Nadia.Derbey@xxxxxxxx wrote: > A couple of weeks ago, a discussion has started after Pierre's proposal for > a new syscall to change an ipc id (see thread > http://lkml.org/lkml/2008/1/29/209). > > > Oren's suggestion was to force an object's id during its creation, rather > than 1. create it, 2. change its id. > > So here is an implementation of what Oren has suggested. > > 2 new files are defined under /proc/self: > . next_ipcid --> next id to use for ipc object creation > . next_pids --> next upid nr(s) to use for next task to be forked > (see patch #2 for more details). Generally looks good. One meta-comment, though: I wonder why you use separate files for separate resources, and why you'd want to write multiple identifiers in one go; it seems to complicate the code and interface with minimal gain. In practice, a process will only do either one or the other, so a single file is enough (e.g. "next_id"). Also, writing a single value at a time followed by the syscall is enough; it's definitely not a performance issue to have multiple calls. We assume the user/caller knows what she's doing, so no need to classify the identifier (that is, tell the kernel it's a pid, or an ipc id) ahead of time. The caller simply writes a value and then calls the relevant syscall, or otherwise the results may not be what she expected... If such context is expected to be required (although I don't see any at the moment), we can require that the user write "TYPE VALUE" pair to the "next_id" file. > > When one of these files (or both of them) is filled, a structure pointed to > by the calling task struct is filled with these ids. > > Then, when the object is created, the id(s) present in that structure are > used, instead of the default ones. > > The patches are against 2.6.25-rc3-mm1, in the following order: > > [PATCH 1/4] adds the procfs facility for next ipc to be created. > [PATCH 2/4] adds the procfs facility for next task to be forked. > [PATCH 3/4] makes use of the specified id (if any) to allocate the new IPC > object (changes the ipc_addid() path). > [PATCH 4/4] uses the specified id(s) (if any) to set the upid nr(s) for a newly > allocated process (changes the alloc_pid()/alloc_pidmap() paths). > > Any comment and/or suggestions are welcome. > > Cc-ing Pavel and Sukadev, since they are the pid namespace authors. > > Regards, > Nadia > > -- > > -- _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers