JDK-8227443 : TemplateInterpreter::_active_table needs to be reexamined
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: runtime
  • Affected Version: 14
  • Priority: P4
  • Status: Resolved
  • Resolution: Not an Issue
  • OS: generic
  • CPU: generic
  • Submitted: 2019-07-09
  • Updated: 2022-01-25
  • Resolved: 2022-01-25
Related Reports
Relates :  
JDK-8227338 - templateInterpreter.cpp: copy_table() needs to be safer
Relates :  
JDK-8227369 - pd_disjoint_words_atomic() needs to be atomic
Description
During the code review of:

    JDK-8227338 templateInterpreter.cpp: copy_table() needs to be safer
    https://bugs.openjdk.java.net/browse/JDK-8227338

The possibility of making TemplateInterpreter::_active_table volatile
in order to limit C++ compiler optimizations was raised. This type
of change will ripple into the various functions that manage the
_active_table.

Coleen also wonders what needs to happen to the _active_table
logic when we eventually only have handshakes for safepoints.
Comments
The safept dispatch table is now only used by JVMTI and we switch between the normal and safept table only at a safepoint (initiated by the JVMTI code). Consequently there are no issues with the updates to the _active_table.
25-01-2022
[~coleenp] [~kbarrett] [~rehn] - Added the three of you as watchers...
09-07-2019