Re: [patch 20/24] perfmon: system calls interface

[Andi Kleen <andi@firstfloor.org>]

>  int pfm_create(int flags, pfarg_sinfo_t *sif, char *fmt_name, void
> *fmt_arg, size_t arg_sz);
> 
> The kernel would look at the last 3 arguments ONLY if it saw the
> PFM_FL_SMPL_FMT bit
>  set in flags. We follow the model used by open(2).

Normally it's a better model to enforce 0 (or whatever appropiate)
in unused argument. That can be done by checking and returning EINVAL.

> 
> I want to double-check that you are fine with this approach.

My recommendation would be to go with the full format 
from the beginning, because otherwise there is a versioning problem 
with glibc.


-Andi

-- 
ak@linux.intel.com