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-rw-r--r--Documentation/trace/ftrace.txt6
-rw-r--r--Documentation/trace/tracepoints.txt5
2 files changed, 10 insertions, 1 deletions
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index ea2d35d64d26..bd365988e8d8 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -655,7 +655,11 @@ explains which is which.
read the irq flags variable, an 'X' will always
be printed here.
- need-resched: 'N' task need_resched is set, '.' otherwise.
+ need-resched:
+ 'N' both TIF_NEED_RESCHED and PREEMPT_NEED_RESCHED is set,
+ 'n' only TIF_NEED_RESCHED is set,
+ 'p' only PREEMPT_NEED_RESCHED is set,
+ '.' otherwise.
hardirq/softirq:
'H' - hard irq occurred inside a softirq.
diff --git a/Documentation/trace/tracepoints.txt b/Documentation/trace/tracepoints.txt
index ac4170dd0f24..6b018b53177a 100644
--- a/Documentation/trace/tracepoints.txt
+++ b/Documentation/trace/tracepoints.txt
@@ -114,3 +114,8 @@ core kernel image or in modules.
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.
+
+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
+ for a series of articles with more details.