1 /* 2 * Copyright (c) 2001, 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_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 ParallelScavengeHeap::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, _min_gen_size, 103 _max_gen_size, _virtual_space); 104 105 // Compute maximum space sizes for performance counters 106 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 107 size_t alignment = heap->space_alignment(); 108 size_t size = virtual_space()->reserved_size(); 109 110 size_t max_survivor_size; 111 size_t max_eden_size; 112 113 if (UseAdaptiveSizePolicy) { 114 max_survivor_size = size / MinSurvivorRatio; 115 116 // round the survivor space size down to the nearest alignment 117 // and make sure its size is greater than 0. 118 max_survivor_size = align_size_down(max_survivor_size, alignment); 119 max_survivor_size = MAX2(max_survivor_size, alignment); 120 121 // set the maximum size of eden to be the size of the young gen 122 // less two times the minimum survivor size. The minimum survivor 123 // size for UseAdaptiveSizePolicy is one alignment. 124 max_eden_size = size - 2 * alignment; 125 } else { 126 max_survivor_size = size / InitialSurvivorRatio; 127 128 // round the survivor space size down to the nearest alignment 129 // and make sure its size is greater than 0. 130 max_survivor_size = align_size_down(max_survivor_size, alignment); 131 max_survivor_size = MAX2(max_survivor_size, alignment); 132 133 // set the maximum size of eden to be the size of the young gen 134 // less two times the survivor size when the generation is 100% 135 // committed. The minimum survivor size for -UseAdaptiveSizePolicy 136 // is dependent on the committed portion (current capacity) of the 137 // generation - the less space committed, the smaller the survivor 138 // space, possibly as small as an alignment. However, we are interested 139 // in the case where the young generation is 100% committed, as this 140 // is the point where eden reaches its maximum size. At this point, 141 // the size of a survivor space is max_survivor_size. 142 max_eden_size = size - 2 * max_survivor_size; 143 } 144 145 _eden_counters = new SpaceCounters("eden", 0, max_eden_size, _eden_space, 146 _gen_counters); 147 _from_counters = new SpaceCounters("s0", 1, max_survivor_size, _from_space, 148 _gen_counters); 149 _to_counters = new SpaceCounters("s1", 2, max_survivor_size, _to_space, 150 _gen_counters); 151 152 compute_initial_space_boundaries(); 153 } 154 155 void PSYoungGen::compute_initial_space_boundaries() { 156 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 157 158 // Compute sizes 159 size_t alignment = heap->space_alignment(); 160 size_t size = virtual_space()->committed_size(); 161 assert(size >= 3 * alignment, "Young space is not large enough for eden + 2 survivors"); 162 163 size_t survivor_size = size / InitialSurvivorRatio; 164 survivor_size = align_size_down(survivor_size, alignment); 165 // ... but never less than an alignment 166 survivor_size = MAX2(survivor_size, alignment); 167 168 // Young generation is eden + 2 survivor spaces 169 size_t eden_size = size - (2 * survivor_size); 170 171 // Now go ahead and set 'em. 172 set_space_boundaries(eden_size, survivor_size); 173 space_invariants(); 174 175 if (UsePerfData) { 176 _eden_counters->update_capacity(); 177 _from_counters->update_capacity(); 178 _to_counters->update_capacity(); 179 } 180 } 181 182 void PSYoungGen::set_space_boundaries(size_t eden_size, size_t survivor_size) { 183 assert(eden_size < virtual_space()->committed_size(), "just checking"); 184 assert(eden_size > 0 && survivor_size > 0, "just checking"); 185 186 // Initial layout is Eden, to, from. After swapping survivor spaces, 187 // that leaves us with Eden, from, to, which is step one in our two 188 // step resize-with-live-data procedure. 189 char *eden_start = virtual_space()->low(); 190 char *to_start = eden_start + eden_size; 191 char *from_start = to_start + survivor_size; 192 char *from_end = from_start + survivor_size; 193 194 assert(from_end == virtual_space()->high(), "just checking"); 195 assert(is_object_aligned((intptr_t)eden_start), "checking alignment"); 196 assert(is_object_aligned((intptr_t)to_start), "checking alignment"); 197 assert(is_object_aligned((intptr_t)from_start), "checking alignment"); 198 199 MemRegion eden_mr((HeapWord*)eden_start, (HeapWord*)to_start); 200 MemRegion to_mr ((HeapWord*)to_start, (HeapWord*)from_start); 201 MemRegion from_mr((HeapWord*)from_start, (HeapWord*)from_end); 202 203 eden_space()->initialize(eden_mr, true, ZapUnusedHeapArea); 204 to_space()->initialize(to_mr , true, ZapUnusedHeapArea); 205 from_space()->initialize(from_mr, true, ZapUnusedHeapArea); 206 } 207 208 #ifndef PRODUCT 209 void PSYoungGen::space_invariants() { 210 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 211 const size_t alignment = heap->space_alignment(); 212 213 // Currently, our eden size cannot shrink to zero 214 guarantee(eden_space()->capacity_in_bytes() >= alignment, "eden too small"); 215 guarantee(from_space()->capacity_in_bytes() >= alignment, "from too small"); 216 guarantee(to_space()->capacity_in_bytes() >= alignment, "to too small"); 217 218 // Relationship of spaces to each other 219 char* eden_start = (char*)eden_space()->bottom(); 220 char* eden_end = (char*)eden_space()->end(); 221 char* from_start = (char*)from_space()->bottom(); 222 char* from_end = (char*)from_space()->end(); 223 char* to_start = (char*)to_space()->bottom(); 224 char* to_end = (char*)to_space()->end(); 225 226 guarantee(eden_start >= virtual_space()->low(), "eden bottom"); 227 guarantee(eden_start < eden_end, "eden space consistency"); 228 guarantee(from_start < from_end, "from space consistency"); 229 guarantee(to_start < to_end, "to space consistency"); 230 231 // Check whether from space is below to space 232 if (from_start < to_start) { 233 // Eden, from, to 234 guarantee(eden_end <= from_start, "eden/from boundary"); 235 guarantee(from_end <= to_start, "from/to boundary"); 236 guarantee(to_end <= virtual_space()->high(), "to end"); 237 } else { 238 // Eden, to, from 239 guarantee(eden_end <= to_start, "eden/to boundary"); 240 guarantee(to_end <= from_start, "to/from boundary"); 241 guarantee(from_end <= virtual_space()->high(), "from end"); 242 } 243 244 // More checks that the virtual space is consistent with the spaces 245 assert(virtual_space()->committed_size() >= 246 (eden_space()->capacity_in_bytes() + 247 to_space()->capacity_in_bytes() + 248 from_space()->capacity_in_bytes()), "Committed size is inconsistent"); 249 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(), 250 "Space invariant"); 251 char* eden_top = (char*)eden_space()->top(); 252 char* from_top = (char*)from_space()->top(); 253 char* to_top = (char*)to_space()->top(); 254 assert(eden_top <= virtual_space()->high(), "eden top"); 255 assert(from_top <= virtual_space()->high(), "from top"); 256 assert(to_top <= virtual_space()->high(), "to top"); 257 258 virtual_space()->verify(); 259 } 260 #endif 261 262 void PSYoungGen::resize(size_t eden_size, size_t survivor_size) { 263 // Resize the generation if needed. If the generation resize 264 // reports false, do not attempt to resize the spaces. 265 if (resize_generation(eden_size, survivor_size)) { 266 // Then we lay out the spaces inside the generation 267 resize_spaces(eden_size, survivor_size); 268 269 space_invariants(); 270 271 if (PrintAdaptiveSizePolicy && Verbose) { 272 gclog_or_tty->print_cr("Young generation size: " 273 "desired eden: " SIZE_FORMAT " survivor: " SIZE_FORMAT 274 " used: " SIZE_FORMAT " capacity: " SIZE_FORMAT 275 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT, 276 eden_size, survivor_size, used_in_bytes(), capacity_in_bytes(), 277 _max_gen_size, min_gen_size()); 278 } 279 } 280 } 281 282 283 bool PSYoungGen::resize_generation(size_t eden_size, size_t survivor_size) { 284 const size_t alignment = virtual_space()->alignment(); 285 size_t orig_size = virtual_space()->committed_size(); 286 bool size_changed = false; 287 288 // There used to be this guarantee there. 289 // guarantee ((eden_size + 2*survivor_size) <= _max_gen_size, "incorrect input arguments"); 290 // Code below forces this requirement. In addition the desired eden 291 // size and desired survivor sizes are desired goals and may 292 // exceed the total generation size. 293 294 assert(min_gen_size() <= orig_size && orig_size <= max_size(), "just checking"); 295 296 // Adjust new generation size 297 const size_t eden_plus_survivors = 298 align_size_up(eden_size + 2 * survivor_size, alignment); 299 size_t desired_size = MAX2(MIN2(eden_plus_survivors, max_size()), 300 min_gen_size()); 301 assert(desired_size <= max_size(), "just checking"); 302 303 if (desired_size > orig_size) { 304 // Grow the generation 305 size_t change = desired_size - orig_size; 306 assert(change % alignment == 0, "just checking"); 307 HeapWord* prev_high = (HeapWord*) virtual_space()->high(); 308 if (!virtual_space()->expand_by(change)) { 309 return false; // Error if we fail to resize! 310 } 311 if (ZapUnusedHeapArea) { 312 // Mangle newly committed space immediately because it 313 // can be done here more simply that after the new 314 // spaces have been computed. 315 HeapWord* new_high = (HeapWord*) virtual_space()->high(); 316 MemRegion mangle_region(prev_high, new_high); 317 SpaceMangler::mangle_region(mangle_region); 318 } 319 size_changed = true; 320 } else if (desired_size < orig_size) { 321 size_t desired_change = orig_size - desired_size; 322 assert(desired_change % alignment == 0, "just checking"); 323 324 desired_change = limit_gen_shrink(desired_change); 325 326 if (desired_change > 0) { 327 virtual_space()->shrink_by(desired_change); 328 reset_survivors_after_shrink(); 329 330 size_changed = true; 331 } 332 } else { 333 if (Verbose && PrintGC) { 334 if (orig_size == gen_size_limit()) { 335 gclog_or_tty->print_cr("PSYoung generation size at maximum: " 336 SIZE_FORMAT "K", orig_size/K); 337 } else if (orig_size == min_gen_size()) { 338 gclog_or_tty->print_cr("PSYoung generation size at minium: " 339 SIZE_FORMAT "K", orig_size/K); 340 } 341 } 342 } 343 344 if (size_changed) { 345 post_resize(); 346 347 if (Verbose && PrintGC) { 348 size_t current_size = virtual_space()->committed_size(); 349 gclog_or_tty->print_cr("PSYoung generation size changed: " 350 SIZE_FORMAT "K->" SIZE_FORMAT "K", 351 orig_size/K, current_size/K); 352 } 353 } 354 355 guarantee(eden_plus_survivors <= virtual_space()->committed_size() || 356 virtual_space()->committed_size() == max_size(), "Sanity"); 357 358 return true; 359 } 360 361 #ifndef PRODUCT 362 // In the numa case eden is not mangled so a survivor space 363 // moving into a region previously occupied by a survivor 364 // may find an unmangled region. Also in the PS case eden 365 // to-space and from-space may not touch (i.e., there may be 366 // gaps between them due to movement while resizing the 367 // spaces). Those gaps must be mangled. 368 void PSYoungGen::mangle_survivors(MutableSpace* s1, 369 MemRegion s1MR, 370 MutableSpace* s2, 371 MemRegion s2MR) { 372 // Check eden and gap between eden and from-space, in deciding 373 // what to mangle in from-space. Check the gap between from-space 374 // and to-space when deciding what to mangle. 375 // 376 // +--------+ +----+ +---+ 377 // | eden | |s1 | |s2 | 378 // +--------+ +----+ +---+ 379 // +-------+ +-----+ 380 // |s1MR | |s2MR | 381 // +-------+ +-----+ 382 // All of survivor-space is properly mangled so find the 383 // upper bound on the mangling for any portion above current s1. 384 HeapWord* delta_end = MIN2(s1->bottom(), s1MR.end()); 385 MemRegion delta1_left; 386 if (s1MR.start() < delta_end) { 387 delta1_left = MemRegion(s1MR.start(), delta_end); 388 s1->mangle_region(delta1_left); 389 } 390 // Find any portion to the right of the current s1. 391 HeapWord* delta_start = MAX2(s1->end(), s1MR.start()); 392 MemRegion delta1_right; 393 if (delta_start < s1MR.end()) { 394 delta1_right = MemRegion(delta_start, s1MR.end()); 395 s1->mangle_region(delta1_right); 396 } 397 398 // Similarly for the second survivor space except that 399 // any of the new region that overlaps with the current 400 // region of the first survivor space has already been 401 // mangled. 402 delta_end = MIN2(s2->bottom(), s2MR.end()); 403 delta_start = MAX2(s2MR.start(), s1->end()); 404 MemRegion delta2_left; 405 if (s2MR.start() < delta_end) { 406 delta2_left = MemRegion(s2MR.start(), delta_end); 407 s2->mangle_region(delta2_left); 408 } 409 delta_start = MAX2(s2->end(), s2MR.start()); 410 MemRegion delta2_right; 411 if (delta_start < s2MR.end()) { 412 s2->mangle_region(delta2_right); 413 } 414 415 if (TraceZapUnusedHeapArea) { 416 // s1 417 gclog_or_tty->print_cr("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") " 418 "New region: [" PTR_FORMAT ", " PTR_FORMAT ")", 419 p2i(s1->bottom()), p2i(s1->end()), 420 p2i(s1MR.start()), p2i(s1MR.end())); 421 gclog_or_tty->print_cr(" Mangle before: [" PTR_FORMAT ", " 422 PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")", 423 p2i(delta1_left.start()), p2i(delta1_left.end()), 424 p2i(delta1_right.start()), p2i(delta1_right.end())); 425 426 // s2 427 gclog_or_tty->print_cr("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") " 428 "New region: [" PTR_FORMAT ", " PTR_FORMAT ")", 429 p2i(s2->bottom()), p2i(s2->end()), 430 p2i(s2MR.start()), p2i(s2MR.end())); 431 gclog_or_tty->print_cr(" Mangle before: [" PTR_FORMAT ", " 432 PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")", 433 p2i(delta2_left.start()), p2i(delta2_left.end()), 434 p2i(delta2_right.start()), p2i(delta2_right.end())); 435 } 436 437 } 438 #endif // NOT PRODUCT 439 440 void PSYoungGen::resize_spaces(size_t requested_eden_size, 441 size_t requested_survivor_size) { 442 assert(UseAdaptiveSizePolicy, "sanity check"); 443 assert(requested_eden_size > 0 && requested_survivor_size > 0, 444 "just checking"); 445 446 // We require eden and to space to be empty 447 if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) { 448 return; 449 } 450 451 if (PrintAdaptiveSizePolicy && Verbose) { 452 gclog_or_tty->print_cr("PSYoungGen::resize_spaces(requested_eden_size: " 453 SIZE_FORMAT 454 ", requested_survivor_size: " SIZE_FORMAT ")", 455 requested_eden_size, requested_survivor_size); 456 gclog_or_tty->print_cr(" eden: [" PTR_FORMAT ".." PTR_FORMAT ") " 457 SIZE_FORMAT, 458 p2i(eden_space()->bottom()), 459 p2i(eden_space()->end()), 460 pointer_delta(eden_space()->end(), 461 eden_space()->bottom(), 462 sizeof(char))); 463 gclog_or_tty->print_cr(" from: [" PTR_FORMAT ".." PTR_FORMAT ") " 464 SIZE_FORMAT, 465 p2i(from_space()->bottom()), 466 p2i(from_space()->end()), 467 pointer_delta(from_space()->end(), 468 from_space()->bottom(), 469 sizeof(char))); 470 gclog_or_tty->print_cr(" to: [" PTR_FORMAT ".." PTR_FORMAT ") " 471 SIZE_FORMAT, 472 p2i(to_space()->bottom()), 473 p2i(to_space()->end()), 474 pointer_delta( to_space()->end(), 475 to_space()->bottom(), 476 sizeof(char))); 477 } 478 479 // There's nothing to do if the new sizes are the same as the current 480 if (requested_survivor_size == to_space()->capacity_in_bytes() && 481 requested_survivor_size == from_space()->capacity_in_bytes() && 482 requested_eden_size == eden_space()->capacity_in_bytes()) { 483 if (PrintAdaptiveSizePolicy && Verbose) { 484 gclog_or_tty->print_cr(" capacities are the right sizes, returning"); 485 } 486 return; 487 } 488 489 char* eden_start = (char*)eden_space()->bottom(); 490 char* eden_end = (char*)eden_space()->end(); 491 char* from_start = (char*)from_space()->bottom(); 492 char* from_end = (char*)from_space()->end(); 493 char* to_start = (char*)to_space()->bottom(); 494 char* to_end = (char*)to_space()->end(); 495 496 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 497 const size_t alignment = heap->space_alignment(); 498 const bool maintain_minimum = 499 (requested_eden_size + 2 * requested_survivor_size) <= min_gen_size(); 500 501 bool eden_from_to_order = from_start < to_start; 502 // Check whether from space is below to space 503 if (eden_from_to_order) { 504 // Eden, from, to 505 eden_from_to_order = true; 506 if (PrintAdaptiveSizePolicy && Verbose) { 507 gclog_or_tty->print_cr(" Eden, from, to:"); 508 } 509 510 // Set eden 511 // "requested_eden_size" is a goal for the size of eden 512 // and may not be attainable. "eden_size" below is 513 // calculated based on the location of from-space and 514 // the goal for the size of eden. from-space is 515 // fixed in place because it contains live data. 516 // The calculation is done this way to avoid 32bit 517 // overflow (i.e., eden_start + requested_eden_size 518 // may too large for representation in 32bits). 519 size_t eden_size; 520 if (maintain_minimum) { 521 // Only make eden larger than the requested size if 522 // the minimum size of the generation has to be maintained. 523 // This could be done in general but policy at a higher 524 // level is determining a requested size for eden and that 525 // should be honored unless there is a fundamental reason. 526 eden_size = pointer_delta(from_start, 527 eden_start, 528 sizeof(char)); 529 } else { 530 eden_size = MIN2(requested_eden_size, 531 pointer_delta(from_start, eden_start, sizeof(char))); 532 } 533 534 eden_end = eden_start + eden_size; 535 assert(eden_end >= eden_start, "addition overflowed"); 536 537 // To may resize into from space as long as it is clear of live data. 538 // From space must remain page aligned, though, so we need to do some 539 // extra calculations. 540 541 // First calculate an optimal to-space 542 to_end = (char*)virtual_space()->high(); 543 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size, 544 sizeof(char)); 545 546 // Does the optimal to-space overlap from-space? 547 if (to_start < (char*)from_space()->end()) { 548 // Calculate the minimum offset possible for from_end 549 size_t from_size = pointer_delta(from_space()->top(), from_start, sizeof(char)); 550 551 // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME! 552 if (from_size == 0) { 553 from_size = alignment; 554 } else { 555 from_size = align_size_up(from_size, alignment); 556 } 557 558 from_end = from_start + from_size; 559 assert(from_end > from_start, "addition overflow or from_size problem"); 560 561 guarantee(from_end <= (char*)from_space()->end(), "from_end moved to the right"); 562 563 // Now update to_start with the new from_end 564 to_start = MAX2(from_end, to_start); 565 } 566 567 guarantee(to_start != to_end, "to space is zero sized"); 568 569 if (PrintAdaptiveSizePolicy && Verbose) { 570 gclog_or_tty->print_cr(" [eden_start .. eden_end): " 571 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 572 p2i(eden_start), 573 p2i(eden_end), 574 pointer_delta(eden_end, eden_start, sizeof(char))); 575 gclog_or_tty->print_cr(" [from_start .. from_end): " 576 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 577 p2i(from_start), 578 p2i(from_end), 579 pointer_delta(from_end, from_start, sizeof(char))); 580 gclog_or_tty->print_cr(" [ to_start .. to_end): " 581 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 582 p2i(to_start), 583 p2i(to_end), 584 pointer_delta( to_end, to_start, sizeof(char))); 585 } 586 } else { 587 // Eden, to, from 588 if (PrintAdaptiveSizePolicy && Verbose) { 589 gclog_or_tty->print_cr(" Eden, to, from:"); 590 } 591 592 // To space gets priority over eden resizing. Note that we position 593 // to space as if we were able to resize from space, even though from 594 // space is not modified. 595 // Giving eden priority was tried and gave poorer performance. 596 to_end = (char*)pointer_delta(virtual_space()->high(), 597 (char*)requested_survivor_size, 598 sizeof(char)); 599 to_end = MIN2(to_end, from_start); 600 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size, 601 sizeof(char)); 602 // if the space sizes are to be increased by several times then 603 // 'to_start' will point beyond the young generation. In this case 604 // 'to_start' should be adjusted. 605 to_start = MAX2(to_start, eden_start + alignment); 606 607 // Compute how big eden can be, then adjust end. 608 // See comments above on calculating eden_end. 609 size_t eden_size; 610 if (maintain_minimum) { 611 eden_size = pointer_delta(to_start, eden_start, sizeof(char)); 612 } else { 613 eden_size = MIN2(requested_eden_size, 614 pointer_delta(to_start, eden_start, sizeof(char))); 615 } 616 eden_end = eden_start + eden_size; 617 assert(eden_end >= eden_start, "addition overflowed"); 618 619 // Could choose to not let eden shrink 620 // to_start = MAX2(to_start, eden_end); 621 622 // Don't let eden shrink down to 0 or less. 623 eden_end = MAX2(eden_end, eden_start + alignment); 624 to_start = MAX2(to_start, eden_end); 625 626 if (PrintAdaptiveSizePolicy && Verbose) { 627 gclog_or_tty->print_cr(" [eden_start .. eden_end): " 628 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 629 p2i(eden_start), 630 p2i(eden_end), 631 pointer_delta(eden_end, eden_start, sizeof(char))); 632 gclog_or_tty->print_cr(" [ to_start .. to_end): " 633 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 634 p2i(to_start), 635 p2i(to_end), 636 pointer_delta( to_end, to_start, sizeof(char))); 637 gclog_or_tty->print_cr(" [from_start .. from_end): " 638 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 639 p2i(from_start), 640 p2i(from_end), 641 pointer_delta(from_end, from_start, sizeof(char))); 642 } 643 } 644 645 646 guarantee((HeapWord*)from_start <= from_space()->bottom(), 647 "from start moved to the right"); 648 guarantee((HeapWord*)from_end >= from_space()->top(), 649 "from end moved into live data"); 650 assert(is_object_aligned((intptr_t)eden_start), "checking alignment"); 651 assert(is_object_aligned((intptr_t)from_start), "checking alignment"); 652 assert(is_object_aligned((intptr_t)to_start), "checking alignment"); 653 654 MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)eden_end); 655 MemRegion toMR ((HeapWord*)to_start, (HeapWord*)to_end); 656 MemRegion fromMR((HeapWord*)from_start, (HeapWord*)from_end); 657 658 // Let's make sure the call to initialize doesn't reset "top"! 659 HeapWord* old_from_top = from_space()->top(); 660 661 // For PrintAdaptiveSizePolicy block below 662 size_t old_from = from_space()->capacity_in_bytes(); 663 size_t old_to = to_space()->capacity_in_bytes(); 664 665 if (ZapUnusedHeapArea) { 666 // NUMA is a special case because a numa space is not mangled 667 // in order to not prematurely bind its address to memory to 668 // the wrong memory (i.e., don't want the GC thread to first 669 // touch the memory). The survivor spaces are not numa 670 // spaces and are mangled. 671 if (UseNUMA) { 672 if (eden_from_to_order) { 673 mangle_survivors(from_space(), fromMR, to_space(), toMR); 674 } else { 675 mangle_survivors(to_space(), toMR, from_space(), fromMR); 676 } 677 } 678 679 // If not mangling the spaces, do some checking to verify that 680 // the spaces are already mangled. 681 // The spaces should be correctly mangled at this point so 682 // do some checking here. Note that they are not being mangled 683 // in the calls to initialize(). 684 // Must check mangling before the spaces are reshaped. Otherwise, 685 // the bottom or end of one space may have moved into an area 686 // covered by another space and a failure of the check may 687 // not correctly indicate which space is not properly mangled. 688 HeapWord* limit = (HeapWord*) virtual_space()->high(); 689 eden_space()->check_mangled_unused_area(limit); 690 from_space()->check_mangled_unused_area(limit); 691 to_space()->check_mangled_unused_area(limit); 692 } 693 // When an existing space is being initialized, it is not 694 // mangled because the space has been previously mangled. 695 eden_space()->initialize(edenMR, 696 SpaceDecorator::Clear, 697 SpaceDecorator::DontMangle); 698 to_space()->initialize(toMR, 699 SpaceDecorator::Clear, 700 SpaceDecorator::DontMangle); 701 from_space()->initialize(fromMR, 702 SpaceDecorator::DontClear, 703 SpaceDecorator::DontMangle); 704 705 assert(from_space()->top() == old_from_top, "from top changed!"); 706 707 if (PrintAdaptiveSizePolicy) { 708 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 709 gclog_or_tty->print("AdaptiveSizePolicy::survivor space sizes: " 710 "collection: %d " 711 "(" SIZE_FORMAT ", " SIZE_FORMAT ") -> " 712 "(" SIZE_FORMAT ", " SIZE_FORMAT ") ", 713 heap->total_collections(), 714 old_from, old_to, 715 from_space()->capacity_in_bytes(), 716 to_space()->capacity_in_bytes()); 717 gclog_or_tty->cr(); 718 } 719 } 720 721 void PSYoungGen::swap_spaces() { 722 MutableSpace* s = from_space(); 723 _from_space = to_space(); 724 _to_space = s; 725 726 // Now update the decorators. 727 PSMarkSweepDecorator* md = from_mark_sweep(); 728 _from_mark_sweep = to_mark_sweep(); 729 _to_mark_sweep = md; 730 731 assert(from_mark_sweep()->space() == from_space(), "Sanity"); 732 assert(to_mark_sweep()->space() == to_space(), "Sanity"); 733 } 734 735 size_t PSYoungGen::capacity_in_bytes() const { 736 return eden_space()->capacity_in_bytes() 737 + from_space()->capacity_in_bytes(); // to_space() is only used during scavenge 738 } 739 740 741 size_t PSYoungGen::used_in_bytes() const { 742 return eden_space()->used_in_bytes() 743 + from_space()->used_in_bytes(); // to_space() is only used during scavenge 744 } 745 746 747 size_t PSYoungGen::free_in_bytes() const { 748 return eden_space()->free_in_bytes() 749 + from_space()->free_in_bytes(); // to_space() is only used during scavenge 750 } 751 752 size_t PSYoungGen::capacity_in_words() const { 753 return eden_space()->capacity_in_words() 754 + from_space()->capacity_in_words(); // to_space() is only used during scavenge 755 } 756 757 758 size_t PSYoungGen::used_in_words() const { 759 return eden_space()->used_in_words() 760 + from_space()->used_in_words(); // to_space() is only used during scavenge 761 } 762 763 764 size_t PSYoungGen::free_in_words() const { 765 return eden_space()->free_in_words() 766 + from_space()->free_in_words(); // to_space() is only used during scavenge 767 } 768 769 void PSYoungGen::object_iterate(ObjectClosure* blk) { 770 eden_space()->object_iterate(blk); 771 from_space()->object_iterate(blk); 772 to_space()->object_iterate(blk); 773 } 774 775 void PSYoungGen::precompact() { 776 eden_mark_sweep()->precompact(); 777 from_mark_sweep()->precompact(); 778 to_mark_sweep()->precompact(); 779 } 780 781 void PSYoungGen::adjust_pointers() { 782 eden_mark_sweep()->adjust_pointers(); 783 from_mark_sweep()->adjust_pointers(); 784 to_mark_sweep()->adjust_pointers(); 785 } 786 787 void PSYoungGen::compact() { 788 eden_mark_sweep()->compact(ZapUnusedHeapArea); 789 from_mark_sweep()->compact(ZapUnusedHeapArea); 790 // Mark sweep stores preserved markOops in to space, don't disturb! 791 to_mark_sweep()->compact(false); 792 } 793 794 void PSYoungGen::print() const { print_on(tty); } 795 void PSYoungGen::print_on(outputStream* st) const { 796 st->print(" %-15s", "PSYoungGen"); 797 if (PrintGCDetails && Verbose) { 798 st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT, 799 capacity_in_bytes(), used_in_bytes()); 800 } else { 801 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K", 802 capacity_in_bytes()/K, used_in_bytes()/K); 803 } 804 virtual_space()->print_space_boundaries_on(st); 805 st->print(" eden"); eden_space()->print_on(st); 806 st->print(" from"); from_space()->print_on(st); 807 st->print(" to "); to_space()->print_on(st); 808 } 809 810 // Note that a space is not printed before the [NAME: 811 void PSYoungGen::print_used_change(size_t prev_used) const { 812 gclog_or_tty->print("[%s:", name()); 813 gclog_or_tty->print(" " SIZE_FORMAT "K" 814 "->" SIZE_FORMAT "K" 815 "(" SIZE_FORMAT "K)", 816 prev_used / K, used_in_bytes() / K, 817 capacity_in_bytes() / K); 818 gclog_or_tty->print("]"); 819 } 820 821 size_t PSYoungGen::available_for_expansion() { 822 ShouldNotReachHere(); 823 } 824 825 size_t PSYoungGen::available_for_contraction() { 826 ShouldNotReachHere(); 827 } 828 829 size_t PSYoungGen::available_to_min_gen() { 830 assert(virtual_space()->committed_size() >= min_gen_size(), "Invariant"); 831 return virtual_space()->committed_size() - min_gen_size(); 832 } 833 834 // This method assumes that from-space has live data and that 835 // any shrinkage of the young gen is limited by location of 836 // from-space. 837 size_t PSYoungGen::available_to_live() { 838 size_t delta_in_survivor = 0; 839 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 840 const size_t space_alignment = heap->space_alignment(); 841 const size_t gen_alignment = heap->generation_alignment(); 842 843 MutableSpace* space_shrinking = NULL; 844 if (from_space()->end() > to_space()->end()) { 845 space_shrinking = from_space(); 846 } else { 847 space_shrinking = to_space(); 848 } 849 850 // Include any space that is committed but not included in 851 // the survivor spaces. 852 assert(((HeapWord*)virtual_space()->high()) >= space_shrinking->end(), 853 "Survivor space beyond high end"); 854 size_t unused_committed = pointer_delta(virtual_space()->high(), 855 space_shrinking->end(), sizeof(char)); 856 857 if (space_shrinking->is_empty()) { 858 // Don't let the space shrink to 0 859 assert(space_shrinking->capacity_in_bytes() >= space_alignment, 860 "Space is too small"); 861 delta_in_survivor = space_shrinking->capacity_in_bytes() - space_alignment; 862 } else { 863 delta_in_survivor = pointer_delta(space_shrinking->end(), 864 space_shrinking->top(), 865 sizeof(char)); 866 } 867 868 size_t delta_in_bytes = unused_committed + delta_in_survivor; 869 delta_in_bytes = align_size_down(delta_in_bytes, gen_alignment); 870 return delta_in_bytes; 871 } 872 873 // Return the number of bytes available for resizing down the young 874 // generation. This is the minimum of 875 // input "bytes" 876 // bytes to the minimum young gen size 877 // bytes to the size currently being used + some small extra 878 size_t PSYoungGen::limit_gen_shrink(size_t bytes) { 879 // Allow shrinkage into the current eden but keep eden large enough 880 // to maintain the minimum young gen size 881 bytes = MIN3(bytes, available_to_min_gen(), available_to_live()); 882 return align_size_down(bytes, virtual_space()->alignment()); 883 } 884 885 void PSYoungGen::reset_after_change() { 886 ShouldNotReachHere(); 887 } 888 889 void PSYoungGen::reset_survivors_after_shrink() { 890 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(), 891 (HeapWord*)virtual_space()->high_boundary()); 892 PSScavenge::reference_processor()->set_span(_reserved); 893 894 MutableSpace* space_shrinking = NULL; 895 if (from_space()->end() > to_space()->end()) { 896 space_shrinking = from_space(); 897 } else { 898 space_shrinking = to_space(); 899 } 900 901 HeapWord* new_end = (HeapWord*)virtual_space()->high(); 902 assert(new_end >= space_shrinking->bottom(), "Shrink was too large"); 903 // Was there a shrink of the survivor space? 904 if (new_end < space_shrinking->end()) { 905 MemRegion mr(space_shrinking->bottom(), new_end); 906 space_shrinking->initialize(mr, 907 SpaceDecorator::DontClear, 908 SpaceDecorator::Mangle); 909 } 910 } 911 912 // This method currently does not expect to expand into eden (i.e., 913 // the virtual space boundaries is expected to be consistent 914 // with the eden boundaries.. 915 void PSYoungGen::post_resize() { 916 assert_locked_or_safepoint(Heap_lock); 917 assert((eden_space()->bottom() < to_space()->bottom()) && 918 (eden_space()->bottom() < from_space()->bottom()), 919 "Eden is assumed to be below the survivor spaces"); 920 921 MemRegion cmr((HeapWord*)virtual_space()->low(), 922 (HeapWord*)virtual_space()->high()); 923 ParallelScavengeHeap::heap()->barrier_set()->resize_covered_region(cmr); 924 space_invariants(); 925 } 926 927 928 929 void PSYoungGen::update_counters() { 930 if (UsePerfData) { 931 _eden_counters->update_all(); 932 _from_counters->update_all(); 933 _to_counters->update_all(); 934 _gen_counters->update_all(); 935 } 936 } 937 938 void PSYoungGen::verify() { 939 eden_space()->verify(); 940 from_space()->verify(); 941 to_space()->verify(); 942 } 943 944 #ifndef PRODUCT 945 void PSYoungGen::record_spaces_top() { 946 assert(ZapUnusedHeapArea, "Not mangling unused space"); 947 eden_space()->set_top_for_allocations(); 948 from_space()->set_top_for_allocations(); 949 to_space()->set_top_for_allocations(); 950 } 951 #endif