src/hotspot/share/code/codeCache.cpp

rev 54936 : [mq]: 8221734-v3
rev 54937 : [mq]: 8221734-v5

*** 1144,1168 ****
  
    Deoptimization::deoptimize_all_marked();
  }
  #endif // INCLUDE_JVMTI
  
! // Deoptimize all(most) methods
  void CodeCache::mark_all_nmethods_for_deoptimization() {
    MutexLocker mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
    CompiledMethodIterator iter(CompiledMethodIterator::only_alive_and_not_unloading);
    while(iter.next()) {
      CompiledMethod* nm = iter.method();
-     // Not installed are unsafe to mark for deopt, normally never deopted.
-     // A not_entrant method may become a zombie at any time,
-     // since we don't know on which side of last safepoint it became not_entrant
-     // (state must be in_use).
-     // Native method are unsafe to mark for deopt, normally never deopted.
      if (!nm->method()->is_method_handle_intrinsic() &&
          !nm->is_not_installed() &&
          nm->is_in_use() &&
          !nm->is_native_method()) {
        nm->mark_for_deoptimization();
      }
    }
  }
  
--- 1144,1168 ----
  
    Deoptimization::deoptimize_all_marked();
  }
  #endif // INCLUDE_JVMTI
  
! // Mark methods for deopt (if safe or possible).
  void CodeCache::mark_all_nmethods_for_deoptimization() {
    MutexLocker mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
    CompiledMethodIterator iter(CompiledMethodIterator::only_alive_and_not_unloading);
    while(iter.next()) {
      CompiledMethod* nm = iter.method();
      if (!nm->method()->is_method_handle_intrinsic() &&
          !nm->is_not_installed() &&
          nm->is_in_use() &&
          !nm->is_native_method()) {
+       // Intrinsics and native methods are never deopted. A method that is
+       // not installed yet or is not in use is not safe to deopt; the
+       // is_in_use() check covers the not_entrant and not zombie cases.
+       // Note: A not_entrant method can become a zombie at anytime if it was
+       // made not_entrant before the previous safepoint/handshake.
        nm->mark_for_deoptimization();
      }
    }
  }
  
*** 1186,1201 ****
  void CodeCache::make_marked_nmethods_not_entrant() {
    assert_locked_or_safepoint(CodeCache_lock);
    CompiledMethodIterator iter(CompiledMethodIterator::only_alive_and_not_unloading);
    while(iter.next()) {
      CompiledMethod* nm = iter.method();
-     // only_alive_and_not_unloading returns not_entrant nmethods.
-     // A not_entrant can become a zombie at anytime,
-     // if it was made not_entrant before previous safepoint/handshake.
-     // We check that it is not not_entrant and not zombie,
-     // by checking is_in_use().
      if (nm->is_marked_for_deoptimization() && nm->is_in_use()) {
        nm->make_not_entrant();
      }
    }
  }
  
--- 1186,1201 ----
  void CodeCache::make_marked_nmethods_not_entrant() {
    assert_locked_or_safepoint(CodeCache_lock);
    CompiledMethodIterator iter(CompiledMethodIterator::only_alive_and_not_unloading);
    while(iter.next()) {
      CompiledMethod* nm = iter.method();
      if (nm->is_marked_for_deoptimization() && nm->is_in_use()) {
+       // only_alive_and_not_unloading() can return not_entrant nmethods.
+       // A not_entrant method can become a zombie at anytime if it was
+       // made not_entrant before the previous safepoint/handshake. The
+       // is_in_use() check covers the not_entrant and not zombie cases
+       // that have become true after the method was marked for deopt.
        nm->make_not_entrant();
      }
    }
  }