Paul Menage wrote: >> Ask yourself this - what do you need the container structure for so >> badly, that virtualising the individual resources does not provide for? >> > Primarily, that otherwise every module that wants to affect/monitor > behaviour of a group of associated processes has to implement its own > process grouping abstraction. >
Not every module, you just make them on sensible, planned groupings. The danger is that the "container" group becomes a fallback grouping for things when people can't be bothered thinking about it properly, and everything including the kitchen sink gets thrown in. Then later you find a real use case where you don't want them together, but it's too late because it's already a part of the official API. > As an example, the CPU accounting patch that in included in my patch > set as an illustration of a simple resource monitoring module is just > 250 lines, almost entirely in one file; if it also had to handle > associating tasks together into groups and presenting a filesystem > interface to the user it would be far larger and would have a much > bigger footprint on the kernel. > It's also less flexible. What if I want to do CPU accounting on some other boundaries than the "virtual server" a process is a part of? > From the point of view of the virtual server containers, the advantage > is that you're integrated with a standard filesystem interface for > determining group membership. It does become simpler to combine > virtual servers and resource controllers, although I grant you that > you could juggle that from userspace without the additional kernel > support. > I'm not disagreeing it's a pragmatic shortcut that has been successful for a number of projects including vserver which I use every day. But it reduces "synergy" by excluding the people working with virtualisation in ways that don't fit its model. Yes, there should be a similarity in the way that you manage namespaces and it should be easy to develop new namespaces without constantly re-inventing the wheel. But why does that imply making binding decisions about the nature of how you can virtualise? IMHO those decisions should be made on a per-subsystem basis. Sam. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
