[Cc Suren and Minchan - the email thread starts here 20190514131654.25463-1-oleksandr@xxxxxxxxxx] On Wed 15-05-19 08:53:11, Michal Hocko wrote: [...] > I will try to comment on the interface itself later. But I have to say > that I am not impressed. Abusing sysfs for per process features is quite > gross to be honest. I have already commented on this in other email. I consider sysfs an unsuitable interface for per-process API. Not to mention this particular one is very KSM specific while the question about setting different hints on memory of a remote process is a more generic question. As already mentioned there are usecases where people would like to say that a certain memory is cold from outside of the process context (e.g. monitor application). So essentially a form of a user space memory management. And this usecase sounds a bit similar to me and having a common api sounds more sensible to me. One thing we were discussing at LSFMM this year was a way to either provide madvise_remote(pid, addr, length, advice) or a fadvise alternative over /proc/<pid>/map_vmas/<range> file descriptors (essentially resembling the existing map_files api) to achieve such a functionality. This is still a very rough idea but the api would sound much more generic to me and it would allow much wider range of usecases. But maybe I am completely wrong and this is just opens a can of worms that we do not want. -- Michal Hocko SUSE Labs
