src/hotspot/share/prims/jvmtiEnvBase.cpp

rev 59077 : 8153224.v2.09b.patch combined with 8153224.v2.10.patch; merge with jdk-15+21.
rev 59078 : eosterlund v2.10 CR: reorganize deflate_monitor_using_JT() to use "early exit" style; dcubed - clarify/fix/rearrange a few comments in deflate_monitor_using_JT(); eosterlund v2.10 CR: simplify install_displaced_markword_in_object() and save_om_ptr(); save_om_ptr()'s call to install_displaced_markword_in_object() can race with the deflater thread's clearing of the object field so handle that; fold 8153224.OMHandle_experiment into 8153224.v2.11.patch; merge with jdk-15+21.

*** 651,660 ****
--- 651,663 ----
    JavaThread *current_jt = JavaThread::current();
    assert(current_jt == java_thread ||
           current_jt == java_thread->active_handshaker(),
           "call by myself or at direct handshake");
    oop obj = NULL;
+   // The ObjectMonitor* can't be async deflated since we are either
+   // at a safepoint or the calling thread is operating on itself so
+   // it cannot leave the underlying wait()/enter() call.
    ObjectMonitor *mon = java_thread->current_waiting_monitor();
    if (mon == NULL) {
      // thread is not doing an Object.wait() call
      mon = java_thread->current_pending_monitor();
      if (mon != NULL) {
*** 728,746 ****
    }
  
    HandleMark hm;
    oop wait_obj = NULL;
    {
!     // save object of current wait() call (if any) for later comparison
      ObjectMonitor *mon = java_thread->current_waiting_monitor();
      if (mon != NULL) {
        wait_obj = (oop)mon->object();
      }
    }
    oop pending_obj = NULL;
    {
!     // save object of current enter() call (if any) for later comparison
      ObjectMonitor *mon = java_thread->current_pending_monitor();
      if (mon != NULL) {
        pending_obj = (oop)mon->object();
      }
    }
--- 731,755 ----
    }
  
    HandleMark hm;
    oop wait_obj = NULL;
    {
!     // The ObjectMonitor* can't be async deflated since we are either
!     // at a safepoint or the calling thread is operating on itself so
!     // it cannot leave the underlying wait() call.
!     // Save object of current wait() call (if any) for later comparison.
      ObjectMonitor *mon = java_thread->current_waiting_monitor();
      if (mon != NULL) {
        wait_obj = (oop)mon->object();
      }
    }
    oop pending_obj = NULL;
    {
!     // The ObjectMonitor* can't be async deflated since we are either
!     // at a safepoint or the calling thread is operating on itself so
!     // it cannot leave the underlying enter() call.
!     // Save object of current enter() call (if any) for later comparison.
      ObjectMonitor *mon = java_thread->current_pending_monitor();
      if (mon != NULL) {
        pending_obj = (oop)mon->object();
      }
    }