1 /* 2 * Copyright (c) 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/shared/markBitMap.inline.hpp" 26 #include "gc/shenandoah/shenandoahHeap.hpp" 27 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp" 28 #include "gc/shenandoah/shenandoahMarkingContext.hpp" 29 30 ShenandoahMarkingContext::ShenandoahMarkingContext(MemRegion heap_region, MemRegion bitmap_region, size_t num_regions) : 31 _top_bitmaps(NEW_C_HEAP_ARRAY(HeapWord*, num_regions, mtGC)), 32 _top_at_mark_starts_base(NEW_C_HEAP_ARRAY(HeapWord*, num_regions, mtGC)), 33 _top_at_mark_starts(_top_at_mark_starts_base - 34 ((uintx) heap_region.start() >> ShenandoahHeapRegion::region_size_bytes_shift())) { 35 _mark_bit_map.initialize(heap_region, bitmap_region); 36 } 37 38 bool ShenandoahMarkingContext::is_bitmap_clear() const { 39 ShenandoahHeap* heap = ShenandoahHeap::heap(); 40 size_t num_regions = heap->num_regions(); 41 for (size_t idx = 0; idx < num_regions; idx++) { 42 ShenandoahHeapRegion* r = heap->get_region(idx); 43 if (heap->is_bitmap_slice_committed(r) && !is_bitmap_clear_range(r->bottom(), r->end())) { 44 return false; 45 } 46 } 47 return true; 48 } 49 50 bool ShenandoahMarkingContext::is_bitmap_clear_range(HeapWord* start, HeapWord* end) const { 51 return _mark_bit_map.get_next_marked_addr(start, end) == end; 52 } 53 54 void ShenandoahMarkingContext::initialize_top_at_mark_start(ShenandoahHeapRegion* r) { 55 size_t idx = r->region_number(); 56 HeapWord *bottom = r->bottom(); 57 _top_at_mark_starts_base[idx] = bottom; 58 _top_bitmaps[idx] = bottom; 59 } 60 61 void ShenandoahMarkingContext::capture_top_at_mark_start(ShenandoahHeapRegion *r) { 62 size_t region_number = r->region_number(); 63 HeapWord* old_tams = _top_at_mark_starts_base[region_number]; 64 HeapWord* new_tams = r->top(); 65 66 assert(new_tams >= old_tams, 67 "Region " SIZE_FORMAT", TAMS updates should be monotonic: " PTR_FORMAT " -> " PTR_FORMAT, 68 region_number, p2i(old_tams), p2i(new_tams)); 69 assert(is_bitmap_clear_range(old_tams, new_tams), 70 "Region " SIZE_FORMAT ", bitmap should be clear while adjusting TAMS: " PTR_FORMAT " -> " PTR_FORMAT, 71 region_number, p2i(old_tams), p2i(new_tams)); 72 73 _top_at_mark_starts_base[region_number] = new_tams; 74 _top_bitmaps[region_number] = new_tams; 75 } 76 77 void ShenandoahMarkingContext::reset_top_at_mark_start(ShenandoahHeapRegion* r) { 78 _top_at_mark_starts_base[r->region_number()] = r->bottom(); 79 } 80 81 HeapWord* ShenandoahMarkingContext::top_at_mark_start(ShenandoahHeapRegion* r) const { 82 return _top_at_mark_starts_base[r->region_number()]; 83 } 84 85 void ShenandoahMarkingContext::reset_top_bitmap(ShenandoahHeapRegion* r) { 86 assert(is_bitmap_clear_range(r->bottom(), r->end()), 87 "Region " SIZE_FORMAT " should have no marks in bitmap", r->region_number()); 88 _top_bitmaps[r->region_number()] = r->bottom(); 89 } 90 91 void ShenandoahMarkingContext::clear_bitmap(ShenandoahHeapRegion* r) { 92 HeapWord* bottom = r->bottom(); 93 HeapWord* top_bitmap = _top_bitmaps[r->region_number()]; 94 if (top_bitmap > bottom) { 95 _mark_bit_map.clear_range_large(MemRegion(bottom, top_bitmap)); 96 _top_bitmaps[r->region_number()] = bottom; 97 } 98 assert(is_bitmap_clear_range(bottom, r->end()), 99 "Region " SIZE_FORMAT " should have no marks in bitmap", r->region_number()); 100 } 101 102 bool ShenandoahMarkingContext::is_complete() { 103 return _is_complete.is_set(); 104 } 105 106 void ShenandoahMarkingContext::mark_complete() { 107 _is_complete.set(); 108 } 109 110 void ShenandoahMarkingContext::mark_incomplete() { 111 _is_complete.unset(); 112 }