On Wed 17-10-18 17:03:03, John Hubbard wrote: > On 10/17/18 4:09 AM, Michal Hocko wrote: > > On Tue 16-10-18 18:48:23, John Hubbard wrote: > > [...] > >> It's hard to say exactly what the active/inactive/unevictable list should > >> be when DMA is done and put_user_page*() is called, because we don't know > >> if some device read, wrote, or ignored any of those pages. Although if > >> put_user_pages_dirty() is called, that's an argument for "active", at least. > > > > Any reason to not use putback_lru_page? > > That does help with which LRU to use. I guess I'd still need to track whether > a page was on an LRU when get_user_pages() was called, because it seems > that that is not necessarily always the case. And putback_lru_page() definitely > wants to deal with a page that *was* previously on an LRU. Well, if you ever g-u-p pages which are never going to go to LRU then sure (e.g. hugetlb pages). -- Michal Hocko SUSE Labs
