[lttng-dev] [RFC PATCH 1/3] Tracepoint: fix documentation of RCU lockdep checks
mathieu.desnoyers at efficios.com
Wed Oct 7 06:39:18 EDT 2015
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
Fixes: a05d59a56733 "tracing: Add condition check to RCU lockdep checks"
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
CC: Dave Hansen <dave at sr71.net>
CC: Steven Rostedt <rostedt at goodmis.org>
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 a5f7f3e..c8e3030 100644
@@ -167,10 +167,11 @@ 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; \
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