[PATCH V4] POWER: perf_event: Skip updating kernel counters if register value shrinks

[David Laight]

> +	if (prev > val && (prev - val) < 256)
> +		delta = 0;
> +
> +	return delta;

Also, 'prev' is a true 64bit value, but 'val' is only ever 32bits.
So once the 64bit 'prev' exceeds 2^32+256 both 'prev > val'
and 'prev - val' are true regardless of the value of 'val'.
This will lead to jumps in the value ....

	David