SI_TIMER
if (likely(q->info.si_code != SI_TIMER)) {
if (si_code == SI_TIMER)
if (unlikely((first->flags & SIGQUEUE_PREALLOC) && (info->si_code == SI_TIMER)))
if (likely(!(q->flags & SIGQUEUE_PREALLOC) || q->info.si_code != SI_TIMER))
new_timer->sigq.info.si_code = SI_TIMER;