1 /*
   2  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   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 #include "precompiled.hpp"
  26 
  27 #include "gc/shared/stringdedup/stringDedup.hpp"
  28 #include "gc/shared/stringdedup/stringDedupQueue.hpp"
  29 #include "runtime/atomic.hpp"
  30 
  31 StringDedupQueue* StringDedupQueue::_queue = NULL;
  32 volatile size_t   StringDedupQueue::_claimed_index = 0;
  33 
  34 size_t StringDedupQueue::claim() {
  35   return Atomic::add(size_t(1), &_claimed_index) - 1;
  36 }
  37 
  38 void StringDedupQueue::unlink_or_oops_do(StringDedupUnlinkOrOopsDoClosure* cl) {
  39   size_t claimed_queue = claim();
  40   while (claimed_queue < queue()->num_queues()) {
  41     queue()->queue_unlink_or_oops_do(cl, claimed_queue);
  42     claimed_queue = claim();
  43   }
  44 }
  45 
  46 void StringDedupQueue::print_statistics() {
  47   queue()->queue_print_statistics();
  48 }
  49 
  50 void StringDedupQueue::verify() {
  51   queue()->queue_verify();
  52 }
  53 
  54 StringDedupQueue* const StringDedupQueue::queue() {
  55   assert(_queue != NULL, "Not yet initialized");
  56   return _queue;
  57 }
  58 
  59 
  60 void StringDedupQueue::gc_prologue() {
  61   _claimed_index = 0;
  62 }
  63 
  64 void StringDedupQueue::gc_epilogue() {
  65   assert(_claimed_index >= queue()->num_queues() || _claimed_index == 0, "All or nothing");
  66 }