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 > >
