RFR: 8328285: GetOwnedMonitorInfo functions should use JvmtiHandshake [v2]

[Patricio Chilano Mateo]

On Wed, 20 Mar 2024 08:12:06 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> src/hotspot/share/prims/jvmtiEnv.cpp line 1368:
>> 
>>> 1366:   if (java_thread != nullptr) {
>>> 1367:     Handle thread_handle(calling_thread, thread_oop);
>>> 1368:     EscapeBarrier eb(true, calling_thread, java_thread);
>> 
>> I see that now we will execute the EscapeBarrier code for the vthread case too. We actually had to disable that for virtual threads since it doesn't work (8285739 and 8305625). But we only addressed the case when targeting all threads and not the single thread one. We would need to add the same check in EscapeBarrier::deoptimize_objects(int d1, int d2) to skip a thread with mounted continuation.
>
> Good suggestion, thanks!
> Would the following fix work ? :
> 
> 
> git diff
> diff --git a/src/hotspot/share/runtime/escapeBarrier.cpp b/src/hotspot/share/runtime/escapeBarrier.cpp
> index bc01d900285..1b6d57644dc 100644
> --- a/src/hotspot/share/runtime/escapeBarrier.cpp
> +++ b/src/hotspot/share/runtime/escapeBarrier.cpp
> @@ -75,7 +75,7 @@ bool EscapeBarrier::deoptimize_objects(int d1, int d2) {
>      // These frames are about to be removed. We must not interfere with that and signal failure.
>      return false;
>    }
> -  if (deoptee_thread()->has_last_Java_frame()) {
> +  if (deoptee_thread()->has_last_Java_frame() && deoptee_thread()->last_continuation() == nullptr) {
>      assert(calling_thread() == Thread::current(), "should be");
>      KeepStackGCProcessedMark ksgcpm(deoptee_thread());
>      ResourceMark rm(calling_thread());
> 
> 
> BTW, it seems the `PopFrame` and the `ForceEarlyReturn<RetType>` are broken the same way and, I hope, the fix above should solve the issue.

Fix looks good.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18332#discussion_r1532363608