vm: add trace output

vm/vm-object.c

@@ -286,6 +286,10 @@ extern struct vm_page *vm_object_alloc_page(
 			return NULL;
 		}
 
+		tracek("vm-object: [%s] alloc offset %zx -> page %zx",
+		       vo->vo_name,
+		       offset,
+		       vm_page_get_paddr(page));
 		page->p_vmo_offset = offset;
 		vo->vo_pages.b_root = &page->p_bnode;
 		btree_insert_fixup(&vo->vo_pages, &page->p_bnode);