13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_GC_G1_SPARSEPRT_HPP
  26 #define SHARE_VM_GC_G1_SPARSEPRT_HPP
  27 
  28 #include "gc/g1/g1CollectedHeap.hpp"
  29 #include "gc/g1/heapRegion.hpp"
  30 #include "gc/shared/cardTableModRefBS.hpp"
  31 #include "memory/allocation.hpp"
  32 #include "runtime/mutex.hpp"

  33 #include "utilities/globalDefinitions.hpp"
  34 
  35 // Sparse remembered set for a heap region (the "owning" region).  Maps
  36 // indices of other regions to short sequences of cards in the other region
  37 // that might contain pointers into the owner region.
  38 
  39 // These tables only expand while they are accessed in parallel --
  40 // deletions may be done in single-threaded code.  This allows us to allow
  41 // unsynchronized reads/iterations, as long as expansions caused by
  42 // insertions only enqueue old versions for deletions, but do not delete
  43 // old versions synchronously.
  44 
  45 class SparsePRTEntry: public CHeapObj<mtGC> {
  46 private:
  47   // The type of a card entry.
  48   typedef uint16_t card_elem_t;
  49 
  50   // We need to make sizeof(SparsePRTEntry) an even multiple of maximum member size,
  51   // in order to force correct alignment that could otherwise cause SIGBUS errors
  52   // when reading the member variables. This calculates the minimum number of card

  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_GC_G1_SPARSEPRT_HPP
  26 #define SHARE_VM_GC_G1_SPARSEPRT_HPP
  27 
  28 #include "gc/g1/g1CollectedHeap.hpp"
  29 #include "gc/g1/heapRegion.hpp"
  30 #include "gc/shared/cardTableModRefBS.hpp"
  31 #include "memory/allocation.hpp"
  32 #include "runtime/mutex.hpp"
  33 #include "utilities/align.hpp"
  34 #include "utilities/globalDefinitions.hpp"
  35 
  36 // Sparse remembered set for a heap region (the "owning" region).  Maps
  37 // indices of other regions to short sequences of cards in the other region
  38 // that might contain pointers into the owner region.
  39 
  40 // These tables only expand while they are accessed in parallel --
  41 // deletions may be done in single-threaded code.  This allows us to allow
  42 // unsynchronized reads/iterations, as long as expansions caused by
  43 // insertions only enqueue old versions for deletions, but do not delete
  44 // old versions synchronously.
  45 
  46 class SparsePRTEntry: public CHeapObj<mtGC> {
  47 private:
  48   // The type of a card entry.
  49   typedef uint16_t card_elem_t;
  50 
  51   // We need to make sizeof(SparsePRTEntry) an even multiple of maximum member size,
  52   // in order to force correct alignment that could otherwise cause SIGBUS errors
  53   // when reading the member variables. This calculates the minimum number of card