mm: add comment why mark_page_accessed() would be better than pte_mkyoung() in follow...

[safe/jmp/linux-2.6] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index 0017111..5b4ad5e 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1151,6 +1151,11 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
                if ((flags & FOLL_WRITE) &&
                    !pte_dirty(pte) && !PageDirty(page))
                        set_page_dirty(page);
+               /*
+                * pte_mkyoung() would be more correct here, but atomic care
+                * is needed to avoid losing the dirty bit: it is easier to use
+                * mark_page_accessed().
+                */
                mark_page_accessed(page);
        }
 unlock: