Re: [PATCH 00/30] C/R OpenVZ/Virtuozzo style

[Alexey Dobriyan <adobriyan@gmail.com>]

On Thu, Apr 09, 2009 at 10:07:11PM -0700, Dave Hansen wrote:
> I'm curious how you see these fitting in with the work that we've been
> doing with Oren.  Do you mean to just start a discussion or are you
> really proposing these as an alternative to what Oren has been posting?

Yes, this is posted as alternative.

Some design decisions are seen as incorrect from here like:
* not rejecting checkpoint with possible "leaks" from container
* not having CAP_SYS_ADMIN on restart(2)
* having small (TASK_COMM_LEN) and bigger (objref[1]) image format
  misdesigns.
* doing fork(2)+restart(2) per restarted task and whole orchestration
  done from userspace/future init task.
* not seeing bigger picture (note, this is not equivalent to supporting
  everything at once, nobody is asking for everything at once) wrt shared
  objects and format and code changes because of that (note again, image
  format will change, but it's easy to design high level structure which
  won't change)
* checking of unsupported features done at wrong place and wrong time
  and runtime overhead because of that on CR=y kernels.

There are also low-level things, but it's cumulative effect.

[1] Do I inderstand correctly that cookie for shared object is an
address on kernel stack? This is obviously unreliable, if yes :-)

	int objref;
		...
	/* adding 'file' to the hash will keep a reference to it */
	new = cr_obj_add_ptr(ctx, file, &objref, CR_OBJ_FILE, 0);
					^^^^^^^