1 /* 2 * Copyright (c) 2001, 2012, 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/parallelScavenge/parallelScavengeHeap.hpp" 27 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp" 28 #include "gc_implementation/parallelScavenge/psScavenge.hpp" 29 #include "gc_implementation/parallelScavenge/psYoungGen.hpp" 30 #include "gc_implementation/shared/gcUtil.hpp" 31 #include "gc_implementation/shared/mutableNUMASpace.hpp" 32 #include "gc_implementation/shared/spaceDecorator.hpp" 33 #include "oops/oop.inline.hpp" 34 #include "runtime/java.hpp" 35 36 PSYoungGen::PSYoungGen(size_t initial_size, 37 size_t min_size, 38 size_t max_size) : 39 _init_gen_size(initial_size), 40 _min_gen_size(min_size), 41 _max_gen_size(max_size) 42 {} 43 44 void PSYoungGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) { 45 assert(_init_gen_size != 0, "Should have a finite size"); 46 _virtual_space = new PSVirtualSpace(rs, alignment); 47 if (!virtual_space()->expand_by(_init_gen_size)) { 48 vm_exit_during_initialization("Could not reserve enough space for " 49 "object heap"); 50 } 51 } 52 53 void PSYoungGen::initialize(ReservedSpace rs, size_t alignment) { 54 initialize_virtual_space(rs, alignment); 55 initialize_work(); 56 } 57 58 void PSYoungGen::initialize_work() { 59 60 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(), 61 (HeapWord*)virtual_space()->high_boundary()); 62 63 MemRegion cmr((HeapWord*)virtual_space()->low(), 64 (HeapWord*)virtual_space()->high()); 65 Universe::heap()->barrier_set()->resize_covered_region(cmr); 66 67 if (ZapUnusedHeapArea) { 68 // Mangle newly committed space immediately because it 69 // can be done here more simply that after the new 70 // spaces have been computed. 71 SpaceMangler::mangle_region(cmr); 72 } 73 74 if (UseNUMA) { 75 _eden_space = new MutableNUMASpace(virtual_space()->alignment()); 76 } else { 77 _eden_space = new MutableSpace(virtual_space()->alignment()); 78 } 79 _from_space = new MutableSpace(virtual_space()->alignment()); 80 _to_space = new MutableSpace(virtual_space()->alignment()); 81 82 if (_eden_space == NULL || _from_space == NULL || _to_space == NULL) { 83 vm_exit_during_initialization("Could not allocate a young gen space"); 84 } 85 86 // Allocate the mark sweep views of spaces 87 _eden_mark_sweep = 88 new PSMarkSweepDecorator(_eden_space, NULL, MarkSweepDeadRatio); 89 _from_mark_sweep = 90 new PSMarkSweepDecorator(_from_space, NULL, MarkSweepDeadRatio); 91 _to_mark_sweep = 92 new PSMarkSweepDecorator(_to_space, NULL, MarkSweepDeadRatio); 93 94 if (_eden_mark_sweep == NULL || 95 _from_mark_sweep == NULL || 96 _to_mark_sweep == NULL) { 97 vm_exit_during_initialization("Could not complete allocation" 98 " of the young generation"); 99 } 100 101 // Generation Counters - generation 0, 3 subspaces 102 _gen_counters = new PSGenerationCounters("new", 0, 3, _virtual_space); 103 104 // Compute maximum space sizes for performance counters 105 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 106 size_t alignment = heap->intra_heap_alignment(); 107 size_t size = virtual_space()->reserved_size(); 108 109 size_t max_survivor_size; 110 size_t max_eden_size; 111 112 if (UseAdaptiveSizePolicy) { 113 max_survivor_size = size / MinSurvivorRatio; 114 115 // round the survivor space size down to the nearest alignment 116 // and make sure its size is greater than 0. 117 max_survivor_size = align_size_down(max_survivor_size, alignment); 118 max_survivor_size = MAX2(max_survivor_size, alignment); 119 120 // set the maximum size of eden to be the size of the young gen 121 // less two times the minimum survivor size. The minimum survivor 122 // size for UseAdaptiveSizePolicy is one alignment. 123 max_eden_size = size - 2 * alignment; 124 } else { 125 max_survivor_size = size / InitialSurvivorRatio; 126 127 // round the survivor space size down to the nearest alignment 128 // and make sure its size is greater than 0. 129 max_survivor_size = align_size_down(max_survivor_size, alignment); 130 max_survivor_size = MAX2(max_survivor_size, alignment); 131 132 // set the maximum size of eden to be the size of the young gen 133 // less two times the survivor size when the generation is 100% 134 // committed. The minimum survivor size for -UseAdaptiveSizePolicy 135 // is dependent on the committed portion (current capacity) of the 136 // generation - the less space committed, the smaller the survivor 137 // space, possibly as small as an alignment. However, we are interested 138 // in the case where the young generation is 100% committed, as this 139 // is the point where eden reaches its maximum size. At this point, 140 // the size of a survivor space is max_survivor_size. 141 max_eden_size = size - 2 * max_survivor_size; 142 } 143 144 _eden_counters = new SpaceCounters("eden", 0, max_eden_size, _eden_space, 145 _gen_counters); 146 _from_counters = new SpaceCounters("s0", 1, max_survivor_size, _from_space, 147 _gen_counters); 148 _to_counters = new SpaceCounters("s1", 2, max_survivor_size, _to_space, 149 _gen_counters); 150 151 compute_initial_space_boundaries(); 152 } 153 154 void PSYoungGen::compute_initial_space_boundaries() { 155 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 156 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); 157 158 // Compute sizes 159 size_t alignment = heap->intra_heap_alignment(); 160 size_t size = virtual_space()->committed_size(); 161 162 size_t survivor_size = size / InitialSurvivorRatio; 163 survivor_size = align_size_down(survivor_size, alignment); 164 // ... but never less than an alignment 165 survivor_size = MAX2(survivor_size, alignment); 166 167 // Young generation is eden + 2 survivor spaces 168 size_t eden_size = size - (2 * survivor_size); 169 170 // Now go ahead and set 'em. 171 set_space_boundaries(eden_size, survivor_size); 172 space_invariants(); 173 174 if (UsePerfData) { 175 _eden_counters->update_capacity(); 176 _from_counters->update_capacity(); 177 _to_counters->update_capacity(); 178 } 179 } 180 181 void PSYoungGen::set_space_boundaries(size_t eden_size, size_t survivor_size) { 182 assert(eden_size < virtual_space()->committed_size(), "just checking"); 183 assert(eden_size > 0 && survivor_size > 0, "just checking"); 184 185 // Initial layout is Eden, to, from. After swapping survivor spaces, 186 // that leaves us with Eden, from, to, which is step one in our two 187 // step resize-with-live-data procedure. 188 char *eden_start = virtual_space()->low(); 189 char *to_start = eden_start + eden_size; 190 char *from_start = to_start + survivor_size; 191 char *from_end = from_start + survivor_size; 192 193 assert(from_end == virtual_space()->high(), "just checking"); 194 assert(is_object_aligned((intptr_t)eden_start), "checking alignment"); 195 assert(is_object_aligned((intptr_t)to_start), "checking alignment"); 196 assert(is_object_aligned((intptr_t)from_start), "checking alignment"); 197 198 MemRegion eden_mr((HeapWord*)eden_start, (HeapWord*)to_start); 199 MemRegion to_mr ((HeapWord*)to_start, (HeapWord*)from_start); 200 MemRegion from_mr((HeapWord*)from_start, (HeapWord*)from_end); 201 202 eden_space()->initialize(eden_mr, true, ZapUnusedHeapArea); 203 to_space()->initialize(to_mr , true, ZapUnusedHeapArea); 204 from_space()->initialize(from_mr, true, ZapUnusedHeapArea); 205 } 206 207 #ifndef PRODUCT 208 void PSYoungGen::space_invariants() { 209 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 210 const size_t alignment = heap->intra_heap_alignment(); 211 212 // Currently, our eden size cannot shrink to zero 213 guarantee(eden_space()->capacity_in_bytes() >= alignment, "eden too small"); 214 guarantee(from_space()->capacity_in_bytes() >= alignment, "from too small"); 215 guarantee(to_space()->capacity_in_bytes() >= alignment, "to too small"); 216 217 // Relationship of spaces to each other 218 char* eden_start = (char*)eden_space()->bottom(); 219 char* eden_end = (char*)eden_space()->end(); 220 char* from_start = (char*)from_space()->bottom(); 221 char* from_end = (char*)from_space()->end(); 222 char* to_start = (char*)to_space()->bottom(); 223 char* to_end = (char*)to_space()->end(); 224 225 guarantee(eden_start >= virtual_space()->low(), "eden bottom"); 226 guarantee(eden_start < eden_end, "eden space consistency"); 227 guarantee(from_start < from_end, "from space consistency"); 228 guarantee(to_start < to_end, "to space consistency"); 229 230 // Check whether from space is below to space 231 if (from_start < to_start) { 232 // Eden, from, to 233 guarantee(eden_end <= from_start, "eden/from boundary"); 234 guarantee(from_end <= to_start, "from/to boundary"); 235 guarantee(to_end <= virtual_space()->high(), "to end"); 236 } else { 237 // Eden, to, from 238 guarantee(eden_end <= to_start, "eden/to boundary"); 239 guarantee(to_end <= from_start, "to/from boundary"); 240 guarantee(from_end <= virtual_space()->high(), "from end"); 241 } 242 243 // More checks that the virtual space is consistent with the spaces 244 assert(virtual_space()->committed_size() >= 245 (eden_space()->capacity_in_bytes() + 246 to_space()->capacity_in_bytes() + 247 from_space()->capacity_in_bytes()), "Committed size is inconsistent"); 248 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(), 249 "Space invariant"); 250 char* eden_top = (char*)eden_space()->top(); 251 char* from_top = (char*)from_space()->top(); 252 char* to_top = (char*)to_space()->top(); 253 assert(eden_top <= virtual_space()->high(), "eden top"); 254 assert(from_top <= virtual_space()->high(), "from top"); 255 assert(to_top <= virtual_space()->high(), "to top"); 256 257 virtual_space()->verify(); 258 } 259 #endif 260 261 void PSYoungGen::resize(size_t eden_size, size_t survivor_size) { 262 // Resize the generation if needed. If the generation resize 263 // reports false, do not attempt to resize the spaces. 264 if (resize_generation(eden_size, survivor_size)) { 265 // Then we lay out the spaces inside the generation 266 resize_spaces(eden_size, survivor_size); 267 268 space_invariants(); 269 270 if (PrintAdaptiveSizePolicy && Verbose) { 271 gclog_or_tty->print_cr("Young generation size: " 272 "desired eden: " SIZE_FORMAT " survivor: " SIZE_FORMAT 273 " used: " SIZE_FORMAT " capacity: " SIZE_FORMAT 274 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT, 275 eden_size, survivor_size, used_in_bytes(), capacity_in_bytes(), 276 _max_gen_size, min_gen_size()); 277 } 278 } 279 } 280 281 282 bool PSYoungGen::resize_generation(size_t eden_size, size_t survivor_size) { 283 const size_t alignment = virtual_space()->alignment(); 284 size_t orig_size = virtual_space()->committed_size(); 285 bool size_changed = false; 286 287 // There used to be this guarantee there. 288 // guarantee ((eden_size + 2*survivor_size) <= _max_gen_size, "incorrect input arguments"); 289 // Code below forces this requirement. In addition the desired eden 290 // size and disired survivor sizes are desired goals and may 291 // exceed the total generation size. 292 293 assert(min_gen_size() <= orig_size && orig_size <= max_size(), "just checking"); 294 295 // Adjust new generation size 296 const size_t eden_plus_survivors = 297 align_size_up(eden_size + 2 * survivor_size, alignment); 298 size_t desired_size = MAX2(MIN2(eden_plus_survivors, max_size()), 299 min_gen_size()); 300 assert(desired_size <= max_size(), "just checking"); 301 302 if (desired_size > orig_size) { 303 // Grow the generation 304 size_t change = desired_size - orig_size; 305 assert(change % alignment == 0, "just checking"); 306 HeapWord* prev_high = (HeapWord*) virtual_space()->high(); 307 if (!virtual_space()->expand_by(change)) { 308 return false; // Error if we fail to resize! 309 } 310 if (ZapUnusedHeapArea) { 311 // Mangle newly committed space immediately because it 312 // can be done here more simply that after the new 313 // spaces have been computed. 314 HeapWord* new_high = (HeapWord*) virtual_space()->high(); 315 MemRegion mangle_region(prev_high, new_high); 316 SpaceMangler::mangle_region(mangle_region); 317 } 318 size_changed = true; 319 } else if (desired_size < orig_size) { 320 size_t desired_change = orig_size - desired_size; 321 assert(desired_change % alignment == 0, "just checking"); 322 323 desired_change = limit_gen_shrink(desired_change); 324 325 if (desired_change > 0) { 326 virtual_space()->shrink_by(desired_change); 327 reset_survivors_after_shrink(); 328 329 size_changed = true; 330 } 331 } else { 332 if (Verbose && PrintGC) { 333 if (orig_size == gen_size_limit()) { 334 gclog_or_tty->print_cr("PSYoung generation size at maximum: " 335 SIZE_FORMAT "K", orig_size/K); 336 } else if (orig_size == min_gen_size()) { 337 gclog_or_tty->print_cr("PSYoung generation size at minium: " 338 SIZE_FORMAT "K", orig_size/K); 339 } 340 } 341 } 342 343 if (size_changed) { 344 post_resize(); 345 346 if (Verbose && PrintGC) { 347 size_t current_size = virtual_space()->committed_size(); 348 gclog_or_tty->print_cr("PSYoung generation size changed: " 349 SIZE_FORMAT "K->" SIZE_FORMAT "K", 350 orig_size/K, current_size/K); 351 } 352 } 353 354 guarantee(eden_plus_survivors <= virtual_space()->committed_size() || 355 virtual_space()->committed_size() == max_size(), "Sanity"); 356 357 return true; 358 } 359 360 #ifndef PRODUCT 361 // In the numa case eden is not mangled so a survivor space 362 // moving into a region previously occupied by a survivor 363 // may find an unmangled region. Also in the PS case eden 364 // to-space and from-space may not touch (i.e., there may be 365 // gaps between them due to movement while resizing the 366 // spaces). Those gaps must be mangled. 367 void PSYoungGen::mangle_survivors(MutableSpace* s1, 368 MemRegion s1MR, 369 MutableSpace* s2, 370 MemRegion s2MR) { 371 // Check eden and gap between eden and from-space, in deciding 372 // what to mangle in from-space. Check the gap between from-space 373 // and to-space when deciding what to mangle. 374 // 375 // +--------+ +----+ +---+ 376 // | eden | |s1 | |s2 | 377 // +--------+ +----+ +---+ 378 // +-------+ +-----+ 379 // |s1MR | |s2MR | 380 // +-------+ +-----+ 381 // All of survivor-space is properly mangled so find the 382 // upper bound on the mangling for any portion above current s1. 383 HeapWord* delta_end = MIN2(s1->bottom(), s1MR.end()); 384 MemRegion delta1_left; 385 if (s1MR.start() < delta_end) { 386 delta1_left = MemRegion(s1MR.start(), delta_end); 387 s1->mangle_region(delta1_left); 388 } 389 // Find any portion to the right of the current s1. 390 HeapWord* delta_start = MAX2(s1->end(), s1MR.start()); 391 MemRegion delta1_right; 392 if (delta_start < s1MR.end()) { 393 delta1_right = MemRegion(delta_start, s1MR.end()); 394 s1->mangle_region(delta1_right); 395 } 396 397 // Similarly for the second survivor space except that 398 // any of the new region that overlaps with the current 399 // region of the first survivor space has already been 400 // mangled. 401 delta_end = MIN2(s2->bottom(), s2MR.end()); 402 delta_start = MAX2(s2MR.start(), s1->end()); 403 MemRegion delta2_left; 404 if (s2MR.start() < delta_end) { 405 delta2_left = MemRegion(s2MR.start(), delta_end); 406 s2->mangle_region(delta2_left); 407 } 408 delta_start = MAX2(s2->end(), s2MR.start()); 409 MemRegion delta2_right; 410 if (delta_start < s2MR.end()) { 411 s2->mangle_region(delta2_right); 412 } 413 414 if (TraceZapUnusedHeapArea) { 415 // s1 416 gclog_or_tty->print_cr("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") " 417 "New region: [" PTR_FORMAT ", " PTR_FORMAT ")", 418 s1->bottom(), s1->end(), s1MR.start(), s1MR.end()); 419 gclog_or_tty->print_cr(" Mangle before: [" PTR_FORMAT ", " 420 PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")", 421 delta1_left.start(), delta1_left.end(), delta1_right.start(), 422 delta1_right.end()); 423 424 // s2 425 gclog_or_tty->print_cr("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") " 426 "New region: [" PTR_FORMAT ", " PTR_FORMAT ")", 427 s2->bottom(), s2->end(), s2MR.start(), s2MR.end()); 428 gclog_or_tty->print_cr(" Mangle before: [" PTR_FORMAT ", " 429 PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")", 430 delta2_left.start(), delta2_left.end(), delta2_right.start(), 431 delta2_right.end()); 432 } 433 434 } 435 #endif // NOT PRODUCT 436 437 void PSYoungGen::resize_spaces(size_t requested_eden_size, 438 size_t requested_survivor_size) { 439 assert(UseAdaptiveSizePolicy, "sanity check"); 440 assert(requested_eden_size > 0 && requested_survivor_size > 0, 441 "just checking"); 442 443 // We require eden and to space to be empty 444 if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) { 445 return; 446 } 447 448 if (PrintAdaptiveSizePolicy && Verbose) { 449 gclog_or_tty->print_cr("PSYoungGen::resize_spaces(requested_eden_size: " 450 SIZE_FORMAT 451 ", requested_survivor_size: " SIZE_FORMAT ")", 452 requested_eden_size, requested_survivor_size); 453 gclog_or_tty->print_cr(" eden: [" PTR_FORMAT ".." PTR_FORMAT ") " 454 SIZE_FORMAT, 455 eden_space()->bottom(), 456 eden_space()->end(), 457 pointer_delta(eden_space()->end(), 458 eden_space()->bottom(), 459 sizeof(char))); 460 gclog_or_tty->print_cr(" from: [" PTR_FORMAT ".." PTR_FORMAT ") " 461 SIZE_FORMAT, 462 from_space()->bottom(), 463 from_space()->end(), 464 pointer_delta(from_space()->end(), 465 from_space()->bottom(), 466 sizeof(char))); 467 gclog_or_tty->print_cr(" to: [" PTR_FORMAT ".." PTR_FORMAT ") " 468 SIZE_FORMAT, 469 to_space()->bottom(), 470 to_space()->end(), 471 pointer_delta( to_space()->end(), 472 to_space()->bottom(), 473 sizeof(char))); 474 } 475 476 // There's nothing to do if the new sizes are the same as the current 477 if (requested_survivor_size == to_space()->capacity_in_bytes() && 478 requested_survivor_size == from_space()->capacity_in_bytes() && 479 requested_eden_size == eden_space()->capacity_in_bytes()) { 480 if (PrintAdaptiveSizePolicy && Verbose) { 481 gclog_or_tty->print_cr(" capacities are the right sizes, returning"); 482 } 483 return; 484 } 485 486 char* eden_start = (char*)eden_space()->bottom(); 487 char* eden_end = (char*)eden_space()->end(); 488 char* from_start = (char*)from_space()->bottom(); 489 char* from_end = (char*)from_space()->end(); 490 char* to_start = (char*)to_space()->bottom(); 491 char* to_end = (char*)to_space()->end(); 492 493 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 494 const size_t alignment = heap->intra_heap_alignment(); 495 const bool maintain_minimum = 496 (requested_eden_size + 2 * requested_survivor_size) <= min_gen_size(); 497 498 bool eden_from_to_order = from_start < to_start; 499 // Check whether from space is below to space 500 if (eden_from_to_order) { 501 // Eden, from, to 502 eden_from_to_order = true; 503 if (PrintAdaptiveSizePolicy && Verbose) { 504 gclog_or_tty->print_cr(" Eden, from, to:"); 505 } 506 507 // Set eden 508 // "requested_eden_size" is a goal for the size of eden 509 // and may not be attainable. "eden_size" below is 510 // calculated based on the location of from-space and 511 // the goal for the size of eden. from-space is 512 // fixed in place because it contains live data. 513 // The calculation is done this way to avoid 32bit 514 // overflow (i.e., eden_start + requested_eden_size 515 // may too large for representation in 32bits). 516 size_t eden_size; 517 if (maintain_minimum) { 518 // Only make eden larger than the requested size if 519 // the minimum size of the generation has to be maintained. 520 // This could be done in general but policy at a higher 521 // level is determining a requested size for eden and that 522 // should be honored unless there is a fundamental reason. 523 eden_size = pointer_delta(from_start, 524 eden_start, 525 sizeof(char)); 526 } else { 527 eden_size = MIN2(requested_eden_size, 528 pointer_delta(from_start, eden_start, sizeof(char))); 529 } 530 531 eden_end = eden_start + eden_size; 532 assert(eden_end >= eden_start, "addition overflowed"); 533 534 // To may resize into from space as long as it is clear of live data. 535 // From space must remain page aligned, though, so we need to do some 536 // extra calculations. 537 538 // First calculate an optimal to-space 539 to_end = (char*)virtual_space()->high(); 540 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size, 541 sizeof(char)); 542 543 // Does the optimal to-space overlap from-space? 544 if (to_start < (char*)from_space()->end()) { 545 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); 546 547 // Calculate the minimum offset possible for from_end 548 size_t from_size = pointer_delta(from_space()->top(), from_start, sizeof(char)); 549 550 // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME! 551 if (from_size == 0) { 552 from_size = alignment; 553 } else { 554 from_size = align_size_up(from_size, alignment); 555 } 556 557 from_end = from_start + from_size; 558 assert(from_end > from_start, "addition overflow or from_size problem"); 559 560 guarantee(from_end <= (char*)from_space()->end(), "from_end moved to the right"); 561 562 // Now update to_start with the new from_end 563 to_start = MAX2(from_end, to_start); 564 } 565 566 guarantee(to_start != to_end, "to space is zero sized"); 567 568 if (PrintAdaptiveSizePolicy && Verbose) { 569 gclog_or_tty->print_cr(" [eden_start .. eden_end): " 570 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 571 eden_start, 572 eden_end, 573 pointer_delta(eden_end, eden_start, sizeof(char))); 574 gclog_or_tty->print_cr(" [from_start .. from_end): " 575 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 576 from_start, 577 from_end, 578 pointer_delta(from_end, from_start, sizeof(char))); 579 gclog_or_tty->print_cr(" [ to_start .. to_end): " 580 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 581 to_start, 582 to_end, 583 pointer_delta( to_end, to_start, sizeof(char))); 584 } 585 } else { 586 // Eden, to, from 587 if (PrintAdaptiveSizePolicy && Verbose) { 588 gclog_or_tty->print_cr(" Eden, to, from:"); 589 } 590 591 // To space gets priority over eden resizing. Note that we position 592 // to space as if we were able to resize from space, even though from 593 // space is not modified. 594 // Giving eden priority was tried and gave poorer performance. 595 to_end = (char*)pointer_delta(virtual_space()->high(), 596 (char*)requested_survivor_size, 597 sizeof(char)); 598 to_end = MIN2(to_end, from_start); 599 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size, 600 sizeof(char)); 601 // if the space sizes are to be increased by several times then 602 // 'to_start' will point beyond the young generation. In this case 603 // 'to_start' should be adjusted. 604 to_start = MAX2(to_start, eden_start + alignment); 605 606 // Compute how big eden can be, then adjust end. 607 // See comments above on calculating eden_end. 608 size_t eden_size; 609 if (maintain_minimum) { 610 eden_size = pointer_delta(to_start, eden_start, sizeof(char)); 611 } else { 612 eden_size = MIN2(requested_eden_size, 613 pointer_delta(to_start, eden_start, sizeof(char))); 614 } 615 eden_end = eden_start + eden_size; 616 assert(eden_end >= eden_start, "addition overflowed"); 617 618 // Could choose to not let eden shrink 619 // to_start = MAX2(to_start, eden_end); 620 621 // Don't let eden shrink down to 0 or less. 622 eden_end = MAX2(eden_end, eden_start + alignment); 623 to_start = MAX2(to_start, eden_end); 624 625 if (PrintAdaptiveSizePolicy && Verbose) { 626 gclog_or_tty->print_cr(" [eden_start .. eden_end): " 627 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 628 eden_start, 629 eden_end, 630 pointer_delta(eden_end, eden_start, sizeof(char))); 631 gclog_or_tty->print_cr(" [ to_start .. to_end): " 632 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 633 to_start, 634 to_end, 635 pointer_delta( to_end, to_start, sizeof(char))); 636 gclog_or_tty->print_cr(" [from_start .. from_end): " 637 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 638 from_start, 639 from_end, 640 pointer_delta(from_end, from_start, sizeof(char))); 641 } 642 } 643 644 645 guarantee((HeapWord*)from_start <= from_space()->bottom(), 646 "from start moved to the right"); 647 guarantee((HeapWord*)from_end >= from_space()->top(), 648 "from end moved into live data"); 649 assert(is_object_aligned((intptr_t)eden_start), "checking alignment"); 650 assert(is_object_aligned((intptr_t)from_start), "checking alignment"); 651 assert(is_object_aligned((intptr_t)to_start), "checking alignment"); 652 653 MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)eden_end); 654 MemRegion toMR ((HeapWord*)to_start, (HeapWord*)to_end); 655 MemRegion fromMR((HeapWord*)from_start, (HeapWord*)from_end); 656 657 // Let's make sure the call to initialize doesn't reset "top"! 658 HeapWord* old_from_top = from_space()->top(); 659 660 // For PrintAdaptiveSizePolicy block below 661 size_t old_from = from_space()->capacity_in_bytes(); 662 size_t old_to = to_space()->capacity_in_bytes(); 663 664 if (ZapUnusedHeapArea) { 665 // NUMA is a special case because a numa space is not mangled 666 // in order to not prematurely bind its address to memory to 667 // the wrong memory (i.e., don't want the GC thread to first 668 // touch the memory). The survivor spaces are not numa 669 // spaces and are mangled. 670 if (UseNUMA) { 671 if (eden_from_to_order) { 672 mangle_survivors(from_space(), fromMR, to_space(), toMR); 673 } else { 674 mangle_survivors(to_space(), toMR, from_space(), fromMR); 675 } 676 } 677 678 // If not mangling the spaces, do some checking to verify that 679 // the spaces are already mangled. 680 // The spaces should be correctly mangled at this point so 681 // do some checking here. Note that they are not being mangled 682 // in the calls to initialize(). 683 // Must check mangling before the spaces are reshaped. Otherwise, 684 // the bottom or end of one space may have moved into an area 685 // covered by another space and a failure of the check may 686 // not correctly indicate which space is not properly mangled. 687 HeapWord* limit = (HeapWord*) virtual_space()->high(); 688 eden_space()->check_mangled_unused_area(limit); 689 from_space()->check_mangled_unused_area(limit); 690 to_space()->check_mangled_unused_area(limit); 691 } 692 // When an existing space is being initialized, it is not 693 // mangled because the space has been previously mangled. 694 eden_space()->initialize(edenMR, 695 SpaceDecorator::Clear, 696 SpaceDecorator::DontMangle); 697 to_space()->initialize(toMR, 698 SpaceDecorator::Clear, 699 SpaceDecorator::DontMangle); 700 from_space()->initialize(fromMR, 701 SpaceDecorator::DontClear, 702 SpaceDecorator::DontMangle); 703 704 assert(from_space()->top() == old_from_top, "from top changed!"); 705 706 if (PrintAdaptiveSizePolicy) { 707 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 708 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); 709 710 gclog_or_tty->print("AdaptiveSizePolicy::survivor space sizes: " 711 "collection: %d " 712 "(" SIZE_FORMAT ", " SIZE_FORMAT ") -> " 713 "(" SIZE_FORMAT ", " SIZE_FORMAT ") ", 714 heap->total_collections(), 715 old_from, old_to, 716 from_space()->capacity_in_bytes(), 717 to_space()->capacity_in_bytes()); 718 gclog_or_tty->cr(); 719 } 720 } 721 722 void PSYoungGen::swap_spaces() { 723 MutableSpace* s = from_space(); 724 _from_space = to_space(); 725 _to_space = s; 726 727 // Now update the decorators. 728 PSMarkSweepDecorator* md = from_mark_sweep(); 729 _from_mark_sweep = to_mark_sweep(); 730 _to_mark_sweep = md; 731 732 assert(from_mark_sweep()->space() == from_space(), "Sanity"); 733 assert(to_mark_sweep()->space() == to_space(), "Sanity"); 734 } 735 736 size_t PSYoungGen::capacity_in_bytes() const { 737 return eden_space()->capacity_in_bytes() 738 + from_space()->capacity_in_bytes(); // to_space() is only used during scavenge 739 } 740 741 742 size_t PSYoungGen::used_in_bytes() const { 743 return eden_space()->used_in_bytes() 744 + from_space()->used_in_bytes(); // to_space() is only used during scavenge 745 } 746 747 748 size_t PSYoungGen::free_in_bytes() const { 749 return eden_space()->free_in_bytes() 750 + from_space()->free_in_bytes(); // to_space() is only used during scavenge 751 } 752 753 size_t PSYoungGen::capacity_in_words() const { 754 return eden_space()->capacity_in_words() 755 + from_space()->capacity_in_words(); // to_space() is only used during scavenge 756 } 757 758 759 size_t PSYoungGen::used_in_words() const { 760 return eden_space()->used_in_words() 761 + from_space()->used_in_words(); // to_space() is only used during scavenge 762 } 763 764 765 size_t PSYoungGen::free_in_words() const { 766 return eden_space()->free_in_words() 767 + from_space()->free_in_words(); // to_space() is only used during scavenge 768 } 769 770 void PSYoungGen::object_iterate(ObjectClosure* blk) { 771 eden_space()->object_iterate(blk); 772 from_space()->object_iterate(blk); 773 to_space()->object_iterate(blk); 774 } 775 776 void PSYoungGen::precompact() { 777 eden_mark_sweep()->precompact(); 778 from_mark_sweep()->precompact(); 779 to_mark_sweep()->precompact(); 780 } 781 782 void PSYoungGen::adjust_pointers() { 783 eden_mark_sweep()->adjust_pointers(); 784 from_mark_sweep()->adjust_pointers(); 785 to_mark_sweep()->adjust_pointers(); 786 } 787 788 void PSYoungGen::compact() { 789 eden_mark_sweep()->compact(ZapUnusedHeapArea); 790 from_mark_sweep()->compact(ZapUnusedHeapArea); 791 // Mark sweep stores preserved markOops in to space, don't disturb! 792 to_mark_sweep()->compact(false); 793 } 794 795 void PSYoungGen::print() const { print_on(tty); } 796 void PSYoungGen::print_on(outputStream* st) const { 797 st->print(" %-15s", "PSYoungGen"); 798 if (PrintGCDetails && Verbose) { 799 st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT, 800 capacity_in_bytes(), used_in_bytes()); 801 } else { 802 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K", 803 capacity_in_bytes()/K, used_in_bytes()/K); 804 } 805 virtual_space()->print_space_boundaries_on(st); 806 st->print(" eden"); eden_space()->print_on(st); 807 st->print(" from"); from_space()->print_on(st); 808 st->print(" to "); to_space()->print_on(st); 809 } 810 811 // Note that a space is not printed before the [NAME: 812 void PSYoungGen::print_used_change(size_t prev_used) const { 813 gclog_or_tty->print("[%s:", name()); 814 gclog_or_tty->print(" " SIZE_FORMAT "K" 815 "->" SIZE_FORMAT "K" 816 "(" SIZE_FORMAT "K)", 817 prev_used / K, used_in_bytes() / K, 818 capacity_in_bytes() / K); 819 gclog_or_tty->print("]"); 820 } 821 822 size_t PSYoungGen::available_for_expansion() { 823 ShouldNotReachHere(); 824 return 0; 825 } 826 827 size_t PSYoungGen::available_for_contraction() { 828 ShouldNotReachHere(); 829 return 0; 830 } 831 832 size_t PSYoungGen::available_to_min_gen() { 833 assert(virtual_space()->committed_size() >= min_gen_size(), "Invariant"); 834 return virtual_space()->committed_size() - min_gen_size(); 835 } 836 837 // This method assumes that from-space has live data and that 838 // any shrinkage of the young gen is limited by location of 839 // from-space. 840 size_t PSYoungGen::available_to_live() { 841 size_t delta_in_survivor = 0; 842 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 843 const size_t space_alignment = heap->intra_heap_alignment(); 844 const size_t gen_alignment = heap->young_gen_alignment(); 845 846 MutableSpace* space_shrinking = NULL; 847 if (from_space()->end() > to_space()->end()) { 848 space_shrinking = from_space(); 849 } else { 850 space_shrinking = to_space(); 851 } 852 853 // Include any space that is committed but not included in 854 // the survivor spaces. 855 assert(((HeapWord*)virtual_space()->high()) >= space_shrinking->end(), 856 "Survivor space beyond high end"); 857 size_t unused_committed = pointer_delta(virtual_space()->high(), 858 space_shrinking->end(), sizeof(char)); 859 860 if (space_shrinking->is_empty()) { 861 // Don't let the space shrink to 0 862 assert(space_shrinking->capacity_in_bytes() >= space_alignment, 863 "Space is too small"); 864 delta_in_survivor = space_shrinking->capacity_in_bytes() - space_alignment; 865 } else { 866 delta_in_survivor = pointer_delta(space_shrinking->end(), 867 space_shrinking->top(), 868 sizeof(char)); 869 } 870 871 size_t delta_in_bytes = unused_committed + delta_in_survivor; 872 delta_in_bytes = align_size_down(delta_in_bytes, gen_alignment); 873 return delta_in_bytes; 874 } 875 876 // Return the number of bytes available for resizing down the young 877 // generation. This is the minimum of 878 // input "bytes" 879 // bytes to the minimum young gen size 880 // bytes to the size currently being used + some small extra 881 size_t PSYoungGen::limit_gen_shrink(size_t bytes) { 882 // Allow shrinkage into the current eden but keep eden large enough 883 // to maintain the minimum young gen size 884 bytes = MIN3(bytes, available_to_min_gen(), available_to_live()); 885 return align_size_down(bytes, virtual_space()->alignment()); 886 } 887 888 void PSYoungGen::reset_after_change() { 889 ShouldNotReachHere(); 890 } 891 892 void PSYoungGen::reset_survivors_after_shrink() { 893 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(), 894 (HeapWord*)virtual_space()->high_boundary()); 895 PSScavenge::reference_processor()->set_span(_reserved); 896 897 MutableSpace* space_shrinking = NULL; 898 if (from_space()->end() > to_space()->end()) { 899 space_shrinking = from_space(); 900 } else { 901 space_shrinking = to_space(); 902 } 903 904 HeapWord* new_end = (HeapWord*)virtual_space()->high(); 905 assert(new_end >= space_shrinking->bottom(), "Shrink was too large"); 906 // Was there a shrink of the survivor space? 907 if (new_end < space_shrinking->end()) { 908 MemRegion mr(space_shrinking->bottom(), new_end); 909 space_shrinking->initialize(mr, 910 SpaceDecorator::DontClear, 911 SpaceDecorator::Mangle); 912 } 913 } 914 915 // This method currently does not expect to expand into eden (i.e., 916 // the virtual space boundaries is expected to be consistent 917 // with the eden boundaries.. 918 void PSYoungGen::post_resize() { 919 assert_locked_or_safepoint(Heap_lock); 920 assert((eden_space()->bottom() < to_space()->bottom()) && 921 (eden_space()->bottom() < from_space()->bottom()), 922 "Eden is assumed to be below the survivor spaces"); 923 924 MemRegion cmr((HeapWord*)virtual_space()->low(), 925 (HeapWord*)virtual_space()->high()); 926 Universe::heap()->barrier_set()->resize_covered_region(cmr); 927 space_invariants(); 928 } 929 930 931 932 void PSYoungGen::update_counters() { 933 if (UsePerfData) { 934 _eden_counters->update_all(); 935 _from_counters->update_all(); 936 _to_counters->update_all(); 937 _gen_counters->update_all(); 938 } 939 } 940 941 void PSYoungGen::verify() { 942 eden_space()->verify(); 943 from_space()->verify(); 944 to_space()->verify(); 945 } 946 947 #ifndef PRODUCT 948 void PSYoungGen::record_spaces_top() { 949 assert(ZapUnusedHeapArea, "Not mangling unused space"); 950 eden_space()->set_top_for_allocations(); 951 from_space()->set_top_for_allocations(); 952 to_space()->set_top_for_allocations(); 953 } 954 #endif