuname;
+                __entry->gpnum = gpnum;
+                __entry->completed = completed;
+                __entry->c = c;
+                __entry->level = level;
+                __entry->grplo = grplo;
+                __entry->grphi = grphi;
+                __entry->gpevent = gpevent;
+        ),
+
+        TP_printk("%s %lu %lu %lu %u %d %d %s",
+                  __entry->rcuname, __entry->gpnum, __entry->completed,
+                  __entry->c, __entry->level, __entry->grplo, __entry->grphi,
+                  __entry->gpevent)
+);
+
+/*
  * Tracepoint for grace-period-initialization events.  These are
  * distinguished by the type of RCU, the new grace-period number, the
  * rcu_node structure level, the starting and ending CPU covered by the
@@ -601,6 +653,9 @@ TRACE_EVENT(rcu_barrier,
 #define trace_rcu_grace_period(rcuname, gpnum, gpevent) do { } while (0)
 #define trace_rcu_grace_period_init(rcuname, gpnum, level, grplo, grphi, \
                                     qsmask) do { } while (0)
+#define trace_rcu_future_grace_period(rcuname, gpnum, completed, c, \
+                                      level, grplo, grphi, event) \
+                                      do { } while (0)
 #define trace_rcu_preempt_task(rcuname, pid, gpnum) do { } while (0)
 #define trace_rcu_unlock_preempted_task(rcuname, gpnum, pid) do { } while (0)
 #define trace_rcu_quiescent_state_report(rcuname, gpnum, mask, qsmask, level, \