29 files changed, 1559 insertions, 177 deletions

diff --git a/Documentation/RCU/trace.txt b/Documentation/RCU/trace.txt
index ec6998b1b6d0..00a3a38b375a 100644
--- a/Documentation/RCU/trace.txt
+++ b/Documentation/RCU/trace.txt
@@ -237,17 +237,17 @@ o	"ktl" is the low-order 16 bits (in hexadecimal) of the count of
 
 The output of "cat rcu/rcu_preempt/rcuexp" looks as follows:
 
-s=21872 wd0=0 wd1=0 wd2=0 wd3=5 n=0 enq=0 sc=21872
+s=21872 wd1=0 wd2=0 wd3=5 n=0 enq=0 sc=21872
 
 These fields are as follows:
 
 o       "s" is the sequence number, with an odd number indicating that
         an expedited grace period is in progress.
 
-o       "wd0", "wd1", "wd2", and "wd3" are the number of times that an
-        attempt to start an expedited grace period found that someone
-        else had completed an expedited grace period that satisfies the
-        attempted request.  "Our work is done."
+o       "wd1", "wd2", and "wd3" are the number of times that an attempt
+        to start an expedited grace period found that someone else had
+        completed an expedited grace period that satisfies the attempted
+        request.  "Our work is done."
 
 o       "n" is number of times that a concurrent CPU-hotplug operation
         forced a fallback to a normal grace period.
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index ecc74fa4bfde..da9ee466789b 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3284,6 +3284,44 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         Lazy RCU callbacks are those which RCU can
                         prove do nothing more than free memory.
 
+        rcuperf.gp_exp= [KNL]
+                        Measure performance of expedited synchronous
+                        grace-period primitives.
+
+        rcuperf.holdoff= [KNL]
+                        Set test-start holdoff period.  The purpose of
+                        this parameter is to delay the start of the
+                        test until boot completes in order to avoid
+                        interference.
+
+        rcuperf.nreaders= [KNL]
+                        Set number of RCU readers.  The value -1 selects
+                        N, where N is the number of CPUs.  A value
+                        "n" less than -1 selects N-n+1, where N is again
+                        the number of CPUs.  For example, -2 selects N
+                        (the number of CPUs), -3 selects N+1, and so on.
+                        A value of "n" less than or equal to -N selects
+                        a single reader.
+
+        rcuperf.nwriters= [KNL]
+                        Set number of RCU writers.  The values operate
+                        the same as for rcuperf.nreaders.
+                        N, where N is the number of CPUs
+
+        rcuperf.perf_runnable= [BOOT]
+                        Start rcuperf running at boot time.
+
+        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.
+
         rcutorture.cbflood_inter_holdoff= [KNL]
                         Set holdoff time (jiffies) between successive
                         callback-flood tests.
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 45de591657a6..5f1533e3d032 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -508,14 +508,7 @@ int rcu_read_lock_bh_held(void);
  * CONFIG_DEBUG_LOCK_ALLOC, this assumes we are in an RCU-sched read-side
  * critical section unless it can prove otherwise.
  */
-#ifdef CONFIG_PREEMPT_COUNT
 int rcu_read_lock_sched_held(void);
-#else /* #ifdef CONFIG_PREEMPT_COUNT */
-static inline int rcu_read_lock_sched_held(void)
-{
-        return 1;
-}
-#endif /* #else #ifdef CONFIG_PREEMPT_COUNT */
 
 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 
@@ -532,18 +525,10 @@ static inline int rcu_read_lock_bh_held(void)
         return 1;
 }
 
-#ifdef CONFIG_PREEMPT_COUNT
 static inline int rcu_read_lock_sched_held(void)
 {
-        return preempt_count() != 0 || irqs_disabled();
+        return !preemptible();
 }
-#else /* #ifdef CONFIG_PREEMPT_COUNT */
-static inline int rcu_read_lock_sched_held(void)
-{
-        return 1;
-}
-#endif /* #else #ifdef CONFIG_PREEMPT_COUNT */
-
 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 
 #ifdef CONFIG_PROVE_RCU
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index 64809aea661c..93aea75029fb 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -149,6 +149,22 @@ static inline unsigned long rcu_batches_completed_sched(void)
         return 0;
 }
 
+/*
+ * Return the number of expedited grace periods completed.
+ */
+static inline unsigned long rcu_exp_batches_completed(void)
+{
+        return 0;
+}
+
+/*
+ * Return the number of expedited sched grace periods completed.
+ */
+static inline unsigned long rcu_exp_batches_completed_sched(void)
+{
+        return 0;
+}
+
 static inline void rcu_force_quiescent_state(void)
 {
 }
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index ad1eda9fa4da..5043cb823fb2 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -87,6 +87,8 @@ unsigned long rcu_batches_started_sched(void);
 unsigned long rcu_batches_completed(void);
 unsigned long rcu_batches_completed_bh(void);
 unsigned long rcu_batches_completed_sched(void);
+unsigned long rcu_exp_batches_completed(void);
+unsigned long rcu_exp_batches_completed_sched(void);
 void show_rcu_gp_kthreads(void);
 
 void rcu_force_quiescent_state(void);
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index ef72c4aada56..d3e756539d44 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -172,6 +172,77 @@ TRACE_EVENT(rcu_grace_period_init,