Merge tag 'trace-v3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "The updates included in this pull request for ftrace are:

   o Several clean ups to the code

     One such clean up was to convert to 64 bit time keeping, in the
     ring buffer benchmark code.

   o Adding of __print_array() helper macro for TRACE_EVENT()

   o Updating the sample/trace_events/ to add samples of different ways
     to make trace events.  Lots of features have been added since the
     sample code was made, and these features are mostly unknown.
     Developers have been making their own hacks to do things that are
     already available.

   o Performance improvements.  Most notably, I found a performance bug
     where a waiter that is waiting for a full page from the ring buffer
     will see that a full page is not available, and go to sleep.  The
     sched event caused by it going to sleep would cause it to wake up
     again.  It would see that there was still not a full page, and go
     back to sleep again, and that would wake it up again, until finally
     it would see a full page.  This change has been marked for stable.

  Other improvements include removing global locks from fast paths"

* tag 'trace-v3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ring-buffer: Do not wake up a splice waiter when page is not full
  tracing: Fix unmapping loop in tracing_mark_write
  tracing: Add samples of DECLARE_EVENT_CLASS() and DEFINE_EVENT()
  tracing: Add TRACE_EVENT_FN example
  tracing: Add TRACE_EVENT_CONDITION sample
  tracing: Update the TRACE_EVENT fields available in the sample code
  tracing: Separate out initializing top level dir from instances
  tracing: Make tracing_init_dentry_tr() static
  trace: Use 64-bit timekeeping
  tracing: Add array printing helper
  tracing: Remove newline from trace_printk warning banner
  tracing: Use IS_ERR() check for return value of tracing_init_dentry()
  tracing: Remove unneeded includes of debugfs.h and fs.h
  tracing: Remove taking of trace_types_lock in pipe files
  tracing: Add ref count to tracer for when they are being read by pipe

2 files changed, 394 insertions, 14 deletions

diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
index aabc4e970911..880a7d1d27d2 100644
--- a/samples/trace_events/trace-events-sample.c
+++ b/samples/trace_events/trace-events-sample.c
@@ -10,12 +10,38 @@
 #define CREATE_TRACE_POINTS
 #include "trace-events-sample.h"
 
+static const char *random_strings[] = {
+        "Mother Goose",
+        "Snoopy",
+        "Gandalf",
+        "Frodo",
+        "One ring to rule them all"
+};
 
 static void simple_thread_func(int cnt)
 {
+        int array[6];
+        int len = cnt % 5;
+        int i;
+
         set_current_state(TASK_INTERRUPTIBLE);
         schedule_timeout(HZ);
-        trace_foo_bar("hello", cnt);
+
+        for (i = 0; i < len; i++)
+                array[i] = i + 1;
+        array[i] = 0;
+
+        /* Silly tracepoints */
+        trace_foo_bar("hello", cnt, array, random_strings[len],
+                      tsk_cpus_allowed(current));
+
+        trace_foo_with_template_simple("HELLO", cnt);
+
+        trace_foo_bar_with_cond("Some times print", cnt);
+
+        trace_foo_with_template_cond("prints other times", cnt);
+
+        trace_foo_with_template_print("I have to be different", cnt);
 }
 
 static int simple_thread(void *arg)
@@ -29,6 +55,53 @@ static int simple_thread(void *arg)
 }
 
 static struct task_struct *simple_tsk;
+static struct task_struct *simple_tsk_fn;
+
+static void simple_thread_func_fn(int cnt)
+{
+        set_current_state(TASK_INTERRUPTIBLE);
+        schedule_timeout(HZ);
+
+        /* More silly tracepoints */
+        trace_foo_bar_with_fn("Look at me", cnt);
+        trace_foo_with_template_fn("Look at me too", cnt);
+}
+
+static int simple_thread_fn(void *arg)
+{
+        int cnt = 0;
+
+        while (!kthread_should_stop())
+                simple_thread_func_fn(cnt++);
+
+        return 0;
+}
+
+static DEFINE_MUTEX(thread_mutex);
+
+void foo_bar_reg(void)
+{
+        pr_info("Starting thread for foo_bar_fn\n");
+        /*
+         * We shouldn't be able to start a trace when the module is
+         * unloading (there's other locks to prevent that). But
+         * for consistency sake, we still take the thread_mutex.
+         */
+        mutex_lock(&thread_mutex);
+        simple_tsk_fn = kthread_run(simple_thread_fn, NULL, "event-sample-fn");
+        mutex_unlock(&thread_mutex);
+}
+
+void foo_bar_unreg(void)
+{
+        pr_info("Killing thread for foo_bar_fn\n");
+        /* protect against module unloading */
+        mutex_lock(&thread_mutex);
+        if (simple_tsk_fn)
+                kthread_stop(simple_tsk_fn);
+        simple_tsk_fn = NULL;
+        mutex_unlock(&thread_mutex);
+}
 
 static int __init trace_event_init(void)
 {
@@ -42,6 +115,11 @@ static int __init trace_event_init(void)
 static void __exit trace_event_exit(void)
 {
         kthread_stop(simple_tsk);
+        mutex_lock(&thread_mutex);
+        if (simple_tsk_fn)
+                kthread_stop(simple_tsk_fn);
+        simple_tsk_fn = NULL;
+        mutex_unlock(&thread_mutex);
 }
 
 module_init(trace_event_init);
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 476429281389..a2c8b02b6359 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -1,6 +1,6 @@
 /*
  * If TRACE_SYSTEM is defined, that will be the directory created
- * in the ftrace directory under /sys/kernel/debug/tracing/events/<system>
+ * in the ftrace directory under /sys/kernel/tracing/events/<system>
  *
  * The define_trace.h below will also look for a file name of
  * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here.
@@ -54,45 +54,347 @@
  *    Here it is simply "foo, bar".
  *
  * struct:  This defines the way the data will be stored in the ring buffer.
- *    There are currently two types of elements. __field and __array.
- *    a __field is broken up into (type, name). Where type can be any
- *    primitive type (integer, long or pointer). __field_struct() can
- *    be any static complex data value (struct, union, but not an array).
- *    For an array. there are three fields. (type, name, size). The
- *    type of elements in the array, the name of the field and the size
- *    of the array.
+ *          The items declared here become part of a special structure
+ *          called "__entry", which can be used in the fast_assign part of the
+ *          TRACE_EVENT macro.
+ *
+ *      Here are the currently defined types you can use:
+ *
+ *   __field : Is broken up into type and name. Where type can be any
+ *         primitive type (integer, long or pointer).
+ *
+ *        __field(int, foo)
+ *
+ *        __entry->foo = 5;
+ *
+ *   __field_struct : This can be any static complex data type (struct, union
+ *         but not an array). Be careful using complex types, as each
+ *         event is limited in size, and copying large amounts of data
+ *         into the ring buffer can slow things down.
+ *
+ *         __field_struct(struct bar, foo)
+ *
+ *         __entry->bar.x = y;
+
+ *   __array: There are three fields (type, name, size). The type is the
+ *         type of elements in teh array, the name is the name of the array.
+ *         size is the number of items in the array (not the total size).
+ *
+ *         __array( char, foo, 10) is the same as saying: char foo[10];
+ *
+ *         Assigning arrays can be done like any array:
+ *
+ *         __entry->foo[0] = 'a';
+ *
+ *         memcpy(__entry->foo, bar, 10);
+ *
+ *   __dynamic_array: This is similar to array, but can vary is size from
+ *         instance to instance of the tracepoint being called.