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

[Tony Printezis]

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 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 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.

Thanks,

Tony

-- 
Tony Printezis | JVM/GC Engineer / VM Team | Twitter

@TonyPrintezis
tprintezis at twitter.com