JDK-8191336 : Deprecate DeferPollingPageLoopCount and start removal
  • Type: CSR
  • Component: hotspot
  • Sub-Component: runtime
  • Priority: P4
  • Status: Closed
  • Resolution: Approved
  • Fix Versions: 10
  • Submitted: 2017-11-15
  • Updated: 2017-11-21
  • Resolved: 2017-11-16
Related Reports
CSR :  
JDK-8191329 - Deprecate DeferPollingPageLoopCount
Description
Summary
-------

Deprecate the unsafe and unstable HotSpot option -XX:DeferPollingPageLoopCount=??.

Problem
-------

The option is unsafe and unstable.
The method SafepointSynchronize::begin have become really large and complicated. 
For future refactoring of this method we should now deprecate this option.

Solution
--------

Deprecate the flag.

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

    diff -r 2233409844b3 src/hotspot/share/runtime/arguments.cpp
    --- a/src/hotspot/share/runtime/arguments.cpp	Wed Nov 15 16:24:46 2017 +0100
    +++ b/src/hotspot/share/runtime/arguments.cpp	Wed Nov 15 16:31:58 2017 +0100
    @@ -389,2 +389,3 @@
       { "DeferThrSuspendLoopCount",     JDK_Version::jdk(10), JDK_Version::jdk(11), JDK_Version::jdk(12) },
    +  { "DeferPollingPageLoopCount",    JDK_Version::jdk(10), JDK_Version::jdk(11), JDK_Version::jdk(12) },
       { "IgnoreUnverifiableClassesDuringDump", JDK_Version::jdk(10),  JDK_Version::undefined(), JDK_Version::undefined() },
    diff -r 2233409844b3 src/hotspot/share/runtime/globals.hpp
    --- a/src/hotspot/share/runtime/globals.hpp	Wed Nov 15 16:24:46 2017 +0100
    +++ b/src/hotspot/share/runtime/globals.hpp	Wed Nov 15 16:31:58 2017 +0100
    @@ -3275,3 +3275,4 @@
       product(intx, DeferPollingPageLoopCount,     -1,                          \
    -          "(Unsafe,Unstable) Number of iterations in safepoint loop "       \
    +          "(Unsafe,Unstable,Deprecated) "                                   \
    +          "Number of iterations in safepoint loop "                         \
               "before changing safepoint polling page to RO ")                  \
Comments
Adding a release note is reasonable if the option has nontrivial usage. Moving to approved.
16-11-2017
I assume that a release note will be created for this.
16-11-2017