1 /* 2 * Copyright (c) 2013, 2018, Red Hat, Inc. All rights reserved. 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/shenandoah/shenandoahHeapRegionSet.hpp" 26 #include "gc/shenandoah/shenandoahHeapRegionSet.inline.hpp" 27 #include "gc/shenandoah/shenandoahHeap.hpp" 28 #include "gc/shenandoah/shenandoahHeap.inline.hpp" 29 #include "gc/shenandoah/shenandoahHeapRegion.hpp" 30 #include "gc/shenandoah/shenandoahUtils.hpp" 31 #include "runtime/atomic.hpp" 32 #include "utilities/copy.hpp" 33 34 ShenandoahHeapRegionSetIterator::ShenandoahHeapRegionSetIterator(const ShenandoahHeapRegionSet* const set) : 35 _set(set), _heap(ShenandoahHeap::heap()), _current_index(0) {} 36 37 void ShenandoahHeapRegionSetIterator::reset(const ShenandoahHeapRegionSet* const set) { 38 _set = set; 39 _current_index = 0; 40 } 41 42 ShenandoahHeapRegionSet::ShenandoahHeapRegionSet() : 43 _heap(ShenandoahHeap::heap()), 44 _map_size(_heap->num_regions()), 45 _region_size_bytes_shift(ShenandoahHeapRegion::region_size_bytes_shift()), 46 _set_map(NEW_C_HEAP_ARRAY(jbyte, _map_size, mtGC)), 47 _biased_set_map(_set_map - ((uintx)_heap->base() >> _region_size_bytes_shift)), 48 _region_count(0) 49 { 50 // Use 1-byte data type 51 STATIC_ASSERT(sizeof(jbyte) == 1); 52 53 // Initialize cset map 54 Copy::zero_to_bytes(_set_map, _map_size); 55 } 56 57 ShenandoahHeapRegionSet::~ShenandoahHeapRegionSet() { 58 FREE_C_HEAP_ARRAY(jbyte, _set_map); 59 } 60 61 void ShenandoahHeapRegionSet::add_region(ShenandoahHeapRegion* r) { 62 assert(!is_in(r), "Already in collection set"); 63 _set_map[r->region_number()] = 1; 64 _region_count++; 65 } 66 67 bool ShenandoahHeapRegionSet::add_region_check_for_duplicates(ShenandoahHeapRegion* r) { 68 if (!is_in(r)) { 69 add_region(r); 70 return true; 71 } else { 72 return false; 73 } 74 } 75 76 void ShenandoahHeapRegionSet::remove_region(ShenandoahHeapRegion* r) { 77 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint"); 78 assert(Thread::current()->is_VM_thread(), "Must be VMThread"); 79 assert(is_in(r), "Not in region set"); 80 _set_map[r->region_number()] = 0; 81 _region_count --; 82 } 83 84 void ShenandoahHeapRegionSet::clear() { 85 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint"); 86 Copy::zero_to_bytes(_set_map, _map_size); 87 88 _region_count = 0; 89 } 90 91 ShenandoahHeapRegion* ShenandoahHeapRegionSetIterator::claim_next() { 92 size_t num_regions = _heap->num_regions(); 93 if (_current_index >= (jint)num_regions) { 94 return NULL; 95 } 96 97 jint saved_current = _current_index; 98 size_t index = (size_t)saved_current; 99 100 while(index < num_regions) { 101 if (_set->is_in(index)) { 102 jint cur = Atomic::cmpxchg((jint)(index + 1), &_current_index, saved_current); 103 assert(cur >= (jint)saved_current, "Must move forward"); 104 if (cur == saved_current) { 105 assert(_set->is_in(index), "Invariant"); 106 return _heap->get_region(index); 107 } else { 108 index = (size_t)cur; 109 saved_current = cur; 110 } 111 } else { 112 index ++; 113 } 114 } 115 return NULL; 116 } 117 118 ShenandoahHeapRegion* ShenandoahHeapRegionSetIterator::next() { 119 size_t num_regions = _heap->num_regions(); 120 for (size_t index = (size_t)_current_index; index < num_regions; index ++) { 121 if (_set->is_in(index)) { 122 _current_index = (jint)(index + 1); 123 return _heap->get_region(index); 124 } 125 } 126 127 return NULL; 128 } 129 130 void ShenandoahHeapRegionSet::print_on(outputStream* out) const { 131 out->print_cr("Region Set : " SIZE_FORMAT "", count()); 132 133 debug_only(size_t regions = 0;) 134 for (size_t index = 0; index < _heap->num_regions(); index ++) { 135 if (is_in(index)) { 136 _heap->get_region(index)->print_on(out); 137 debug_only(regions ++;) 138 } 139 } 140 assert(regions == count(), "Must match"); 141 }