MF_MUST_KILL
flags |= MF_MUST_KILL;
unmap_success = !unmap_poisoned_folio(folio, pfn, flags & MF_MUST_KILL);
forcekill = folio_test_dirty(folio) || (flags & MF_MUST_KILL) ||
kill_procs(to_kill, !!(flags & MF_MUST_KILL), pfn, flags);
flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
mf_flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;