RFR 8209844: MemberNameLeak.java fails when ResolvedMethod entry is not removed

Patricio Chilano patricio.chilano.mateo at oracle.com
Wed Sep 5 00:11:41 UTC 2018

Hi David,

On 9/3/18 12:27 AM, David Holmes wrote:
> I'm somewhat surprised this test didn't already fail intermittently as 
> it assumes a single explicit System.gc() is enough to trigger the 
> cleanup it is checking for! If that assumption is not valid then the 
> test will now hang (in a busy polling loop!) until the test harness 
> times it out and forcibly terminates it. (Previously it would have 
> failed due to the missing output immediately after the gc() call 
> returned.)
I see that System.gc() ends up calling 
Universe::heap()->collect(GCCause::_java_lang_system_gc) which I 
understand will always reach SystemDictionary::do_unloading() eventually 
before the call returns. That would guarantee the table will be cleaned 
up before the program exits (provided the busy loop is there).

> Exposing the actual change to the resolved method table via the WB API 
> seems quite reasonable, but in general busy polling loops should be 
> avoided by inserting short sleeps between polls.
I can add a delay since I have to fix the test to add the 
UnlockDiagnosticVMOptions flag as you correctly found (I was running all 
tests in debug mode). I see some tests have delays of 100ms, should that 
delay be okay?



> On 29/08/2018 7:52 AM, Patricio Chilano wrote:
>> Hi all,
>> Could you review this change that addresses the intermittent failure 
>> of test MemberNameLeak.java after 8206423 ?
>> The test had intermittent failures due to the ServiceThread not being 
>> able to clean up the resolved method table before the process exited. 
>> Now a counter is used to guarantee entries in the table are removed 
>> before exiting. Also variables _oops_removed and _oops_counted were 
>> declared local in ResolvedMethodTable::unlink() since they are not 
>> used outside it.
>> Webrev URL: http://cr.openjdk.java.net/~pchilanomate/8209844.01/webrev
>> Bug URL: https://bugs.openjdk.java.net/browse/JDK-8209844
>> Thanks,
>> Patricio

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