1067 lines
39 KiB
C++
1067 lines
39 KiB
C++
/*
|
|
* Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
|
|
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
|
|
*
|
|
* This code is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 only, as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This code is distributed in the hope that it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* version 2 for more details (a copy is included in the LICENSE file that
|
|
* accompanied this code).
|
|
*
|
|
* You should have received a copy of the GNU General Public License version
|
|
* 2 along with this work; if not, write to the Free Software Foundation,
|
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*
|
|
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
|
|
* or visit www.oracle.com if you need additional information or have any
|
|
* questions.
|
|
*
|
|
*/
|
|
|
|
#include "precompiled.hpp"
|
|
#include "gc_implementation/shared/collectorCounters.hpp"
|
|
#include "gc_implementation/shared/gcPolicyCounters.hpp"
|
|
#include "gc_implementation/shared/gcHeapSummary.hpp"
|
|
#include "gc_implementation/shared/gcTimer.hpp"
|
|
#include "gc_implementation/shared/gcTraceTime.hpp"
|
|
#include "gc_implementation/shared/gcTrace.hpp"
|
|
#include "gc_implementation/shared/spaceDecorator.hpp"
|
|
#include "memory/defNewGeneration.inline.hpp"
|
|
#include "memory/gcLocker.inline.hpp"
|
|
#include "memory/genCollectedHeap.hpp"
|
|
#include "memory/genOopClosures.inline.hpp"
|
|
#include "memory/genRemSet.hpp"
|
|
#include "memory/generationSpec.hpp"
|
|
#include "memory/iterator.hpp"
|
|
#include "memory/referencePolicy.hpp"
|
|
#include "memory/space.inline.hpp"
|
|
#include "oops/instanceRefKlass.hpp"
|
|
#include "oops/oop.inline.hpp"
|
|
#include "runtime/atomic.inline.hpp"
|
|
#include "runtime/java.hpp"
|
|
#include "runtime/prefetch.inline.hpp"
|
|
#include "runtime/thread.inline.hpp"
|
|
#include "utilities/copy.hpp"
|
|
#include "utilities/globalDefinitions.hpp"
|
|
#include "utilities/stack.inline.hpp"
|
|
|
|
PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
|
|
|
|
//
|
|
// DefNewGeneration functions.
|
|
|
|
// Methods of protected closure types.
|
|
|
|
DefNewGeneration::IsAliveClosure::IsAliveClosure(Generation* g) : _g(g) {
|
|
assert(g->level() == 0, "Optimized for youngest gen.");
|
|
}
|
|
bool DefNewGeneration::IsAliveClosure::do_object_b(oop p) {
|
|
return (HeapWord*)p >= _g->reserved().end() || p->is_forwarded();
|
|
}
|
|
|
|
DefNewGeneration::KeepAliveClosure::
|
|
KeepAliveClosure(ScanWeakRefClosure* cl) : _cl(cl) {
|
|
GenRemSet* rs = GenCollectedHeap::heap()->rem_set();
|
|
_rs = (CardTableRS*)rs;
|
|
}
|
|
|
|
void DefNewGeneration::KeepAliveClosure::do_oop(oop* p) { DefNewGeneration::KeepAliveClosure::do_oop_work(p); }
|
|
void DefNewGeneration::KeepAliveClosure::do_oop(narrowOop* p) { DefNewGeneration::KeepAliveClosure::do_oop_work(p); }
|
|
|
|
|
|
DefNewGeneration::FastKeepAliveClosure::
|
|
FastKeepAliveClosure(DefNewGeneration* g, ScanWeakRefClosure* cl) :
|
|
DefNewGeneration::KeepAliveClosure(cl) {
|
|
_boundary = g->reserved().end();
|
|
}
|
|
|
|
void DefNewGeneration::FastKeepAliveClosure::do_oop(oop* p) { DefNewGeneration::FastKeepAliveClosure::do_oop_work(p); }
|
|
void DefNewGeneration::FastKeepAliveClosure::do_oop(narrowOop* p) { DefNewGeneration::FastKeepAliveClosure::do_oop_work(p); }
|
|
|
|
DefNewGeneration::EvacuateFollowersClosure::
|
|
EvacuateFollowersClosure(GenCollectedHeap* gch, int level,
|
|
ScanClosure* cur, ScanClosure* older) :
|
|
_gch(gch), _level(level),
|
|
_scan_cur_or_nonheap(cur), _scan_older(older)
|
|
{}
|
|
|
|
void DefNewGeneration::EvacuateFollowersClosure::do_void() {
|
|
do {
|
|
_gch->oop_since_save_marks_iterate(_level, _scan_cur_or_nonheap,
|
|
_scan_older);
|
|
} while (!_gch->no_allocs_since_save_marks(_level));
|
|
}
|
|
|
|
DefNewGeneration::FastEvacuateFollowersClosure::
|
|
FastEvacuateFollowersClosure(GenCollectedHeap* gch, int level,
|
|
DefNewGeneration* gen,
|
|
FastScanClosure* cur, FastScanClosure* older) :
|
|
_gch(gch), _level(level), _gen(gen),
|
|
_scan_cur_or_nonheap(cur), _scan_older(older)
|
|
{}
|
|
|
|
void DefNewGeneration::FastEvacuateFollowersClosure::do_void() {
|
|
do {
|
|
_gch->oop_since_save_marks_iterate(_level, _scan_cur_or_nonheap,
|
|
_scan_older);
|
|
} while (!_gch->no_allocs_since_save_marks(_level));
|
|
guarantee(_gen->promo_failure_scan_is_complete(), "Failed to finish scan");
|
|
}
|
|
|
|
ScanClosure::ScanClosure(DefNewGeneration* g, bool gc_barrier) :
|
|
OopsInKlassOrGenClosure(g), _g(g), _gc_barrier(gc_barrier)
|
|
{
|
|
assert(_g->level() == 0, "Optimized for youngest generation");
|
|
_boundary = _g->reserved().end();
|
|
}
|
|
|
|
void ScanClosure::do_oop(oop* p) { ScanClosure::do_oop_work(p); }
|
|
void ScanClosure::do_oop(narrowOop* p) { ScanClosure::do_oop_work(p); }
|
|
|
|
FastScanClosure::FastScanClosure(DefNewGeneration* g, bool gc_barrier) :
|
|
OopsInKlassOrGenClosure(g), _g(g), _gc_barrier(gc_barrier)
|
|
{
|
|
assert(_g->level() == 0, "Optimized for youngest generation");
|
|
_boundary = _g->reserved().end();
|
|
}
|
|
|
|
void FastScanClosure::do_oop(oop* p) { FastScanClosure::do_oop_work(p); }
|
|
void FastScanClosure::do_oop(narrowOop* p) { FastScanClosure::do_oop_work(p); }
|
|
|
|
void KlassScanClosure::do_klass(Klass* klass) {
|
|
#ifndef PRODUCT
|
|
if (TraceScavenge) {
|
|
ResourceMark rm;
|
|
gclog_or_tty->print_cr("KlassScanClosure::do_klass " PTR_FORMAT ", %s, dirty: %s",
|
|
klass,
|
|
klass->external_name(),
|
|
klass->has_modified_oops() ? "true" : "false");
|
|
}
|
|
#endif
|
|
|
|
// If the klass has not been dirtied we know that there's
|
|
// no references into the young gen and we can skip it.
|
|
if (klass->has_modified_oops()) {
|
|
if (_accumulate_modified_oops) {
|
|
klass->accumulate_modified_oops();
|
|
}
|
|
|
|
// Clear this state since we're going to scavenge all the metadata.
|
|
klass->clear_modified_oops();
|
|
|
|
// Tell the closure which Klass is being scanned so that it can be dirtied
|
|
// if oops are left pointing into the young gen.
|
|
_scavenge_closure->set_scanned_klass(klass);
|
|
|
|
klass->oops_do(_scavenge_closure);
|
|
|
|
_scavenge_closure->set_scanned_klass(NULL);
|
|
}
|
|
}
|
|
|
|
ScanWeakRefClosure::ScanWeakRefClosure(DefNewGeneration* g) :
|
|
_g(g)
|
|
{
|
|
assert(_g->level() == 0, "Optimized for youngest generation");
|
|
_boundary = _g->reserved().end();
|
|
}
|
|
|
|
void ScanWeakRefClosure::do_oop(oop* p) { ScanWeakRefClosure::do_oop_work(p); }
|
|
void ScanWeakRefClosure::do_oop(narrowOop* p) { ScanWeakRefClosure::do_oop_work(p); }
|
|
|
|
void FilteringClosure::do_oop(oop* p) { FilteringClosure::do_oop_work(p); }
|
|
void FilteringClosure::do_oop(narrowOop* p) { FilteringClosure::do_oop_work(p); }
|
|
|
|
KlassScanClosure::KlassScanClosure(OopsInKlassOrGenClosure* scavenge_closure,
|
|
KlassRemSet* klass_rem_set)
|
|
: _scavenge_closure(scavenge_closure),
|
|
_accumulate_modified_oops(klass_rem_set->accumulate_modified_oops()) {}
|
|
|
|
|
|
DefNewGeneration::DefNewGeneration(ReservedSpace rs,
|
|
size_t initial_size,
|
|
int level,
|
|
const char* policy)
|
|
: Generation(rs, initial_size, level),
|
|
_promo_failure_drain_in_progress(false),
|
|
_should_allocate_from_space(false)
|
|
{
|
|
MemRegion cmr((HeapWord*)_virtual_space.low(),
|
|
(HeapWord*)_virtual_space.high());
|
|
Universe::heap()->barrier_set()->resize_covered_region(cmr);
|
|
|
|
_eden_space = new ContiguousSpace();
|
|
_from_space = new ContiguousSpace();
|
|
_to_space = new ContiguousSpace();
|
|
|
|
if (_eden_space == NULL || _from_space == NULL || _to_space == NULL)
|
|
vm_exit_during_initialization("Could not allocate a new gen space");
|
|
|
|
// Compute the maximum eden and survivor space sizes. These sizes
|
|
// are computed assuming the entire reserved space is committed.
|
|
// These values are exported as performance counters.
|
|
uintx alignment = GenCollectedHeap::heap()->collector_policy()->space_alignment();
|
|
uintx size = _virtual_space.reserved_size();
|
|
_max_survivor_size = compute_survivor_size(size, alignment);
|
|
_max_eden_size = size - (2*_max_survivor_size);
|
|
|
|
// allocate the performance counters
|
|
GenCollectorPolicy* gcp = (GenCollectorPolicy*) GenCollectedHeap::heap()->collector_policy();
|
|
|
|
// Generation counters -- generation 0, 3 subspaces
|
|
_gen_counters = new GenerationCounters("new", 0, 3,
|
|
gcp->min_young_size(), gcp->max_young_size(), &_virtual_space);
|
|
_gc_counters = new CollectorCounters(policy, 0);
|
|
|
|
_eden_counters = new CSpaceCounters("eden", 0, _max_eden_size, _eden_space,
|
|
_gen_counters);
|
|
_from_counters = new CSpaceCounters("s0", 1, _max_survivor_size, _from_space,
|
|
_gen_counters);
|
|
_to_counters = new CSpaceCounters("s1", 2, _max_survivor_size, _to_space,
|
|
_gen_counters);
|
|
|
|
compute_space_boundaries(0, SpaceDecorator::Clear, SpaceDecorator::Mangle);
|
|
update_counters();
|
|
_next_gen = NULL;
|
|
_tenuring_threshold = MaxTenuringThreshold;
|
|
_pretenure_size_threshold_words = PretenureSizeThreshold >> LogHeapWordSize;
|
|
|
|
_gc_timer = new (ResourceObj::C_HEAP, mtGC) STWGCTimer();
|
|
}
|
|
|
|
void DefNewGeneration::compute_space_boundaries(uintx minimum_eden_size,
|
|
bool clear_space,
|
|
bool mangle_space) {
|
|
uintx alignment =
|
|
GenCollectedHeap::heap()->collector_policy()->space_alignment();
|
|
|
|
// If the spaces are being cleared (only done at heap initialization
|
|
// currently), the survivor spaces need not be empty.
|
|
// Otherwise, no care is taken for used areas in the survivor spaces
|
|
// so check.
|
|
assert(clear_space || (to()->is_empty() && from()->is_empty()),
|
|
"Initialization of the survivor spaces assumes these are empty");
|
|
|
|
// Compute sizes
|
|
uintx size = _virtual_space.committed_size();
|
|
uintx survivor_size = compute_survivor_size(size, alignment);
|
|
uintx eden_size = size - (2*survivor_size);
|
|
assert(eden_size > 0 && survivor_size <= eden_size, "just checking");
|
|
|
|
if (eden_size < minimum_eden_size) {
|
|
// May happen due to 64Kb rounding, if so adjust eden size back up
|
|
minimum_eden_size = align_size_up(minimum_eden_size, alignment);
|
|
uintx maximum_survivor_size = (size - minimum_eden_size) / 2;
|
|
uintx unaligned_survivor_size =
|
|
align_size_down(maximum_survivor_size, alignment);
|
|
survivor_size = MAX2(unaligned_survivor_size, alignment);
|
|
eden_size = size - (2*survivor_size);
|
|
assert(eden_size > 0 && survivor_size <= eden_size, "just checking");
|
|
assert(eden_size >= minimum_eden_size, "just checking");
|
|
}
|
|
|
|
char *eden_start = _virtual_space.low();
|
|
char *from_start = eden_start + eden_size;
|
|
char *to_start = from_start + survivor_size;
|
|
char *to_end = to_start + survivor_size;
|
|
|
|
assert(to_end == _virtual_space.high(), "just checking");
|
|
assert(Space::is_aligned((HeapWord*)eden_start), "checking alignment");
|
|
assert(Space::is_aligned((HeapWord*)from_start), "checking alignment");
|
|
assert(Space::is_aligned((HeapWord*)to_start), "checking alignment");
|
|
|
|
MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)from_start);
|
|
MemRegion fromMR((HeapWord*)from_start, (HeapWord*)to_start);
|
|
MemRegion toMR ((HeapWord*)to_start, (HeapWord*)to_end);
|
|
|
|
// A minimum eden size implies that there is a part of eden that
|
|
// is being used and that affects the initialization of any
|
|
// newly formed eden.
|
|
bool live_in_eden = minimum_eden_size > 0;
|
|
|
|
// If not clearing the spaces, do some checking to verify that
|
|
// the space are already mangled.
|
|
if (!clear_space) {
|
|
// Must check mangling before the spaces are reshaped. Otherwise,
|
|
// the bottom or end of one space may have moved into another
|
|
// a failure of the check may not correctly indicate which space
|
|
// is not properly mangled.
|
|
if (ZapUnusedHeapArea) {
|
|
HeapWord* limit = (HeapWord*) _virtual_space.high();
|
|
eden()->check_mangled_unused_area(limit);
|
|
from()->check_mangled_unused_area(limit);
|
|
to()->check_mangled_unused_area(limit);
|
|
}
|
|
}
|
|
|
|
// Reset the spaces for their new regions.
|
|
eden()->initialize(edenMR,
|
|
clear_space && !live_in_eden,
|
|
SpaceDecorator::Mangle);
|
|
// If clear_space and live_in_eden, we will not have cleared any
|
|
// portion of eden above its top. This can cause newly
|
|
// expanded space not to be mangled if using ZapUnusedHeapArea.
|
|
// We explicitly do such mangling here.
|
|
if (ZapUnusedHeapArea && clear_space && live_in_eden && mangle_space) {
|
|
eden()->mangle_unused_area();
|
|
}
|
|
from()->initialize(fromMR, clear_space, mangle_space);
|
|
to()->initialize(toMR, clear_space, mangle_space);
|
|
|
|
// Set next compaction spaces.
|
|
eden()->set_next_compaction_space(from());
|
|
// The to-space is normally empty before a compaction so need
|
|
// not be considered. The exception is during promotion
|
|
// failure handling when to-space can contain live objects.
|
|
from()->set_next_compaction_space(NULL);
|
|
}
|
|
|
|
void DefNewGeneration::swap_spaces() {
|
|
ContiguousSpace* s = from();
|
|
_from_space = to();
|
|
_to_space = s;
|
|
eden()->set_next_compaction_space(from());
|
|
// The to-space is normally empty before a compaction so need
|
|
// not be considered. The exception is during promotion
|
|
// failure handling when to-space can contain live objects.
|
|
from()->set_next_compaction_space(NULL);
|
|
|
|
if (UsePerfData) {
|
|
CSpaceCounters* c = _from_counters;
|
|
_from_counters = _to_counters;
|
|
_to_counters = c;
|
|
}
|
|
}
|
|
|
|
bool DefNewGeneration::expand(size_t bytes) {
|
|
MutexLocker x(ExpandHeap_lock);
|
|
HeapWord* prev_high = (HeapWord*) _virtual_space.high();
|
|
bool success = _virtual_space.expand_by(bytes);
|
|
if (success && ZapUnusedHeapArea) {
|
|
// Mangle newly committed space immediately because it
|
|
// can be done here more simply that after the new
|
|
// spaces have been computed.
|
|
HeapWord* new_high = (HeapWord*) _virtual_space.high();
|
|
MemRegion mangle_region(prev_high, new_high);
|
|
SpaceMangler::mangle_region(mangle_region);
|
|
}
|
|
|
|
// Do not attempt an expand-to-the reserve size. The
|
|
// request should properly observe the maximum size of
|
|
// the generation so an expand-to-reserve should be
|
|
// unnecessary. Also a second call to expand-to-reserve
|
|
// value potentially can cause an undue expansion.
|
|
// For example if the first expand fail for unknown reasons,
|
|
// but the second succeeds and expands the heap to its maximum
|
|
// value.
|
|
if (GC_locker::is_active()) {
|
|
if (PrintGC && Verbose) {
|
|
gclog_or_tty->print_cr("Garbage collection disabled, "
|
|
"expanded heap instead");
|
|
}
|
|
}
|
|
|
|
return success;
|
|
}
|
|
|
|
|
|
void DefNewGeneration::compute_new_size() {
|
|
// This is called after a gc that includes the following generation
|
|
// (which is required to exist.) So from-space will normally be empty.
|
|
// Note that we check both spaces, since if scavenge failed they revert roles.
|
|
// If not we bail out (otherwise we would have to relocate the objects)
|
|
if (!from()->is_empty() || !to()->is_empty()) {
|
|
return;
|
|
}
|
|
|
|
int next_level = level() + 1;
|
|
GenCollectedHeap* gch = GenCollectedHeap::heap();
|
|
assert(next_level < gch->_n_gens,
|
|
"DefNewGeneration cannot be an oldest gen");
|
|
|
|
Generation* next_gen = gch->_gens[next_level];
|
|
size_t old_size = next_gen->capacity();
|
|
size_t new_size_before = _virtual_space.committed_size();
|
|
size_t min_new_size = spec()->init_size();
|
|
size_t max_new_size = reserved().byte_size();
|
|
assert(min_new_size <= new_size_before &&
|
|
new_size_before <= max_new_size,
|
|
"just checking");
|
|
// All space sizes must be multiples of Generation::GenGrain.
|
|
size_t alignment = Generation::GenGrain;
|
|
|
|
// Compute desired new generation size based on NewRatio and
|
|
// NewSizeThreadIncrease
|
|
size_t desired_new_size = old_size/NewRatio;
|
|
int threads_count = Threads::number_of_non_daemon_threads();
|
|
size_t thread_increase_size = threads_count * NewSizeThreadIncrease;
|
|
desired_new_size = align_size_up(desired_new_size + thread_increase_size, alignment);
|
|
|
|
// Adjust new generation size
|
|
desired_new_size = MAX2(MIN2(desired_new_size, max_new_size), min_new_size);
|
|
assert(desired_new_size <= max_new_size, "just checking");
|
|
|
|
bool changed = false;
|
|
if (desired_new_size > new_size_before) {
|
|
size_t change = desired_new_size - new_size_before;
|
|
assert(change % alignment == 0, "just checking");
|
|
if (expand(change)) {
|
|
changed = true;
|
|
}
|
|
// If the heap failed to expand to the desired size,
|
|
// "changed" will be false. If the expansion failed
|
|
// (and at this point it was expected to succeed),
|
|
// ignore the failure (leaving "changed" as false).
|
|
}
|
|
if (desired_new_size < new_size_before && eden()->is_empty()) {
|
|
// bail out of shrinking if objects in eden
|
|
size_t change = new_size_before - desired_new_size;
|
|
assert(change % alignment == 0, "just checking");
|
|
_virtual_space.shrink_by(change);
|
|
changed = true;
|
|
}
|
|
if (changed) {
|
|
// The spaces have already been mangled at this point but
|
|
// may not have been cleared (set top = bottom) and should be.
|
|
// Mangling was done when the heap was being expanded.
|
|
compute_space_boundaries(eden()->used(),
|
|
SpaceDecorator::Clear,
|
|
SpaceDecorator::DontMangle);
|
|
MemRegion cmr((HeapWord*)_virtual_space.low(),
|
|
(HeapWord*)_virtual_space.high());
|
|
Universe::heap()->barrier_set()->resize_covered_region(cmr);
|
|
if (Verbose && PrintGC) {
|
|
size_t new_size_after = _virtual_space.committed_size();
|
|
size_t eden_size_after = eden()->capacity();
|
|
size_t survivor_size_after = from()->capacity();
|
|
gclog_or_tty->print("New generation size " SIZE_FORMAT "K->"
|
|
SIZE_FORMAT "K [eden="
|
|
SIZE_FORMAT "K,survivor=" SIZE_FORMAT "K]",
|
|
new_size_before/K, new_size_after/K,
|
|
eden_size_after/K, survivor_size_after/K);
|
|
if (WizardMode) {
|
|
gclog_or_tty->print("[allowed " SIZE_FORMAT "K extra for %d threads]",
|
|
thread_increase_size/K, threads_count);
|
|
}
|
|
gclog_or_tty->cr();
|
|
}
|
|
}
|
|
}
|
|
|
|
void DefNewGeneration::younger_refs_iterate(OopsInGenClosure* cl) {
|
|
assert(false, "NYI -- are you sure you want to call this?");
|
|
}
|
|
|
|
|
|
size_t DefNewGeneration::capacity() const {
|
|
return eden()->capacity()
|
|
+ from()->capacity(); // to() is only used during scavenge
|
|
}
|
|
|
|
|
|
size_t DefNewGeneration::used() const {
|
|
return eden()->used()
|
|
+ from()->used(); // to() is only used during scavenge
|
|
}
|
|
|
|
|
|
size_t DefNewGeneration::free() const {
|
|
return eden()->free()
|
|
+ from()->free(); // to() is only used during scavenge
|
|
}
|
|
|
|
size_t DefNewGeneration::max_capacity() const {
|
|
const size_t alignment = GenCollectedHeap::heap()->collector_policy()->space_alignment();
|
|
const size_t reserved_bytes = reserved().byte_size();
|
|
return reserved_bytes - compute_survivor_size(reserved_bytes, alignment);
|
|
}
|
|
|
|
size_t DefNewGeneration::unsafe_max_alloc_nogc() const {
|
|
return eden()->free();
|
|
}
|
|
|
|
size_t DefNewGeneration::capacity_before_gc() const {
|
|
return eden()->capacity();
|
|
}
|
|
|
|
size_t DefNewGeneration::contiguous_available() const {
|
|
return eden()->free();
|
|
}
|
|
|
|
|
|
HeapWord** DefNewGeneration::top_addr() const { return eden()->top_addr(); }
|
|
HeapWord** DefNewGeneration::end_addr() const { return eden()->end_addr(); }
|
|
|
|
void DefNewGeneration::object_iterate(ObjectClosure* blk) {
|
|
eden()->object_iterate(blk);
|
|
from()->object_iterate(blk);
|
|
}
|
|
|
|
|
|
void DefNewGeneration::space_iterate(SpaceClosure* blk,
|
|
bool usedOnly) {
|
|
blk->do_space(eden());
|
|
blk->do_space(from());
|
|
blk->do_space(to());
|
|
}
|
|
|
|
// The last collection bailed out, we are running out of heap space,
|
|
// so we try to allocate the from-space, too.
|
|
HeapWord* DefNewGeneration::allocate_from_space(size_t size) {
|
|
HeapWord* result = NULL;
|
|
if (Verbose && PrintGCDetails) {
|
|
gclog_or_tty->print("DefNewGeneration::allocate_from_space(" SIZE_FORMAT "):"
|
|
" will_fail: %s"
|
|
" heap_lock: %s"
|
|
" free: " SIZE_FORMAT,
|
|
size,
|
|
GenCollectedHeap::heap()->incremental_collection_will_fail(false /* don't consult_young */) ?
|
|
"true" : "false",
|
|
Heap_lock->is_locked() ? "locked" : "unlocked",
|
|
from()->free());
|
|
}
|
|
if (should_allocate_from_space() || GC_locker::is_active_and_needs_gc()) {
|
|
if (Heap_lock->owned_by_self() ||
|
|
(SafepointSynchronize::is_at_safepoint() &&
|
|
Thread::current()->is_VM_thread())) {
|
|
// If the Heap_lock is not locked by this thread, this will be called
|
|
// again later with the Heap_lock held.
|
|
result = from()->allocate(size);
|
|
} else if (PrintGC && Verbose) {
|
|
gclog_or_tty->print_cr(" Heap_lock is not owned by self");
|
|
}
|
|
} else if (PrintGC && Verbose) {
|
|
gclog_or_tty->print_cr(" should_allocate_from_space: NOT");
|
|
}
|
|
if (PrintGC && Verbose) {
|
|
gclog_or_tty->print_cr(" returns %s", result == NULL ? "NULL" : "object");
|
|
}
|
|
return result;
|
|
}
|
|
|
|
HeapWord* DefNewGeneration::expand_and_allocate(size_t size,
|
|
bool is_tlab,
|
|
bool parallel) {
|
|
// We don't attempt to expand the young generation (but perhaps we should.)
|
|
return allocate(size, is_tlab);
|
|
}
|
|
|
|
void DefNewGeneration::adjust_desired_tenuring_threshold() {
|
|
// Set the desired survivor size to half the real survivor space
|
|
_tenuring_threshold =
|
|
age_table()->compute_tenuring_threshold(to()->capacity()/HeapWordSize);
|
|
}
|
|
|
|
void DefNewGeneration::collect(bool full,
|
|
bool clear_all_soft_refs,
|
|
size_t size,
|
|
bool is_tlab) {
|
|
assert(full || size > 0, "otherwise we don't want to collect");
|
|
|
|
GenCollectedHeap* gch = GenCollectedHeap::heap();
|
|
|
|
_gc_timer->register_gc_start();
|
|
DefNewTracer gc_tracer;
|
|
gc_tracer.report_gc_start(gch->gc_cause(), _gc_timer->gc_start());
|
|
|
|
_next_gen = gch->next_gen(this);
|
|
|
|
// If the next generation is too full to accommodate promotion
|
|
// from this generation, pass on collection; let the next generation
|
|
// do it.
|
|
if (!collection_attempt_is_safe()) {
|
|
if (Verbose && PrintGCDetails) {
|
|
gclog_or_tty->print(" :: Collection attempt not safe :: ");
|
|
}
|
|
gch->set_incremental_collection_failed(); // Slight lie: we did not even attempt one
|
|
return;
|
|
}
|
|
assert(to()->is_empty(), "Else not collection_attempt_is_safe");
|
|
|
|
init_assuming_no_promotion_failure();
|
|
|
|
GCTraceTime t1(GCCauseString("GC", gch->gc_cause()), PrintGC && !PrintGCDetails, true, NULL, gc_tracer.gc_id());
|
|
// Capture heap used before collection (for printing).
|
|
size_t gch_prev_used = gch->used();
|
|
|
|
gch->trace_heap_before_gc(&gc_tracer);
|
|
|
|
SpecializationStats::clear();
|
|
|
|
// These can be shared for all code paths
|
|
IsAliveClosure is_alive(this);
|
|
ScanWeakRefClosure scan_weak_ref(this);
|
|
|
|
age_table()->clear();
|
|
to()->clear(SpaceDecorator::Mangle);
|
|
|
|
gch->rem_set()->prepare_for_younger_refs_iterate(false);
|
|
|
|
assert(gch->no_allocs_since_save_marks(0),
|
|
"save marks have not been newly set.");
|
|
|
|
// Not very pretty.
|
|
CollectorPolicy* cp = gch->collector_policy();
|
|
|
|
FastScanClosure fsc_with_no_gc_barrier(this, false);
|
|
FastScanClosure fsc_with_gc_barrier(this, true);
|
|
|
|
KlassScanClosure klass_scan_closure(&fsc_with_no_gc_barrier,
|
|
gch->rem_set()->klass_rem_set());
|
|
CLDToKlassAndOopClosure cld_scan_closure(&klass_scan_closure,
|
|
&fsc_with_no_gc_barrier,
|
|
false);
|
|
|
|
set_promo_failure_scan_stack_closure(&fsc_with_no_gc_barrier);
|
|
FastEvacuateFollowersClosure evacuate_followers(gch, _level, this,
|
|
&fsc_with_no_gc_barrier,
|
|
&fsc_with_gc_barrier);
|
|
|
|
assert(gch->no_allocs_since_save_marks(0),
|
|
"save marks have not been newly set.");
|
|
|
|
gch->gen_process_roots(_level,
|
|
true, // Process younger gens, if any,
|
|
// as strong roots.
|
|
true, // activate StrongRootsScope
|
|
SharedHeap::SO_ScavengeCodeCache,
|
|
GenCollectedHeap::StrongAndWeakRoots,
|
|
&fsc_with_no_gc_barrier,
|
|
&fsc_with_gc_barrier,
|
|
&cld_scan_closure);
|
|
|
|
// "evacuate followers".
|
|
evacuate_followers.do_void();
|
|
|
|
FastKeepAliveClosure keep_alive(this, &scan_weak_ref);
|
|
ReferenceProcessor* rp = ref_processor();
|
|
rp->setup_policy(clear_all_soft_refs);
|
|
const ReferenceProcessorStats& stats =
|
|
rp->process_discovered_references(&is_alive, &keep_alive, &evacuate_followers,
|
|
NULL, _gc_timer, gc_tracer.gc_id());
|
|
gc_tracer.report_gc_reference_stats(stats);
|
|
|
|
if (!_promotion_failed) {
|
|
// Swap the survivor spaces.
|
|
eden()->clear(SpaceDecorator::Mangle);
|
|
from()->clear(SpaceDecorator::Mangle);
|
|
if (ZapUnusedHeapArea) {
|
|
// This is now done here because of the piece-meal mangling which
|
|
// can check for valid mangling at intermediate points in the
|
|
// collection(s). When a minor collection fails to collect
|
|
// sufficient space resizing of the young generation can occur
|
|
// an redistribute the spaces in the young generation. Mangle
|
|
// here so that unzapped regions don't get distributed to
|
|
// other spaces.
|
|
to()->mangle_unused_area();
|
|
}
|
|
swap_spaces();
|
|
|
|
assert(to()->is_empty(), "to space should be empty now");
|
|
|
|
adjust_desired_tenuring_threshold();
|
|
|
|
// A successful scavenge should restart the GC time limit count which is
|
|
// for full GC's.
|
|
AdaptiveSizePolicy* size_policy = gch->gen_policy()->size_policy();
|
|
size_policy->reset_gc_overhead_limit_count();
|
|
assert(!gch->incremental_collection_failed(), "Should be clear");
|
|
} else {
|
|
assert(_promo_failure_scan_stack.is_empty(), "post condition");
|
|
_promo_failure_scan_stack.clear(true); // Clear cached segments.
|
|
|
|
remove_forwarding_pointers();
|
|
if (PrintGCDetails) {
|
|
gclog_or_tty->print(" (promotion failed) ");
|
|
}
|
|
// Add to-space to the list of space to compact
|
|
// when a promotion failure has occurred. In that
|
|
// case there can be live objects in to-space
|
|
// as a result of a partial evacuation of eden
|
|
// and from-space.
|
|
swap_spaces(); // For uniformity wrt ParNewGeneration.
|
|
from()->set_next_compaction_space(to());
|
|
gch->set_incremental_collection_failed();
|
|
|
|
// Inform the next generation that a promotion failure occurred.
|
|
_next_gen->promotion_failure_occurred();
|
|
gc_tracer.report_promotion_failed(_promotion_failed_info);
|
|
|
|
// Reset the PromotionFailureALot counters.
|
|
NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();)
|
|
}
|
|
if (PrintGC && !PrintGCDetails) {
|
|
gch->print_heap_change(gch_prev_used);
|
|
}
|
|
// set new iteration safe limit for the survivor spaces
|
|
from()->set_concurrent_iteration_safe_limit(from()->top());
|
|
to()->set_concurrent_iteration_safe_limit(to()->top());
|
|
SpecializationStats::print();
|
|
|
|
// We need to use a monotonically non-decreasing time in ms
|
|
// or we will see time-warp warnings and os::javaTimeMillis()
|
|
// does not guarantee monotonicity.
|
|
jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
|
|
update_time_of_last_gc(now);
|
|
|
|
gch->trace_heap_after_gc(&gc_tracer);
|
|
gc_tracer.report_tenuring_threshold(tenuring_threshold());
|
|
|
|
_gc_timer->register_gc_end();
|
|
|
|
gc_tracer.report_gc_end(_gc_timer->gc_end(), _gc_timer->time_partitions());
|
|
}
|
|
|
|
class RemoveForwardPointerClosure: public ObjectClosure {
|
|
public:
|
|
void do_object(oop obj) {
|
|
obj->init_mark();
|
|
}
|
|
};
|
|
|
|
void DefNewGeneration::init_assuming_no_promotion_failure() {
|
|
_promotion_failed = false;
|
|
_promotion_failed_info.reset();
|
|
from()->set_next_compaction_space(NULL);
|
|
}
|
|
|
|
void DefNewGeneration::remove_forwarding_pointers() {
|
|
RemoveForwardPointerClosure rspc;
|
|
eden()->object_iterate(&rspc);
|
|
from()->object_iterate(&rspc);
|
|
|
|
// Now restore saved marks, if any.
|
|
assert(_objs_with_preserved_marks.size() == _preserved_marks_of_objs.size(),
|
|
"should be the same");
|
|
while (!_objs_with_preserved_marks.is_empty()) {
|
|
oop obj = _objs_with_preserved_marks.pop();
|
|
markOop m = _preserved_marks_of_objs.pop();
|
|
obj->set_mark(m);
|
|
}
|
|
_objs_with_preserved_marks.clear(true);
|
|
_preserved_marks_of_objs.clear(true);
|
|
}
|
|
|
|
void DefNewGeneration::preserve_mark(oop obj, markOop m) {
|
|
assert(_promotion_failed && m->must_be_preserved_for_promotion_failure(obj),
|
|
"Oversaving!");
|
|
_objs_with_preserved_marks.push(obj);
|
|
_preserved_marks_of_objs.push(m);
|
|
}
|
|
|
|
void DefNewGeneration::preserve_mark_if_necessary(oop obj, markOop m) {
|
|
if (m->must_be_preserved_for_promotion_failure(obj)) {
|
|
preserve_mark(obj, m);
|
|
}
|
|
}
|
|
|
|
void DefNewGeneration::handle_promotion_failure(oop old) {
|
|
if (PrintPromotionFailure && !_promotion_failed) {
|
|
gclog_or_tty->print(" (promotion failure size = %d) ",
|
|
old->size());
|
|
}
|
|
_promotion_failed = true;
|
|
_promotion_failed_info.register_copy_failure(old->size());
|
|
preserve_mark_if_necessary(old, old->mark());
|
|
// forward to self
|
|
old->forward_to(old);
|
|
|
|
_promo_failure_scan_stack.push(old);
|
|
|
|
if (!_promo_failure_drain_in_progress) {
|
|
// prevent recursion in copy_to_survivor_space()
|
|
_promo_failure_drain_in_progress = true;
|
|
drain_promo_failure_scan_stack();
|
|
_promo_failure_drain_in_progress = false;
|
|
}
|
|
}
|
|
|
|
oop DefNewGeneration::copy_to_survivor_space(oop old) {
|
|
assert(is_in_reserved(old) && !old->is_forwarded(),
|
|
"shouldn't be scavenging this oop");
|
|
size_t s = old->size();
|
|
oop obj = NULL;
|
|
|
|
// Try allocating obj in to-space (unless too old)
|
|
if (old->age() < tenuring_threshold()) {
|
|
obj = (oop) to()->allocate_aligned(s);
|
|
}
|
|
|
|
// Otherwise try allocating obj tenured
|
|
if (obj == NULL) {
|
|
obj = _next_gen->promote(old, s);
|
|
if (obj == NULL) {
|
|
handle_promotion_failure(old);
|
|
return old;
|
|
}
|
|
} else {
|
|
// Prefetch beyond obj
|
|
const intx interval = PrefetchCopyIntervalInBytes;
|
|
Prefetch::write(obj, interval);
|
|
|
|
// Copy obj
|
|
Copy::aligned_disjoint_words((HeapWord*)old, (HeapWord*)obj, s);
|
|
|
|
// Increment age if obj still in new generation
|
|
obj->incr_age();
|
|
age_table()->add(obj, s);
|
|
}
|
|
|
|
// Done, insert forward pointer to obj in this header
|
|
old->forward_to(obj);
|
|
|
|
return obj;
|
|
}
|
|
|
|
void DefNewGeneration::drain_promo_failure_scan_stack() {
|
|
while (!_promo_failure_scan_stack.is_empty()) {
|
|
oop obj = _promo_failure_scan_stack.pop();
|
|
obj->oop_iterate(_promo_failure_scan_stack_closure);
|
|
}
|
|
}
|
|
|
|
void DefNewGeneration::save_marks() {
|
|
eden()->set_saved_mark();
|
|
to()->set_saved_mark();
|
|
from()->set_saved_mark();
|
|
}
|
|
|
|
|
|
void DefNewGeneration::reset_saved_marks() {
|
|
eden()->reset_saved_mark();
|
|
to()->reset_saved_mark();
|
|
from()->reset_saved_mark();
|
|
}
|
|
|
|
|
|
bool DefNewGeneration::no_allocs_since_save_marks() {
|
|
assert(eden()->saved_mark_at_top(), "Violated spec - alloc in eden");
|
|
assert(from()->saved_mark_at_top(), "Violated spec - alloc in from");
|
|
return to()->saved_mark_at_top();
|
|
}
|
|
|
|
#define DefNew_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \
|
|
\
|
|
void DefNewGeneration:: \
|
|
oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
|
|
cl->set_generation(this); \
|
|
eden()->oop_since_save_marks_iterate##nv_suffix(cl); \
|
|
to()->oop_since_save_marks_iterate##nv_suffix(cl); \
|
|
from()->oop_since_save_marks_iterate##nv_suffix(cl); \
|
|
cl->reset_generation(); \
|
|
save_marks(); \
|
|
}
|
|
|
|
ALL_SINCE_SAVE_MARKS_CLOSURES(DefNew_SINCE_SAVE_MARKS_DEFN)
|
|
|
|
#undef DefNew_SINCE_SAVE_MARKS_DEFN
|
|
|
|
void DefNewGeneration::contribute_scratch(ScratchBlock*& list, Generation* requestor,
|
|
size_t max_alloc_words) {
|
|
if (requestor == this || _promotion_failed) return;
|
|
assert(requestor->level() > level(), "DefNewGeneration must be youngest");
|
|
|
|
/* $$$ Assert this? "trace" is a "MarkSweep" function so that's not appropriate.
|
|
if (to_space->top() > to_space->bottom()) {
|
|
trace("to_space not empty when contribute_scratch called");
|
|
}
|
|
*/
|
|
|
|
ContiguousSpace* to_space = to();
|
|
assert(to_space->end() >= to_space->top(), "pointers out of order");
|
|
size_t free_words = pointer_delta(to_space->end(), to_space->top());
|
|
if (free_words >= MinFreeScratchWords) {
|
|
ScratchBlock* sb = (ScratchBlock*)to_space->top();
|
|
sb->num_words = free_words;
|
|
sb->next = list;
|
|
list = sb;
|
|
}
|
|
}
|
|
|
|
void DefNewGeneration::reset_scratch() {
|
|
// If contributing scratch in to_space, mangle all of
|
|
// to_space if ZapUnusedHeapArea. This is needed because
|
|
// top is not maintained while using to-space as scratch.
|
|
if (ZapUnusedHeapArea) {
|
|
to()->mangle_unused_area_complete();
|
|
}
|
|
}
|
|
|
|
bool DefNewGeneration::collection_attempt_is_safe() {
|
|
if (!to()->is_empty()) {
|
|
if (Verbose && PrintGCDetails) {
|
|
gclog_or_tty->print(" :: to is not empty :: ");
|
|
}
|
|
return false;
|
|
}
|
|
if (_next_gen == NULL) {
|
|
GenCollectedHeap* gch = GenCollectedHeap::heap();
|
|
_next_gen = gch->next_gen(this);
|
|
}
|
|
return _next_gen->promotion_attempt_is_safe(used());
|
|
}
|
|
|
|
void DefNewGeneration::gc_epilogue(bool full) {
|
|
DEBUG_ONLY(static bool seen_incremental_collection_failed = false;)
|
|
|
|
assert(!GC_locker::is_active(), "We should not be executing here");
|
|
// Check if the heap is approaching full after a collection has
|
|
// been done. Generally the young generation is empty at
|
|
// a minimum at the end of a collection. If it is not, then
|
|
// the heap is approaching full.
|
|
GenCollectedHeap* gch = GenCollectedHeap::heap();
|
|
if (full) {
|
|
DEBUG_ONLY(seen_incremental_collection_failed = false;)
|
|
if (!collection_attempt_is_safe() && !_eden_space->is_empty()) {
|
|
if (Verbose && PrintGCDetails) {
|
|
gclog_or_tty->print("DefNewEpilogue: cause(%s), full, not safe, set_failed, set_alloc_from, clear_seen",
|
|
GCCause::to_string(gch->gc_cause()));
|
|
}
|
|
gch->set_incremental_collection_failed(); // Slight lie: a full gc left us in that state
|
|
set_should_allocate_from_space(); // we seem to be running out of space
|
|
} else {
|
|
if (Verbose && PrintGCDetails) {
|
|
gclog_or_tty->print("DefNewEpilogue: cause(%s), full, safe, clear_failed, clear_alloc_from, clear_seen",
|
|
GCCause::to_string(gch->gc_cause()));
|
|
}
|
|
gch->clear_incremental_collection_failed(); // We just did a full collection
|
|
clear_should_allocate_from_space(); // if set
|
|
}
|
|
} else {
|
|
#ifdef ASSERT
|
|
// It is possible that incremental_collection_failed() == true
|
|
// here, because an attempted scavenge did not succeed. The policy
|
|
// is normally expected to cause a full collection which should
|
|
// clear that condition, so we should not be here twice in a row
|
|
// with incremental_collection_failed() == true without having done
|
|
// a full collection in between.
|
|
if (!seen_incremental_collection_failed &&
|
|
gch->incremental_collection_failed()) {
|
|
if (Verbose && PrintGCDetails) {
|
|
gclog_or_tty->print("DefNewEpilogue: cause(%s), not full, not_seen_failed, failed, set_seen_failed",
|
|
GCCause::to_string(gch->gc_cause()));
|
|
}
|
|
seen_incremental_collection_failed = true;
|
|
} else if (seen_incremental_collection_failed) {
|
|
if (Verbose && PrintGCDetails) {
|
|
gclog_or_tty->print("DefNewEpilogue: cause(%s), not full, seen_failed, will_clear_seen_failed",
|
|
GCCause::to_string(gch->gc_cause()));
|
|
}
|
|
assert(gch->gc_cause() == GCCause::_scavenge_alot ||
|
|
(gch->gc_cause() == GCCause::_java_lang_system_gc && UseConcMarkSweepGC && ExplicitGCInvokesConcurrent) ||
|
|
!gch->incremental_collection_failed(),
|
|
"Twice in a row");
|
|
seen_incremental_collection_failed = false;
|
|
}
|
|
#endif // ASSERT
|
|
}
|
|
|
|
if (ZapUnusedHeapArea) {
|
|
eden()->check_mangled_unused_area_complete();
|
|
from()->check_mangled_unused_area_complete();
|
|
to()->check_mangled_unused_area_complete();
|
|
}
|
|
|
|
if (!CleanChunkPoolAsync) {
|
|
Chunk::clean_chunk_pool();
|
|
}
|
|
|
|
// update the generation and space performance counters
|
|
update_counters();
|
|
gch->collector_policy()->counters()->update_counters();
|
|
}
|
|
|
|
void DefNewGeneration::record_spaces_top() {
|
|
assert(ZapUnusedHeapArea, "Not mangling unused space");
|
|
eden()->set_top_for_allocations();
|
|
to()->set_top_for_allocations();
|
|
from()->set_top_for_allocations();
|
|
}
|
|
|
|
void DefNewGeneration::ref_processor_init() {
|
|
Generation::ref_processor_init();
|
|
}
|
|
|
|
|
|
void DefNewGeneration::update_counters() {
|
|
if (UsePerfData) {
|
|
_eden_counters->update_all();
|
|
_from_counters->update_all();
|
|
_to_counters->update_all();
|
|
_gen_counters->update_all();
|
|
}
|
|
}
|
|
|
|
void DefNewGeneration::verify() {
|
|
eden()->verify();
|
|
from()->verify();
|
|
to()->verify();
|
|
}
|
|
|
|
void DefNewGeneration::print_on(outputStream* st) const {
|
|
Generation::print_on(st);
|
|
st->print(" eden");
|
|
eden()->print_on(st);
|
|
st->print(" from");
|
|
from()->print_on(st);
|
|
st->print(" to ");
|
|
to()->print_on(st);
|
|
}
|
|
|
|
|
|
const char* DefNewGeneration::name() const {
|
|
return "def new generation";
|
|
}
|
|
|
|
// Moved from inline file as they are not called inline
|
|
CompactibleSpace* DefNewGeneration::first_compaction_space() const {
|
|
return eden();
|
|
}
|
|
|
|
HeapWord* DefNewGeneration::allocate(size_t word_size,
|
|
bool is_tlab) {
|
|
// This is the slow-path allocation for the DefNewGeneration.
|
|
// Most allocations are fast-path in compiled code.
|
|
// We try to allocate from the eden. If that works, we are happy.
|
|
// Note that since DefNewGeneration supports lock-free allocation, we
|
|
// have to use it here, as well.
|
|
HeapWord* result = eden()->par_allocate(word_size);
|
|
if (result != NULL) {
|
|
if (CMSEdenChunksRecordAlways && _next_gen != NULL) {
|
|
_next_gen->sample_eden_chunk();
|
|
}
|
|
} else {
|
|
// If the eden is full and the last collection bailed out, we are running
|
|
// out of heap space, and we try to allocate the from-space, too.
|
|
// allocate_from_space can't be inlined because that would introduce a
|
|
// circular dependency at compile time.
|
|
result = allocate_from_space(word_size);
|
|
}
|
|
return result;
|
|
}
|
|
|
|
HeapWord* DefNewGeneration::par_allocate(size_t word_size,
|
|
bool is_tlab) {
|
|
HeapWord* res = eden()->par_allocate(word_size);
|
|
if (CMSEdenChunksRecordAlways && _next_gen != NULL) {
|
|
_next_gen->sample_eden_chunk();
|
|
}
|
|
return res;
|
|
}
|
|
|
|
size_t DefNewGeneration::tlab_capacity() const {
|
|
return eden()->capacity();
|
|
}
|
|
|
|
size_t DefNewGeneration::tlab_used() const {
|
|
return eden()->used();
|
|
}
|
|
|
|
size_t DefNewGeneration::unsafe_max_tlab_alloc() const {
|
|
return unsafe_max_alloc_nogc();
|
|
}
|