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

[serguei.spitsyn at oracle.com]

Hi Kevin,

This looks good but one comment needs to be corrected:

http://cr.openjdk.java.net/~kevinw/8162795/webrev.00/src/share/vm/prims/methodHandles.cpp.udiff.html

+ // This is linear because these because these are short lists. The 
"because these" repeated twice.



Thanks,
Serguei


On 2/20/17 07:24, 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
>
>