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authorMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>2008-11-14 17:47:40 -0500
committerIngo Molnar <mingo@elte.hu>2008-11-16 09:01:30 +0100
commita0bca6a59ebc052751eed6e3b182c153495672d8 (patch)
tree657ca4a1c63cb6303a28a7b512a99af592e45a20
parentc1df1bd2c4d4b20c83755a0f41956b57aec4842a (diff)
downloadlinux-a0bca6a59ebc052751eed6e3b182c153495672d8.tar.gz
markers: create DEFINE_MARKER and GET_MARKER (new API)
Impact: new API. Allow markers to be used only for declaration, without function call associated. Useful to create specialized probes. The problem we had is that two function calls were required when one wanted to put a marker in a tracepoint probe. Now the marker can be used simply for trace data type declaration, leaving the trace write work within the tracepoint probe without any additional function call. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--Documentation/markers.txt14
-rw-r--r--include/linux/marker.h39
2 files changed, 37 insertions, 16 deletions
diff --git a/Documentation/markers.txt b/Documentation/markers.txt
index 089f6138fcd9..6d275e4ef385 100644
--- a/Documentation/markers.txt
+++ b/Documentation/markers.txt
@@ -70,6 +70,20 @@ a printk warning which identifies the inconsistency:
"Format mismatch for probe probe_name (format), marker (format)"
+Another way to use markers is to simply define the marker without generating any
+function call to actually call into the marker. This is useful in combination
+with tracepoint probes in a scheme like this :
+
+void probe_tracepoint_name(unsigned int arg1, struct task_struct *tsk);
+
+DEFINE_MARKER_TP(marker_eventname, tracepoint_name, probe_tracepoint_name,
+ "arg1 %u pid %d");
+
+notrace void probe_tracepoint_name(unsigned int arg1, struct task_struct *tsk)
+{
+ struct marker *marker = &GET_MARKER(kernel_irq_entry);
+ /* write data to trace buffers ... */
+}
* Probe / marker example
diff --git a/include/linux/marker.h b/include/linux/marker.h
index 57a307018ceb..34c14bc957f5 100644
--- a/include/linux/marker.h
+++ b/include/linux/marker.h
@@ -55,6 +55,22 @@ struct marker {
#ifdef CONFIG_MARKERS
+#define _DEFINE_MARKER(name, tp_name_str, tp_cb, format) \
+ static const char __mstrtab_##name[] \
+ __attribute__((section("__markers_strings"))) \
+ = #name "\0" format; \
+ static struct marker __mark_##name \
+ __attribute__((section("__markers"), aligned(8))) = \
+ { __mstrtab_##name, &__mstrtab_##name[sizeof(#name)], \
+ 0, 0, marker_probe_cb, { __mark_empty_function, NULL},\
+ NULL, tp_name_str, tp_cb }
+
+#define DEFINE_MARKER(name, format) \
+ _DEFINE_MARKER(name, NULL, NULL, format)
+
+#define DEFINE_MARKER_TP(name, tp_name, tp_cb, format) \
+ _DEFINE_MARKER(name, #tp_name, tp_cb, format)
+
/*
* Note : the empty asm volatile with read constraint is used here instead of a
* "used" attribute to fix a gcc 4.1.x bug.
@@ -68,14 +84,7 @@ struct marker {
*/
#define __trace_mark(generic, name, call_private, format, args...) \
do { \
- static const char __mstrtab_##name[] \
- __attribute__((section("__markers_strings"))) \
- = #name "\0" format; \
- static struct marker __mark_##name \
- __attribute__((section("__markers"), aligned(8))) = \
- { __mstrtab_##name, &__mstrtab_##name[sizeof(#name)], \
- 0, 0, marker_probe_cb, \
- { __mark_empty_function, NULL}, NULL, NULL, NULL }; \
+ DEFINE_MARKER(name, format); \
__mark_check_format(format, ## args); \
if (unlikely(__mark_##name.state)) { \
(*__mark_##name.call) \
@@ -89,14 +98,7 @@ struct marker {
{ \
register_trace_##tp_name(tp_cb); \
} \
- static const char __mstrtab_##name[] \
- __attribute__((section("__markers_strings"))) \
- = #name "\0" format; \
- static struct marker __mark_##name \
- __attribute__((section("__markers"), aligned(8))) = \
- { __mstrtab_##name, &__mstrtab_##name[sizeof(#name)], \
- 0, 0, marker_probe_cb, \
- { __mark_empty_function, NULL}, NULL, #tp_name, tp_cb };\
+ DEFINE_MARKER_TP(name, tp_name, tp_cb, format); \
__mark_check_format(format, ## args); \
(*__mark_##name.call)(&__mark_##name, call_private, \
## args); \
@@ -104,7 +106,11 @@ struct marker {
extern void marker_update_probe_range(struct marker *begin,
struct marker *end);
+
+#define GET_MARKER(name) (__mark_##name)
+
#else /* !CONFIG_MARKERS */
+#define DEFINE_MARKER(name, tp_name, tp_cb, format)
#define __trace_mark(generic, name, call_private, format, args...) \
__mark_check_format(format, ## args)
#define __trace_mark_tp(name, call_private, tp_name, tp_cb, format, args...) \
@@ -118,6 +124,7 @@ extern void marker_update_probe_range(struct marker *begin,
static inline void marker_update_probe_range(struct marker *begin,
struct marker *end)
{ }
+#define GET_MARKER(name)
#endif /* CONFIG_MARKERS */
/**