1 /* 2 * Copyright (c) 2005, 2017, 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.inline.hpp" 27 #include "gc/parallel/psCompactionManager.inline.hpp" 28 #include "gc/parallel/psParallelCompact.inline.hpp" 29 #include "oops/oop.inline.hpp" 30 #include "runtime/atomic.hpp" 31 #include "runtime/os.hpp" 32 #include "services/memTracker.hpp" 33 #include "utilities/align.hpp" 34 #include "utilities/bitMap.inline.hpp" 35 36 bool 37 ParMarkBitMap::initialize(MemRegion covered_region) 38 { 39 const idx_t bits = bits_required(covered_region); 40 // The bits will be divided evenly between two bitmaps; each of them should be 41 // an integral number of words. 42 assert(bits % (BitsPerWord * 2) == 0, "region size unaligned"); 43 44 const size_t words = bits / BitsPerWord; 45 const size_t raw_bytes = words * sizeof(idx_t); 46 const size_t page_sz = os::page_size_for_region_aligned(raw_bytes, 10); 47 const size_t granularity = os::vm_allocation_granularity(); 48 _reserved_byte_size = align_up(raw_bytes, MAX2(page_sz, granularity)); 49 50 const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 : 51 MAX2(page_sz, granularity); 52 ReservedSpace rs(_reserved_byte_size, rs_align, rs_align > 0); 53 os::trace_page_sizes("Mark Bitmap", raw_bytes, raw_bytes, page_sz, 54 rs.base(), rs.size()); 55 56 MemTracker::record_virtual_memory_type((address)rs.base(), mtGC); 57 58 _virtual_space = new PSVirtualSpace(rs, page_sz); 59 if (_virtual_space != NULL && _virtual_space->expand_by(_reserved_byte_size)) { 60 _region_start = covered_region.start(); 61 _region_size = covered_region.word_size(); 62 BitMap::bm_word_t* map = (BitMap::bm_word_t*)_virtual_space->reserved_low_addr(); 63 _beg_bits = BitMapView(map, bits / 2); 64 _end_bits = BitMapView(map + words / 2, 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(&mark_bitmap_count)); 93 DEBUG_ONLY(Atomic::add_ptr(size, &mark_bitmap_size)); 94 return true; 95 } 96 return false; 97 } 98 99 inline bool 100 ParMarkBitMap::is_live_words_in_range_in_cache(ParCompactionManager* cm, HeapWord* beg_addr) const { 101 return cm->last_query_begin() == beg_addr; 102 } 103 104 inline void 105 ParMarkBitMap::update_live_words_in_range_cache(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj, size_t result) const { 106 cm->set_last_query_begin(beg_addr); 107 cm->set_last_query_object(end_obj); 108 cm->set_last_query_return(result); 109 } 110 111 size_t 112 ParMarkBitMap::live_words_in_range_helper(HeapWord* beg_addr, oop end_obj) const 113 { 114 assert(beg_addr <= (HeapWord*)end_obj, "bad range"); 115 assert(is_marked(end_obj), "end_obj must be live"); 116 117 idx_t live_bits = 0; 118 119 // The bitmap routines require the right boundary to be word-aligned. 120 const idx_t end_bit = addr_to_bit((HeapWord*)end_obj); 121 const idx_t range_end = BitMap::word_align_up(end_bit); 122 123 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end); 124 while (beg_bit < end_bit) { 125 idx_t tmp_end = find_obj_end(beg_bit, range_end); 126 assert(tmp_end < end_bit, "missing end bit"); 127 live_bits += tmp_end - beg_bit + 1; 128 beg_bit = find_obj_beg(tmp_end + 1, range_end); 129 } 130 return bits_to_words(live_bits); 131 } 132 133 size_t 134 ParMarkBitMap::live_words_in_range_use_cache(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj) const 135 { 136 HeapWord* last_beg = cm->last_query_begin(); 137 oop last_obj = cm->last_query_object(); 138 size_t last_ret = cm->last_query_return(); 139 if (end_obj > last_obj) { 140 last_ret = last_ret + live_words_in_range_helper((HeapWord*)last_obj, end_obj); 141 last_obj = end_obj; 142 } else if (end_obj < last_obj) { 143 // The cached value is for an object that is to the left (lower address) of the current 144 // end_obj. Calculate back from that cached value. 145 if (pointer_delta((HeapWord*)end_obj, (HeapWord*)beg_addr) > pointer_delta((HeapWord*)last_obj, (HeapWord*)end_obj)) { 146 last_ret = last_ret - live_words_in_range_helper((HeapWord*)end_obj, last_obj); 147 } else { 148 last_ret = live_words_in_range_helper(beg_addr, end_obj); 149 } 150 last_obj = end_obj; 151 } 152 153 update_live_words_in_range_cache(cm, last_beg, last_obj, last_ret); 154 return last_ret; 155 } 156 157 size_t 158 ParMarkBitMap::live_words_in_range(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj) const 159 { 160 // Try to reuse result from ParCompactionManager cache first. 161 if (is_live_words_in_range_in_cache(cm, beg_addr)) { 162 return live_words_in_range_use_cache(cm, beg_addr, end_obj); 163 } 164 size_t ret = live_words_in_range_helper(beg_addr, end_obj); 165 update_live_words_in_range_cache(cm, beg_addr, end_obj, ret); 166 return ret; 167 } 168 169 ParMarkBitMap::IterationStatus 170 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure, 171 idx_t range_beg, idx_t range_end) const 172 { 173 DEBUG_ONLY(verify_bit(range_beg);) 174 DEBUG_ONLY(verify_bit(range_end);) 175 assert(range_beg <= range_end, "live range invalid"); 176 177 // The bitmap routines require the right boundary to be word-aligned. 178 const idx_t search_end = BitMap::word_align_up(range_end); 179 180 idx_t cur_beg = find_obj_beg(range_beg, search_end); 181 while (cur_beg < range_end) { 182 const idx_t cur_end = find_obj_end(cur_beg, search_end); 183 if (cur_end >= range_end) { 184 // The obj ends outside the range. 185 live_closure->set_source(bit_to_addr(cur_beg)); 186 return incomplete; 187 } 188 189 const size_t size = obj_size(cur_beg, cur_end); 190 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size); 191 if (status != incomplete) { 192 assert(status == would_overflow || status == full, "sanity"); 193 return status; 194 } 195 196 // Successfully processed the object; look for the next object. 197 cur_beg = find_obj_beg(cur_end + 1, search_end); 198 } 199 200 live_closure->set_source(bit_to_addr(range_end)); 201 return complete; 202 } 203 204 ParMarkBitMap::IterationStatus 205 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure, 206 ParMarkBitMapClosure* dead_closure, 207 idx_t range_beg, idx_t range_end, 208 idx_t dead_range_end) const 209 { 210 DEBUG_ONLY(verify_bit(range_beg);) 211 DEBUG_ONLY(verify_bit(range_end);) 212 DEBUG_ONLY(verify_bit(dead_range_end);) 213 assert(range_beg <= range_end, "live range invalid"); 214 assert(range_end <= dead_range_end, "dead range invalid"); 215 216 // The bitmap routines require the right boundary to be word-aligned. 217 const idx_t live_search_end = BitMap::word_align_up(range_end); 218 const idx_t dead_search_end = BitMap::word_align_up(dead_range_end); 219 220 idx_t cur_beg = range_beg; 221 if (range_beg < range_end && is_unmarked(range_beg)) { 222 // The range starts with dead space. Look for the next object, then fill. 223 cur_beg = find_obj_beg(range_beg + 1, dead_search_end); 224 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1); 225 const size_t size = obj_size(range_beg, dead_space_end); 226 dead_closure->do_addr(bit_to_addr(range_beg), size); 227 } 228 229 while (cur_beg < range_end) { 230 const idx_t cur_end = find_obj_end(cur_beg, live_search_end); 231 if (cur_end >= range_end) { 232 // The obj ends outside the range. 233 live_closure->set_source(bit_to_addr(cur_beg)); 234 return incomplete; 235 } 236 237 const size_t size = obj_size(cur_beg, cur_end); 238 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size); 239 if (status != incomplete) { 240 assert(status == would_overflow || status == full, "sanity"); 241 return status; 242 } 243 244 // Look for the start of the next object. 245 const idx_t dead_space_beg = cur_end + 1; 246 cur_beg = find_obj_beg(dead_space_beg, dead_search_end); 247 if (cur_beg > dead_space_beg) { 248 // Found dead space; compute the size and invoke the dead closure. 249 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1); 250 const size_t size = obj_size(dead_space_beg, dead_space_end); 251 dead_closure->do_addr(bit_to_addr(dead_space_beg), size); 252 } 253 } 254 255 live_closure->set_source(bit_to_addr(range_end)); 256 return complete; 257 } 258 259 #ifdef ASSERT 260 void ParMarkBitMap::verify_clear() const 261 { 262 const idx_t* const beg = (const idx_t*)_virtual_space->committed_low_addr(); 263 const idx_t* const end = (const idx_t*)_virtual_space->committed_high_addr(); 264 for (const idx_t* p = beg; p < end; ++p) { 265 assert(*p == 0, "bitmap not clear"); 266 } 267 } 268 #endif // #ifdef ASSERT