src/hotspot/share/memory/metaspace/virtualSpaceList.cpp

Concurrent class unloading

*** 70,80 ****
  
  // Walk the list of VirtualSpaceNodes and delete
  // nodes with a 0 container_count.  Remove Metachunks in
  // the node from their respective freelists.
  void VirtualSpaceList::purge(ChunkManager* chunk_manager) {
!   assert(SafepointSynchronize::is_at_safepoint(), "must be called at safepoint for contains to work");
    assert_lock_strong(MetaspaceExpand_lock);
    // Don't use a VirtualSpaceListIterator because this
    // list is being changed and a straightforward use of an iterator is not safe.
    VirtualSpaceNode* purged_vsl = NULL;
    VirtualSpaceNode* prev_vsl = virtual_space_list();
--- 70,80 ----
  
  // Walk the list of VirtualSpaceNodes and delete
  // nodes with a 0 container_count.  Remove Metachunks in
  // the node from their respective freelists.
  void VirtualSpaceList::purge(ChunkManager* chunk_manager) {
!   assert(UseZGC || SafepointSynchronize::is_at_safepoint(), "must be called at safepoint for contains to work");
    assert_lock_strong(MetaspaceExpand_lock);
    // Don't use a VirtualSpaceListIterator because this
    // list is being changed and a straightforward use of an iterator is not safe.
    VirtualSpaceNode* purged_vsl = NULL;
    VirtualSpaceNode* prev_vsl = virtual_space_list();
***************
*** 123,132 ****
--- 123,134 ----
  
  // This function looks at the mmap regions in the metaspace without locking.
  // The chunks are added with store ordering and not deleted except for at
  // unloading time during a safepoint.
  bool VirtualSpaceList::contains(const void* ptr) {
+   MutexLockerEx cl(MetaspaceExpand_lock,
+                    Mutex::_no_safepoint_check_flag);
    // List should be stable enough to use an iterator here because removing virtual
    // space nodes is only allowed at a safepoint.
    VirtualSpaceListIterator iter(virtual_space_list());
    while (iter.repeat()) {
      VirtualSpaceNode* vsn = iter.get_next();
***************
*** 382,387 ****
      i ++;
    }
  }
  
  } // namespace metaspace
- 
--- 384,388 ----