src/share/vm/gc/g1/g1CardCounts.cpp

rev 10742 : Make fields used in lock-free algorithms volatile

@@ -81,11 +81,11 @@
     _reserved_max_card_num = mapper->reserved().byte_size();
     mapper->set_mapping_changed_listener(&_listener);
   }
 }
 
-uint G1CardCounts::add_card_count(jbyte* card_ptr) {
+uint G1CardCounts::add_card_count(volatile jbyte* card_ptr) {
   // Returns the number of times the card has been refined.
   // If we failed to reserve/commit the counts table, return 0.
   // If card_ptr is beyond the committed end of the counts table,
   // return 0.
   // Otherwise return the actual count.

@@ -116,15 +116,15 @@
   clear_range(mr);
 }
 
 void G1CardCounts::clear_range(MemRegion mr) {
   if (has_count_table()) {
-    const jbyte* from_card_ptr = _ct_bs->byte_for_const(mr.start());
+    const volatile jbyte* from_card_ptr = _ct_bs->byte_for_const(mr.start());
     // We use the last address in the range as the range could represent the
     // last region in the heap. In which case trying to find the card will be an
     // OOB access to the card table.
-    const jbyte* last_card_ptr = _ct_bs->byte_for_const(mr.last());
+    const volatile jbyte* last_card_ptr = _ct_bs->byte_for_const(mr.last());
 
 #ifdef ASSERT
     HeapWord* start_addr = _ct_bs->addr_for(from_card_ptr);
     assert(start_addr == mr.start(), "MemRegion start must be aligned to a card.");
     HeapWord* last_addr = _ct_bs->addr_for(last_card_ptr);