RFR (L): JDK-8061308: Remove iCMS
Jon Masamitsu
jon.masamitsu at oracle.com
Tue Oct 21 17:42:17 UTC 2014
On 10/17/14 4:43 AM, Bengt Rutisson wrote:
>
> Hi everyone,
>
> Can I have a couple of reviews for this change?
>
> HotSpot changes:
> http://cr.openjdk.java.net/~brutisso/8061308/hotspot/
Bengt,
Looks good. In fact, looks beautiful.
There are a couple of comments in the
concurrentMarkSweepGeneration.* files than
mention EdenSpace that you might want to
clean up.
5566 // a set of parallel tasks (via the sampling that the [abortable]
5567 // preclean phase did of EdenSpace, plus the [two] tasks of
5568 // scanning the [two] survivor spaces. Further fine-grain
5188 if (chunk_top == 0) { // no samples were taken
5189 assert(nth_task == 0 && n_tasks == 1, "Can have only 1
EdenSpace ta sk");
5190 start = space->bottom();
Reviewed.
>
> JDK changes:
> http://cr.openjdk.java.net/~brutisso/8061308/jdk/
> (Just a small update to a test library class.)
Looks good.
Reviewed.
Jon
>
> JBS bug:
> https://bugs.openjdk.java.net/browse/JDK-8061308
>
> The change removes the incremental mode of CMS. This work is part of
> JEP 214 (http://openjdk.java.net/jeps/214). There are quite a few
> lines changed. Mostly it is just removal of code and it should
> hopefully be fairly straight forward to review.
>
> One interesting side effect of removing iCMS was that the
> ConcEdenSpace (a subclass in the Space hierarchy) could be removed. It
> implemented the "soft-end" feature that only iCMS was taking advantage
> of. When I had removed ConcEdenSpace it turned out that its
> superclass, EdenSpace, was actually an unnecessary class that did not
> add anything so I removed that too. When I then went to update the
> comment in space.hpp that describes the Space hierarchy I noticed that
> the description of the hierarchy was completely out-dated. Rather than
> bringing it up-to-date I removed the comment. I think that type of
> information will only get out-dated quickly again and it is much
> easier to let your IDE create the correct type hierarchy view
> dynamically for you.
>
> Thanks,
> Bengt
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