1 /* 2 * Copyright (c) 2013, 2018, 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/shenandoahHeapRegionSet.hpp" 26 #include "gc_implementation/shenandoah/shenandoahHeapRegionSet.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 "runtime/atomic.hpp" 31 #include "utilities/copy.hpp" 32 33 ShenandoahHeapRegionSetIterator::ShenandoahHeapRegionSetIterator(const ShenandoahHeapRegionSet* const set) : 34 _set(set), _current_index(0), _heap(ShenandoahHeap::heap()) {} 35 36 ShenandoahHeapRegionSetIterator& ShenandoahHeapRegionSetIterator::operator=(const ShenandoahHeapRegionSetIterator& o) { 37 _current_index = o._current_index; 38 assert(_set == o._set, "must be same"); 39 assert(_heap == o._heap, "must be same"); 40 return *this; 41 } 42 43 ShenandoahHeapRegionSet::ShenandoahHeapRegionSet() : 44 _heap(ShenandoahHeap::heap()), 45 _map_size(_heap->num_regions()), 46 _set_map(NEW_C_HEAP_ARRAY(jbyte, _map_size, mtGC)), 47 // Bias set map's base address for fast test if an oop is in set 48 _biased_set_map(_set_map - ((uintx)_heap->base() >> ShenandoahHeapRegion::region_size_bytes_shift())), 49 _region_count(0) 50 { 51 // Use 1-byte data type 52 STATIC_ASSERT(sizeof(jbyte) == 1); 53 54 // Initialize cset map 55 Copy::zero_to_bytes(_set_map, _map_size); 56 } 57 58 ShenandoahHeapRegionSet::~ShenandoahHeapRegionSet() { 59 FREE_C_HEAP_ARRAY(jbyte, _set_map, mtGC); 60 } 61 62 void ShenandoahHeapRegionSet::add_region(ShenandoahHeapRegion* r) { 63 assert(!is_in(r), "Already in collection set"); 64 _set_map[r->region_number()] = 1; 65 _region_count++; 66 } 67 68 bool ShenandoahHeapRegionSet::add_region_check_for_duplicates(ShenandoahHeapRegion* r) { 69 if (!is_in(r)) { 70 add_region(r); 71 return true; 72 } else { 73 return false; 74 } 75 } 76 77 void ShenandoahHeapRegionSet::remove_region(ShenandoahHeapRegion* r) { 78 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint"); 79 assert(Thread::current()->is_VM_thread(), "Must be VMThread"); 80 assert(is_in(r), "Not in region set"); 81 _set_map[r->region_number()] = 0; 82 _region_count --; 83 } 84 85 void ShenandoahHeapRegionSet::clear() { 86 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint"); 87 Copy::zero_to_bytes(_set_map, _map_size); 88 89 _region_count = 0; 90 } 91 92 ShenandoahHeapRegion* ShenandoahHeapRegionSetIterator::claim_next() { 93 size_t num_regions = _heap->num_regions(); 94 if (_current_index >= (jint)num_regions) { 95 return NULL; 96 } 97 98 jint saved_current = _current_index; 99 size_t index = (size_t)saved_current; 100 101 while(index < num_regions) { 102 if (_set->is_in(index)) { 103 jint cur = Atomic::cmpxchg((jint)(index + 1), &_current_index, saved_current); 104 assert(cur >= (jint)saved_current, "Must move forward"); 105 if (cur == saved_current) { 106 assert(_set->is_in(index), "Invariant"); 107 return _heap->get_region(index); 108 } else { 109 index = (size_t)cur; 110 saved_current = cur; 111 } 112 } else { 113 index ++; 114 } 115 } 116 return NULL; 117 } 118 119 ShenandoahHeapRegion* ShenandoahHeapRegionSetIterator::next() { 120 size_t num_regions = _heap->num_regions(); 121 for (size_t index = (size_t)_current_index; index < num_regions; index ++) { 122 if (_set->is_in(index)) { 123 _current_index = (jint)(index + 1); 124 return _heap->get_region(index); 125 } 126 } 127 128 return NULL; 129 } 130 131 void ShenandoahHeapRegionSet::print_on(outputStream* out) const { 132 out->print_cr("Region Set : " SIZE_FORMAT "", count()); 133 134 debug_only(size_t regions = 0;) 135 for (size_t index = 0; index < _heap->num_regions(); index ++) { 136 if (is_in(index)) { 137 _heap->get_region(index)->print_on(out); 138 debug_only(regions ++;) 139 } 140 } 141 assert(regions == count(), "Must match"); 142 }