RFR: 8259349: -XX:AvgMonitorsPerThreadEstimate=1 does not work right [v4]

[Daniel D.Daugherty]

On Fri, 8 Jan 2021 22:30:15 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Daniel D. Daugherty has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   delete bad assert found by linux build.
>
> src/hotspot/share/runtime/globals.hpp line 718:
> 
>> 716:           range(0, max_jint)                                                \
>> 717:                                                                             \
>> 718:   /* notice: the max range value here is max_jint, not max_intx  */         \
> 
> The comment is no longer applicable.

Deleted

> src/hotspot/share/runtime/synchronizer.cpp line 257:
> 
>> 255: // which is called after cmd line options are processed.
>> 256: // This is a 'jint' because the range of AvgMonitorsPerThreadEstimate
>> 257: // is 0..max_jint:
> 
> Do we need this comment now?

Yes. The range for AvgMonitorsPerThreadEstimate is still 0..max_jint.

> src/hotspot/share/runtime/synchronizer.cpp line 1178:
> 
>> 1176: }
>> 1177: 
>> 1178: void ObjectSynchronizer::set_in_use_list_ceiling(size_t new_value) {
> 
> new_value should just be declared as int or jint now and the cast and comments removed.

I don't think so. For some reason @fisk used size_t for MonitorList
_count and _max fields so the ceiling that is passed in and returned
should be size_t. The only reason that the _in_use_list_ceiling is jint
is because the range is 0..max_jint. At one point I tried to change it
to size_t and ran into build issues, but I don't remember the details.

-------------

PR: https://git.openjdk.java.net/jdk/pull/1992