Re: [PATCH 0/3] Some cleanups for page isolation

[Matthew Wilcox]

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.