Re: 2.6.23-rc2-mm1: rcutorture xtime usage

Paul E. McKenney
2007-08-10T02:01:16Z

On Fri, Aug 10, 2007 at 03:31:46AM +0200, Adrian Bunk wrote:
> On Thu, Aug 09, 2007 at 01:51:06AM -0700, Andrew Morton wrote:
> >...
> > Changes since 2.6.23-rc2-mm1:
> >...
> > +allow-rcutorture-to-handle-synchronize_sched.patch
> >...
> > 2.6.23 queue
> >...
>
> All drivers were converted to no longer use xtime directly since it
> might be quite outdated, but this patch adds a usage of xtime.tv_nsec
> as RNG...

This code doesn't care if the time is outdated, as it is simply
periodically perturbing an RNG, but OK.

So, what interface are we supposed to be using instead? I cannot use
get_random_bytes() due to locking issues. This is not a cryptographically
secure usage, so the perturbation does not need to be extremely high
quality.

On x86, I would just grab the low-order bits of the TSC, but all of the
world is not an x86. ;-)

Thanx, Paul