Support for TRACE_DEFINE_SIZEOF() has been added to the kernel. Lets document the use of the new macro and correct a couple of minor spelling mistakes.
Signed-off-by: Jeremy Linton <[email protected]> --- samples/trace_events/trace-events-sample.h | 38 +++++++++++++++++++----------- 1 file changed, 24 insertions(+), 14 deletions(-) diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h index 76a75ab..0b45272 100644 --- a/samples/trace_events/trace-events-sample.h +++ b/samples/trace_events/trace-events-sample.h @@ -95,7 +95,7 @@ * __entry->bar.x = y; * __array: There are three fields (type, name, size). The type is the - * type of elements in teh array, the name is the name of the array. + * type of elements in the array, the name is the name of the array. * size is the number of items in the array (not the total size). * * __array( char, foo, 10) is the same as saying: char foo[10]; @@ -112,7 +112,7 @@ * type is the type of the element, name is the name of the array. * The size is different than __array. It is not a static number, * but the algorithm to figure out the length of the array for the - * specific instance of tracepoint. Again, size is the numebr of + * specific instance of tracepoint. Again, size is the number of * items in the array, not the total length in bytes. * * __dynamic_array( int, foo, bar) is similar to: int foo[bar]; @@ -125,9 +125,9 @@ * Notice, that "__entry" is not needed here. * * __string: This is a special kind of __dynamic_array. It expects to - * have a nul terminated character array passed to it (it allows + * have a null terminated character array passed to it (it allows * for NULL too, which would be converted into "(null)"). __string - * takes two paramenter (name, src), where name is the name of + * takes two parameter (name, src), where name is the name of * the string saved, and src is the string to copy into the * ring buffer. * @@ -225,26 +225,36 @@ TRACE_DEFINE_ENUM(TRACE_SAMPLE_FOO); TRACE_DEFINE_ENUM(TRACE_SAMPLE_BAR); TRACE_DEFINE_ENUM(TRACE_SAMPLE_ZOO); +/* + * The same problem as above applies to sizeof(), so there is also + * a macro to solve that problem. In the case show below, foo_bar/format + * contains a string "__print_array(...,sizeof(phys_addr_t))" for which + * the sizeof() result varies depending on the kernel. Adding the following + * macro decodes the size before transferring it to user space. + */ + +TRACE_DEFINE_SIZEOF(phys_addr_t); + TRACE_EVENT(foo_bar, - TP_PROTO(const char *foo, int bar, const int *lst, + TP_PROTO(const char *foo, int bar, const phys_addr_t *lst, const char *string, const struct cpumask *mask), TP_ARGS(foo, bar, lst, string, mask), TP_STRUCT__entry( - __array( char, foo, 10 ) - __field( int, bar ) - __dynamic_array(int, list, __length_of(lst)) - __string( str, string ) - __bitmask( cpus, num_possible_cpus() ) + __array( char, foo, 10 ) + __field( int, bar ) + __dynamic_array(phys_addr_t, list, __length_of(lst) ) + __string( str, string ) + __bitmask( cpus, num_possible_cpus() ) ), TP_fast_assign( strlcpy(__entry->foo, foo, 10); __entry->bar = bar; memcpy(__get_dynamic_array(list), lst, - __length_of(lst) * sizeof(int)); + __length_of(lst) * sizeof(phys_addr_t)); __assign_str(str, string); __assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus()); ), @@ -291,8 +301,8 @@ TRACE_EVENT(foo_bar, * This prints out the array that is defined by __array in a nice format. */ __print_array(__get_dynamic_array(list), - __get_dynamic_array_len(list) / sizeof(int), - sizeof(int)), + __get_dynamic_array_len(list) / sizeof(phys_addr_t), + sizeof(phys_addr_t)), __get_str(str), __get_bitmask(cpus)) ); @@ -444,7 +454,7 @@ DECLARE_EVENT_CLASS(foo_template, /* * Here's a better way for the previous samples (except, the first - * exmaple had more fields and could not be used here). + * example had more fields and could not be used here). */ DEFINE_EVENT(foo_template, foo_with_template_simple, TP_PROTO(const char *foo, int bar), -- 2.9.4
