JDK-8180929 : Deprecate -XX:+/-MonitorInUseLists option
  • Type: CSR
  • Component: hotspot
  • Sub-Component: runtime
  • Priority: P3
  • Status: Closed
  • Resolution: Approved
  • Fix Versions: 10
  • Submitted: 2017-05-24
  • Updated: 2017-07-26
  • Resolved: 2017-07-26
Related Reports
CSR :  
Description
Summary
-------

Deprecate -XX:+/-MonitorInUseLists option.

Problem
-------

-XX:+/-MonitorInUseLists controls whether or not thread-local monitor lists should be used vs. global monitor lists. It is purely a guard for a new code path. Thread-local monitor lists are more efficient to inflate, deflate and iterate over. It potentially leads to more monitors in circulation. The code has been around since JDK8, has been enabled by default in JDK9. It should be deprecated in JDK10.

Solution
--------

Mark the MonitorInUseLists as deprecated in JDK10.

Specification
-------------

    diff --git a/src/share/vm/runtime/arguments.cpp b/src/share/vm/runtime/arguments.cpp
    --- a/src/share/vm/runtime/arguments.cpp
    +++ b/src/share/vm/runtime/arguments.cpp
    @@ -376,6 +376,7 @@
       // --- Non-alias flags - sorted by obsolete_in then expired_in:
       { "MaxGCMinorPauseMillis",        JDK_Version::jdk(8), JDK_Version::undefined(), JDK_Version::undefined() },
       { "UseConcMarkSweepGC",           JDK_Version::jdk(9), JDK_Version::undefined(), JDK_Version::undefined() },
    +  { "MonitorInUseLists",            JDK_Version::jdk(10),JDK_Version::undefined(), JDK_Version::undefined() },
     
       // --- Deprecated alias flags (see also aliased_jvm_flags) - sorted by obsolete_in then expired_in:
       { "DefaultMaxRAMFraction",        JDK_Version::jdk(8), JDK_Version::undefined(), JDK_Version::undefined() },


Comments
Moving to approved.
26-07-2017

Thanks Joe (and Harold for sending me email).
24-07-2017

@Dan, if you hit "Edit" on the request, there is a reviewer field you can add yourself too. HTH
24-07-2017

Reviewed. I'm not seeing any widgets that I need to click on here...
24-07-2017

Moving request to Provisional state. @Roman, please have a HotSpot-area engineer review the request before moving it to Finalized state for the second phase of CSR review.
24-07-2017