SDT_TASK_ENTS_PER_PAGE_SHIFT
const __u64 mask = (1 << SDT_TASK_ENTS_PER_PAGE_SHIFT) - 1;
shift = (SDT_TASK_LEVELS - 1 - level) * SDT_TASK_ENTS_PER_PAGE_SHIFT;
idx <<= SDT_TASK_ENTS_PER_PAGE_SHIFT;
SDT_TASK_ENTS_PER_CHUNK = 1 << SDT_TASK_ENTS_PER_PAGE_SHIFT,