1 /* 2 * Copyright (c) 2017, 2020, Red Hat, Inc. 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 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHSTRDEDUPQUEUE_INLINE_HPP 26 #define SHARE_GC_SHENANDOAH_SHENANDOAHSTRDEDUPQUEUE_INLINE_HPP 27 28 #include "gc/shenandoah/shenandoahStrDedupQueue.hpp" 29 #include "oops/access.hpp" 30 #include "runtime/atomic.hpp" 31 32 // With concurrent string dedup cleaning up, GC worker threads 33 // may see oops just enqueued, so release_store and load_acquire 34 // relationship needs to be established between enqueuing threads 35 // and GC workers. 36 // For example, when GC sees a slot (index), there must be a valid 37 // (dead or live) oop. 38 // Note: There is no concern if GC misses newly enqueued oops, 39 // since LRB ensures they are in to-space. 40 template <uint buffer_size> 41 ShenandoahOopBuffer<buffer_size>::ShenandoahOopBuffer() : 42 _index(0), _next(NULL) { 43 } 44 45 template <uint buffer_size> 46 bool ShenandoahOopBuffer<buffer_size>::is_full() const { 47 return index_acquire() >= buffer_size; 48 } 49 50 template <uint buffer_size> 51 bool ShenandoahOopBuffer<buffer_size>::is_empty() const { 52 return index_acquire() == 0; 53 } 54 55 template <uint buffer_size> 56 uint ShenandoahOopBuffer<buffer_size>::size() const { 57 return index_acquire(); 58 } 59 60 template <uint buffer_size> 61 void ShenandoahOopBuffer<buffer_size>::push(oop obj) { 62 assert(!is_full(), "Buffer is full"); 63 uint idx = index_acquire(); 64 RawAccess<IS_NOT_NULL>::oop_store(&_buf[idx], obj); 65 set_index_release(idx + 1); 66 } 67 68 template <uint buffer_size> 69 oop ShenandoahOopBuffer<buffer_size>::pop() { 70 assert(!is_empty(), "Buffer is empty"); 71 uint idx = index_acquire() - 1; 72 oop value = NativeAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE | MO_ACQUIRE>::oop_load(&_buf[idx]); 73 set_index_release(idx); 74 return value; 75 } 76 77 template <uint buffer_size> 78 void ShenandoahOopBuffer<buffer_size>::set_next(ShenandoahOopBuffer<buffer_size>* next) { 79 _next = next; 80 } 81 82 template <uint buffer_size> 83 ShenandoahOopBuffer<buffer_size>* ShenandoahOopBuffer<buffer_size>::next() const { 84 return _next; 85 } 86 87 template <uint buffer_size> 88 void ShenandoahOopBuffer<buffer_size>::reset() { 89 _index = 0; 90 _next = NULL; 91 } 92 93 template <uint buffer_size> 94 uint ShenandoahOopBuffer<buffer_size>::index_acquire() const { 95 return Atomic::load_acquire(&_index); 96 } 97 98 template <uint buffer_size> 99 void ShenandoahOopBuffer<buffer_size>::set_index_release(uint index) { 100 return Atomic::release_store(&_index, index); 101 } 102 103 template <uint buffer_size> 104 void ShenandoahOopBuffer<buffer_size>::unlink_or_oops_do(StringDedupUnlinkOrOopsDoClosure* cl) { 105 uint len = size(); 106 for (uint index = 0; index < len; index ++) { 107 oop* obj_addr = &_buf[index]; 108 if (*obj_addr != NULL) { 109 if (cl->is_alive(*obj_addr)) { 110 cl->keep_alive(obj_addr); 111 } else { 112 RawAccess<MO_RELEASE>::oop_store(&_buf[index], oop()); 113 } 114 } 115 } 116 } 117 118 template <uint buffer_size> 119 void ShenandoahOopBuffer<buffer_size>::oops_do(OopClosure* cl) { 120 uint len = size(); 121 for (uint index = 0; index < len; index ++) { 122 cl->do_oop(&_buf[index]); 123 } 124 } 125 126 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHSTRDEDUPQUEUE_INLINE_HPP