Re: Revisit AF_BUS: is it a better way to implement KDBUS?

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Jul 30, 2015 at 11:12:44AM -0700, Andy Lutomirski wrote:
> On Thu, Jul 30, 2015 at 6:09 AM, cee1 <fykcee1@gmail.com> wrote:
> > Hi all,
> >
> > I'm interested in the idea of AF_BUS.
> >
> > There have already been varies discussions about it:
> > * Missing the AF_BUS - https://lwn.net/Articles/504970/
> > * Kroah-Hartman: AF_BUS, D-Bus, and the Linux kernel -
> > http://lwn.net/Articles/537021/
> > * presentation-kdbus -
> > https://github.com/gregkh/presentation-kdbus/blob/master/kdbus.txt
> > * Re: [GIT PULL] kdbus for 4.1-rc1 - https://lwn.net/Articles/641278/
> > * The kdbuswreck - https://lwn.net/Articles/641275/
> >
> > I'm wondering whether it is a better way, that is, a general mechanism
> > to implement varies __Bus__ orientated IPCs, such as Binder[1],
> > DBus[2], etc.
> 
> I find myself wondering whether an in-kernel *bus* is a good idea at
> all.  Creating a bus that unprivileged programs are allowed to
> broadcast on (which is kind of the point) opens up big cans of worms.
> Namely: what happens when producers produce data faster than the
> consumers consume it?  Keep in mind that, with a bus, this scales
> pretty badly.  Each producer's sends are multiplied by the number of
> participants.
> 
> At some point soon, I'm planning on playing with Fedora Rawhide with
> kdbus.  Anything's possible (maybe), but I'd be rather surprised if it
> holds up under abuse of the bus.

Just boot Fedora Rawhide with "kdbus=1" on the kernel command line and
you should be set.  If not, please let the kdbus developers know.

thanks,

greg k-h