RFR: Restore string table rehashing task in cleanup tasks

[Aleksey Shipilev]

On 06/14/2018 03:05 PM, Zhengyu Gu wrote:
> On 06/14/2018 08:39 AM, Aleksey Shipilev wrote:
>> On 06/14/2018 02:00 PM, Zhengyu Gu wrote:
>>> I wrongly removed string table rehashing task from safeppont cleanup phase, thought it should be
>>> performed concurrently.
>>>
>>> I believe that StringInternCleanup test failure is due to upstream bug - I filed JDK-8205006
>>> (https://bugs.openjdk.java.net/browse/JDK-8205006) and temporary disable the test till the bug is
>>> fixed.
>>>
>>> Webrev: http://cr.openjdk.java.net/~zgu/shenandoah/restore_stringtable_rehashing/webrev.00/
>>
>> I think ignoring the test masks the issue. Can we keep the test around, but disable rehashing with
>> UseShenandoahGC? E.g.:
>>
>>   // Workaround upstream bug in StringTable rehashing, see JDK-8205006.
>>   if (StringTable::needs_rehashing() && !UseShenandoahGC) {
>>
> This functional equivalents to what we have right now, another option is to defer this till
> JDK-8205006 fixed upstream?

It would be better to revert to upstream state, has one-liner workaround, then and mark it with
TODO, for our future reference.

-Aleksey