From: Li Zefan __string() is limited: - it's a char array, but we may want to define array with other types - a source string should be available, but we may just know the string size We introduce __dynamic_array() to break those limitations, and __string() becomes a wrapper of it. As a side effect, now __get_str() can be used in TP_fast_assign but not only TP_print. Take XFS for example, we have the string length in the dirent, but the string itself is not NULL-terminated, so __dynamic_array() can be used: TRACE_EVENT(xfs_dir2, TP_PROTO(struct xfs_da_args *args), TP_ARGS(args), TP_STRUCT__entry( __field(int, namelen) __dynamic_array(char, name, args->namelen + 1) ... ), TP_fast_assign( char *name = __get_str(name); if (args->namelen) memcpy(name, args->name, args->namelen); name[args->namelen] = '\0'; __entry->namelen = args->namelen; ), TP_printk("name %.*s namelen %d", __entry->namelen ? __get_str(name) : NULL __entry->namelen) ); [ Impact: allow defining dynamic size arrays ] Signed-off-by: Li Zefan LKML-Reference: <4A2384D2.3080403@cn.fujitsu.com> Signed-off-by: Steven Rostedt --- include/trace/ftrace.h | 122 ++++++++++++++++++++++++++---------- kernel/trace/trace_events_filter.c | 6 +- 2 files changed, 91 insertions(+), 37 deletions(-) diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index ee92682..b5478da 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -18,14 +18,17 @@ #include +#undef __field +#define __field(type, item) type item; + #undef __array #define __array(type, item, len) type item[len]; -#undef __field -#define __field(type, item) type item; +#undef __dynamic_array +#define __dynamic_array(type, item, len) unsigned short __data_loc_##item; #undef __string -#define __string(item, src) unsigned short __str_loc_##item; +#define __string(item, src) __dynamic_array(char, item, -1) #undef TP_STRUCT__entry #define TP_STRUCT__entry(args...) args @@ -35,7 +38,7 @@ struct ftrace_raw_##name { \ struct trace_entry ent; \ tstruct \ - char __str_data[0]; \ + char __data[0]; \ }; \ static struct ftrace_event_call event_##name @@ -47,30 +50,31 @@ * * Include the following: * - * struct ftrace_str_offsets_ { - * int ; - * int ; + * struct ftrace_data_offsets_ { + * int ; + * int ; * [...] * }; * - * The __string() macro will create each int , this is to - * keep the offset of each string from the beggining of the event - * once we perform the strlen() of the src strings. - * + * The __dynamic_array() macro will create each int , this is + * to keep the offset of each array from the beginning of the event. */ +#undef __field +#define __field(type, item); + #undef __array #define __array(type, item, len) -#undef __field -#define __field(type, item); +#undef __dynamic_array +#define __dynamic_array(type, item, len) int item; #undef __string -#define __string(item, src) int item; +#define __string(item, src) __dynamic_array(char, item, -1) #undef TRACE_EVENT #define TRACE_EVENT(call, proto, args, tstruct, assign, print) \ - struct ftrace_str_offsets_##call { \ + struct ftrace_data_offsets_##call { \ tstruct; \ }; @@ -119,8 +123,12 @@ #undef TP_printk #define TP_printk(fmt, args...) fmt "\n", args +#undef __get_dynamic_array +#define __get_dynamic_array(field) \ + ((void *)__entry + __entry->__data_loc_##field) + #undef __get_str -#define __get_str(field) ((char *)__entry + __entry->__str_loc_##field) +#define __get_str(field) (char *)__get_dynamic_array(field) #undef __print_flags #define __print_flags(flag, delim, flag_array...) \ @@ -207,16 +215,19 @@ ftrace_raw_output_##call(struct trace_iterator *iter, int flags) \ if (!ret) \ return 0; -#undef __string -#define __string(item, src) \ - ret = trace_seq_printf(s, "\tfield:__str_loc " #item ";\t" \ +#undef __dynamic_array +#define __dynamic_array(type, item, len) \ + ret = trace_seq_printf(s, "\tfield:__data_loc " #item ";\t" \ "offset:%u;\tsize:%u;\n", \ (unsigned int)offsetof(typeof(field), \ - __str_loc_##item), \ - (unsigned int)sizeof(field.__str_loc_##item)); \ + __data_loc_##item), \ + (unsigned int)sizeof(field.__data_loc_##item)); \ if (!ret) \ return 0; +#undef __string +#define __string(item, src) __dynamic_array(char, item, -1) + #undef __entry #define __entry REC @@ -260,11 +271,14 @@ ftrace_format_##call(struct trace_seq *s) \ if (ret) \ return ret; +#undef __dynamic_array +#define __dynamic_array(type, item, len) \ + ret = trace_define_field(event_call, "__data_loc" "[" #type "]", #item,\ + offsetof(typeof(field), __data_loc_##item), \ + sizeof(field.__data_loc_##item), 0); + #undef __string -#define __string(item, src) \ - ret = trace_define_field(event_call, "__str_loc", #item, \ - offsetof(typeof(field), __str_loc_##item), \ - sizeof(field.__str_loc_##item), 0); +#define __string(item, src) __dynamic_array(char, item, -1) #undef TRACE_EVENT #define TRACE_EVENT(call, proto, args, tstruct, func, print) \ @@ -289,6 +303,43 @@ ftrace_define_fields_##call(void) \ #include TRACE_INCLUDE(TRACE_INCLUDE_FILE) /* + * remember the offset of each array from the beginning of the event. + */ + +#undef __entry +#define __entry entry + +#undef __field +#define __field(type, item) + +#undef __array +#define __array(type, item, len) + +#undef __dynamic_array +#define __dynamic_array(type, item, len) \ + __data_offsets->item = __data_size + \ + offsetof(typeof(*entry), __data); \ + __data_size += (len) * sizeof(type); + +#undef __string +#define __string(item, src) __dynamic_array(char, item, strlen(src) + 1) \ + +#undef TRACE_EVENT +#define TRACE_EVENT(call, proto, args, tstruct, assign, print) \ +static inline int ftrace_get_offsets_##call( \ + struct ftrace_data_offsets_##call *__data_offsets, proto) \ +{ \ + int __data_size = 0; \ + struct ftrace_raw_##call __maybe_unused *entry; \ + \ + tstruct; \ + \ + return __data_size; \ +} + +#include TRACE_INCLUDE(TRACE_INCLUDE_FILE) + +/* * Stage 4 of the trace events. * * Override the macros in to include the following: @@ -432,15 +483,15 @@ static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\ #undef __array #define __array(type, item, len) +#undef __dynamic_array +#define __dynamic_array(type, item, len) \ + __entry->__data_loc_##item = __data_offsets.item; + #undef __string -#define __string(item, src) \ - __str_offsets.item = __str_size + \ - offsetof(typeof(*entry), __str_data); \ - __str_size += strlen(src) + 1; +#define __string(item, src) __dynamic_array(char, item, -1) \ #undef __assign_str #define __assign_str(dst, src) \ - __entry->__str_loc_##dst = __str_offsets.dst; \ strcpy(__get_str(dst), src); #undef TRACE_EVENT @@ -451,26 +502,29 @@ static struct ftrace_event_call event_##call; \ \ static void ftrace_raw_event_##call(proto) \ { \ - struct ftrace_str_offsets_##call __maybe_unused __str_offsets; \ + struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\ struct ftrace_event_call *event_call = &event_##call; \ struct ring_buffer_event *event; \ struct ftrace_raw_##call *entry; \ unsigned long irq_flags; \ - int __str_size = 0; \ + int __data_size; \ int pc; \ \ local_save_flags(irq_flags); \ pc = preempt_count(); \ \ - tstruct; \ + __data_size = ftrace_get_offsets_##call(&__data_offsets, args); \ \ event = trace_current_buffer_lock_reserve(event_##call.id, \ - sizeof(struct ftrace_raw_##call) + __str_size,\ + sizeof(*entry) + __data_size, \ irq_flags, pc); \ if (!event) \ return; \ entry = ring_buffer_event_data(event); \ \ + \ + tstruct \ + \ { assign; } \ \ if (!filter_current_check_discard(event_call, entry, event)) \ diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index a7430b1..db6e54b 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -478,12 +478,12 @@ enum { static int is_string_field(const char *type) { + if (strstr(type, "__data_loc") && strstr(type, "char")) + return FILTER_DYN_STRING; + if (strchr(type, '[') && strstr(type, "char")) return FILTER_STATIC_STRING; - if (!strcmp(type, "__str_loc")) - return FILTER_DYN_STRING; - return 0; } -- 1.6.3.1 -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/