On Tue, Dec 29, 2020 at 11:11:56AM +0800, Rongwei Wang wrote:
> When I was doing some memory-related projects, it always reported error
> "nonzero mapcount", but its judgment condition was that _mapcount was not
> equal
> to -1, so I felt the original string was a bit inappropriate, so I tried to
> update it.
But '_mapcount' of -1 _is_ a mapcount of 0. If we need to improve the
documentation somewhere, that'd be better than changing this message.
I do wonder if we want to add:
if (unlikely(page_has_type(page))
bad_reason = "page still typed";
It's covered by the non-zero mapcount case, but is slightly misleading.
> if (unlikely(atomic_read(&page->_mapcount) != -1))
> - bad_reason = "nonzero mapcount";
> + bad_reason = "non-(-1) _mapcount";
> if (unlikely(page->mapping != NULL))
> bad_reason = "non-NULL mapping";
> if (unlikely(page_ref_count(page) != 0))
> --
> 1.8.3.1
>
>
