On Wed 04-09-19 02:18:38, sunqiuyang wrote: > The isolate path of non-lru movable pages: > > isolate_migratepages_block > isolate_movable_page > trylock_page > // if PageIsolated, goto out_no_isolated > a_ops->isolate_page > __SetPageIsolated > unlock_page > list_add(&page->lru, &cc->migratepages) > > The migration path: > > unmap_and_move > __unmap_and_move > lock_page > move_to_new_page > a_ops->migratepage > __ClearPageIsolated > unlock_page > /* here, the page could be isolated again by another thread, and added into another cc->migratepages, > since PG_Isolated has been cleared, and not protected by page_lock */ > list_del(&page->lru) But the page has been migrated already and not freed yet because there is still a pin on it. So nobody should be touching it at this stage. Or do I still miss something? -- Michal Hocko SUSE Labs
