| From: "Matthew Wilcox (Oracle)" <willy@infradead.org> |
| Subject: mm: remove stale example from comment |
| Date: Mon, 11 Dec 2023 16:22:10 +0000 |
| |
| folio_add_new_anon_rmap() no longer works this way, so just remove the |
| entire example. |
| |
| Link: https://lkml.kernel.org/r/20231211162214.2146080-6-willy@infradead.org |
| Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> |
| Reviewed-by: David Hildenbrand <david@redhat.com> |
| Cc: Ralph Campbell <rcampbell@nvidia.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| --- |
| |
| mm/memremap.c | 18 ++++-------------- |
| 1 file changed, 4 insertions(+), 14 deletions(-) |
| |
| --- a/mm/memremap.c~mm-remove-stale-example-from-comment |
| +++ a/mm/memremap.c |
| @@ -473,21 +473,11 @@ void free_zone_device_page(struct page * |
| __ClearPageAnonExclusive(page); |
| |
| /* |
| - * When a device managed page is freed, the page->mapping field |
| + * When a device managed page is freed, the folio->mapping field |
| * may still contain a (stale) mapping value. For example, the |
| - * lower bits of page->mapping may still identify the page as an |
| - * anonymous page. Ultimately, this entire field is just stale |
| - * and wrong, and it will cause errors if not cleared. One |
| - * example is: |
| - * |
| - * migrate_vma_pages() |
| - * migrate_vma_insert_page() |
| - * page_add_new_anon_rmap() |
| - * __page_set_anon_rmap() |
| - * ...checks page->mapping, via PageAnon(page) call, |
| - * and incorrectly concludes that the page is an |
| - * anonymous page. Therefore, it incorrectly, |
| - * silently fails to set up the new anon rmap. |
| + * lower bits of folio->mapping may still identify the folio as an |
| + * anonymous folio. Ultimately, this entire field is just stale |
| + * and wrong, and it will cause errors if not cleared. |
| * |
| * For other types of ZONE_DEVICE pages, migration is either |
| * handled differently or not done at all, so there is no need |
| _ |
