RFR: 8240556: Abort concurrent mark after effective eager reclamation of humongous objects [v3]

[Thomas Schatzl]

On Thu, 24 Sep 2020 07:37:52 GMT, Stefan Johansson <sjohanss at openjdk.org> wrote:

>> Thomas Schatzl has updated the pull request with a new target base due to a merge or a rebase. The pull request now
>> contains five commits:
>>  - sjohanss comments #2
>>  - reviews sjohanns and ayang; merged Command and Status plus cleanup
>>  - Remove test that only accidentally worked: G1 never sent the AllocationRequiringGC
>>    event for GCs caused by going over the IHOP threshold for humongous allocations.
>>    
>>    That test previously only worked because G1 could not reclaim the humongous objects
>>    fast enough so crossing the IHOP threshold causes a full concurrent mark. Allocations
>>    during that concurrent mark do not cause a GC that can reclaim these objects, so
>>    ultimately some young GC that sends the AllocationRequiringGC event will be sent.
>>    
>>    With concurrent undo this is not guaranteed any more, i.e. only in environments where
>>    concurrent undo is slow (and we'll improve it soon) this test works.
>>    
>>    The test is too timing dependent, so removing it.
>>  - Fixed test
>>  - Initial import
>
> Thanks for doing this additional refactoring Thomas.
> 
> I think this is good now, just one more small suggestion.

Testing: hs-tier1-3

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PR: https://git.openjdk.java.net/jdk/pull/177