Oren Laadan <orenl@xxxxxxxxxxxxxxx> writes: > Eric W. Biederman wrote: >> Pavel Emelyanov <xemul@xxxxxxxxxxxxx> writes: >> >>>>> Yet another set of per-namespace IDs along with CLONE_NEWXXX ones? >>>>> I currently have a way to create all namespaces we have with one >>>>> syscall. Why don't we have an ability to enter them all with one syscall? >>>> The CLONE_NEWXXX series of bits has been an royal pain to work with, >>>> and it appears to be unnecessary complications for no gain. >>> That's the answer for the "Yet another set..." question. >>> How about the "Why don't we have..." one? >> >> I am not certain which question you are asking: >> >> Why don't we have an ability to enter all namespaces with one syscall >> invocation? > > That's how I understood the question, and I, too, wonder why not ? > > By the way, an alternative to using bitmap is to change the prototype > of setns() to accept an array of FD's: > > int setns(int *fds, int nfds); > > So the process will atomically enter all the namespaces as specified > by the FDs. We could. Mostly I implemented things in the simplest way possible. Semantically I know of no reason why need to enter more than one namespace at once, and I don't expect entering a namespace to be on anyone's fast path so every last drop of performance was not crucial. The only justification I can think of for more than one namespace at a time is that because we have a synchronize_rcu() in the kernel we can loop in the kernel much more quickly than we can loop in userspace. Eric _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
