Re: intercommunications between Linux kernel modules

[Cyclonus J <cyclonusj@gmail.com>]

On Thu, Oct 06, 2011 at 09:00:13PM -0700, david@lang.hm wrote:
> On Thu, 6 Oct 2011, Cyclonus J wrote:
> 
> >On Thu, Oct 6, 2011 at 7:04 PM, Andi Kleen <andi@firstfloor.org> wrote:
> >>Cyclonus J <cyclonusj@gmail.com> writes:
> >>
> >>>I am looking for a way to do an IPC-like communications between two
> >>>linux kernel modules, such as mqueue or shared memory. After searching
> >>>for a while, I can't find such information available inside existing
> >>>linux kernel or online.
> >>>
> >>>So, my question is if this is something discussed before here and gets
> >>>rejected or still might be accepted in the mainstream kernel tree?
> >>
> >>All kernel memory is shared in Linux, so the concept doesn't make sense.
> >>
> >>If you want to send messages or communicate inside the kernel there are
> >>lots of different facilities available.
> >
> >Andi,
> >
> >That would be great! Could you point me to some facilities that can do
> >this message passing between kernels?
> 
> what you are missing is that there aren't two different kernels.
> it's one big process. think multi-threaded programming instead of
> inter-process communication. You don't even have well defined
> threads to work with so you can't say "I'm in thread 1 and need to
> communicate with thread 2", you need to think "I'm in this routine
> and I need to set a message in a way that another routine will read
> it", this can be as simple as just setting a variable (although you
> do need to make it the equivalent of 'thread safe' through
> appropriate locking or lock-free protection)

David,

Yes, it is multi-threaded. I have two kernel modules and each of them will
create its own kernel thread just for communication purpose (message passing).

Do you know if there is any message primitves I can use to achieve this inside
kernel?

Thanks,
CJ

> 
> David Lang