Re: [PATCH] locking/lockdep: Use sched_clock() for random numbers.

[Jason A. Donenfeld]

Hi Sebastian,

Interesting RT consideration. I hope there aren't too many of these
special cases that would necessitate a general mechanism. Fingers
crossed this is the only one.

On Tue, May 17, 2022 at 11:16:14AM +0200, Sebastian Andrzej Siewior wrote:
> -			cookie.val = 1 + (prandom_u32() >> 16);
> +			cookie.val = 1 + (sched_clock() & 0xffff);
>  			hlock->pin_count += cookie.val;
 
I have no idea what the requirements here are. What would happen if you
just did atomic_inc_return(&some_global) instead? That'd be faster
anyhow, and it's not like 16 bits gives you much variance anyway...

Jason