1 /* 2 * Copyright (c) 2005, 2016, 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/bitMap.inline.hpp" 34 35 bool 36 ParMarkBitMap::initialize(MemRegion covered_region) 37 { 38 const idx_t bits = bits_required(covered_region); 39 // The bits will be divided evenly between two bitmaps; each of them should be 40 // an integral number of words. 41 assert(bits % (BitsPerWord * 2) == 0, "region size unaligned"); 42 43 const size_t words = bits / BitsPerWord; 44 const size_t raw_bytes = words * sizeof(idx_t); 45 const size_t page_sz = os::page_size_for_region_aligned(raw_bytes, 10); 46 const size_t granularity = os::vm_allocation_granularity(); 47 _reserved_byte_size = align_up(raw_bytes, MAX2(page_sz, granularity)); 48 49 const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 : 50 MAX2(page_sz, granularity); 51 ReservedSpace rs(_reserved_byte_size, rs_align, rs_align > 0); 52 os::trace_page_sizes("Mark Bitmap", raw_bytes, raw_bytes, page_sz, 53 rs.base(), rs.size()); 54 55 MemTracker::record_virtual_memory_type((address)rs.base(), mtGC); 56 57 _virtual_space = new PSVirtualSpace(rs, page_sz); 58 if (_virtual_space != NULL && _virtual_space->expand_by(_reserved_byte_size)) { 59 _region_start = covered_region.start(); 60 _region_size = covered_region.word_size(); 61 BitMap::bm_word_t* map = (BitMap::bm_word_t*)_virtual_space->reserved_low_addr(); 62 _beg_bits = BitMapView(map, bits / 2); 63 _end_bits = BitMapView(map + words / 2, bits / 2); 64 return true; 65 } 66 67 _region_start = 0; 68 _region_size = 0; 69 if (_virtual_space != NULL) { 70 delete _virtual_space; 71 _virtual_space = NULL; 72 // Release memory reserved in the space. 73 rs.release(); 74 } 75 return false; 76 } 77 78 #ifdef ASSERT 79 extern size_t mark_bitmap_count; 80 extern size_t mark_bitmap_size; 81 #endif // #ifdef ASSERT 82 83 bool 84 ParMarkBitMap::mark_obj(HeapWord* addr, size_t size) 85 { 86 const idx_t beg_bit = addr_to_bit(addr); 87 if (_beg_bits.par_set_bit(beg_bit)) { 88 const idx_t end_bit = addr_to_bit(addr + size - 1); 89 bool end_bit_ok = _end_bits.par_set_bit(end_bit); 90 assert(end_bit_ok, "concurrency problem"); 91 DEBUG_ONLY(Atomic::inc_ptr(&mark_bitmap_count)); 92 DEBUG_ONLY(Atomic::add_ptr(size, &mark_bitmap_size)); 93 return true; 94 } 95 return false; 96 } 97 98 inline bool 99 ParMarkBitMap::is_live_words_in_range_in_cache(ParCompactionManager* cm, HeapWord* beg_addr) const { 100 return cm->last_query_begin() == beg_addr; 101 } 102 103 inline void 104 ParMarkBitMap::update_live_words_in_range_cache(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj, size_t result) const { 105 cm->set_last_query_begin(beg_addr); 106 cm->set_last_query_object(end_obj); 107 cm->set_last_query_return(result); 108 } 109 110 size_t 111 ParMarkBitMap::live_words_in_range_helper(HeapWord* beg_addr, oop end_obj) const 112 { 113 assert(beg_addr <= (HeapWord*)end_obj, "bad range"); 114 assert(is_marked(end_obj), "end_obj must be live"); 115 116 idx_t live_bits = 0; 117 118 // The bitmap routines require the right boundary to be word-aligned. 119 const idx_t end_bit = addr_to_bit((HeapWord*)end_obj); 120 const idx_t range_end = BitMap::word_align_up(end_bit); 121 122 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end); 123 while (beg_bit < end_bit) { 124 idx_t tmp_end = find_obj_end(beg_bit, range_end); 125 assert(tmp_end < end_bit, "missing end bit"); 126 live_bits += tmp_end - beg_bit + 1; 127 beg_bit = find_obj_beg(tmp_end + 1, range_end); 128 } 129 return bits_to_words(live_bits); 130 } 131 132 size_t 133 ParMarkBitMap::live_words_in_range_use_cache(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj) const 134 { 135 HeapWord* last_beg = cm->last_query_begin(); 136 oop last_obj = cm->last_query_object(); 137 size_t last_ret = cm->last_query_return(); 138 if (end_obj > last_obj) { 139 last_ret = last_ret + live_words_in_range_helper((HeapWord*)last_obj, end_obj); 140 last_obj = end_obj; 141 } else if (end_obj < last_obj) { 142 // The cached value is for an object that is to the left (lower address) of the current 143 // end_obj. Calculate back from that cached value. 144 if (pointer_delta((HeapWord*)end_obj, (HeapWord*)beg_addr) > pointer_delta((HeapWord*)last_obj, (HeapWord*)end_obj)) { 145 last_ret = last_ret - live_words_in_range_helper((HeapWord*)end_obj, last_obj); 146 } else { 147 last_ret = live_words_in_range_helper(beg_addr, end_obj); 148 } 149 last_obj = end_obj; 150 } 151 152 update_live_words_in_range_cache(cm, last_beg, last_obj, last_ret); 153 return last_ret; 154 } 155 156 size_t 157 ParMarkBitMap::live_words_in_range(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj) const 158 { 159 // Try to reuse result from ParCompactionManager cache first. 160 if (is_live_words_in_range_in_cache(cm, beg_addr)) { 161 return live_words_in_range_use_cache(cm, beg_addr, end_obj); 162 } 163 size_t ret = live_words_in_range_helper(beg_addr, end_obj); 164 update_live_words_in_range_cache(cm, beg_addr, end_obj, ret); 165 return ret; 166 } 167 168 ParMarkBitMap::IterationStatus 169 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure, 170 idx_t range_beg, idx_t range_end) const 171 { 172 DEBUG_ONLY(verify_bit(range_beg);) 173 DEBUG_ONLY(verify_bit(range_end);) 174 assert(range_beg <= range_end, "live range invalid"); 175 176 // The bitmap routines require the right boundary to be word-aligned. 177 const idx_t search_end = BitMap::word_align_up(range_end); 178 179 idx_t cur_beg = find_obj_beg(range_beg, search_end); 180 while (cur_beg < range_end) { 181 const idx_t cur_end = find_obj_end(cur_beg, 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 // Successfully processed the object; look for the next object. 196 cur_beg = find_obj_beg(cur_end + 1, search_end); 197 } 198 199 live_closure->set_source(bit_to_addr(range_end)); 200 return complete; 201 } 202 203 ParMarkBitMap::IterationStatus 204 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure, 205 ParMarkBitMapClosure* dead_closure, 206 idx_t range_beg, idx_t range_end, 207 idx_t dead_range_end) const 208 { 209 DEBUG_ONLY(verify_bit(range_beg);) 210 DEBUG_ONLY(verify_bit(range_end);) 211 DEBUG_ONLY(verify_bit(dead_range_end);) 212 assert(range_beg <= range_end, "live range invalid"); 213 assert(range_end <= dead_range_end, "dead range invalid"); 214 215 // The bitmap routines require the right boundary to be word-aligned. 216 const idx_t live_search_end = BitMap::word_align_up(range_end); 217 const idx_t dead_search_end = BitMap::word_align_up(dead_range_end); 218 219 idx_t cur_beg = range_beg; 220 if (range_beg < range_end && is_unmarked(range_beg)) { 221 // The range starts with dead space. Look for the next object, then fill. 222 cur_beg = find_obj_beg(range_beg + 1, dead_search_end); 223 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1); 224 const size_t size = obj_size(range_beg, dead_space_end); 225 dead_closure->do_addr(bit_to_addr(range_beg), size); 226 } 227 228 while (cur_beg < range_end) { 229 const idx_t cur_end = find_obj_end(cur_beg, live_search_end); 230 if (cur_end >= range_end) { 231 // The obj ends outside the range. 232 live_closure->set_source(bit_to_addr(cur_beg)); 233 return incomplete; 234 } 235 236 const size_t size = obj_size(cur_beg, cur_end); 237 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size); 238 if (status != incomplete) { 239 assert(status == would_overflow || status == full, "sanity"); 240 return status; 241 } 242 243 // Look for the start of the next object. 244 const idx_t dead_space_beg = cur_end + 1; 245 cur_beg = find_obj_beg(dead_space_beg, dead_search_end); 246 if (cur_beg > dead_space_beg) { 247 // Found dead space; compute the size and invoke the dead closure. 248 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1); 249 const size_t size = obj_size(dead_space_beg, dead_space_end); 250 dead_closure->do_addr(bit_to_addr(dead_space_beg), size); 251 } 252 } 253 254 live_closure->set_source(bit_to_addr(range_end)); 255 return complete; 256 } 257 258 #ifdef ASSERT 259 void ParMarkBitMap::verify_clear() const 260 { 261 const idx_t* const beg = (const idx_t*)_virtual_space->committed_low_addr(); 262 const idx_t* const end = (const idx_t*)_virtual_space->committed_high_addr(); 263 for (const idx_t* p = beg; p < end; ++p) { 264 assert(*p == 0, "bitmap not clear"); 265 } 266 } 267 #endif // #ifdef ASSERT