8162795: RFR: [REDO] MemberNameTable doesn't purge stale entries

[coleen.phillimore at oracle.com]

Hi Kevin, you are checking this in under this bug-id right?

https://bugs.openjdk.java.net/browse/JDK-8166852

thanks,
Coleen

On 2/21/17 5:11 AM, Kevin Walls wrote:
> Thanks Coleen!
>
>
> On 20/02/2017 22:04, coleen.phillimore at oracle.com wrote:
>> This looks good.
>> Thanks for diagnosing this for this internal customer.
>> Coleen
>>
>> On 2/20/17 10:24 AM, Kevin Walls wrote:
>>> Hi,
>>>
>>> This is a review request for:
>>> [REDO] MemberNameTable doesn't purge stale entries
>>> https://bugs.openjdk.java.net/browse/JDK-8162795
>>>
>>> For certain apps, such as those with heavy use of the JavaScript 
>>> engine, the MemberNameTable and its weak references can introduce 
>>> considerable GC overhead.  In some cases GC cannot keep up with the 
>>> activity and collection times continually increase.  This is a 
>>> regression in jdk8 or later, compared to e.g. jdk7.
>>>
>>> The change in 8152271:
>>> https://bugs.openjdk.java.net/browse/JDK-8152271
>>> MemberNameTable doesn't purge stale entries
>>>
>>> ...fixes this, but that was reverted from 9 due to a regression in a 
>>> microbenchmark.  While that benchmark is a concern, more serious is 
>>> the regression currently out there for certain apps when moving up 
>>> to JDK 8 or 9.  Adding back the change in 8152271 fixes this.
>>>
>>> Re-applying the original change from 8152271 by Coleen still works, 
>>> with one copyright date fixup.  A webrev is:
>>>
>>> http://cr.openjdk.java.net/~kevinw/8162795/webrev.00/
>>>
>>> Plan is to re-integrate the 8152271 change in 9 (this request), and 
>>> backport to 8.  Meanwhile, a better solution for MemberNameTable in 
>>> jdk10 is being pursued in 
>>> https://bugs.openjdk.java.net/browse/JDK-8174749
>>>
>>> Thanks
>>> Kevin
>>>
>>>
>>
>