[for-next][PATCH 01/13] tracepoints: Fix documentation of RCU lockdep checks

From: Steven Rostedt
Date: Wed Nov 04 2015 - 10:30:23 EST


From: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>

The documentation on top of __DECLARE_TRACE() does not match its
implementation since the condition check has been added to the
RCU lockdep checks. Update the documentation to match its
implementation.

Link: http://lkml.kernel.org/r/1446504164-21563-1-git-send-email-mathieu.desnoyers@xxxxxxxxxxxx

CC: Dave Hansen <dave@xxxxxxxx>
Fixes: a05d59a56733 "tracing: Add condition check to RCU lockdep checks"
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
include/linux/tracepoint.h | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 6b79537a42b1..696a339c592c 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -184,10 +184,11 @@ extern void syscall_unregfunc(void);
* structure. Force alignment to the same alignment as the section start.
*
* When lockdep is enabled, we make sure to always do the RCU portions of
- * the tracepoint code, regardless of whether tracing is on or we match the
- * condition. This lets us find RCU issues triggered with tracepoints even
- * when this tracepoint is off. This code has no purpose other than poking
- * RCU a bit.
+ * the tracepoint code, regardless of whether tracing is on. However,
+ * don't check if the condition is false, due to interaction with idle
+ * instrumentation. This lets us find RCU issues triggered with tracepoints
+ * even when this tracepoint is off. This code has no purpose other than
+ * poking RCU a bit.
*/
#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
extern struct tracepoint __tracepoint_##name; \
--
2.6.1


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