bch_extent_sort_cmp
bch_extent_sort_cmp(i[0], i[1]))
heap_sift(iter, i - top, bch_extent_sort_cmp);
heap_sift(iter, i - top, bch_extent_sort_cmp);
heap_sift(iter, 0, bch_extent_sort_cmp);
.sort_cmp = bch_extent_sort_cmp,