RFR: 8066827: Remove ReferenceProcessor::clean_up_discovered_references()

Jon Masamitsu jon.masamitsu at oracle.com
Wed Dec 17 23:56:40 UTC 2014


On 12/17/2014 10:53 AM, Kim Barrett wrote:
> Thanks for your review and offer of sponsorship.
>
> On Dec 17, 2014, at 10:17 AM, Jon Masamitsu <jon.masamitsu at oracle.com> wrote:
>> Change looks good but I would suggest a different wording in
>> one of the comments.
>>
>> http://cr.openjdk.java.net/~kbarrett/8066827/webrev/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp.udiff.html
>>
>> +  // references lists.  Abandon those references, since some
>> +  // of them may have become unreachable due to later mutator
>> +  // activity, and the compacting collector we're about to run
>> +  // won't see them as live.
>>
>> // reference lists.  Abandon those references since the STW collector will
>> // redo discovery more precisely (will not be subject to floating garbage).
>>
>> I think referring to liveness and mutator activity, while correct, makes it
>> sound more complicated then needed.  I think the overriding point is that
>> discovery is going to be redone and redone more precisely since it's STW.
> How about this:
>
>    // If the collection is being acquired from the background
>    // collector, there may be references on the discovered
>    // references lists.  Abandon those references, since some
>    // of them may have become unreachable after concurrent
>    // discovery; the STW compacting collector will redo discovery
>    // more precisely, without being subject to floating garbage.
>    // Leaving otherwise unreachable references in the discovered
>    // lists would require special handling.
>
I like it.

Reviewed.

Jon


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