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