On Wed 13-06-18 09:51:23, Vlastimil Babka wrote: > On 06/13/2018 09:15 AM, Michal Hocko wrote: > > On Wed 13-06-18 08:32:19, Vlastimil Babka wrote: [...] > >> I think more concerning than guaranteeing no later major fault is > >> possible data loss, e.g. replacing data with zero-filled pages. > > > > But MADV_DONTNEED is an explicit call for data loss. Or do I miss your > > point? > > My point is that if somebody is relying on MADV_DONTNEED not affecting > mlocked pages, the consequences will be unexpected data loss, not just > extra page faults. OK, I see your point now. I would consider this an application bug though. Calling MADV_DONTNEED and wondering that the content is gone is, ehm, questionable at best. Why would anybody do that in the first place? Anyway, I think that we cannot change the behavior because of mlockall semantic as mentioned earlier. -- Michal Hocko SUSE Labs
