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src/hotspot/share/gc/g1/heapRegionType.hpp

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   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_GC_G1_HEAPREGIONTYPE_HPP
  26 #define SHARE_VM_GC_G1_HEAPREGIONTYPE_HPP
  27 
  28 #include "gc/g1/g1HeapRegionTraceType.hpp"
  29 #include "memory/allocation.hpp"
  30 
  31 #define hrt_assert_is_valid(tag) \
  32   assert(is_valid((tag)), "invalid HR type: %u", (uint) (tag))
  33 
  34 class HeapRegionType VALUE_OBJ_CLASS_SPEC {
  35 friend class VMStructs;
  36 
  37 private:
  38   // We encode the value of the heap region type so the generation can be
  39   // determined quickly. The tag is split into two parts:
  40   //
  41   //   major type (young, old, humongous, archive)           : top N-1 bits
  42   //   minor type (eden / survivor, starts / cont hum, etc.) : bottom 1 bit
  43   //
  44   // If there's need to increase the number of minor types in the
  45   // future, we'll have to increase the size of the latter and hence
  46   // decrease the size of the former.
  47   //
  48   // 00000 0 [ 0] Free
  49   //
  50   // 00001 0 [ 2] Young Mask
  51   // 00001 0 [ 2] Eden
  52   // 00001 1 [ 3] Survivor
  53   //
  54   // 00010 0 [ 4] Humongous Mask




   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_GC_G1_HEAPREGIONTYPE_HPP
  26 #define SHARE_VM_GC_G1_HEAPREGIONTYPE_HPP
  27 
  28 #include "gc/g1/g1HeapRegionTraceType.hpp"

  29 
  30 #define hrt_assert_is_valid(tag) \
  31   assert(is_valid((tag)), "invalid HR type: %u", (uint) (tag))
  32 
  33 class HeapRegionType {
  34 friend class VMStructs;
  35 
  36 private:
  37   // We encode the value of the heap region type so the generation can be
  38   // determined quickly. The tag is split into two parts:
  39   //
  40   //   major type (young, old, humongous, archive)           : top N-1 bits
  41   //   minor type (eden / survivor, starts / cont hum, etc.) : bottom 1 bit
  42   //
  43   // If there's need to increase the number of minor types in the
  44   // future, we'll have to increase the size of the latter and hence
  45   // decrease the size of the former.
  46   //
  47   // 00000 0 [ 0] Free
  48   //
  49   // 00001 0 [ 2] Young Mask
  50   // 00001 0 [ 2] Eden
  51   // 00001 1 [ 3] Survivor
  52   //
  53   // 00010 0 [ 4] Humongous Mask


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