RFR: 8253064: monitor list simplifications and getting rid of TSM [v4]

[Daniel D.Daugherty]

On Tue, 10 Nov 2020 16:41:49 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> Daniel D. Daugherty has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   dholmes-ora - convert inner while loop to do-while loop in unlink_deflated().
>
> src/hotspot/share/oops/markWord.cpp line 63:
> 
>> 61:   fatal("bad header=" INTPTR_FORMAT, value());
>> 62: }
>> 63: 
> 
> This makes it so much clearer where the displaced markWord is.

Yup. That was the point. Get rid of the magic offset zero coding...

> src/hotspot/share/runtime/globals.hpp line 750:
> 
>> 748:   product(intx, MonitorUsedDeflationThreshold, 90, EXPERIMENTAL,            \
>> 749:           "Percentage of used monitors before triggering deflation (0 is "  \
>> 750:           "off). The check is performed on GuaranteedSafepointInterval "    \
> 
> Should there still be experimental options after this change?

Robbin added MonitorUsedDeflationThreshold as an experimental
option back in JDK10. See the longer reply to David's comment.
I don't plan to change that option with this changeset.

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PR: https://git.openjdk.java.net/jdk/pull/642