1 /* 2 * Copyright (c) 2016, Red Hat, Inc. and/or its affiliates. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 * 22 */ 23 24 #include "precompiled.hpp" 25 #include "gc_implementation/shenandoah/shenandoahCollectionSet.hpp" 26 #include "gc_implementation/shenandoah/shenandoahCollectionSet.inline.hpp" 27 #include "gc_implementation/shenandoah/shenandoahHeap.hpp" 28 #include "gc_implementation/shenandoah/shenandoahHeap.inline.hpp" 29 #include "gc_implementation/shenandoah/shenandoahHeapRegion.hpp" 30 #include "gc_implementation/shenandoah/shenandoahHeapRegionSet.hpp" 31 #include "runtime/atomic.hpp" 32 #include "utilities/copy.hpp" 33 34 ShenandoahCollectionSet::ShenandoahCollectionSet(ShenandoahHeap* heap, HeapWord* heap_base) : 35 _map_size(heap->num_regions()), 36 _region_size_bytes_shift(ShenandoahHeapRegion::region_size_bytes_shift()), 37 _cset_map(NEW_C_HEAP_ARRAY(jbyte, _map_size, mtGC)), 38 _biased_cset_map(_cset_map - ((uintx)heap_base >> _region_size_bytes_shift)), 39 _heap(heap), 40 _garbage(0), 41 _live_data(0), 42 _used(0), 43 _region_count(0), 44 _current_index(0) { 45 // Use 1-byte data type 46 STATIC_ASSERT(sizeof(jbyte) == 1); 47 48 // Initialize cset map 49 Copy::zero_to_bytes(_cset_map, _map_size); 50 } 51 52 void ShenandoahCollectionSet::add_region(ShenandoahHeapRegion* r) { 53 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint"); 54 assert(Thread::current()->is_VM_thread(), "Must be VMThread"); 55 assert(!is_in(r), "Already in collection set"); 56 _cset_map[r->region_number()] = 1; 57 _region_count ++; 58 _garbage += r->garbage(); 59 _live_data += r->get_live_data_bytes(); 60 _used += r->used(); 61 } 62 63 void ShenandoahCollectionSet::remove_region(ShenandoahHeapRegion* r) { 64 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint"); 65 assert(Thread::current()->is_VM_thread(), "Must be VMThread"); 66 assert(is_in(r), "Not in collection set"); 67 _cset_map[r->region_number()] = 0; 68 _region_count --; 69 } 70 71 void ShenandoahCollectionSet::update_region_status() { 72 for (size_t index = 0; index < _heap->num_regions(); index ++) { 73 ShenandoahHeapRegion* r = _heap->get_region(index); 74 if (is_in(r)) { 75 r->make_cset(); 76 } else { 77 assert (!r->is_cset(), "should not be cset"); 78 } 79 } 80 } 81 82 void ShenandoahCollectionSet::clear() { 83 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint"); 84 Copy::zero_to_bytes(_cset_map, _map_size); 85 86 #ifdef ASSERT 87 for (size_t index = 0; index < _heap->num_regions(); index ++) { 88 assert (!_heap->get_region(index)->is_cset(), "should have been cleared before"); 89 } 90 #endif 91 92 _garbage = 0; 93 _live_data = 0; 94 _used = 0; 95 96 _region_count = 0; 97 _current_index = 0; 98 } 99 100 ShenandoahHeapRegion* ShenandoahCollectionSet::claim_next() { 101 size_t num_regions = _heap->num_regions(); 102 if (_current_index >= (jint)num_regions) { 103 return NULL; 104 } 105 106 jint saved_current = _current_index; 107 size_t index = (size_t)saved_current; 108 109 while(index < num_regions) { 110 if (is_in(index)) { 111 jint cur = Atomic::cmpxchg((jint)(index + 1), &_current_index, saved_current); 112 assert(cur >= (jint)saved_current, "Must move forward"); 113 if (cur == saved_current) { 114 assert(is_in(index), "Invariant"); 115 return _heap->get_region(index); 116 } else { 117 index = (size_t)cur; 118 saved_current = cur; 119 } 120 } else { 121 index ++; 122 } 123 } 124 return NULL; 125 } 126 127 128 ShenandoahHeapRegion* ShenandoahCollectionSet::next() { 129 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint"); 130 assert(Thread::current()->is_VM_thread(), "Must be VMThread"); 131 size_t num_regions = _heap->num_regions(); 132 for (size_t index = (size_t)_current_index; index < num_regions; index ++) { 133 if (is_in(index)) { 134 _current_index = (jint)(index + 1); 135 return _heap->get_region(index); 136 } 137 } 138 139 return NULL; 140 } 141 142 143 void ShenandoahCollectionSet::print_on(outputStream* out) const { 144 out->print_cr("Collection Set : " SIZE_FORMAT "", count()); 145 146 debug_only(size_t regions = 0;) 147 for (size_t index = 0; index < _heap->num_regions(); index ++) { 148 if (is_in(index)) { 149 _heap->get_region(index)->print_on(out); 150 debug_only(regions ++;) 151 } 152 } 153 assert(regions == count(), "Must match"); 154 }