1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/memory/generation.cpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,874 @@
1.4 +/*
1.5 + * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#include "precompiled.hpp"
1.29 +#include "gc_implementation/shared/gcTimer.hpp"
1.30 +#include "gc_implementation/shared/gcTrace.hpp"
1.31 +#include "gc_implementation/shared/spaceDecorator.hpp"
1.32 +#include "gc_interface/collectedHeap.inline.hpp"
1.33 +#include "memory/allocation.inline.hpp"
1.34 +#include "memory/blockOffsetTable.inline.hpp"
1.35 +#include "memory/cardTableRS.hpp"
1.36 +#include "memory/gcLocker.inline.hpp"
1.37 +#include "memory/genCollectedHeap.hpp"
1.38 +#include "memory/genMarkSweep.hpp"
1.39 +#include "memory/genOopClosures.hpp"
1.40 +#include "memory/genOopClosures.inline.hpp"
1.41 +#include "memory/generation.hpp"
1.42 +#include "memory/generation.inline.hpp"
1.43 +#include "memory/space.inline.hpp"
1.44 +#include "oops/oop.inline.hpp"
1.45 +#include "runtime/java.hpp"
1.46 +#include "utilities/copy.hpp"
1.47 +#include "utilities/events.hpp"
1.48 +
1.49 +PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
1.50 +
1.51 +Generation::Generation(ReservedSpace rs, size_t initial_size, int level) :
1.52 + _level(level),
1.53 + _ref_processor(NULL) {
1.54 + if (!_virtual_space.initialize(rs, initial_size)) {
1.55 + vm_exit_during_initialization("Could not reserve enough space for "
1.56 + "object heap");
1.57 + }
1.58 + // Mangle all of the the initial generation.
1.59 + if (ZapUnusedHeapArea) {
1.60 + MemRegion mangle_region((HeapWord*)_virtual_space.low(),
1.61 + (HeapWord*)_virtual_space.high());
1.62 + SpaceMangler::mangle_region(mangle_region);
1.63 + }
1.64 + _reserved = MemRegion((HeapWord*)_virtual_space.low_boundary(),
1.65 + (HeapWord*)_virtual_space.high_boundary());
1.66 +}
1.67 +
1.68 +GenerationSpec* Generation::spec() {
1.69 + GenCollectedHeap* gch = GenCollectedHeap::heap();
1.70 + assert(0 <= level() && level() < gch->_n_gens, "Bad gen level");
1.71 + return gch->_gen_specs[level()];
1.72 +}
1.73 +
1.74 +size_t Generation::max_capacity() const {
1.75 + return reserved().byte_size();
1.76 +}
1.77 +
1.78 +void Generation::print_heap_change(size_t prev_used) const {
1.79 + if (PrintGCDetails && Verbose) {
1.80 + gclog_or_tty->print(" " SIZE_FORMAT
1.81 + "->" SIZE_FORMAT
1.82 + "(" SIZE_FORMAT ")",
1.83 + prev_used, used(), capacity());
1.84 + } else {
1.85 + gclog_or_tty->print(" " SIZE_FORMAT "K"
1.86 + "->" SIZE_FORMAT "K"
1.87 + "(" SIZE_FORMAT "K)",
1.88 + prev_used / K, used() / K, capacity() / K);
1.89 + }
1.90 +}
1.91 +
1.92 +// By default we get a single threaded default reference processor;
1.93 +// generations needing multi-threaded refs processing or discovery override this method.
1.94 +void Generation::ref_processor_init() {
1.95 + assert(_ref_processor == NULL, "a reference processor already exists");
1.96 + assert(!_reserved.is_empty(), "empty generation?");
1.97 + _ref_processor = new ReferenceProcessor(_reserved); // a vanilla reference processor
1.98 + if (_ref_processor == NULL) {
1.99 + vm_exit_during_initialization("Could not allocate ReferenceProcessor object");
1.100 + }
1.101 +}
1.102 +
1.103 +void Generation::print() const { print_on(tty); }
1.104 +
1.105 +void Generation::print_on(outputStream* st) const {
1.106 + st->print(" %-20s", name());
1.107 + st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
1.108 + capacity()/K, used()/K);
1.109 + st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
1.110 + _virtual_space.low_boundary(),
1.111 + _virtual_space.high(),
1.112 + _virtual_space.high_boundary());
1.113 +}
1.114 +
1.115 +void Generation::print_summary_info() { print_summary_info_on(tty); }
1.116 +
1.117 +void Generation::print_summary_info_on(outputStream* st) {
1.118 + StatRecord* sr = stat_record();
1.119 + double time = sr->accumulated_time.seconds();
1.120 + st->print_cr("[Accumulated GC generation %d time %3.7f secs, "
1.121 + "%d GC's, avg GC time %3.7f]",
1.122 + level(), time, sr->invocations,
1.123 + sr->invocations > 0 ? time / sr->invocations : 0.0);
1.124 +}
1.125 +
1.126 +// Utility iterator classes
1.127 +
1.128 +class GenerationIsInReservedClosure : public SpaceClosure {
1.129 + public:
1.130 + const void* _p;
1.131 + Space* sp;
1.132 + virtual void do_space(Space* s) {
1.133 + if (sp == NULL) {
1.134 + if (s->is_in_reserved(_p)) sp = s;
1.135 + }
1.136 + }
1.137 + GenerationIsInReservedClosure(const void* p) : _p(p), sp(NULL) {}
1.138 +};
1.139 +
1.140 +class GenerationIsInClosure : public SpaceClosure {
1.141 + public:
1.142 + const void* _p;
1.143 + Space* sp;
1.144 + virtual void do_space(Space* s) {
1.145 + if (sp == NULL) {
1.146 + if (s->is_in(_p)) sp = s;
1.147 + }
1.148 + }
1.149 + GenerationIsInClosure(const void* p) : _p(p), sp(NULL) {}
1.150 +};
1.151 +
1.152 +bool Generation::is_in(const void* p) const {
1.153 + GenerationIsInClosure blk(p);
1.154 + ((Generation*)this)->space_iterate(&blk);
1.155 + return blk.sp != NULL;
1.156 +}
1.157 +
1.158 +DefNewGeneration* Generation::as_DefNewGeneration() {
1.159 + assert((kind() == Generation::DefNew) ||
1.160 + (kind() == Generation::ParNew) ||
1.161 + (kind() == Generation::ASParNew),
1.162 + "Wrong youngest generation type");
1.163 + return (DefNewGeneration*) this;
1.164 +}
1.165 +
1.166 +Generation* Generation::next_gen() const {
1.167 + GenCollectedHeap* gch = GenCollectedHeap::heap();
1.168 + int next = level() + 1;
1.169 + if (next < gch->_n_gens) {
1.170 + return gch->_gens[next];
1.171 + } else {
1.172 + return NULL;
1.173 + }
1.174 +}
1.175 +
1.176 +size_t Generation::max_contiguous_available() const {
1.177 + // The largest number of contiguous free words in this or any higher generation.
1.178 + size_t max = 0;
1.179 + for (const Generation* gen = this; gen != NULL; gen = gen->next_gen()) {
1.180 + size_t avail = gen->contiguous_available();
1.181 + if (avail > max) {
1.182 + max = avail;
1.183 + }
1.184 + }
1.185 + return max;
1.186 +}
1.187 +
1.188 +bool Generation::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const {
1.189 + size_t available = max_contiguous_available();
1.190 + bool res = (available >= max_promotion_in_bytes);
1.191 + if (PrintGC && Verbose) {
1.192 + gclog_or_tty->print_cr(
1.193 + "Generation: promo attempt is%s safe: available("SIZE_FORMAT") %s max_promo("SIZE_FORMAT")",
1.194 + res? "":" not", available, res? ">=":"<",
1.195 + max_promotion_in_bytes);
1.196 + }
1.197 + return res;
1.198 +}
1.199 +
1.200 +// Ignores "ref" and calls allocate().
1.201 +oop Generation::promote(oop obj, size_t obj_size) {
1.202 + assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1.203 +
1.204 +#ifndef PRODUCT
1.205 + if (Universe::heap()->promotion_should_fail()) {
1.206 + return NULL;
1.207 + }
1.208 +#endif // #ifndef PRODUCT
1.209 +
1.210 + HeapWord* result = allocate(obj_size, false);
1.211 + if (result != NULL) {
1.212 + Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1.213 + return oop(result);
1.214 + } else {
1.215 + GenCollectedHeap* gch = GenCollectedHeap::heap();
1.216 + return gch->handle_failed_promotion(this, obj, obj_size);
1.217 + }
1.218 +}
1.219 +
1.220 +oop Generation::par_promote(int thread_num,
1.221 + oop obj, markOop m, size_t word_sz) {
1.222 + // Could do a bad general impl here that gets a lock. But no.
1.223 + ShouldNotCallThis();
1.224 + return NULL;
1.225 +}
1.226 +
1.227 +void Generation::par_promote_alloc_undo(int thread_num,
1.228 + HeapWord* obj, size_t word_sz) {
1.229 + // Could do a bad general impl here that gets a lock. But no.
1.230 + guarantee(false, "No good general implementation.");
1.231 +}
1.232 +
1.233 +Space* Generation::space_containing(const void* p) const {
1.234 + GenerationIsInReservedClosure blk(p);
1.235 + // Cast away const
1.236 + ((Generation*)this)->space_iterate(&blk);
1.237 + return blk.sp;
1.238 +}
1.239 +
1.240 +// Some of these are mediocre general implementations. Should be
1.241 +// overridden to get better performance.
1.242 +
1.243 +class GenerationBlockStartClosure : public SpaceClosure {
1.244 + public:
1.245 + const void* _p;
1.246 + HeapWord* _start;
1.247 + virtual void do_space(Space* s) {
1.248 + if (_start == NULL && s->is_in_reserved(_p)) {
1.249 + _start = s->block_start(_p);
1.250 + }
1.251 + }
1.252 + GenerationBlockStartClosure(const void* p) { _p = p; _start = NULL; }
1.253 +};
1.254 +
1.255 +HeapWord* Generation::block_start(const void* p) const {
1.256 + GenerationBlockStartClosure blk(p);
1.257 + // Cast away const
1.258 + ((Generation*)this)->space_iterate(&blk);
1.259 + return blk._start;
1.260 +}
1.261 +
1.262 +class GenerationBlockSizeClosure : public SpaceClosure {
1.263 + public:
1.264 + const HeapWord* _p;
1.265 + size_t size;
1.266 + virtual void do_space(Space* s) {
1.267 + if (size == 0 && s->is_in_reserved(_p)) {
1.268 + size = s->block_size(_p);
1.269 + }
1.270 + }
1.271 + GenerationBlockSizeClosure(const HeapWord* p) { _p = p; size = 0; }
1.272 +};
1.273 +
1.274 +size_t Generation::block_size(const HeapWord* p) const {
1.275 + GenerationBlockSizeClosure blk(p);
1.276 + // Cast away const
1.277 + ((Generation*)this)->space_iterate(&blk);
1.278 + assert(blk.size > 0, "seems reasonable");
1.279 + return blk.size;
1.280 +}
1.281 +
1.282 +class GenerationBlockIsObjClosure : public SpaceClosure {
1.283 + public:
1.284 + const HeapWord* _p;
1.285 + bool is_obj;
1.286 + virtual void do_space(Space* s) {
1.287 + if (!is_obj && s->is_in_reserved(_p)) {
1.288 + is_obj |= s->block_is_obj(_p);
1.289 + }
1.290 + }
1.291 + GenerationBlockIsObjClosure(const HeapWord* p) { _p = p; is_obj = false; }
1.292 +};
1.293 +
1.294 +bool Generation::block_is_obj(const HeapWord* p) const {
1.295 + GenerationBlockIsObjClosure blk(p);
1.296 + // Cast away const
1.297 + ((Generation*)this)->space_iterate(&blk);
1.298 + return blk.is_obj;
1.299 +}
1.300 +
1.301 +class GenerationOopIterateClosure : public SpaceClosure {
1.302 + public:
1.303 + ExtendedOopClosure* cl;
1.304 + MemRegion mr;
1.305 + virtual void do_space(Space* s) {
1.306 + s->oop_iterate(mr, cl);
1.307 + }
1.308 + GenerationOopIterateClosure(ExtendedOopClosure* _cl, MemRegion _mr) :
1.309 + cl(_cl), mr(_mr) {}
1.310 +};
1.311 +
1.312 +void Generation::oop_iterate(ExtendedOopClosure* cl) {
1.313 + GenerationOopIterateClosure blk(cl, _reserved);
1.314 + space_iterate(&blk);
1.315 +}
1.316 +
1.317 +void Generation::oop_iterate(MemRegion mr, ExtendedOopClosure* cl) {
1.318 + GenerationOopIterateClosure blk(cl, mr);
1.319 + space_iterate(&blk);
1.320 +}
1.321 +
1.322 +void Generation::younger_refs_in_space_iterate(Space* sp,
1.323 + OopsInGenClosure* cl) {
1.324 + GenRemSet* rs = SharedHeap::heap()->rem_set();
1.325 + rs->younger_refs_in_space_iterate(sp, cl);
1.326 +}
1.327 +
1.328 +class GenerationObjIterateClosure : public SpaceClosure {
1.329 + private:
1.330 + ObjectClosure* _cl;
1.331 + public:
1.332 + virtual void do_space(Space* s) {
1.333 + s->object_iterate(_cl);
1.334 + }
1.335 + GenerationObjIterateClosure(ObjectClosure* cl) : _cl(cl) {}
1.336 +};
1.337 +
1.338 +void Generation::object_iterate(ObjectClosure* cl) {
1.339 + GenerationObjIterateClosure blk(cl);
1.340 + space_iterate(&blk);
1.341 +}
1.342 +
1.343 +class GenerationSafeObjIterateClosure : public SpaceClosure {
1.344 + private:
1.345 + ObjectClosure* _cl;
1.346 + public:
1.347 + virtual void do_space(Space* s) {
1.348 + s->safe_object_iterate(_cl);
1.349 + }
1.350 + GenerationSafeObjIterateClosure(ObjectClosure* cl) : _cl(cl) {}
1.351 +};
1.352 +
1.353 +void Generation::safe_object_iterate(ObjectClosure* cl) {
1.354 + GenerationSafeObjIterateClosure blk(cl);
1.355 + space_iterate(&blk);
1.356 +}
1.357 +
1.358 +void Generation::prepare_for_compaction(CompactPoint* cp) {
1.359 + // Generic implementation, can be specialized
1.360 + CompactibleSpace* space = first_compaction_space();
1.361 + while (space != NULL) {
1.362 + space->prepare_for_compaction(cp);
1.363 + space = space->next_compaction_space();
1.364 + }
1.365 +}
1.366 +
1.367 +class AdjustPointersClosure: public SpaceClosure {
1.368 + public:
1.369 + void do_space(Space* sp) {
1.370 + sp->adjust_pointers();
1.371 + }
1.372 +};
1.373 +
1.374 +void Generation::adjust_pointers() {
1.375 + // Note that this is done over all spaces, not just the compactible
1.376 + // ones.
1.377 + AdjustPointersClosure blk;
1.378 + space_iterate(&blk, true);
1.379 +}
1.380 +
1.381 +void Generation::compact() {
1.382 + CompactibleSpace* sp = first_compaction_space();
1.383 + while (sp != NULL) {
1.384 + sp->compact();
1.385 + sp = sp->next_compaction_space();
1.386 + }
1.387 +}
1.388 +
1.389 +CardGeneration::CardGeneration(ReservedSpace rs, size_t initial_byte_size,
1.390 + int level,
1.391 + GenRemSet* remset) :
1.392 + Generation(rs, initial_byte_size, level), _rs(remset),
1.393 + _shrink_factor(0), _min_heap_delta_bytes(), _capacity_at_prologue(),
1.394 + _used_at_prologue()
1.395 +{
1.396 + HeapWord* start = (HeapWord*)rs.base();
1.397 + size_t reserved_byte_size = rs.size();
1.398 + assert((uintptr_t(start) & 3) == 0, "bad alignment");
1.399 + assert((reserved_byte_size & 3) == 0, "bad alignment");
1.400 + MemRegion reserved_mr(start, heap_word_size(reserved_byte_size));
1.401 + _bts = new BlockOffsetSharedArray(reserved_mr,
1.402 + heap_word_size(initial_byte_size));
1.403 + MemRegion committed_mr(start, heap_word_size(initial_byte_size));
1.404 + _rs->resize_covered_region(committed_mr);
1.405 + if (_bts == NULL)
1.406 + vm_exit_during_initialization("Could not allocate a BlockOffsetArray");
1.407 +
1.408 + // Verify that the start and end of this generation is the start of a card.
1.409 + // If this wasn't true, a single card could span more than on generation,
1.410 + // which would cause problems when we commit/uncommit memory, and when we
1.411 + // clear and dirty cards.
1.412 + guarantee(_rs->is_aligned(reserved_mr.start()), "generation must be card aligned");
1.413 + if (reserved_mr.end() != Universe::heap()->reserved_region().end()) {
1.414 + // Don't check at the very end of the heap as we'll assert that we're probing off
1.415 + // the end if we try.
1.416 + guarantee(_rs->is_aligned(reserved_mr.end()), "generation must be card aligned");
1.417 + }
1.418 + _min_heap_delta_bytes = MinHeapDeltaBytes;
1.419 + _capacity_at_prologue = initial_byte_size;
1.420 + _used_at_prologue = 0;
1.421 +}
1.422 +
1.423 +bool CardGeneration::expand(size_t bytes, size_t expand_bytes) {
1.424 + assert_locked_or_safepoint(Heap_lock);
1.425 + if (bytes == 0) {
1.426 + return true; // That's what grow_by(0) would return
1.427 + }
1.428 + size_t aligned_bytes = ReservedSpace::page_align_size_up(bytes);
1.429 + if (aligned_bytes == 0){
1.430 + // The alignment caused the number of bytes to wrap. An expand_by(0) will
1.431 + // return true with the implication that an expansion was done when it
1.432 + // was not. A call to expand implies a best effort to expand by "bytes"
1.433 + // but not a guarantee. Align down to give a best effort. This is likely
1.434 + // the most that the generation can expand since it has some capacity to
1.435 + // start with.
1.436 + aligned_bytes = ReservedSpace::page_align_size_down(bytes);
1.437 + }
1.438 + size_t aligned_expand_bytes = ReservedSpace::page_align_size_up(expand_bytes);
1.439 + bool success = false;
1.440 + if (aligned_expand_bytes > aligned_bytes) {
1.441 + success = grow_by(aligned_expand_bytes);
1.442 + }
1.443 + if (!success) {
1.444 + success = grow_by(aligned_bytes);
1.445 + }
1.446 + if (!success) {
1.447 + success = grow_to_reserved();
1.448 + }
1.449 + if (PrintGC && Verbose) {
1.450 + if (success && GC_locker::is_active_and_needs_gc()) {
1.451 + gclog_or_tty->print_cr("Garbage collection disabled, expanded heap instead");
1.452 + }
1.453 + }
1.454 +
1.455 + return success;
1.456 +}
1.457 +
1.458 +
1.459 +// No young generation references, clear this generation's cards.
1.460 +void CardGeneration::clear_remembered_set() {
1.461 + _rs->clear(reserved());
1.462 +}
1.463 +
1.464 +
1.465 +// Objects in this generation may have moved, invalidate this
1.466 +// generation's cards.
1.467 +void CardGeneration::invalidate_remembered_set() {
1.468 + _rs->invalidate(used_region());
1.469 +}
1.470 +
1.471 +
1.472 +void CardGeneration::compute_new_size() {
1.473 + assert(_shrink_factor <= 100, "invalid shrink factor");
1.474 + size_t current_shrink_factor = _shrink_factor;
1.475 + _shrink_factor = 0;
1.476 +
1.477 + // We don't have floating point command-line arguments
1.478 + // Note: argument processing ensures that MinHeapFreeRatio < 100.
1.479 + const double minimum_free_percentage = MinHeapFreeRatio / 100.0;
1.480 + const double maximum_used_percentage = 1.0 - minimum_free_percentage;
1.481 +
1.482 + // Compute some numbers about the state of the heap.
1.483 + const size_t used_after_gc = used();
1.484 + const size_t capacity_after_gc = capacity();
1.485 +
1.486 + const double min_tmp = used_after_gc / maximum_used_percentage;
1.487 + size_t minimum_desired_capacity = (size_t)MIN2(min_tmp, double(max_uintx));
1.488 + // Don't shrink less than the initial generation size
1.489 + minimum_desired_capacity = MAX2(minimum_desired_capacity,
1.490 + spec()->init_size());
1.491 + assert(used_after_gc <= minimum_desired_capacity, "sanity check");
1.492 +
1.493 + if (PrintGC && Verbose) {
1.494 + const size_t free_after_gc = free();
1.495 + const double free_percentage = ((double)free_after_gc) / capacity_after_gc;
1.496 + gclog_or_tty->print_cr("TenuredGeneration::compute_new_size: ");
1.497 + gclog_or_tty->print_cr(" "
1.498 + " minimum_free_percentage: %6.2f"
1.499 + " maximum_used_percentage: %6.2f",
1.500 + minimum_free_percentage,
1.501 + maximum_used_percentage);
1.502 + gclog_or_tty->print_cr(" "
1.503 + " free_after_gc : %6.1fK"
1.504 + " used_after_gc : %6.1fK"
1.505 + " capacity_after_gc : %6.1fK",
1.506 + free_after_gc / (double) K,
1.507 + used_after_gc / (double) K,
1.508 + capacity_after_gc / (double) K);
1.509 + gclog_or_tty->print_cr(" "
1.510 + " free_percentage: %6.2f",
1.511 + free_percentage);
1.512 + }
1.513 +
1.514 + if (capacity_after_gc < minimum_desired_capacity) {
1.515 + // If we have less free space than we want then expand
1.516 + size_t expand_bytes = minimum_desired_capacity - capacity_after_gc;
1.517 + // Don't expand unless it's significant
1.518 + if (expand_bytes >= _min_heap_delta_bytes) {
1.519 + expand(expand_bytes, 0); // safe if expansion fails
1.520 + }
1.521 + if (PrintGC && Verbose) {
1.522 + gclog_or_tty->print_cr(" expanding:"
1.523 + " minimum_desired_capacity: %6.1fK"
1.524 + " expand_bytes: %6.1fK"
1.525 + " _min_heap_delta_bytes: %6.1fK",
1.526 + minimum_desired_capacity / (double) K,
1.527 + expand_bytes / (double) K,
1.528 + _min_heap_delta_bytes / (double) K);
1.529 + }
1.530 + return;
1.531 + }
1.532 +
1.533 + // No expansion, now see if we want to shrink
1.534 + size_t shrink_bytes = 0;
1.535 + // We would never want to shrink more than this
1.536 + size_t max_shrink_bytes = capacity_after_gc - minimum_desired_capacity;
1.537 +
1.538 + if (MaxHeapFreeRatio < 100) {
1.539 + const double maximum_free_percentage = MaxHeapFreeRatio / 100.0;
1.540 + const double minimum_used_percentage = 1.0 - maximum_free_percentage;
1.541 + const double max_tmp = used_after_gc / minimum_used_percentage;
1.542 + size_t maximum_desired_capacity = (size_t)MIN2(max_tmp, double(max_uintx));
1.543 + maximum_desired_capacity = MAX2(maximum_desired_capacity,
1.544 + spec()->init_size());
1.545 + if (PrintGC && Verbose) {
1.546 + gclog_or_tty->print_cr(" "
1.547 + " maximum_free_percentage: %6.2f"
1.548 + " minimum_used_percentage: %6.2f",
1.549 + maximum_free_percentage,
1.550 + minimum_used_percentage);
1.551 + gclog_or_tty->print_cr(" "
1.552 + " _capacity_at_prologue: %6.1fK"
1.553 + " minimum_desired_capacity: %6.1fK"
1.554 + " maximum_desired_capacity: %6.1fK",
1.555 + _capacity_at_prologue / (double) K,
1.556 + minimum_desired_capacity / (double) K,
1.557 + maximum_desired_capacity / (double) K);
1.558 + }
1.559 + assert(minimum_desired_capacity <= maximum_desired_capacity,
1.560 + "sanity check");
1.561 +
1.562 + if (capacity_after_gc > maximum_desired_capacity) {
1.563 + // Capacity too large, compute shrinking size
1.564 + shrink_bytes = capacity_after_gc - maximum_desired_capacity;
1.565 + // We don't want shrink all the way back to initSize if people call
1.566 + // System.gc(), because some programs do that between "phases" and then
1.567 + // we'd just have to grow the heap up again for the next phase. So we
1.568 + // damp the shrinking: 0% on the first call, 10% on the second call, 40%
1.569 + // on the third call, and 100% by the fourth call. But if we recompute
1.570 + // size without shrinking, it goes back to 0%.
1.571 + shrink_bytes = shrink_bytes / 100 * current_shrink_factor;
1.572 + assert(shrink_bytes <= max_shrink_bytes, "invalid shrink size");
1.573 + if (current_shrink_factor == 0) {
1.574 + _shrink_factor = 10;
1.575 + } else {
1.576 + _shrink_factor = MIN2(current_shrink_factor * 4, (size_t) 100);
1.577 + }
1.578 + if (PrintGC && Verbose) {
1.579 + gclog_or_tty->print_cr(" "
1.580 + " shrinking:"
1.581 + " initSize: %.1fK"
1.582 + " maximum_desired_capacity: %.1fK",
1.583 + spec()->init_size() / (double) K,
1.584 + maximum_desired_capacity / (double) K);
1.585 + gclog_or_tty->print_cr(" "
1.586 + " shrink_bytes: %.1fK"
1.587 + " current_shrink_factor: %d"
1.588 + " new shrink factor: %d"
1.589 + " _min_heap_delta_bytes: %.1fK",
1.590 + shrink_bytes / (double) K,
1.591 + current_shrink_factor,
1.592 + _shrink_factor,
1.593 + _min_heap_delta_bytes / (double) K);
1.594 + }
1.595 + }
1.596 + }
1.597 +
1.598 + if (capacity_after_gc > _capacity_at_prologue) {
1.599 + // We might have expanded for promotions, in which case we might want to
1.600 + // take back that expansion if there's room after GC. That keeps us from
1.601 + // stretching the heap with promotions when there's plenty of room.
1.602 + size_t expansion_for_promotion = capacity_after_gc - _capacity_at_prologue;
1.603 + expansion_for_promotion = MIN2(expansion_for_promotion, max_shrink_bytes);
1.604 + // We have two shrinking computations, take the largest
1.605 + shrink_bytes = MAX2(shrink_bytes, expansion_for_promotion);
1.606 + assert(shrink_bytes <= max_shrink_bytes, "invalid shrink size");
1.607 + if (PrintGC && Verbose) {
1.608 + gclog_or_tty->print_cr(" "
1.609 + " aggressive shrinking:"
1.610 + " _capacity_at_prologue: %.1fK"
1.611 + " capacity_after_gc: %.1fK"
1.612 + " expansion_for_promotion: %.1fK"
1.613 + " shrink_bytes: %.1fK",
1.614 + capacity_after_gc / (double) K,
1.615 + _capacity_at_prologue / (double) K,
1.616 + expansion_for_promotion / (double) K,
1.617 + shrink_bytes / (double) K);
1.618 + }
1.619 + }
1.620 + // Don't shrink unless it's significant
1.621 + if (shrink_bytes >= _min_heap_delta_bytes) {
1.622 + shrink(shrink_bytes);
1.623 + }
1.624 +}
1.625 +
1.626 +// Currently nothing to do.
1.627 +void CardGeneration::prepare_for_verify() {}
1.628 +
1.629 +
1.630 +void OneContigSpaceCardGeneration::collect(bool full,
1.631 + bool clear_all_soft_refs,
1.632 + size_t size,
1.633 + bool is_tlab) {
1.634 + GenCollectedHeap* gch = GenCollectedHeap::heap();
1.635 +
1.636 + SpecializationStats::clear();
1.637 + // Temporarily expand the span of our ref processor, so
1.638 + // refs discovery is over the entire heap, not just this generation
1.639 + ReferenceProcessorSpanMutator
1.640 + x(ref_processor(), gch->reserved_region());
1.641 +
1.642 + STWGCTimer* gc_timer = GenMarkSweep::gc_timer();
1.643 + gc_timer->register_gc_start();
1.644 +
1.645 + SerialOldTracer* gc_tracer = GenMarkSweep::gc_tracer();
1.646 + gc_tracer->report_gc_start(gch->gc_cause(), gc_timer->gc_start());
1.647 +
1.648 + GenMarkSweep::invoke_at_safepoint(_level, ref_processor(), clear_all_soft_refs);
1.649 +
1.650 + gc_timer->register_gc_end();
1.651 +
1.652 + gc_tracer->report_gc_end(gc_timer->gc_end(), gc_timer->time_partitions());
1.653 +
1.654 + SpecializationStats::print();
1.655 +}
1.656 +
1.657 +HeapWord*
1.658 +OneContigSpaceCardGeneration::expand_and_allocate(size_t word_size,
1.659 + bool is_tlab,
1.660 + bool parallel) {
1.661 + assert(!is_tlab, "OneContigSpaceCardGeneration does not support TLAB allocation");
1.662 + if (parallel) {
1.663 + MutexLocker x(ParGCRareEvent_lock);
1.664 + HeapWord* result = NULL;
1.665 + size_t byte_size = word_size * HeapWordSize;
1.666 + while (true) {
1.667 + expand(byte_size, _min_heap_delta_bytes);
1.668 + if (GCExpandToAllocateDelayMillis > 0) {
1.669 + os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
1.670 + }
1.671 + result = _the_space->par_allocate(word_size);
1.672 + if ( result != NULL) {
1.673 + return result;
1.674 + } else {
1.675 + // If there's not enough expansion space available, give up.
1.676 + if (_virtual_space.uncommitted_size() < byte_size) {
1.677 + return NULL;
1.678 + }
1.679 + // else try again
1.680 + }
1.681 + }
1.682 + } else {
1.683 + expand(word_size*HeapWordSize, _min_heap_delta_bytes);
1.684 + return _the_space->allocate(word_size);
1.685 + }
1.686 +}
1.687 +
1.688 +bool OneContigSpaceCardGeneration::expand(size_t bytes, size_t expand_bytes) {
1.689 + GCMutexLocker x(ExpandHeap_lock);
1.690 + return CardGeneration::expand(bytes, expand_bytes);
1.691 +}
1.692 +
1.693 +
1.694 +void OneContigSpaceCardGeneration::shrink(size_t bytes) {
1.695 + assert_locked_or_safepoint(ExpandHeap_lock);
1.696 + size_t size = ReservedSpace::page_align_size_down(bytes);
1.697 + if (size > 0) {
1.698 + shrink_by(size);
1.699 + }
1.700 +}
1.701 +
1.702 +
1.703 +size_t OneContigSpaceCardGeneration::capacity() const {
1.704 + return _the_space->capacity();
1.705 +}
1.706 +
1.707 +
1.708 +size_t OneContigSpaceCardGeneration::used() const {
1.709 + return _the_space->used();
1.710 +}
1.711 +
1.712 +
1.713 +size_t OneContigSpaceCardGeneration::free() const {
1.714 + return _the_space->free();
1.715 +}
1.716 +
1.717 +MemRegion OneContigSpaceCardGeneration::used_region() const {
1.718 + return the_space()->used_region();
1.719 +}
1.720 +
1.721 +size_t OneContigSpaceCardGeneration::unsafe_max_alloc_nogc() const {
1.722 + return _the_space->free();
1.723 +}
1.724 +
1.725 +size_t OneContigSpaceCardGeneration::contiguous_available() const {
1.726 + return _the_space->free() + _virtual_space.uncommitted_size();
1.727 +}
1.728 +
1.729 +bool OneContigSpaceCardGeneration::grow_by(size_t bytes) {
1.730 + assert_locked_or_safepoint(ExpandHeap_lock);
1.731 + bool result = _virtual_space.expand_by(bytes);
1.732 + if (result) {
1.733 + size_t new_word_size =
1.734 + heap_word_size(_virtual_space.committed_size());
1.735 + MemRegion mr(_the_space->bottom(), new_word_size);
1.736 + // Expand card table
1.737 + Universe::heap()->barrier_set()->resize_covered_region(mr);
1.738 + // Expand shared block offset array
1.739 + _bts->resize(new_word_size);
1.740 +
1.741 + // Fix for bug #4668531
1.742 + if (ZapUnusedHeapArea) {
1.743 + MemRegion mangle_region(_the_space->end(),
1.744 + (HeapWord*)_virtual_space.high());
1.745 + SpaceMangler::mangle_region(mangle_region);
1.746 + }
1.747 +
1.748 + // Expand space -- also expands space's BOT
1.749 + // (which uses (part of) shared array above)
1.750 + _the_space->set_end((HeapWord*)_virtual_space.high());
1.751 +
1.752 + // update the space and generation capacity counters
1.753 + update_counters();
1.754 +
1.755 + if (Verbose && PrintGC) {
1.756 + size_t new_mem_size = _virtual_space.committed_size();
1.757 + size_t old_mem_size = new_mem_size - bytes;
1.758 + gclog_or_tty->print_cr("Expanding %s from " SIZE_FORMAT "K by "
1.759 + SIZE_FORMAT "K to " SIZE_FORMAT "K",
1.760 + name(), old_mem_size/K, bytes/K, new_mem_size/K);
1.761 + }
1.762 + }
1.763 + return result;
1.764 +}
1.765 +
1.766 +
1.767 +bool OneContigSpaceCardGeneration::grow_to_reserved() {
1.768 + assert_locked_or_safepoint(ExpandHeap_lock);
1.769 + bool success = true;
1.770 + const size_t remaining_bytes = _virtual_space.uncommitted_size();
1.771 + if (remaining_bytes > 0) {
1.772 + success = grow_by(remaining_bytes);
1.773 + DEBUG_ONLY(if (!success) warning("grow to reserved failed");)
1.774 + }
1.775 + return success;
1.776 +}
1.777 +
1.778 +void OneContigSpaceCardGeneration::shrink_by(size_t bytes) {
1.779 + assert_locked_or_safepoint(ExpandHeap_lock);
1.780 + // Shrink committed space
1.781 + _virtual_space.shrink_by(bytes);
1.782 + // Shrink space; this also shrinks the space's BOT
1.783 + _the_space->set_end((HeapWord*) _virtual_space.high());
1.784 + size_t new_word_size = heap_word_size(_the_space->capacity());
1.785 + // Shrink the shared block offset array
1.786 + _bts->resize(new_word_size);
1.787 + MemRegion mr(_the_space->bottom(), new_word_size);
1.788 + // Shrink the card table
1.789 + Universe::heap()->barrier_set()->resize_covered_region(mr);
1.790 +
1.791 + if (Verbose && PrintGC) {
1.792 + size_t new_mem_size = _virtual_space.committed_size();
1.793 + size_t old_mem_size = new_mem_size + bytes;
1.794 + gclog_or_tty->print_cr("Shrinking %s from " SIZE_FORMAT "K to " SIZE_FORMAT "K",
1.795 + name(), old_mem_size/K, new_mem_size/K);
1.796 + }
1.797 +}
1.798 +
1.799 +// Currently nothing to do.
1.800 +void OneContigSpaceCardGeneration::prepare_for_verify() {}
1.801 +
1.802 +
1.803 +// Override for a card-table generation with one contiguous
1.804 +// space. NOTE: For reasons that are lost in the fog of history,
1.805 +// this code is used when you iterate over perm gen objects,
1.806 +// even when one uses CDS, where the perm gen has a couple of
1.807 +// other spaces; this is because CompactingPermGenGen derives
1.808 +// from OneContigSpaceCardGeneration. This should be cleaned up,
1.809 +// see CR 6897789..
1.810 +void OneContigSpaceCardGeneration::object_iterate(ObjectClosure* blk) {
1.811 + _the_space->object_iterate(blk);
1.812 +}
1.813 +
1.814 +void OneContigSpaceCardGeneration::space_iterate(SpaceClosure* blk,
1.815 + bool usedOnly) {
1.816 + blk->do_space(_the_space);
1.817 +}
1.818 +
1.819 +void OneContigSpaceCardGeneration::younger_refs_iterate(OopsInGenClosure* blk) {
1.820 + blk->set_generation(this);
1.821 + younger_refs_in_space_iterate(_the_space, blk);
1.822 + blk->reset_generation();
1.823 +}
1.824 +
1.825 +void OneContigSpaceCardGeneration::save_marks() {
1.826 + _the_space->set_saved_mark();
1.827 +}
1.828 +
1.829 +
1.830 +void OneContigSpaceCardGeneration::reset_saved_marks() {
1.831 + _the_space->reset_saved_mark();
1.832 +}
1.833 +
1.834 +
1.835 +bool OneContigSpaceCardGeneration::no_allocs_since_save_marks() {
1.836 + return _the_space->saved_mark_at_top();
1.837 +}
1.838 +
1.839 +#define OneContig_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
1.840 + \
1.841 +void OneContigSpaceCardGeneration:: \
1.842 +oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) { \
1.843 + blk->set_generation(this); \
1.844 + _the_space->oop_since_save_marks_iterate##nv_suffix(blk); \
1.845 + blk->reset_generation(); \
1.846 + save_marks(); \
1.847 +}
1.848 +
1.849 +ALL_SINCE_SAVE_MARKS_CLOSURES(OneContig_SINCE_SAVE_MARKS_ITERATE_DEFN)
1.850 +
1.851 +#undef OneContig_SINCE_SAVE_MARKS_ITERATE_DEFN
1.852 +
1.853 +
1.854 +void OneContigSpaceCardGeneration::gc_epilogue(bool full) {
1.855 + _last_gc = WaterMark(the_space(), the_space()->top());
1.856 +
1.857 + // update the generation and space performance counters
1.858 + update_counters();
1.859 + if (ZapUnusedHeapArea) {
1.860 + the_space()->check_mangled_unused_area_complete();
1.861 + }
1.862 +}
1.863 +
1.864 +void OneContigSpaceCardGeneration::record_spaces_top() {
1.865 + assert(ZapUnusedHeapArea, "Not mangling unused space");
1.866 + the_space()->set_top_for_allocations();
1.867 +}
1.868 +
1.869 +void OneContigSpaceCardGeneration::verify() {
1.870 + the_space()->verify();
1.871 +}
1.872 +
1.873 +void OneContigSpaceCardGeneration::print_on(outputStream* st) const {
1.874 + Generation::print_on(st);
1.875 + st->print(" the");
1.876 + the_space()->print_on(st);
1.877 +}
