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-rw-r--r--samples/trace_events/trace-events-sample.h32
1 files changed, 28 insertions, 4 deletions
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index cbbbb83beced..1a92226202fc 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -141,6 +141,27 @@
* In most cases, the __assign_str() macro will take the same
* parameters as the __string() macro had to declare the string.
*
+ * __vstring: This is similar to __string() but instead of taking a
+ * dynamic length, it takes a variable list va_list 'va' variable.
+ * Some event callers already have a message from parameters saved
+ * in a va_list. Passing in the format and the va_list variable
+ * will save just enough on the ring buffer for that string.
+ * Note, the va variable used is a pointer to a va_list, not
+ * to the va_list directly.
+ *
+ * (va_list *va)
+ *
+ * __vstring(foo, fmt, va) is similar to: vsnprintf(foo, fmt, va)
+ *
+ * To assign the string, use the helper macro __assign_vstr().
+ *
+ * __assign_vstr(foo, fmt, va);
+ *
+ * In most cases, the __assign_vstr() macro will take the same
+ * parameters as the __vstring() macro had to declare the string.
+ * Use __get_str() to retrieve the __vstring() just like it would for
+ * __string().
+ *
* __string_len: This is a helper to a __dynamic_array, but it understands
* that the array has characters in it, and with the combined
* use of __assign_str_len(), it will allocate 'len' + 1 bytes
@@ -256,9 +277,10 @@ TRACE_DEFINE_ENUM(TRACE_SAMPLE_ZOO);
TRACE_EVENT(foo_bar,
TP_PROTO(const char *foo, int bar, const int *lst,
- const char *string, const struct cpumask *mask),
+ const char *string, const struct cpumask *mask,
+ const char *fmt, va_list *va),
- TP_ARGS(foo, bar, lst, string, mask),
+ TP_ARGS(foo, bar, lst, string, mask, fmt, va),
TP_STRUCT__entry(
__array( char, foo, 10 )
@@ -266,6 +288,7 @@ TRACE_EVENT(foo_bar,
__dynamic_array(int, list, __length_of(lst))
__string( str, string )
__bitmask( cpus, num_possible_cpus() )
+ __vstring( vstr, fmt, va )
),
TP_fast_assign(
@@ -274,10 +297,11 @@ TRACE_EVENT(foo_bar,
memcpy(__get_dynamic_array(list), lst,
__length_of(lst) * sizeof(int));
__assign_str(str, string);
+ __assign_vstr(vstr, fmt, va);
__assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());
),
- TP_printk("foo %s %d %s %s %s %s (%s)", __entry->foo, __entry->bar,
+ TP_printk("foo %s %d %s %s %s %s (%s) %s", __entry->foo, __entry->bar,
/*
* Notice here the use of some helper functions. This includes:
@@ -321,7 +345,7 @@ TRACE_EVENT(foo_bar,
__print_array(__get_dynamic_array(list),
__get_dynamic_array_len(list) / sizeof(int),
sizeof(int)),
- __get_str(str), __get_bitmask(cpus))
+ __get_str(str), __get_bitmask(cpus), __get_str(vstr))
);
/*