On Sat 04-11-17 17:28:05, Hugh Dickins wrote: > On Fri, 3 Nov 2017, Michal Hocko wrote: > > On Fri 03-11-17 00:46:18, Hugh Dickins wrote: > > > > > > NAK. shmem_wait_for_pins() is waiting for temporary pins on the pages > > > to go away, and using lru_add_drain_all() in the usual way, to lower > > > the refcount of pages temporarily pinned in a pagevec somewhere. Page > > > count is touched by draining pagevecs: I'm surprised to see you say > > > that it isn't - or have pagevec page references been eliminated by > > > a recent commit that I missed? > > > > I must be missing something here. __pagevec_lru_add_fn merely about > > moving the page into the appropriate LRU list, pagevec_move_tail only > > rotates, lru_deactivate_file_fn moves from active to inactive LRUs, > > lru_lazyfree_fn moves from anon to file LRUs and activate_page_drain > > just moves to the active list. None of those operations touch the page > > count AFAICS. So I would agree that some pages might be pinned outside > > of the LRU (lru_add_pvec) and thus unreclaimable but does this really > > matter. Or what else I am missing? > > Line 213 of mm/swap.c? Where pagevec_lru_move_fn() calls release_pages() > to release the extra references (which each page came in with when added). I am obviously blind. I was staring at that function many times simply missing this part. My bad and sorry about not taking a deeper look. Shame... -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
