1 /* 2 * Copyright (c) 2005, 2015, Oracle and/or its affiliates. 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 #include "precompiled.hpp" 26 #include "gc/parallel/parMarkBitMap.hpp" 27 #include "gc/parallel/psParallelCompact.hpp" 28 #include "oops/oop.inline.hpp" 29 #include "runtime/atomic.inline.hpp" 30 #include "runtime/os.hpp" 31 #include "services/memTracker.hpp" 32 #include "utilities/bitMap.inline.hpp" 33 34 bool 35 ParMarkBitMap::initialize(MemRegion covered_region) 36 { 37 const idx_t bits = bits_required(covered_region); 38 // The bits will be divided evenly between two bitmaps; each of them should be 39 // an integral number of words. 40 assert(bits % (BitsPerWord * 2) == 0, "region size unaligned"); 41 42 const size_t words = bits / BitsPerWord; 43 const size_t raw_bytes = words * sizeof(idx_t); 44 const size_t page_sz = os::page_size_for_region_aligned(raw_bytes, 10); 45 const size_t granularity = os::vm_allocation_granularity(); 46 _reserved_byte_size = align_size_up(raw_bytes, MAX2(page_sz, granularity)); 47 48 const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 : 49 MAX2(page_sz, granularity); 50 ReservedSpace rs(_reserved_byte_size, rs_align, rs_align > 0); 51 os::trace_page_sizes("par bitmap", raw_bytes, raw_bytes, page_sz, 52 rs.base(), rs.size()); 53 54 MemTracker::record_virtual_memory_type((address)rs.base(), mtGC); 55 56 _virtual_space = new PSVirtualSpace(rs, page_sz); 57 if (_virtual_space != NULL && _virtual_space->expand_by(_reserved_byte_size)) { 58 _region_start = covered_region.start(); 59 _region_size = covered_region.word_size(); 60 BitMap::bm_word_t* map = (BitMap::bm_word_t*)_virtual_space->reserved_low_addr(); 61 _beg_bits.set_map(map); 62 _beg_bits.set_size(bits / 2); 63 _end_bits.set_map(map + words / 2); 64 _end_bits.set_size(bits / 2); 65 return true; 66 } 67 68 _region_start = 0; 69 _region_size = 0; 70 if (_virtual_space != NULL) { 71 delete _virtual_space; 72 _virtual_space = NULL; 73 // Release memory reserved in the space. 74 rs.release(); 75 } 76 return false; 77 } 78 79 #ifdef ASSERT 80 extern size_t mark_bitmap_count; 81 extern size_t mark_bitmap_size; 82 #endif // #ifdef ASSERT 83 84 bool 85 ParMarkBitMap::mark_obj(HeapWord* addr, size_t size) 86 { 87 const idx_t beg_bit = addr_to_bit(addr); 88 if (_beg_bits.par_set_bit(beg_bit)) { 89 const idx_t end_bit = addr_to_bit(addr + size - 1); 90 bool end_bit_ok = _end_bits.par_set_bit(end_bit); 91 assert(end_bit_ok, "concurrency problem"); 92 DEBUG_ONLY(Atomic::inc_ptr(&mark_bitmap_count)); 93 DEBUG_ONLY(Atomic::add_ptr(size, &mark_bitmap_size)); 94 return true; 95 } 96 return false; 97 } 98 99 size_t ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, oop end_obj) const 100 { 101 assert(beg_addr <= (HeapWord*)end_obj, "bad range"); 102 assert(is_marked(end_obj), "end_obj must be live"); 103 104 idx_t live_bits = 0; 105 106 // The bitmap routines require the right boundary to be word-aligned. 107 const idx_t end_bit = addr_to_bit((HeapWord*)end_obj); 108 const idx_t range_end = BitMap::word_align_up(end_bit); 109 110 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end); 111 while (beg_bit < end_bit) { 112 idx_t tmp_end = find_obj_end(beg_bit, range_end); 113 assert(tmp_end < end_bit, "missing end bit"); 114 live_bits += tmp_end - beg_bit + 1; 115 beg_bit = find_obj_beg(tmp_end + 1, range_end); 116 } 117 return bits_to_words(live_bits); 118 } 119 120 ParMarkBitMap::IterationStatus 121 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure, 122 idx_t range_beg, idx_t range_end) const 123 { 124 DEBUG_ONLY(verify_bit(range_beg);) 125 DEBUG_ONLY(verify_bit(range_end);) 126 assert(range_beg <= range_end, "live range invalid"); 127 128 // The bitmap routines require the right boundary to be word-aligned. 129 const idx_t search_end = BitMap::word_align_up(range_end); 130 131 idx_t cur_beg = find_obj_beg(range_beg, search_end); 132 while (cur_beg < range_end) { 133 const idx_t cur_end = find_obj_end(cur_beg, search_end); 134 if (cur_end >= range_end) { 135 // The obj ends outside the range. 136 live_closure->set_source(bit_to_addr(cur_beg)); 137 return incomplete; 138 } 139 140 const size_t size = obj_size(cur_beg, cur_end); 141 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size); 142 if (status != incomplete) { 143 assert(status == would_overflow || status == full, "sanity"); 144 return status; 145 } 146 147 // Successfully processed the object; look for the next object. 148 cur_beg = find_obj_beg(cur_end + 1, search_end); 149 } 150 151 live_closure->set_source(bit_to_addr(range_end)); 152 return complete; 153 } 154 155 ParMarkBitMap::IterationStatus 156 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure, 157 ParMarkBitMapClosure* dead_closure, 158 idx_t range_beg, idx_t range_end, 159 idx_t dead_range_end) const 160 { 161 DEBUG_ONLY(verify_bit(range_beg);) 162 DEBUG_ONLY(verify_bit(range_end);) 163 DEBUG_ONLY(verify_bit(dead_range_end);) 164 assert(range_beg <= range_end, "live range invalid"); 165 assert(range_end <= dead_range_end, "dead range invalid"); 166 167 // The bitmap routines require the right boundary to be word-aligned. 168 const idx_t live_search_end = BitMap::word_align_up(range_end); 169 const idx_t dead_search_end = BitMap::word_align_up(dead_range_end); 170 171 idx_t cur_beg = range_beg; 172 if (range_beg < range_end && is_unmarked(range_beg)) { 173 // The range starts with dead space. Look for the next object, then fill. 174 cur_beg = find_obj_beg(range_beg + 1, dead_search_end); 175 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1); 176 const size_t size = obj_size(range_beg, dead_space_end); 177 dead_closure->do_addr(bit_to_addr(range_beg), size); 178 } 179 180 while (cur_beg < range_end) { 181 const idx_t cur_end = find_obj_end(cur_beg, live_search_end); 182 if (cur_end >= range_end) { 183 // The obj ends outside the range. 184 live_closure->set_source(bit_to_addr(cur_beg)); 185 return incomplete; 186 } 187 188 const size_t size = obj_size(cur_beg, cur_end); 189 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size); 190 if (status != incomplete) { 191 assert(status == would_overflow || status == full, "sanity"); 192 return status; 193 } 194 195 // Look for the start of the next object. 196 const idx_t dead_space_beg = cur_end + 1; 197 cur_beg = find_obj_beg(dead_space_beg, dead_search_end); 198 if (cur_beg > dead_space_beg) { 199 // Found dead space; compute the size and invoke the dead closure. 200 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1); 201 const size_t size = obj_size(dead_space_beg, dead_space_end); 202 dead_closure->do_addr(bit_to_addr(dead_space_beg), size); 203 } 204 } 205 206 live_closure->set_source(bit_to_addr(range_end)); 207 return complete; 208 } 209 210 #ifdef ASSERT 211 void ParMarkBitMap::verify_clear() const 212 { 213 const idx_t* const beg = (const idx_t*)_virtual_space->committed_low_addr(); 214 const idx_t* const end = (const idx_t*)_virtual_space->committed_high_addr(); 215 for (const idx_t* p = beg; p < end; ++p) { 216 assert(*p == 0, "bitmap not clear"); 217 } 218 } 219 #endif // #ifdef ASSERT