8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  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_MEMORY_PADDED_HPP
  26 #define SHARE_VM_MEMORY_PADDED_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "utilities/align.hpp"
  30 #include "utilities/globalDefinitions.hpp"
  31 
  32 // Bytes needed to pad type to avoid cache-line sharing; alignment should be the
  33 // expected cache line size (a power of two).  The first addend avoids sharing
  34 // when the start address is not a multiple of alignment; the second maintains
  35 // alignment of starting addresses that happen to be a multiple.
  36 #define PADDING_SIZE(type, alignment)                           \
  37   ((alignment) + align_up_(sizeof(type), (alignment)))
  38 
  39 // Templates to create a subclass padded to avoid cache line sharing.  These are
  40 // effective only when applied to derived-most (leaf) classes.
  41 
  42 // When no args are passed to the base ctor.
  43 template <class T, size_t alignment = DEFAULT_CACHE_LINE_SIZE>
  44 class Padded : public T {
  45  private:
  46   char _pad_buf_[PADDING_SIZE(T, alignment)];
  47 };
  48 

   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  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_MEMORY_PADDED_HPP
  26 #define SHARE_VM_MEMORY_PADDED_HPP
  27 

  28 #include "utilities/align.hpp"
  29 #include "utilities/globalDefinitions.hpp"
  30 
  31 // Bytes needed to pad type to avoid cache-line sharing; alignment should be the
  32 // expected cache line size (a power of two).  The first addend avoids sharing
  33 // when the start address is not a multiple of alignment; the second maintains
  34 // alignment of starting addresses that happen to be a multiple.
  35 #define PADDING_SIZE(type, alignment)                           \
  36   ((alignment) + align_up_(sizeof(type), (alignment)))
  37 
  38 // Templates to create a subclass padded to avoid cache line sharing.  These are
  39 // effective only when applied to derived-most (leaf) classes.
  40 
  41 // When no args are passed to the base ctor.
  42 template <class T, size_t alignment = DEFAULT_CACHE_LINE_SIZE>
  43 class Padded : public T {
  44  private:
  45   char _pad_buf_[PADDING_SIZE(T, alignment)];
  46 };
  47