[8u] RFR (S): 8147087: Race when reusing PerRegionTable bitmaps may result in dropped remembered set entries

[Thomas Schatzl]

Hi all,

  can I get re-reviews for a backport of the JDK-8147087 change to 8u?

As mentioned in the 9 review-request, I intend to backport this change
to earlier versions as usual, waiting for a successful nightly at
least.

However yesterday we decided internally that 9/hs-rt should not be
pushed into to help current stabilization efforts. But it would be nice
to have the change in 8u by tomorrow due to rdp2. So I would like to
push to 8u first to meet that, and only later push the jdk9 change as
reviewed.

I would also need an 8u "R"eviewer to look at this, as Tom and Mikael
are only Committers at most.

The 8u version requires some changes to the existing code, namely

- path updates
- merge errors with the copyright date
- merge errors with the asserts, i.e. instead of

assert(contains_reference(from), " some text ", p2i(from));

8u requires the use of the err_msg() method in the assert, i.e.

assert(contains_reference(from), err_msg(" some text ", from));

CR:
https://bugs.openjdk.java.net/browse/JDK-8147087
Webrev:
http://cr.openjdk.java.net/~tschatzl/8147087/webrev.8u/
Original 9 review thread:
http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2016-January/0162
44.html
Testing:
jprt

Thanks,
  Thomas