6 files changed, 54 insertions, 7 deletions

diff --git a/Documentation/trace/events-power.txt b/Documentation/trace/events-power.txt
index 3bd33b8dc7c4..21d514ced212 100644
--- a/Documentation/trace/events-power.txt
+++ b/Documentation/trace/events-power.txt
@@ -92,5 +92,5 @@ dev_pm_qos_remove_request          "device=%s type=%s new_value=%d"
 
 The first parameter gives the device name which tries to add/update/remove
 QoS requests.
-The second parameter gives the request type (e.g. "DEV_PM_QOS_LATENCY").
+The second parameter gives the request type (e.g. "DEV_PM_QOS_RESUME_LATENCY").
 The third parameter is value to be added/updated/removed.
diff --git a/Documentation/trace/events.txt b/Documentation/trace/events.txt
index c94435df2037..75d25a1d6e42 100644
--- a/Documentation/trace/events.txt
+++ b/Documentation/trace/events.txt
@@ -443,7 +443,7 @@ The following commands are supported:
   The following command creates a snapshot every time a block request
   queue is unplugged with a depth > 1.  If you were tracing a set of
   events or functions at the time, the snapshot trace buffer would
-  capture those events when the trigger event occured:
+  capture those events when the trigger event occurred:
 
   # echo 'snapshot if nr_rq > 1' > \
         /sys/kernel/debug/tracing/events/block/block_unplug/trigger
diff --git a/Documentation/trace/ftrace-design.txt b/Documentation/trace/ftrace-design.txt
index 79fcafc7fd64..3f669b9e8852 100644
--- a/Documentation/trace/ftrace-design.txt
+++ b/Documentation/trace/ftrace-design.txt
@@ -358,11 +358,8 @@ Every arch has an init callback function.  If you need to do something early on
 to initialize some state, this is the time to do that.  Otherwise, this simple
 function below should be sufficient for most people:
 
-int __init ftrace_dyn_arch_init(void *data)
+int __init ftrace_dyn_arch_init(void)
 {
-	/* return value is done indirectly via data */
-	*(unsigned long *)data = 0;
-
 	return 0;
 }
 
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index bd365988e8d8..2479b2a0c77c 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -2003,6 +2003,32 @@ want, depending on your needs.
   360.774530 |   1)   0.594 us    |                                          __phys_addr();
 
 
+The function name is always displayed after the closing bracket
+for a function if the start of that function is not in the
+trace buffer.
+
+Display of the function name after the closing bracket may be
+enabled for functions whose start is in the trace buffer,
+allowing easier searching with grep for function durations.
+It is default disabled.
+
+	hide: echo nofuncgraph-tail > trace_options
+	show: echo funcgraph-tail > trace_options
+
+  Example with nofuncgraph-tail (default):
+  0)               |      putname() {
+  0)               |        kmem_cache_free() {
+  0)   0.518 us    |          __phys_addr();
+  0)   1.757 us    |        }
+  0)   2.861 us    |      }
+
+  Example with funcgraph-tail:
+  0)               |      putname() {
+  0)               |        kmem_cache_free() {
+  0)   0.518 us    |          __phys_addr();
+  0)   1.757 us    |        } /* kmem_cache_free() */
+  0)   2.861 us    |      } /* putname() */
+
 You can put some comments on specific functions by using
 trace_printk() For example, if you want to put a comment inside
 the __might_sleep() function, you just have to include
diff --git a/Documentation/trace/ring-buffer-design.txt b/Documentation/trace/ring-buffer-design.txt
index 7d350b496585..ff747b6fa39b 100644
--- a/Documentation/trace/ring-buffer-design.txt
+++ b/Documentation/trace/ring-buffer-design.txt
@@ -683,7 +683,7 @@ against nested writers.
   cmpxchg(tail_page, temp_page, next_page)
 
 The above will update the tail page if it is still pointing to the expected
-page. If this fails, a nested write pushed it forward, the the current write
+page. If this fails, a nested write pushed it forward, the current write
 does not need to push it.
 
 
diff --git a/Documentation/trace/tracepoints.txt b/Documentation/trace/tracepoints.txt
index 6b018b53177a..a3efac621c5a 100644
--- a/Documentation/trace/tracepoints.txt
+++ b/Documentation/trace/tracepoints.txt
@@ -115,6 +115,30 @@ If the tracepoint has to be used in kernel modules, an
 EXPORT_TRACEPOINT_SYMBOL_GPL() or EXPORT_TRACEPOINT_SYMBOL() can be
 used to export the defined tracepoints.
 
+If you need to do a bit of work for a tracepoint parameter, and
+that work is only used for the tracepoint, that work can be encapsulated
+within an if statement with the following:
+
+	if (trace_foo_bar_enabled()) {
+		int i;
+		int tot = 0;
+
+		for (i = 0; i < count; i++)
+			tot += calculate_nuggets();
+
+		trace_foo_bar(tot);
+	}
+
+All trace_<tracepoint>() calls have a matching trace_<tracepoint>_enabled()
+function defined that returns true if the tracepoint is enabled and
+false otherwise. The trace_<tracepoint>() should always be within the
+block of the if (trace_<tracepoint>_enabled()) to prevent races between
+the tracepoint being enabled and the check being seen.
+
+The advantage of using the trace_<tracepoint>_enabled() is that it uses
+the static_key of the tracepoint to allow the if statement to be implemented
+with jump labels and avoid conditional branches.
+
 Note: The convenience macro TRACE_EVENT provides an alternative way to
       define tracepoints. Check http://lwn.net/Articles/379903,
       http://lwn.net/Articles/381064 and http://lwn.net/Articles/383362