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

Concurrent class unloading

 
 // 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(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();

@@ -123,10 +123,12
 
 // 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();

@@ -382,6 +384,5
     i ++;
   }
 }
 
 } // namespace metaspace
-