1 /* 2 * Copyright (c) 2001, 2014, 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_implementation/g1/heapRegion.hpp" 27 #include "gc_implementation/g1/heapRegionManager.inline.hpp" 28 #include "gc_implementation/g1/heapRegionSet.inline.hpp" 29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" 30 #include "gc_implementation/g1/concurrentG1Refine.hpp" 31 #include "memory/allocation.hpp" 32 33 void HeapRegionManager::initialize(G1RegionToSpaceMapper* heap_storage, 34 G1RegionToSpaceMapper* prev_bitmap, 35 G1RegionToSpaceMapper* next_bitmap, 36 G1RegionToSpaceMapper* bot, 37 G1RegionToSpaceMapper* cardtable, 38 G1RegionToSpaceMapper* card_counts) { 39 _allocated_heapregions_length = 0; 40 41 _heap_mapper = heap_storage; 42 43 _prev_bitmap_mapper = prev_bitmap; 44 _next_bitmap_mapper = next_bitmap; 45 46 _bot_mapper = bot; 47 _cardtable_mapper = cardtable; 48 49 _card_counts_mapper = card_counts; 50 51 MemRegion reserved = heap_storage->reserved(); 52 _regions.initialize(reserved.start(), reserved.end(), HeapRegion::GrainBytes); 53 54 _available_map.resize(_regions.length(), false); 55 _available_map.clear(); 56 } 57 58 bool HeapRegionManager::is_available(uint region) const { 59 return _available_map.at(region); 60 } 61 62 #ifdef ASSERT 63 bool HeapRegionManager::is_free(HeapRegion* hr) const { 64 return _free_list.contains(hr); 65 } 66 #endif 67 68 HeapRegion* HeapRegionManager::new_heap_region(uint hrm_index) { 69 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 70 HeapWord* bottom = g1h->bottom_addr_for_region(hrm_index); 71 MemRegion mr(bottom, bottom + HeapRegion::GrainWords); 72 assert(reserved().contains(mr), "invariant"); 73 return g1h->allocator()->new_heap_region(hrm_index, g1h->bot_shared(), mr); 74 } 75 76 void HeapRegionManager::commit_regions(uint index, size_t num_regions) { 77 guarantee(num_regions > 0, "Must commit more than zero regions"); 78 guarantee(_num_committed + num_regions <= max_length(), "Cannot commit more than the maximum amount of regions"); 79 80 _num_committed += (uint)num_regions; 81 82 _heap_mapper->commit_regions(index, num_regions); 83 84 // Also commit auxiliary data 85 _prev_bitmap_mapper->commit_regions(index, num_regions); 86 _next_bitmap_mapper->commit_regions(index, num_regions); 87 88 _bot_mapper->commit_regions(index, num_regions); 89 _cardtable_mapper->commit_regions(index, num_regions); 90 91 _card_counts_mapper->commit_regions(index, num_regions); 92 } 93 94 void HeapRegionManager::uncommit_regions(uint start, size_t num_regions) { 95 guarantee(num_regions >= 1, err_msg("Need to specify at least one region to uncommit, tried to uncommit zero regions at %u", start)); 96 guarantee(_num_committed >= num_regions, "pre-condition"); 97 98 // Print before uncommitting. 99 if (G1CollectedHeap::heap()->hr_printer()->is_active()) { 100 for (uint i = start; i < start + num_regions; i++) { 101 HeapRegion* hr = at(i); 102 G1CollectedHeap::heap()->hr_printer()->uncommit(hr->bottom(), hr->end()); 103 } 104 } 105 106 _num_committed -= (uint)num_regions; 107 108 _available_map.par_clear_range(start, start + num_regions, BitMap::unknown_range); 109 _heap_mapper->uncommit_regions(start, num_regions); 110 111 // Also uncommit auxiliary data 112 _prev_bitmap_mapper->uncommit_regions(start, num_regions); 113 _next_bitmap_mapper->uncommit_regions(start, num_regions); 114 115 _bot_mapper->uncommit_regions(start, num_regions); 116 _cardtable_mapper->uncommit_regions(start, num_regions); 117 118 _card_counts_mapper->uncommit_regions(start, num_regions); 119 } 120 121 void HeapRegionManager::make_regions_available(uint start, uint num_regions) { 122 guarantee(num_regions > 0, "No point in calling this for zero regions"); 123 commit_regions(start, num_regions); 124 for (uint i = start; i < start + num_regions; i++) { 125 if (_regions.get_by_index(i) == NULL) { 126 HeapRegion* new_hr = new_heap_region(i); 127 _regions.set_by_index(i, new_hr); 128 _allocated_heapregions_length = MAX2(_allocated_heapregions_length, i + 1); 129 } 130 } 131 132 _available_map.par_set_range(start, start + num_regions, BitMap::unknown_range); 133 134 for (uint i = start; i < start + num_regions; i++) { 135 assert(is_available(i), err_msg("Just made region %u available but is apparently not.", i)); 136 HeapRegion* hr = at(i); 137 if (G1CollectedHeap::heap()->hr_printer()->is_active()) { 138 G1CollectedHeap::heap()->hr_printer()->commit(hr->bottom(), hr->end()); 139 } 140 HeapWord* bottom = G1CollectedHeap::heap()->bottom_addr_for_region(i); 141 MemRegion mr(bottom, bottom + HeapRegion::GrainWords); 142 143 hr->initialize(mr); 144 insert_into_free_list(at(i)); 145 } 146 } 147 148 uint HeapRegionManager::expand_by(uint num_regions) { 149 return expand_at(0, num_regions); 150 } 151 152 uint HeapRegionManager::expand_at(uint start, uint num_regions) { 153 if (num_regions == 0) { 154 return 0; 155 } 156 157 uint cur = start; 158 uint idx_last_found = 0; 159 uint num_last_found = 0; 160 161 uint expanded = 0; 162 163 while (expanded < num_regions && 164 (num_last_found = find_unavailable_from_idx(cur, &idx_last_found)) > 0) { 165 uint to_expand = MIN2(num_regions - expanded, num_last_found); 166 make_regions_available(idx_last_found, to_expand); 167 expanded += to_expand; 168 cur = idx_last_found + num_last_found + 1; 169 } 170 171 verify_optional(); 172 return expanded; 173 } 174 175 uint HeapRegionManager::find_contiguous(size_t num, bool empty_only) { 176 uint found = 0; 177 size_t length_found = 0; 178 uint cur = 0; 179 180 while (length_found < num && cur < max_length()) { 181 HeapRegion* hr = _regions.get_by_index(cur); 182 if ((!empty_only && !is_available(cur)) || (is_available(cur) && hr != NULL && hr->is_empty())) { 183 // This region is a potential candidate for allocation into. 184 length_found++; 185 } else { 186 // This region is not a candidate. The next region is the next possible one. 187 found = cur + 1; 188 length_found = 0; 189 } 190 cur++; 191 } 192 193 if (length_found == num) { 194 for (uint i = found; i < (found + num); i++) { 195 HeapRegion* hr = _regions.get_by_index(i); 196 // sanity check 197 guarantee((!empty_only && !is_available(i)) || (is_available(i) && hr != NULL && hr->is_empty()), 198 err_msg("Found region sequence starting at " UINT32_FORMAT ", length " SIZE_FORMAT 199 " that is not empty at " UINT32_FORMAT ". Hr is " PTR_FORMAT, found, num, i, p2i(hr))); 200 } 201 return found; 202 } else { 203 return G1_NO_HRM_INDEX; 204 } 205 } 206 207 HeapRegion* HeapRegionManager::next_region_in_heap(const HeapRegion* r) const { 208 guarantee(r != NULL, "Start region must be a valid region"); 209 guarantee(is_available(r->hrm_index()), err_msg("Trying to iterate starting from region %u which is not in the heap", r->hrm_index())); 210 for (uint i = r->hrm_index() + 1; i < _allocated_heapregions_length; i++) { 211 HeapRegion* hr = _regions.get_by_index(i); 212 if (is_available(i)) { 213 return hr; 214 } 215 } 216 return NULL; 217 } 218 219 void HeapRegionManager::iterate(HeapRegionClosure* blk) const { 220 uint len = max_length(); 221 222 for (uint i = 0; i < len; i++) { 223 if (!is_available(i)) { 224 continue; 225 } 226 guarantee(at(i) != NULL, err_msg("Tried to access region %u that has a NULL HeapRegion*", i)); 227 bool res = blk->doHeapRegion(at(i)); 228 if (res) { 229 blk->incomplete(); 230 return; 231 } 232 } 233 } 234 235 uint HeapRegionManager::find_unavailable_from_idx(uint start_idx, uint* res_idx) const { 236 guarantee(res_idx != NULL, "checking"); 237 guarantee(start_idx <= (max_length() + 1), "checking"); 238 239 uint num_regions = 0; 240 241 uint cur = start_idx; 242 while (cur < max_length() && is_available(cur)) { 243 cur++; 244 } 245 if (cur == max_length()) { 246 return num_regions; 247 } 248 *res_idx = cur; 249 while (cur < max_length() && !is_available(cur)) { 250 cur++; 251 } 252 num_regions = cur - *res_idx; 253 #ifdef ASSERT 254 for (uint i = *res_idx; i < (*res_idx + num_regions); i++) { 255 assert(!is_available(i), "just checking"); 256 } 257 assert(cur == max_length() || num_regions == 0 || is_available(cur), 258 err_msg("The region at the current position %u must be available or at the end of the heap.", cur)); 259 #endif 260 return num_regions; 261 } 262 263 uint HeapRegionManager::start_region_for_worker(uint worker_i, uint num_workers, uint num_regions) const { 264 return num_regions * worker_i / num_workers; 265 } 266 267 void HeapRegionManager::par_iterate(HeapRegionClosure* blk, uint worker_id, uint num_workers, jint claim_value) const { 268 const uint start_index = start_region_for_worker(worker_id, num_workers, _allocated_heapregions_length); 269 270 // Every worker will actually look at all regions, skipping over regions that 271 // are currently not committed. 272 // This also (potentially) iterates over regions newly allocated during GC. This 273 // is no problem except for some extra work. 274 for (uint count = 0; count < _allocated_heapregions_length; count++) { 275 const uint index = (start_index + count) % _allocated_heapregions_length; 276 assert(0 <= index && index < _allocated_heapregions_length, "sanity"); 277 // Skip over unavailable regions 278 if (!is_available(index)) { 279 continue; 280 } 281 HeapRegion* r = _regions.get_by_index(index); 282 // We'll ignore "continues humongous" regions (we'll process them 283 // when we come across their corresponding "start humongous" 284 // region) and regions already claimed. 285 if (r->claim_value() == claim_value || r->is_continues_humongous()) { 286 continue; 287 } 288 // OK, try to claim it 289 if (!r->claimHeapRegion(claim_value)) { 290 continue; 291 } 292 // Success! 293 if (r->is_starts_humongous()) { 294 // If the region is "starts humongous" we'll iterate over its 295 // "continues humongous" first; in fact we'll do them 296 // first. The order is important. In one case, calling the 297 // closure on the "starts humongous" region might de-allocate 298 // and clear all its "continues humongous" regions and, as a 299 // result, we might end up processing them twice. So, we'll do 300 // them first (note: most closures will ignore them anyway) and 301 // then we'll do the "starts humongous" region. 302 for (uint ch_index = index + 1; ch_index < index + r->region_num(); ch_index++) { 303 HeapRegion* chr = _regions.get_by_index(ch_index); 304 305 assert(chr->is_continues_humongous(), "Must be humongous region"); 306 assert(chr->humongous_start_region() == r, 307 err_msg("Must work on humongous continuation of the original start region " 308 PTR_FORMAT ", but is " PTR_FORMAT, p2i(r), p2i(chr))); 309 assert(chr->claim_value() != claim_value, 310 "Must not have been claimed yet because claiming of humongous continuation first claims the start region"); 311 312 bool claim_result = chr->claimHeapRegion(claim_value); 313 // We should always be able to claim it; no one else should 314 // be trying to claim this region. 315 guarantee(claim_result, "We should always be able to claim the is_continues_humongous part of the humongous object"); 316 317 bool res2 = blk->doHeapRegion(chr); 318 if (res2) { 319 return; 320 } 321 322 // Right now, this holds (i.e., no closure that actually 323 // does something with "continues humongous" regions 324 // clears them). We might have to weaken it in the future, 325 // but let's leave these two asserts here for extra safety. 326 assert(chr->is_continues_humongous(), "should still be the case"); 327 assert(chr->humongous_start_region() == r, "sanity"); 328 } 329 } 330 331 bool res = blk->doHeapRegion(r); 332 if (res) { 333 return; 334 } 335 } 336 } 337 338 uint HeapRegionManager::shrink_by(uint num_regions_to_remove) { 339 assert(length() > 0, "the region sequence should not be empty"); 340 assert(length() <= _allocated_heapregions_length, "invariant"); 341 assert(_allocated_heapregions_length > 0, "we should have at least one region committed"); 342 assert(num_regions_to_remove < length(), "We should never remove all regions"); 343 344 if (num_regions_to_remove == 0) { 345 return 0; 346 } 347 348 uint removed = 0; 349 uint cur = _allocated_heapregions_length - 1; 350 uint idx_last_found = 0; 351 uint num_last_found = 0; 352 353 while ((removed < num_regions_to_remove) && 354 (num_last_found = find_empty_from_idx_reverse(cur, &idx_last_found)) > 0) { 355 uint to_remove = MIN2(num_regions_to_remove - removed, num_last_found); 356 357 uncommit_regions(idx_last_found + num_last_found - to_remove, to_remove); 358 359 cur -= num_last_found; 360 removed += to_remove; 361 } 362 363 verify_optional(); 364 365 return removed; 366 } 367 368 uint HeapRegionManager::find_empty_from_idx_reverse(uint start_idx, uint* res_idx) const { 369 guarantee(start_idx < _allocated_heapregions_length, "checking"); 370 guarantee(res_idx != NULL, "checking"); 371 372 uint num_regions_found = 0; 373 374 jlong cur = start_idx; 375 while (cur != -1 && !(is_available(cur) && at(cur)->is_empty())) { 376 cur--; 377 } 378 if (cur == -1) { 379 return num_regions_found; 380 } 381 jlong old_cur = cur; 382 // cur indexes the first empty region 383 while (cur != -1 && is_available(cur) && at(cur)->is_empty()) { 384 cur--; 385 } 386 *res_idx = cur + 1; 387 num_regions_found = old_cur - cur; 388 389 #ifdef ASSERT 390 for (uint i = *res_idx; i < (*res_idx + num_regions_found); i++) { 391 assert(at(i)->is_empty(), "just checking"); 392 } 393 #endif 394 return num_regions_found; 395 } 396 397 void HeapRegionManager::verify() { 398 guarantee(length() <= _allocated_heapregions_length, 399 err_msg("invariant: _length: %u _allocated_length: %u", 400 length(), _allocated_heapregions_length)); 401 guarantee(_allocated_heapregions_length <= max_length(), 402 err_msg("invariant: _allocated_length: %u _max_length: %u", 403 _allocated_heapregions_length, max_length())); 404 405 bool prev_committed = true; 406 uint num_committed = 0; 407 HeapWord* prev_end = heap_bottom(); 408 for (uint i = 0; i < _allocated_heapregions_length; i++) { 409 if (!is_available(i)) { 410 prev_committed = false; 411 continue; 412 } 413 num_committed++; 414 HeapRegion* hr = _regions.get_by_index(i); 415 guarantee(hr != NULL, err_msg("invariant: i: %u", i)); 416 guarantee(!prev_committed || hr->bottom() == prev_end, 417 err_msg("invariant i: %u "HR_FORMAT" prev_end: "PTR_FORMAT, 418 i, HR_FORMAT_PARAMS(hr), p2i(prev_end))); 419 guarantee(hr->hrm_index() == i, 420 err_msg("invariant: i: %u hrm_index(): %u", i, hr->hrm_index())); 421 // Asserts will fire if i is >= _length 422 HeapWord* addr = hr->bottom(); 423 guarantee(addr_to_region(addr) == hr, "sanity"); 424 // We cannot check whether the region is part of a particular set: at the time 425 // this method may be called, we have only completed allocation of the regions, 426 // but not put into a region set. 427 prev_committed = true; 428 if (hr->is_starts_humongous()) { 429 prev_end = hr->orig_end(); 430 } else { 431 prev_end = hr->end(); 432 } 433 } 434 for (uint i = _allocated_heapregions_length; i < max_length(); i++) { 435 guarantee(_regions.get_by_index(i) == NULL, err_msg("invariant i: %u", i)); 436 } 437 438 guarantee(num_committed == _num_committed, err_msg("Found %u committed regions, but should be %u", num_committed, _num_committed)); 439 _free_list.verify(); 440 } 441 442 #ifndef PRODUCT 443 void HeapRegionManager::verify_optional() { 444 verify(); 445 } 446 #endif // PRODUCT 447