Hello, Matt. On Thu, Oct 18, 2012 at 04:47:26PM -0700, Matt Helsley wrote: > > I think the only sane way would be having a userland arbitrator which > > owns the kernel interface to itself and makes policy decisions from > > userland clients and configures cgroup accordingly. > > OK -- yeah, solving the arbitration issue in userspace might be best. Yeah, I think we need that but there currently isn't any concrete (or even floppy) plan for it. If anyone is interested, beer is on me. :) > > I think that should be solved via userland policies rather than > > depending on this accidental cgroup_freezer feature. > > It's not accidental -- it *was an intended feature*: > > 22 # This bash script tests freezer code by starting a long sleep process. > 23 # The sleep process is frozen. We then move the sleep process to a THAWED > 24 # cgroup. We expect moving the sleep process to fail. > > ( This atrocious link is the easiest way to see the testcase: > http://ltp.git.sourceforge.net/git/gitweb.cgi?p=ltp/ltp.git;a=blob;f=testcases/kernel/controllers/freezer/freeze_move_thaw.sh;h=b2d5a83506a8425b117be9ff775d9f73d2d58393;hb=0436176dbfe6fdaaf97590d2356eb23d2739b2c2 > ) > > It was intended for something very much like the CRIU case I mentioned > :). I probably have chosen the wrong word. I mean that it's a hierarchy management feature implemented at the wrong layer. If we want to provide cgroup migration locking, it should be implemented at the cgroup core layer as a controller independent feature. It's kinda interesting the incorrect layering here almost directly caused messy locking problem too. I hope we don't need it with (the imaginary) proper userland arbitration but even if we do implementing it in cgroup proper as a separate feature would be a lot less messy. Thanks. -- tejun _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
