int segment_manager_add_segment (segment_manager_t * sm, uword segment_size);
void segment_manager_del_segment (segment_manager_t * sm,
fifo_segment_t * fs);
int segment_manager_add_segment (segment_manager_t * sm, uword segment_size);
void segment_manager_del_segment (segment_manager_t * sm,
fifo_segment_t * fs);