1 /* 2 * Copyright (c) 2003, 2008, 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 "incls/_precompiled.incl" 26 # include "incls/_asPSYoungGen.cpp.incl" 27 28 ASPSYoungGen::ASPSYoungGen(size_t init_byte_size, 29 size_t minimum_byte_size, 30 size_t byte_size_limit) : 31 PSYoungGen(init_byte_size, minimum_byte_size, byte_size_limit), 32 _gen_size_limit(byte_size_limit) { 33 } 34 35 36 ASPSYoungGen::ASPSYoungGen(PSVirtualSpace* vs, 37 size_t init_byte_size, 38 size_t minimum_byte_size, 39 size_t byte_size_limit) : 40 //PSYoungGen(init_byte_size, minimum_byte_size, byte_size_limit), 41 PSYoungGen(vs->committed_size(), minimum_byte_size, byte_size_limit), 42 _gen_size_limit(byte_size_limit) { 43 44 assert(vs->committed_size() == init_byte_size, "Cannot replace with"); 45 46 _virtual_space = vs; 47 } 48 49 void ASPSYoungGen::initialize_virtual_space(ReservedSpace rs, 50 size_t alignment) { 51 assert(_init_gen_size != 0, "Should have a finite size"); 52 _virtual_space = new PSVirtualSpaceHighToLow(rs, alignment); 53 if (!_virtual_space->expand_by(_init_gen_size)) { 54 vm_exit_during_initialization("Could not reserve enough space for " 55 "object heap"); 56 } 57 } 58 59 void ASPSYoungGen::initialize(ReservedSpace rs, size_t alignment) { 60 initialize_virtual_space(rs, alignment); 61 initialize_work(); 62 } 63 64 size_t ASPSYoungGen::available_for_expansion() { 65 66 size_t current_committed_size = virtual_space()->committed_size(); 67 assert((gen_size_limit() >= current_committed_size), 68 "generation size limit is wrong"); 69 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 70 size_t result = gen_size_limit() - current_committed_size; 71 size_t result_aligned = align_size_down(result, heap->young_gen_alignment()); 72 return result_aligned; 73 } 74 75 // Return the number of bytes the young gen is willing give up. 76 // 77 // Future implementations could check the survivors and if to_space is in the 78 // right place (below from_space), take a chunk from to_space. 79 size_t ASPSYoungGen::available_for_contraction() { 80 81 size_t uncommitted_bytes = virtual_space()->uncommitted_size(); 82 if (uncommitted_bytes != 0) { 83 return uncommitted_bytes; 84 } 85 86 if (eden_space()->is_empty()) { 87 // Respect the minimum size for eden and for the young gen as a whole. 88 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 89 const size_t eden_alignment = heap->intra_heap_alignment(); 90 const size_t gen_alignment = heap->young_gen_alignment(); 91 92 assert(eden_space()->capacity_in_bytes() >= eden_alignment, 93 "Alignment is wrong"); 94 size_t eden_avail = eden_space()->capacity_in_bytes() - eden_alignment; 95 eden_avail = align_size_down(eden_avail, gen_alignment); 96 97 assert(virtual_space()->committed_size() >= min_gen_size(), 98 "minimum gen size is wrong"); 99 size_t gen_avail = virtual_space()->committed_size() - min_gen_size(); 100 assert(virtual_space()->is_aligned(gen_avail), "not aligned"); 101 102 const size_t max_contraction = MIN2(eden_avail, gen_avail); 103 // See comment for ASPSOldGen::available_for_contraction() 104 // for reasons the "increment" fraction is used. 105 PSAdaptiveSizePolicy* policy = heap->size_policy(); 106 size_t result = policy->eden_increment_aligned_down(max_contraction); 107 size_t result_aligned = align_size_down(result, gen_alignment); 108 if (PrintAdaptiveSizePolicy && Verbose) { 109 gclog_or_tty->print_cr("ASPSYoungGen::available_for_contraction: %d K", 110 result_aligned/K); 111 gclog_or_tty->print_cr(" max_contraction %d K", max_contraction/K); 112 gclog_or_tty->print_cr(" eden_avail %d K", eden_avail/K); 113 gclog_or_tty->print_cr(" gen_avail %d K", gen_avail/K); 114 } 115 return result_aligned; 116 117 } 118 119 return 0; 120 } 121 122 // The current implementation only considers to the end of eden. 123 // If to_space is below from_space, to_space is not considered. 124 // to_space can be. 125 size_t ASPSYoungGen::available_to_live() { 126 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 127 const size_t alignment = heap->intra_heap_alignment(); 128 129 // Include any space that is committed but is not in eden. 130 size_t available = pointer_delta(eden_space()->bottom(), 131 virtual_space()->low(), 132 sizeof(char)); 133 134 const size_t eden_capacity = eden_space()->capacity_in_bytes(); 135 if (eden_space()->is_empty() && eden_capacity > alignment) { 136 available += eden_capacity - alignment; 137 } 138 return available; 139 } 140 141 // Similar to PSYoungGen::resize_generation() but 142 // allows sum of eden_size and 2 * survivor_size to exceed _max_gen_size 143 // expands at the low end of the virtual space 144 // moves the boundary between the generations in order to expand 145 // some additional diagnostics 146 // If no additional changes are required, this can be deleted 147 // and the changes factored back into PSYoungGen::resize_generation(). 148 bool ASPSYoungGen::resize_generation(size_t eden_size, size_t survivor_size) { 149 const size_t alignment = virtual_space()->alignment(); 150 size_t orig_size = virtual_space()->committed_size(); 151 bool size_changed = false; 152 153 // There used to be a guarantee here that 154 // (eden_size + 2*survivor_size) <= _max_gen_size 155 // This requirement is enforced by the calculation of desired_size 156 // below. It may not be true on entry since the size of the 157 // eden_size is no bounded by the generation size. 158 159 assert(max_size() == reserved().byte_size(), "max gen size problem?"); 160 assert(min_gen_size() <= orig_size && orig_size <= max_size(), 161 "just checking"); 162 163 // Adjust new generation size 164 const size_t eden_plus_survivors = 165 align_size_up(eden_size + 2 * survivor_size, alignment); 166 size_t desired_size = MAX2(MIN2(eden_plus_survivors, gen_size_limit()), 167 min_gen_size()); 168 assert(desired_size <= gen_size_limit(), "just checking"); 169 170 if (desired_size > orig_size) { 171 // Grow the generation 172 size_t change = desired_size - orig_size; 173 HeapWord* prev_low = (HeapWord*) virtual_space()->low(); 174 if (!virtual_space()->expand_by(change)) { 175 return false; 176 } 177 if (ZapUnusedHeapArea) { 178 // Mangle newly committed space immediately because it 179 // can be done here more simply that after the new 180 // spaces have been computed. 181 HeapWord* new_low = (HeapWord*) virtual_space()->low(); 182 assert(new_low < prev_low, "Did not grow"); 183 184 MemRegion mangle_region(new_low, prev_low); 185 SpaceMangler::mangle_region(mangle_region); 186 } 187 size_changed = true; 188 } else if (desired_size < orig_size) { 189 size_t desired_change = orig_size - desired_size; 190 191 // How much is available for shrinking. 192 size_t available_bytes = limit_gen_shrink(desired_change); 193 size_t change = MIN2(desired_change, available_bytes); 194 virtual_space()->shrink_by(change); 195 size_changed = true; 196 } else { 197 if (Verbose && PrintGC) { 198 if (orig_size == gen_size_limit()) { 199 gclog_or_tty->print_cr("ASPSYoung generation size at maximum: " 200 SIZE_FORMAT "K", orig_size/K); 201 } else if (orig_size == min_gen_size()) { 202 gclog_or_tty->print_cr("ASPSYoung generation size at minium: " 203 SIZE_FORMAT "K", orig_size/K); 204 } 205 } 206 } 207 208 if (size_changed) { 209 reset_after_change(); 210 if (Verbose && PrintGC) { 211 size_t current_size = virtual_space()->committed_size(); 212 gclog_or_tty->print_cr("ASPSYoung generation size changed: " 213 SIZE_FORMAT "K->" SIZE_FORMAT "K", 214 orig_size/K, current_size/K); 215 } 216 } 217 218 guarantee(eden_plus_survivors <= virtual_space()->committed_size() || 219 virtual_space()->committed_size() == max_size(), "Sanity"); 220 221 return true; 222 } 223 224 // Similar to PSYoungGen::resize_spaces() but 225 // eden always starts at the low end of the committed virtual space 226 // current implementation does not allow holes between the spaces 227 // _young_generation_boundary has to be reset because it changes. 228 // so additional verification 229 230 void ASPSYoungGen::resize_spaces(size_t requested_eden_size, 231 size_t requested_survivor_size) { 232 assert(UseAdaptiveSizePolicy, "sanity check"); 233 assert(requested_eden_size > 0 && requested_survivor_size > 0, 234 "just checking"); 235 236 space_invariants(); 237 238 // We require eden and to space to be empty 239 if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) { 240 return; 241 } 242 243 if (PrintAdaptiveSizePolicy && Verbose) { 244 gclog_or_tty->print_cr("PSYoungGen::resize_spaces(requested_eden_size: " 245 SIZE_FORMAT 246 ", requested_survivor_size: " SIZE_FORMAT ")", 247 requested_eden_size, requested_survivor_size); 248 gclog_or_tty->print_cr(" eden: [" PTR_FORMAT ".." PTR_FORMAT ") " 249 SIZE_FORMAT, 250 eden_space()->bottom(), 251 eden_space()->end(), 252 pointer_delta(eden_space()->end(), 253 eden_space()->bottom(), 254 sizeof(char))); 255 gclog_or_tty->print_cr(" from: [" PTR_FORMAT ".." PTR_FORMAT ") " 256 SIZE_FORMAT, 257 from_space()->bottom(), 258 from_space()->end(), 259 pointer_delta(from_space()->end(), 260 from_space()->bottom(), 261 sizeof(char))); 262 gclog_or_tty->print_cr(" to: [" PTR_FORMAT ".." PTR_FORMAT ") " 263 SIZE_FORMAT, 264 to_space()->bottom(), 265 to_space()->end(), 266 pointer_delta( to_space()->end(), 267 to_space()->bottom(), 268 sizeof(char))); 269 } 270 271 // There's nothing to do if the new sizes are the same as the current 272 if (requested_survivor_size == to_space()->capacity_in_bytes() && 273 requested_survivor_size == from_space()->capacity_in_bytes() && 274 requested_eden_size == eden_space()->capacity_in_bytes()) { 275 if (PrintAdaptiveSizePolicy && Verbose) { 276 gclog_or_tty->print_cr(" capacities are the right sizes, returning"); 277 } 278 return; 279 } 280 281 char* eden_start = (char*)virtual_space()->low(); 282 char* eden_end = (char*)eden_space()->end(); 283 char* from_start = (char*)from_space()->bottom(); 284 char* from_end = (char*)from_space()->end(); 285 char* to_start = (char*)to_space()->bottom(); 286 char* to_end = (char*)to_space()->end(); 287 288 assert(eden_start < from_start, "Cannot push into from_space"); 289 290 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 291 const size_t alignment = heap->intra_heap_alignment(); 292 const bool maintain_minimum = 293 (requested_eden_size + 2 * requested_survivor_size) <= min_gen_size(); 294 295 bool eden_from_to_order = from_start < to_start; 296 // Check whether from space is below to space 297 if (eden_from_to_order) { 298 // Eden, from, to 299 300 if (PrintAdaptiveSizePolicy && Verbose) { 301 gclog_or_tty->print_cr(" Eden, from, to:"); 302 } 303 304 // Set eden 305 // "requested_eden_size" is a goal for the size of eden 306 // and may not be attainable. "eden_size" below is 307 // calculated based on the location of from-space and 308 // the goal for the size of eden. from-space is 309 // fixed in place because it contains live data. 310 // The calculation is done this way to avoid 32bit 311 // overflow (i.e., eden_start + requested_eden_size 312 // may too large for representation in 32bits). 313 size_t eden_size; 314 if (maintain_minimum) { 315 // Only make eden larger than the requested size if 316 // the minimum size of the generation has to be maintained. 317 // This could be done in general but policy at a higher 318 // level is determining a requested size for eden and that 319 // should be honored unless there is a fundamental reason. 320 eden_size = pointer_delta(from_start, 321 eden_start, 322 sizeof(char)); 323 } else { 324 eden_size = MIN2(requested_eden_size, 325 pointer_delta(from_start, eden_start, sizeof(char))); 326 } 327 328 eden_end = eden_start + eden_size; 329 assert(eden_end >= eden_start, "addition overflowed"); 330 331 // To may resize into from space as long as it is clear of live data. 332 // From space must remain page aligned, though, so we need to do some 333 // extra calculations. 334 335 // First calculate an optimal to-space 336 to_end = (char*)virtual_space()->high(); 337 to_start = (char*)pointer_delta(to_end, 338 (char*)requested_survivor_size, 339 sizeof(char)); 340 341 // Does the optimal to-space overlap from-space? 342 if (to_start < (char*)from_space()->end()) { 343 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); 344 345 // Calculate the minimum offset possible for from_end 346 size_t from_size = 347 pointer_delta(from_space()->top(), from_start, sizeof(char)); 348 349 // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME! 350 if (from_size == 0) { 351 from_size = alignment; 352 } else { 353 from_size = align_size_up(from_size, alignment); 354 } 355 356 from_end = from_start + from_size; 357 assert(from_end > from_start, "addition overflow or from_size problem"); 358 359 guarantee(from_end <= (char*)from_space()->end(), 360 "from_end moved to the right"); 361 362 // Now update to_start with the new from_end 363 to_start = MAX2(from_end, to_start); 364 } 365 366 guarantee(to_start != to_end, "to space is zero sized"); 367 368 if (PrintAdaptiveSizePolicy && Verbose) { 369 gclog_or_tty->print_cr(" [eden_start .. eden_end): " 370 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 371 eden_start, 372 eden_end, 373 pointer_delta(eden_end, eden_start, sizeof(char))); 374 gclog_or_tty->print_cr(" [from_start .. from_end): " 375 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 376 from_start, 377 from_end, 378 pointer_delta(from_end, from_start, sizeof(char))); 379 gclog_or_tty->print_cr(" [ to_start .. to_end): " 380 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 381 to_start, 382 to_end, 383 pointer_delta( to_end, to_start, sizeof(char))); 384 } 385 } else { 386 // Eden, to, from 387 if (PrintAdaptiveSizePolicy && Verbose) { 388 gclog_or_tty->print_cr(" Eden, to, from:"); 389 } 390 391 // To space gets priority over eden resizing. Note that we position 392 // to space as if we were able to resize from space, even though from 393 // space is not modified. 394 // Giving eden priority was tried and gave poorer performance. 395 to_end = (char*)pointer_delta(virtual_space()->high(), 396 (char*)requested_survivor_size, 397 sizeof(char)); 398 to_end = MIN2(to_end, from_start); 399 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size, 400 sizeof(char)); 401 // if the space sizes are to be increased by several times then 402 // 'to_start' will point beyond the young generation. In this case 403 // 'to_start' should be adjusted. 404 to_start = MAX2(to_start, eden_start + alignment); 405 406 // Compute how big eden can be, then adjust end. 407 // See comments above on calculating eden_end. 408 size_t eden_size; 409 if (maintain_minimum) { 410 eden_size = pointer_delta(to_start, eden_start, sizeof(char)); 411 } else { 412 eden_size = MIN2(requested_eden_size, 413 pointer_delta(to_start, eden_start, sizeof(char))); 414 } 415 eden_end = eden_start + eden_size; 416 assert(eden_end >= eden_start, "addition overflowed"); 417 418 // Don't let eden shrink down to 0 or less. 419 eden_end = MAX2(eden_end, eden_start + alignment); 420 to_start = MAX2(to_start, eden_end); 421 422 if (PrintAdaptiveSizePolicy && Verbose) { 423 gclog_or_tty->print_cr(" [eden_start .. eden_end): " 424 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 425 eden_start, 426 eden_end, 427 pointer_delta(eden_end, eden_start, sizeof(char))); 428 gclog_or_tty->print_cr(" [ to_start .. to_end): " 429 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 430 to_start, 431 to_end, 432 pointer_delta( to_end, to_start, sizeof(char))); 433 gclog_or_tty->print_cr(" [from_start .. from_end): " 434 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, 435 from_start, 436 from_end, 437 pointer_delta(from_end, from_start, sizeof(char))); 438 } 439 } 440 441 442 guarantee((HeapWord*)from_start <= from_space()->bottom(), 443 "from start moved to the right"); 444 guarantee((HeapWord*)from_end >= from_space()->top(), 445 "from end moved into live data"); 446 assert(is_object_aligned((intptr_t)eden_start), "checking alignment"); 447 assert(is_object_aligned((intptr_t)from_start), "checking alignment"); 448 assert(is_object_aligned((intptr_t)to_start), "checking alignment"); 449 450 MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)eden_end); 451 MemRegion toMR ((HeapWord*)to_start, (HeapWord*)to_end); 452 MemRegion fromMR((HeapWord*)from_start, (HeapWord*)from_end); 453 454 // Let's make sure the call to initialize doesn't reset "top"! 455 DEBUG_ONLY(HeapWord* old_from_top = from_space()->top();) 456 457 // For PrintAdaptiveSizePolicy block below 458 size_t old_from = from_space()->capacity_in_bytes(); 459 size_t old_to = to_space()->capacity_in_bytes(); 460 461 if (ZapUnusedHeapArea) { 462 // NUMA is a special case because a numa space is not mangled 463 // in order to not prematurely bind its address to memory to 464 // the wrong memory (i.e., don't want the GC thread to first 465 // touch the memory). The survivor spaces are not numa 466 // spaces and are mangled. 467 if (UseNUMA) { 468 if (eden_from_to_order) { 469 mangle_survivors(from_space(), fromMR, to_space(), toMR); 470 } else { 471 mangle_survivors(to_space(), toMR, from_space(), fromMR); 472 } 473 } 474 475 // If not mangling the spaces, do some checking to verify that 476 // the spaces are already mangled. 477 // The spaces should be correctly mangled at this point so 478 // do some checking here. Note that they are not being mangled 479 // in the calls to initialize(). 480 // Must check mangling before the spaces are reshaped. Otherwise, 481 // the bottom or end of one space may have moved into an area 482 // covered by another space and a failure of the check may 483 // not correctly indicate which space is not properly mangled. 484 485 HeapWord* limit = (HeapWord*) virtual_space()->high(); 486 eden_space()->check_mangled_unused_area(limit); 487 from_space()->check_mangled_unused_area(limit); 488 to_space()->check_mangled_unused_area(limit); 489 } 490 // When an existing space is being initialized, it is not 491 // mangled because the space has been previously mangled. 492 eden_space()->initialize(edenMR, 493 SpaceDecorator::Clear, 494 SpaceDecorator::DontMangle); 495 to_space()->initialize(toMR, 496 SpaceDecorator::Clear, 497 SpaceDecorator::DontMangle); 498 from_space()->initialize(fromMR, 499 SpaceDecorator::DontClear, 500 SpaceDecorator::DontMangle); 501 502 PSScavenge::set_young_generation_boundary(eden_space()->bottom()); 503 504 assert(from_space()->top() == old_from_top, "from top changed!"); 505 506 if (PrintAdaptiveSizePolicy) { 507 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 508 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); 509 510 gclog_or_tty->print("AdaptiveSizePolicy::survivor space sizes: " 511 "collection: %d " 512 "(" SIZE_FORMAT ", " SIZE_FORMAT ") -> " 513 "(" SIZE_FORMAT ", " SIZE_FORMAT ") ", 514 heap->total_collections(), 515 old_from, old_to, 516 from_space()->capacity_in_bytes(), 517 to_space()->capacity_in_bytes()); 518 gclog_or_tty->cr(); 519 } 520 space_invariants(); 521 } 522 void ASPSYoungGen::reset_after_change() { 523 assert_locked_or_safepoint(Heap_lock); 524 525 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(), 526 (HeapWord*)virtual_space()->high_boundary()); 527 PSScavenge::reference_processor()->set_span(_reserved); 528 529 HeapWord* new_eden_bottom = (HeapWord*)virtual_space()->low(); 530 HeapWord* eden_bottom = eden_space()->bottom(); 531 if (new_eden_bottom != eden_bottom) { 532 MemRegion eden_mr(new_eden_bottom, eden_space()->end()); 533 eden_space()->initialize(eden_mr, 534 SpaceDecorator::Clear, 535 SpaceDecorator::Mangle); 536 PSScavenge::set_young_generation_boundary(eden_space()->bottom()); 537 } 538 MemRegion cmr((HeapWord*)virtual_space()->low(), 539 (HeapWord*)virtual_space()->high()); 540 Universe::heap()->barrier_set()->resize_covered_region(cmr); 541 542 space_invariants(); 543 }