Dave Hansen wrote: > On Fri, 2009-03-20 at 17:26 -0400, Oren Laadan wrote: >> Dave Hansen wrote: >>> On Fri, 2009-03-20 at 16:48 -0400, Oren Laadan wrote: >>>> Does that scale well with many (1000's) of tasks ? >>>> >>>> (The motivation to expose 'nsproxy_objref' to user space was to allow >>>> user-space to decide on a sequence of clones/unshared that will create >>>> an equivalent process tree with space-efficient nsproxy's). >>> OK, so you're saying that there's no way for userspace to tell that a >>> set of tasks share an nsproxy other than exporting that nsproxy? >> I don't think so. Maybe the namespaces people know better. > > Please go look at the code. Heheh .. read: "I don't think so" as in "I don't think tasks in user space can tell whether or not they share an nsproxy in the kernel." (and the corollary follows ...) > > Two processes share an nsproxy (or *can* share an nsproxy) when all of > the namespace pointers are the same. After allocation and > initialization, we basically don't ever write to the nsproxy. We just > hook it into a task and run with it. > > If anything ever unshares one of the nsproxy namespaces, before writing > to it we *first* create a new nsproxy which is a copy of the old one. > > We basically open-code copy-on-write semantics for the nsproxy. > > This means that it is safe for any two tasks that share all of the > pointers in the nsproxy to share an nsproxy itself. > > -- Dave _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
