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

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

@@ -62,11 +62,11 @@
 
   // Max capacity of the reserved space for the counts table
   size_t _reserved_max_card_num;
 
   // CardTable bottom.
-  const jbyte* _ct_bot;
+  const volatile jbyte* _ct_bot;
 
   // Barrier set
   CardTableModRefBS* _ct_bs;
 
   // Returns true if the card counts table has been reserved.

@@ -75,26 +75,26 @@
   // Returns true if the card counts table has been reserved and committed.
   bool has_count_table() {
     return has_reserved_count_table();
   }
 
-  size_t ptr_2_card_num(const jbyte* card_ptr) {
+  size_t ptr_2_card_num(const volatile jbyte* card_ptr) {
     assert(card_ptr >= _ct_bot,
            "Invalid card pointer: "
            "card_ptr: " PTR_FORMAT ", "
            "_ct_bot: " PTR_FORMAT,
-           p2i(card_ptr), p2i(_ct_bot));
-    size_t card_num = pointer_delta(card_ptr, _ct_bot, sizeof(jbyte));
+           p2i((jbyte*)card_ptr), p2i((jbyte*)_ct_bot));
+    size_t card_num = pointer_delta((void*)card_ptr, (jbyte*)_ct_bot, sizeof(jbyte));
     assert(card_num < _reserved_max_card_num,
-           "card pointer out of range: " PTR_FORMAT, p2i(card_ptr));
+           "card pointer out of range: " PTR_FORMAT, p2i((jbyte*)card_ptr));
     return card_num;
   }
 
-  jbyte* card_num_2_ptr(size_t card_num) {
+  volatile jbyte* card_num_2_ptr(size_t card_num) {
     assert(card_num < _reserved_max_card_num,
            "card num out of range: " SIZE_FORMAT, card_num);
-    return (jbyte*) (_ct_bot + card_num);
+    return (volatile jbyte*) (_ct_bot + card_num);
   }
 
   // Clear the counts table for the given (exclusive) index range.
   void clear_range(size_t from_card_num, size_t to_card_num);
 

@@ -111,11 +111,11 @@
 
   void initialize(G1RegionToSpaceMapper* mapper);
 
   // Increments the refinement count for the given card.
   // Returns the pre-increment count value.
-  uint add_card_count(jbyte* card_ptr);
+  uint add_card_count(volatile jbyte* card_ptr);
 
   // Returns true if the given count is high enough to be considered
   // 'hot'; false otherwise.
   bool is_hot(uint count);