On Mon, Jan 06, 2020 at 11:23:45AM +0100, Michal Hocko wrote: >On Fri 03-01-20 22:34:07, Wei Yang wrote: >> As all the other places, we grab the lock before manipulate the defer list. >> Current implementation may face a race condition. > >Please always make sure to describe the effect of the change. Why a racy >list_empty check matters? > Hmm... access the list without proper lock leads to many bad behaviors. For example, if we grab the lock after checking list_empty, the page may already be removed from list in split_huge_page_list. And then list_del_init would trigger bug. -- Wei Yang Help you, Help me
