Re: [patch 2/2] x86/tsc: Force TSC_ADJUST register to value >= zero

[Peter Zijlstra]

On Tue, Dec 13, 2016 at 01:14:17PM -0000, Thomas Gleixner wrote:
> @@ -429,8 +447,13 @@ void check_tsc_sync_target(void)
>  	 * that the warp is not longer detectable when the observed warp
>  	 * value is used. In the worst case the adjustment needs to go
>  	 * through a 3rd run for fine tuning.
> +	 *
> +	 * But we must make sure that the value doesn't become negative
> +	 * otherwise TSC deadline timer will create an interrupt storm.
>  	 */
>  	cur->adjusted += cur_max_warp;
> +	if (cur->adjusted < 0)
> +		cur->adjusted = 0;
>  

So depending on how horrid we want to make this we could work around
this by increasing the ADJUST of the other CPUs by the amount we're
negative.

But yes, yuck.