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

[Daniel D.Daugherty]

On Tue, 10 Nov 2020 21:08:53 GMT, Daniel D. Daugherty <dcubed at openjdk.org> wrote:

>> 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.

Filed the following new RFE:
    JDK-8256304 should MonitorUsedDeflationThreshold be experimental or diagnostic
    https://bugs.openjdk.java.net/browse/JDK-8256304

>> src/hotspot/share/runtime/objectMonitor.cpp line 509:
>> 
>>> 507: //
>>> 508: bool ObjectMonitor::deflate_monitor() {
>>> 509:   if (is_busy()) {
>> 
>> is_busy should be checked != 0 since it doesn't return a bool.
>
> Nice catch! That has been there for many, many years...

Filed the following new RFE:
    JDK-8256301 ObjectMonitor::is_busy() should return bool
    https://bugs.openjdk.java.net/browse/JDK-8256301

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