vn_pages_remove
vn_pages_remove(vp, OFF_TO_IDX(start), OFF_TO_IDX(end + PAGE_SIZE - 1));
void vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end);
vn_pages_remove(vp,
vn_pages_remove(vp, extend, 0);
vn_pages_remove(vp, OFF_TO_IDX(OFF_MAX), end);