Re: [PATCH 00/16] dyn_array and nr_irqs support v2

["H. Peter Anvin" <hpa@zytor.com>]

Eric W. Biederman wrote:
> 
> Yes.  I want the option of using those bits.  It might not be smart to
> use them to encode a physical location and the irq number but just
> having the option would be nice.
> 

Urk!  First of all, there isn't enough space as we have already proven 
(on the machines where it actually matters there just aren't enough 
bits), but doing this kind of stuff *optionally* is going to hurt even 
worse.

Furthermore, this crap will break anyway the *next* time someone comes 
up with a new clever way to do interrupts -- and to truly get stable 
identifiers, we can't treat HyperTransport MSI as APICs anymore, yadda, 
yadda...

> Making /proc/interrupts useful without breaking user space is going to be
> an interesting challenge one of these days.

If changing to non-numbers in /proc/interrupts will break userspace, 
then userspace will have to deal with a numeric token in 
/proc/interrupts which will have to be looked up elsewhere (perhaps in a 
sysfs directory) to get a more meaningful index.

	-hpa