Re: PROPOSAL: /proc/dev

Richard Gooch (rgooch@atnf.CSIRO.AU)
Thu, 1 Jan 1998 15:37:22 +1100

H. Peter Anvin writes:
> > > These are the arguments the proponents shoot down constantly, but they
> > > never address any of the REAL (IMO) problems (although the kernel
> > > space usage is likely to be prohibitive if done anything remotely like
> > > correctly.) YOU REALLY DON'T WANT CALLBACKS -- if you do, then your
> > > device performance and reliability is going straight into the toilet.
> >
> > We already have callbacks for the f_ops. So this scheme will increase
> > the callback depth by one. Is that really a big deal? We're only
> > talking about a handfull of cycles or so. I'm sure the syscall
> > overhead is much greater.
>
> I'm talking about user space callbacks, as were you. They are
> expensive and fragile.

Ah, I see. I'm proposing something that explicitely *does not* have a
user-space daemon. I personally find kernel code that relys on a
user-space daemon to complete it's work as ugly (though of course
there are some cases where you don't have a choice in order to avoid
kernel bloat).

I'm proposing a small, kernel-space only scheme. Either /proc/dev, or
possibly devfs.

> > > At some point I'll probably get my act together and write an FAQ on
> > > this. I'm sick and tired of rehashing the same argument every four
> > > months for about four years now...
> >
> > Jeez, take it easy. I'm just trying to be constructive.
>
> Sorry, sometimes even my patience wears thin... not with you put the
> fact that this gets re-suggested over and over and over and over and
> over...

:-)

Regards,

Richard....