src/hotspot/share/gc/shenandoah/shenandoahLock.cpp

rev 59811 : 8247670: Shenandoah: deadlock during class unloading OOME

*** 41,50 ****
--- 41,54 ----
  
  void ShenandoahSimpleLock::unlock() {
    _lock.unlock();
  }
  
+ bool ShenandoahSimpleLock::try_lock() {
+   return _lock.try_lock();
+ }
+ 
  ShenandoahReentrantLock::ShenandoahReentrantLock() :
    ShenandoahSimpleLock(), _owner(NULL), _count(0) {
    assert(os::mutex_init_done(), "Too early!");
  }
  
*** 62,71 ****
--- 66,90 ----
    }
  
    _count++;
  }
  
+ bool ShenandoahReentrantLock::try_lock() {
+   Thread* const thread = Thread::current();
+   Thread* const owner = Atomic::load(&_owner);
+ 
+   if (owner != thread) {
+     if (!ShenandoahSimpleLock::try_lock()) {
+       return false;
+     }
+     Atomic::store(&_owner, thread);
+   }
+ 
+   _count++;
+   return true;
+ }
+ 
  void ShenandoahReentrantLock::unlock() {
    assert(owned_by_self(), "Invalid owner");
    assert(_count > 0, "Invalid count");
  
    _count--;