On Tue, May 03, 2016 at 02:33:51PM +0200, jgli...@redhat.com wrote: > From: Jérôme Glisse <jgli...@redhat.com> > > 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 <jgli...@redhat.com> > Acked-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com> > Cc: Mel Gorman <mgor...@suse.de> > Cc: Hugh Dickins <hu...@google.com> > Cc: Andrea Arcangeli <aarca...@redhat.com>
Acked-by: Mel Gorman <mgor...@suse.de> -- Mel Gorman SUSE Labs
