Re: RFR: 8242425: JVMTI monitor operations should use Thread-Local Handshakes

[serguei.spit...@oracle.com]

Hi Yasumasa,

Thank you for the update.
It looks good.

Thanks,
Serguei


On 4/10/20 04:30, Yasumasa Suenaga wrote:

Hi Serguei,

I use current_jt in this webrev. Could you review again?

  http://cr.openjdk.java.net/~ysuenaga/JDK-8242425/webrev.02/

I tested this change with vmTestbase/nsk/jvmti, they are fine on my Linux x64.

Thanks,

Yasumasa


On 2020/04/10 17:21, serguei.spit...@oracle.com wrote:

Hi Yasumasa,

Thank you for the update.

Minor:

http://cr.openjdk.java.net/~ysuenaga/JDK-8242425/webrev.01/src/hotspot/share/prims/jvmtiEnvBase.cpp.udiff.html

+ err = get_locked_objects_in_frame(JavaThread::current(), java_thread, jvf, owned_monitors_list, depth-1); . . .

+ JvmtiMonitorClosure jmc(java_thread, JavaThread::current(), owned_monitors_list, this);

You can use current_jt instead of JavaThread::current() above.

There is also some test coverage in the vmTestbase/nsk/jvmti/scenarios tests.

This one as well:

test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/nosuspendMonitorInfo/JvmtiTest

Probably it is easier to run all vmTestbase/nsk/jvmti tests.

Thanks,
Serguei


On 4/10/20 01:05, Yasumasa Suenaga wrote:

Hi Serguei,

Thanks for your comment!
I uploaded new webrev:

http://cr.openjdk.java.net/~ysuenaga/JDK-8242425/webrev.01/

I ran following tests, and all of them were passed on my Linux x64.

 - vmTestbase/nsk/jvmti/GetCurrentContendedMonitor
 - vmTestbase/nsk/jvmti/GetOwnedMonitorInfo
 - vmTestbase/nsk/jdi
 - vmTestbase/nsk/jdwp
 - serviceability/jvmti/GetOwnedMonitorInfo
 - serviceability/jvmti/GetOwnedMonitorStackDepthInfo
 - serviceability/jdwp


Thanks,

Yasumasa


On 2020/04/10 14:50, serguei.spit...@oracle.com wrote:

Hi Yasumasa,

It looks pretty good in general.
A couple of comments though.

http://cr.openjdk.java.net/~ysuenaga/JDK-8242425/webrev.00/src/hotspot/share/prims/jvmtiEnvBase.cpp.frames.html

650 JvmtiEnvBase::get_current_contended_monitor(JavaThread *java_thread, jobject *monitor_ptr) {

651 assert(!Thread::current()->is_VM_thread() &&
652 (Thread::current() == java_thread ||
653 Thread::current() == java_thread->active_handshaker()),
654 "call by myself or at direct handshake");

  ...

685 JvmtiEnvBase::get_owned_monitors(JavaThread* java_thread,

  686 GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list) {

  687   jvmtiError err = JVMTI_ERROR_NONE;
688 assert(!Thread::current()->is_VM_thread() &&
689 (Thread::current() == java_thread ||
690 Thread::current() == java_thread->active_handshaker()),
691 "call by myself or at direct handshake");

I'd suggest to add this at the beginning:
   JavaThread *current_jt = JavaThread::current();

676 JavaThread *current_jt = reinterpret_cast<JavaThread *>(JavaThread::current());

There is not need in reinterpret_cast<JavaThread *>. Also, you can use the current_jt defined above.

Also, please, removed these two definitions as they became unused with your fix:     src/hotspot/share/runtime/vmOperations.hpp: template(GGetCurrentContendedMonitoretOwnedMonitorInfo) \     src/hotspot/share/runtime/vmOperations.hpp: template()            \

The impacted JVMTI monitor functions are used in the JDWP agent to support the JDI ThreadReference implementation. To be safe the JDI & JDWP tests have to be run as well. It is well covered by the tier-5.

Thanks,
Serguei


On 4/9/20 21:46, Yasumasa Suenaga wrote:

Hi all,

Please review this change:

  JBS: https://bugs.openjdk.java.net/browse/JDK-8242425
  webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8242425/webrev.00/

We've discussed to use Thread-Local Handshake in some JVMTI functions [1]. This change is for monitor functions. It affects GetOwnedMonitorInfo(), GetOwnedMonitorStackDepthInfo(), GetCurrentContendedMonitor().

It passed tests on submit repo (mach5-one-ysuenaga-JDK-8242425-20200410-0228-10075639), and also I confirmed to pass following tests:

 - serviceability/jvmti/GetOwnedMonitorInfo
 - serviceability/jvmti/GetOwnedMonitorStackDepthInfo
 - vmTestbase/nsk/jvmti/GetCurrentContendedMonitor
 - vmTestbase/nsk/jvmti/GetOwnedMonitorInfo


Thanks,

Yasumasa

[1] https://mail.openjdk.java.net/pipermail/serviceability-dev/2020-March/030890.html