Quoting Aleksa Sarai (asarai@xxxxxxx): > >>I feel like the permission model makes sense in certain cases (the common > >>ancestor restriction, as well as the ability for a parent to apply limits to > >>children by setting its own limits). Neither of those are violated (if you > >>read the commit that introduced the common ancestor restriction). > >> > >>Maybe if you give me a usecase of when it might be important that a process > >>must not be able to move to a sub-cgroup of its current one, I might be able > >>to understand your concerns? From my perspective, I think that's actually > >>quite useful. > > > >cgroup is used to keep track of which processes belong where and > >allowing processes to be moved out of its cgroup like this would be > >surprising to say the least. > > Would you find it acceptable if we added a bit that would make this > not happen (you could specify that a cgroup should not allow a > process to move itself to a sub-cgroup)? Or an aggregate > cgroup.procs that gives you all of the processes in the entire > branch of the tree? Surely this is something that can be fixed > without unnecessarily restricting users from doing useful things. > > >>The reason I'm doing this is so that we might be able to _practically_ use > >>cgroups as an unprivileged user (something that will almost certainly be > >>useful to not just the container crowd, but people also planning on using > >>cgroups as advanced forms of rlimits). > > > >I don't get why we need this fragile dance with permissions at all > >when the same functionality can be achieved by delegating explicitly. > > The key words being "unprivileged user". Currently, if I am a > regular user on a system and I want to use the freezer cgroup to > pause a process I am running, I have to *go to the administrator and > ask them to give me permission to do that*. Why is that necessary? I Ths is of course solvable using something like libpam-cgfs or libpam-cgm (and others). Since this sounds like a question of policy, not mechanism, userspace seems like the right place. Is there a downside to that (or, as Tejun put it, "delegating explicitly")? -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
