Re: [1/1] connector/CBUS: new messaging subsystem. Revision number next.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wednesday 27 April 2005 00:32, Evgeniy Polyakov wrote:
> On Wed, 2005-04-27 at 00:16 -0500, Dmitry Torokhov wrote:
> > On Tuesday 26 April 2005 23:06, Evgeniy Polyakov wrote:
> > > Let's clarify that we are talking about userspace->kernelspace
> > > direction.
> > > Only for that messages callback path is invoked.
> > 
> > What about kernelspace->userspace or kernelspace->kernelspace?
> > From what I see nothing stops kernel code from calling cn_netlink_send,
> > in fact your cbus does exactly that. So I am confused why you singled
> > out userspace->kernelspace direction.
> 
> You miunderstand the code -
> cn_netlink_send() never ends up in callback invocation, 
> it can only deliver messages in kernelspace->userspace direction.
> kernelspace->userspace direction ends up adding buffer into
> socket queue, from which userspace may read data using recv() system
> call.

Yes, you are right, sorry. I missed the fact that message is not injected
into callback queue. Hmm, might be useful if it was, for implementing
various kinds of in-kernel notifications.

Other thing to consider - even if there is explicit schedule on userspace->
kernelspace path there is no quarantee that connector thread will be
scheduled before userspace - userspace could be higher-priority bursty task.
Although this scenario it not likely I guess.

-- 
Dmitry
-
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/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux