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>
1b20d9491c