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src/share/vm/gc/g1/g1StringDedupTable.cpp

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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 #include "precompiled.hpp"
  26 #include "classfile/altHashing.hpp"
  27 #include "classfile/javaClasses.inline.hpp"
  28 #include "gc/g1/g1CollectedHeap.inline.hpp"
  29 #include "gc/g1/g1SATBCardTableModRefBS.hpp"
  30 #include "gc/g1/g1StringDedup.hpp"
  31 #include "gc/g1/g1StringDedupTable.hpp"
  32 #include "gc/shared/gcLocker.hpp"

  33 #include "logging/log.hpp"
  34 #include "memory/padded.inline.hpp"
  35 #include "oops/oop.inline.hpp"
  36 #include "oops/typeArrayOop.hpp"
  37 #include "runtime/mutexLocker.hpp"
  38 
  39 //
  40 // Freelist in the deduplication table entry cache. Links table
  41 // entries together using their _next fields.
  42 //
  43 class G1StringDedupEntryFreeList : public CHeapObj<mtGC> {
  44 private:
  45   G1StringDedupEntry* _list;
  46   size_t              _length;
  47 
  48 public:
  49   G1StringDedupEntryFreeList() :
  50     _list(NULL),
  51     _length(0) {
  52   }


 326     if (use_java_hash() && hash != 0) {
 327       // Store hash code in cache
 328       java_lang_String::set_hash(java_string, hash);
 329     }
 330   }
 331 
 332   typeArrayOop existing_value = lookup_or_add(value, latin1, hash);
 333   if (existing_value == value) {
 334     // Same value, already known
 335     stat.inc_known();
 336     return;
 337   }
 338 
 339   // Get size of value array
 340   uintx size_in_bytes = value->size() * HeapWordSize;
 341   stat.inc_new(size_in_bytes);
 342 
 343   if (existing_value != NULL) {
 344     // Enqueue the reference to make sure it is kept alive. Concurrent mark might
 345     // otherwise declare it dead if there are no other strong references to this object.
 346     G1SATBCardTableModRefBS::enqueue(existing_value);
 347 
 348     // Existing value found, deduplicate string
 349     java_lang_String::set_value(java_string, existing_value);
 350 
 351     if (G1CollectedHeap::heap()->is_in_young(value)) {
 352       stat.inc_deduped_young(size_in_bytes);
 353     } else {
 354       stat.inc_deduped_old(size_in_bytes);
 355     }
 356   }
 357 }
 358 
 359 G1StringDedupTable* G1StringDedupTable::prepare_resize() {
 360   size_t size = _table->_size;
 361 
 362   // Check if the hashtable needs to be resized
 363   if (_table->_entries > _table->_grow_threshold) {
 364     // Grow table, double the size
 365     size *= 2;
 366     if (size > _max_size) {




   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 #include "precompiled.hpp"
  26 #include "classfile/altHashing.hpp"
  27 #include "classfile/javaClasses.inline.hpp"
  28 #include "gc/g1/g1CollectedHeap.inline.hpp"

  29 #include "gc/g1/g1StringDedup.hpp"
  30 #include "gc/g1/g1StringDedupTable.hpp"
  31 #include "gc/shared/gcLocker.hpp"
  32 #include "gc/shared/satbMarkQueue.hpp"
  33 #include "logging/log.hpp"
  34 #include "memory/padded.inline.hpp"
  35 #include "oops/oop.inline.hpp"
  36 #include "oops/typeArrayOop.hpp"
  37 #include "runtime/mutexLocker.hpp"
  38 
  39 //
  40 // Freelist in the deduplication table entry cache. Links table
  41 // entries together using their _next fields.
  42 //
  43 class G1StringDedupEntryFreeList : public CHeapObj<mtGC> {
  44 private:
  45   G1StringDedupEntry* _list;
  46   size_t              _length;
  47 
  48 public:
  49   G1StringDedupEntryFreeList() :
  50     _list(NULL),
  51     _length(0) {
  52   }


 326     if (use_java_hash() && hash != 0) {
 327       // Store hash code in cache
 328       java_lang_String::set_hash(java_string, hash);
 329     }
 330   }
 331 
 332   typeArrayOop existing_value = lookup_or_add(value, latin1, hash);
 333   if (existing_value == value) {
 334     // Same value, already known
 335     stat.inc_known();
 336     return;
 337   }
 338 
 339   // Get size of value array
 340   uintx size_in_bytes = value->size() * HeapWordSize;
 341   stat.inc_new(size_in_bytes);
 342 
 343   if (existing_value != NULL) {
 344     // Enqueue the reference to make sure it is kept alive. Concurrent mark might
 345     // otherwise declare it dead if there are no other strong references to this object.
 346     SATBMarkQueue::enqueue(existing_value);
 347 
 348     // Existing value found, deduplicate string
 349     java_lang_String::set_value(java_string, existing_value);
 350 
 351     if (G1CollectedHeap::heap()->is_in_young(value)) {
 352       stat.inc_deduped_young(size_in_bytes);
 353     } else {
 354       stat.inc_deduped_old(size_in_bytes);
 355     }
 356   }
 357 }
 358 
 359 G1StringDedupTable* G1StringDedupTable::prepare_resize() {
 360   size_t size = _table->_size;
 361 
 362   // Check if the hashtable needs to be resized
 363   if (_table->_entries > _table->_grow_threshold) {
 364     // Grow table, double the size
 365     size *= 2;
 366     if (size > _max_size) {


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