On Fri, Oct 03, 2014 at 07:08:00PM +0200, Andrea Arcangeli wrote: > There's one constraint enforced to allow this simplification: the > source pages passed to remap_anon_pages must be mapped only in one > vma, but this is not a limitation when used to handle userland page > faults with MADV_USERFAULT. The source addresses passed to > remap_anon_pages should be set as VM_DONTCOPY with MADV_DONTFORK to > avoid any risk of the mapcount of the pages increasing, if fork runs > in parallel in another thread, before or while remap_anon_pages runs. Have you considered triggering COW instead of adding limitation on pages' mapcount? The limitation looks artificial from interface POV. -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>