page_xchg_last_nid(new_page, page_last_nid(page));
isolated = numamigrate_isolate_page(pgdat, page);
- if (!isolated) {
+
+ /*
+ * Failing to isolate or a GUP pin prevents migration. The expected
+ * page count is 2. 1 for anonymous pages without a mapping and 1
+ * for the callers pin. If the page was isolated, the page will
+ * need to be put back on the LRU.
+ */
+ if (!isolated || page_count(page) != 2) {
count_vm_events(PGMIGRATE_FAIL, HPAGE_PMD_NR);
put_page(new_page);
+ if (isolated) {
+ putback_lru_page(page);
+ isolated = 0;
+ goto out;
+ }
goto out_keep_locked;
}