On Fri 17-05-13 09:57:37, Konstantin Khlebnikov wrote: > Michal Hocko wrote: > >On Thu 16-05-13 08:28:33, Konstantin Khlebnikov wrote: [...] > >>If somebody needs more detailed information there are enough ways to get it. > >>Amount of mapped pages can be estimated via summing rss counters from mm-structs. > >>Exact numbers can be obtained via examining /proc/pid/pagemap. > > > >How do you find out whether given pages were charged to the group of > >interest - e.g. shared data or taks that has moved from a different > >group without move_at_immigrate? > > For example we can export pages ownership and charging state via > single file in proc, something similar to /proc/kpageflags So you would like to add a new interface with cryptic api (I consider kpageflags to be a devel tool not an admin aid) to replace something that is easy to use? Doesn't make much sense to me. > BTW > In our kernel the memory controller tries to change page's ownership > at first mmap and at each page activation, probably it's worth to add > this into mainline memcg too. Dunno, there are different approaches for this. I haven't evalueted them so I don't know all the pros and cons. Why not just unmap&uncharge the page when the charging process dies. This should be more lightweight wrt. recharge on re-activation. > >>I don't think that simulating 'Mapped' line in /proc/mapfile is a worth reason > >>for adding such weird stuff into the rmap code on map/unmap paths. > > > >The accounting code is trying to be not intrusive as much as possible. > >This patchset makes it more complicated without a good reason and that > >is why it has been Nacked by me. > > I think we can remove it or replace it with something different but > much less intrusive, if nobody strictly requires exactly this approach > in managing 'mapped' pages counters. Do you have any numbers on the intrusiveness? I do not mind to change the internal implementation but the file is a part of the user space API so we cannot get rid of it. -- 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>