On Tue, Feb 14, 2023 at 11:18:05AM +0800, Baolin Wang wrote: > The page isolation functions did not return a boolean to indicate > success or not, instead it will return a negative error when failed > to isolate a page. So it's better to check the negative error explicitly > for isolation to make the code more clear per Linus's suggestion in [1]. Only one caller of isolate_lru_page() or folio_isolate_lru() actually uses the errno. And the errno can only be 0 or -EBUSY. It'd be better to change the three functions to return bool and fix add_page_for_migration() to set the errno to -EBUSY itself.
