| Message ID | 20201007184403.1902111-2-axelrasmussen@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add tracepoints around mmap_lock acquisition | expand |
On Wed, Oct 7, 2020 at 11:44 AM Axel Rasmussen <axelrasmussen@google.com> wrote: > It's common [1] to define tracepoint fields as "bool" when they contain > a true / false value. Currently, defining a synthetic event with a > "bool" field yields EINVAL. It's possible to work around this by using > e.g. u8 (assuming sizeof(bool) is 1, and bool is unsigned; if either of > these properties don't match, you get EINVAL [2]). > > Supporting "bool" explicitly makes hooking this up easier and more > portable for userspace. Acked-by: Michel Lespinasse <walken@google.com> Looks fine to me, but you really want to get Steven's opinion over mine here :)
diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c index 742ce5f62d6d..92eb530ec287 100644 --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -187,6 +187,8 @@ static int synth_field_size(char *type) size = sizeof(long); else if (strcmp(type, "unsigned long") == 0) size = sizeof(unsigned long); + else if (strcmp(type, "bool") == 0) + size = sizeof(bool); else if (strcmp(type, "pid_t") == 0) size = sizeof(pid_t); else if (strcmp(type, "gfp_t") == 0) @@ -229,6 +231,8 @@ static const char *synth_field_fmt(char *type) fmt = "%ld"; else if (strcmp(type, "unsigned long") == 0) fmt = "%lu"; + else if (strcmp(type, "bool") == 0) + fmt = "%d"; else if (strcmp(type, "pid_t") == 0) fmt = "%d"; else if (strcmp(type, "gfp_t") == 0)
It's common [1] to define tracepoint fields as "bool" when they contain a true / false value. Currently, defining a synthetic event with a "bool" field yields EINVAL. It's possible to work around this by using e.g. u8 (assuming sizeof(bool) is 1, and bool is unsigned; if either of these properties don't match, you get EINVAL [2]). Supporting "bool" explicitly makes hooking this up easier and more portable for userspace. [1]: grep -r "bool" include/trace/events/ [2]: check_synth_field() in kernel/trace/trace_events_hist.c Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> --- kernel/trace/trace_events_synth.c | 4 ++++ 1 file changed, 4 insertions(+)