RFR: 8229516: Thread.isInterrupted() always returns false after thread termination

David Holmes david.holmes at oracle.com
Tue Oct 29 07:42:08 UTC 2019

Bug: https://bugs.openjdk.java.net/browse/JDK-8229516
CSR: https://bugs.openjdk.java.net/browse/JDK-8232676 (already approved)
webrev: http://cr.openjdk.java.net/~dholmes/8229516/webrev/

This cross-cuts core-libs, hotspot-runtime and the JIT compilers, but 
only in small pieces each. There is also a small touch to serviceability 

This change is "simply" moving the "interrupted" field out of the 
osThread and into the java.lang.Thread so that it can be set 
independently of whether the thread is alive (and to make things easier 
for loom in the near future). It is very straightforward:

- old scheme
   - interrupted field is in osThread
   - VM can read/write directly
   - Java code calls into VM to read/write

- new scheme
   - interrupted field is in java.lang.Thread
   - VM has to use javaCalls to read/write "directly"
   - Java code can read/write directly

No changes to any of the semantics regarding the actual interrupt 
mechanism. Special thanks to Patricio for tracking down a bug I had 
introduced in that regard!

Special Note (Hi Roger!): on windows we still need to set/clear the 
_interrupt_event used by the Process.waitFor logic. To facilitate 
clearing via Thread.interrupted() I had to introduce a native method 
that is a no-op except on Windows. This seemed the cheapest and least 
intrusive means to achieve this.

Other changes revolve around the fact we used to have an intrinsic for 
Thread.isInterrupted and that is not needed any more. So we strip some 
code out of C1/C2.

The changes in the JVMCI/Graal code are a bit more far reaching as 
entire classes disappear. I've cc'd Doug and Tom at Vladimir's request 
so that they can comment on the JVMCI changes and whether I have gone 
too far or not far enough. There are a bunch of tests for interruption 
in JVMCI that could potentially be deleted if they are only intended to 
test the JVMCI handling of interrupt:


  - Tiers 1-3 on all Oracle platforms
  - Focused testing on Linux x64:
     - Stress runs of JSR166TestCase
     - Anything that seems to use interrupt():
       - JDK
         - java/lang/Thread
         - java/util/concurrent
         - jdk/internal/loader/InterruptedClassLoad.java
         - javax/management
         - java/nio/file/Files
         - java/nio/channels
         - java/net/Socket/Timeouts.java
         - java/lang/Runtime/shutdown/
         - java/lang/ProcessBuilder/Basic.java
         - com/sun/jdi/
       - Hotspot
         - vmTestbase/nsk/monitoring/
         - vmTestbase/nsk/jdwp
         - vmTestbase/nsk/jdb/
         - vmTestbase/nsk/jdi/
         - vmTestbase/nsk/jvmti/
         - runtime/Thread
         - serviceability/jvmti/
         - serviceability/jdwp
         - serviceability/sa


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