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author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-03-24 23:08:48 +0300 |
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committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-06-18 16:22:54 +0300 |
commit | 1b20d9491cf9cf180f1f2a46c80d69af0f775d55 (patch) | |
tree | 55fff8c5abbd05b80a439c6cf5cd2cc339b7629a /tools/lib/traceevent/event-parse.c | |
parent | 74621d929d944529a5e2878a84f48bfa6fb69a66 (diff) | |
download | linux-1b20d9491cf9cf180f1f2a46c80d69af0f775d55.tar.xz |
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/event-parse.c')
-rw-r--r-- | tools/lib/traceevent/event-parse.c | 35 |
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) { |