Fix for JDK-8048556 (GCLocker issues): feedback and some testing please?

[Mikael Gerdin]

Hi Tony,

On 2014-08-28 04:06, Tony Printezis wrote:
> Hi all,
>
> I have a fix for the GCLocker causing unnecessary young GCs issue
> (JDK-8048556). Here's the webrev:
>
> http://cr.openjdk.java.net/~tonyp/8048556/webrev.0/
>
> Any chance of a) getting some feedback on whether the fix is reasonable
> and b) getting it through some testing (I did as much testing as I could
> but you know how fragile the GCLocker is...)?

I've started some testing on this fix (JPRT, GC test suite).

>
> I didn't really want to change the CollectedHeap API. However, I can't
> work out another way to pass the two GC counts to the VM op without
> changes to the CollectedHeap. I could have expanded the collect() method
> to also accept the count arguments. However, I don't think collect()
> should really be used for the GCLocker GC and I feel that a separate
> method is appropriate here.

I agree that it's reasonable to have a separate collect_for_gc_locker.

>
> I also ended up renaming an argument to a c'tor from _cause to cause, as
> the former should only be used for class members. Hope that's OK.

Yep, that's always bothered me.

/Mikael

>
> Thanks,
>
> Tony
>