On Tue, May 03, 2016 at 02:33:51PM +0200, jglisse@xxxxxxxxxx wrote: > From: Jérôme Glisse <jglisse@xxxxxxxxxx> > > Fix assumptions in migrate_misplaced_transhuge_page() which is only > call by do_huge_pmd_numa_page() itself only call by __handle_mm_fault() > for pmd with PROT_NONE. This means that if the pmd stays the same > then there can be no concurrent get_user_pages / get_user_pages_fast > (GUP/GUP_fast). More over because migrate_misplaced_transhuge_page() > abort if page is mapped more than once then there can be no GUP from > a different process. Finaly, holding the pmd lock assure us that no > other part of the kernel can take an extra reference on the page. > > In the end this means that the failure code path should never be > taken unless something is horribly wrong, so convert it to BUG_ON(). > > Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx> > Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > Cc: Mel Gorman <mgorman@xxxxxxx> > Cc: Hugh Dickins <hughd@xxxxxxxxxx> > Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Acked-by: Mel Gorman <mgorman@xxxxxxx> -- Mel Gorman SUSE Labs -- 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>