Messages in this thread | | | Subject | Re: Which of the virtualization approaches is more suitable for kernel? | From | (Eric W. Biederman) | Date | Mon, 27 Feb 2006 14:14:20 -0700 |
| |
Dave Hansen <haveblue@us.ibm.com> writes:
> On Fri, 2006-02-24 at 14:44 -0700, Eric W. Biederman wrote: >> We can start on a broad front, looking at several different things. >> But I suggest the first thing we all look at is SYSVIPC. It is >> currently a clearly recognized namespace in the kernel so the scope is >> well defined. SYSVIPC is just complicated enough to have a >> non-trivial implementation while at the same time being simple enough >> that we can go through the code in exhausting detail. Getting the >> group dynamics working properly. > > Here's a quick stab at the ipc/msg.c portion of this work. The basic > approach was to move msg_ids, msg_bytes, and msg_hdrs into a structure, > put a pointer to that structure in the task_struct and then dynamically > allocate it. > > There is still only one system-wide one of these for now. It can > obviously be extended, though. :) > > This is a very simple, brute-force, hack-until-it-compiles-and-boots > approach. (I just realized that I didn't check the return of the alloc > properly.) > > Is this the form that we'd like these patches to take? Any comments > about the naming? Do we want to keep the _namespace nomenclature, or > does the "context" that I used here make more sense
I think from 10,000 feet the form is about right.
I like the namespace nomenclature. (It can be shorted to _space or _ns). In part because it shortens well, and in part because it emphasizes that we are *just* dealing with the names.
You split the resolution at just ipc_msgs. When I really think it should be everything ipcs deals with.
Performing the assignment inside the tasklist_lock is not something we want to do in do_fork().
So it looks like a good start. There are a lot of details yet to be filled in, proc, sysctl, cleanup on namespace release. (We can still provide the create destroy methods even if we don't hook the up).
I think in this case I would put the actual namespace structure definition in util.h, and just put a struct ipc_ns in sched.h. sysvipc is isolated enough that nothing outside of the ipc/ directory needs to know the implementation details.
It probably makes sense to have a statically structure and to set the pointer initially in init_task.h
Until we reach the point where we can multiple instances that even removes the need to have a pointer copy in do_fork() as that happens already as part of the structure copy.
Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |