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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2020-03-24 16:08:48 -0400
committerArnaldo Carvalho de Melo <acme@redhat.com>2020-06-18 10:22:54 -0300
commit1b20d9491cf9cf180f1f2a46c80d69af0f775d55 (patch)
tree55fff8c5abbd05b80a439c6cf5cd2cc339b7629a /tools/lib/traceevent
parent74621d929d944529a5e2878a84f48bfa6fb69a66 (diff)
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tools lib traceevent: Add handler for __builtin_expect()
In order to move pointer checks like IS_ERR_VALUE() out of the hotpath and into the reader path of a trace event, user space tools need to be able to parse that. IS_ERR_VALUE() is defined as: #define IS_ERR_VALUE() unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) Which eventually turns into: __builtin_expect(!!((unsigned long)(void *)(x) >= (unsigned long)-4095), 0) Now the traceevent parser can handle most of that except for the __builtin_expect(), which needs to be added. Link: https://lore.kernel.org/linux-mm/20200320055823.27089-3-jaewon31.kim@samsung.com/ Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jaewon Kim <jaewon31.kim@samsung.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kees Kook <keescook@chromium.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: linux-mm@kvack.org Cc: linux-trace-devel@vger.kernel.org Link: http://lore.kernel.org/lkml/20200324200956.821799393@goodmis.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/lib/traceevent')
-rw-r--r--tools/lib/traceevent/event-parse.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index 010e60d5a081..5b36c589a029 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -3085,6 +3085,37 @@ err:
}
static enum tep_event_type
+process_builtin_expect(struct tep_event *event, struct tep_print_arg *arg, char **tok)
+{
+ enum tep_event_type type;
+ char *token = NULL;
+
+ /* Handle __builtin_expect( cond, #) */
+ type = process_arg(event, arg, &token);
+
+ if (type != TEP_EVENT_DELIM || token[0] != ',')
+ goto out_free;
+
+ free_token(token);
+
+ /* We don't care what the second parameter is of the __builtin_expect() */
+ if (read_expect_type(TEP_EVENT_ITEM, &token) < 0)
+ goto out_free;
+
+ if (read_expected(TEP_EVENT_DELIM, ")") < 0)
+ goto out_free;
+
+ free_token(token);
+ type = read_token_item(tok);
+ return type;
+
+out_free:
+ free_token(token);
+ *tok = NULL;
+ return TEP_EVENT_ERROR;
+}
+
+static enum tep_event_type
process_function(struct tep_event *event, struct tep_print_arg *arg,
char *token, char **tok)
{
@@ -3128,6 +3159,10 @@ process_function(struct tep_event *event, struct tep_print_arg *arg,
free_token(token);
return process_dynamic_array_len(event, arg, tok);
}
+ if (strcmp(token, "__builtin_expect") == 0) {
+ free_token(token);
+ return process_builtin_expect(event, arg, tok);
+ }
func = find_func_handler(event->tep, token);
if (func) {