On Wed, Feb 03, 2021 at 04:13:21PM +0000, Joao Martins wrote: > If check_and_migrate_movable_pages() is meant to migrate unpinned > pages, then rather than pinning+unpinning+moving, perhaps it would > be called in __get_user_pages() place where we are walking page > tables and know if it's a PUD/PMD and can skip all the subpages and > just record and migrate those instead. Was that your thinking? I think a reasonable approach is to detect non-pinnable pages while walking the VMAs, when found isolate them and thread them on a linked list. When the VMA walk is done you'll have a linked list of isolated pages that need migration. So the check_and_migrate_movable_pages() gets split into the top half being diffused in the VMA walk and the bottom half still called after __get_user_pages() returns. Jason
