diff options
| -rw-r--r-- | mm/rmap.c | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index 1ea4e6fcee77..059774712c08 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -659,23 +659,30 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma) } /* - * It would be tidy to reset the PageAnon mapping here, - * but that might overwrite a racing page_add_anon_rmap - * which increments mapcount after us but sets mapping - * before us: so leave the reset to free_hot_cold_page, - * and remember that it's only reliable while mapped. - * Leaving it set also helps swapoff to reinstate ptes - * faster for those pages still in swapcache. + * Now that the last pte has gone, s390 must transfer dirty + * flag from storage key to struct page. We can usually skip + * this if the page is anon, so about to be freed; but perhaps + * not if it's in swapcache - there might be another pte slot + * containing the swap entry, but page not yet written to swap. */ if ((!PageAnon(page) || PageSwapCache(page)) && page_test_dirty(page)) { page_clear_dirty(page); set_page_dirty(page); } - mem_cgroup_uncharge_page(page); + mem_cgroup_uncharge_page(page); __dec_zone_page_state(page, - PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED); + PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED); + /* + * It would be tidy to reset the PageAnon mapping here, + * but that might overwrite a racing page_add_anon_rmap + * which increments mapcount after us but sets mapping + * before us: so leave the reset to free_hot_cold_page, + * and remember that it's only reliable while mapped. + * Leaving it set also helps swapoff to reinstate ptes + * faster for those pages still in swapcache. + */ } } |