RFR: [8u] Critical backports to sh/jdk8u

[Aleksey Shipilev]

On 01/26/2018 06:37 PM, Christine Flood wrote:
> void ShenandoahHeap::try_inject_alloc_failure() {
> +   if (ShenandoahAllocFailureALot && !cancelled_concgc() &&
> ((os::random() % 1000) > 950)) {
> +     _inject_alloc_failure.set();
> +     Thread::current()->_ParkEvent->park(1);
> +     if (cancelled_concgc()) {
> +       log_info(gc)("Allocation failure was successfully injected");
> +     }
> +   }
> + }
> 
> Is it possible that there is a race and we get to the test for
> cancelled_concgc before it actually gets set?

Yes, but we don't care. This is mostly to observe that any thread had reacted on this failure within
the time set -- a debugging measure.

> Is there any reason not to try JCStressTests with frequent allocation
> failures?

JCStressTests are mostly for testing internal compiler/oop verification, supposed to be fast. Other
tests figure out what happens on alloc failures.

-Aleksey