#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/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/java.hpp"

#include "utilities/copy.hpp"

#include "utilities/stack.inline.hpp"

#ifdef TARGET_OS_FAMILY_linux

# include "thread_linux.inline.hpp"

#endif

#ifdef TARGET_OS_FAMILY_solaris

# include "thread_solaris.inline.hpp"

#endif

#ifdef TARGET_OS_FAMILY_windows

# include "thread_windows.inline.hpp"

#endif

#ifdef TARGET_OS_FAMILY_bsd

# include "thread_bsd.inline.hpp"

#endif

DefNewGeneration::IsAliveClosure::IsAliveClosure(Generation* g) : _g(g) {

assert(g->level() == 0, "Optimized for youngest gen.");

}

void DefNewGeneration::IsAliveClosure::do_object(oop p) {

assert(false, "Do not call.");

}

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();

assert(rs->rs_kind() == GenRemSet::CardTable, "Wrong rem set kind.");

_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) :

OopsInGenClosure(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) :

OopsInGenClosure(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); }

ScanWeakRefClosure::ScanWeakRefClosure(DefNewGeneration* g) :

OopClosure(g->ref_processor()), _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); }

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);

if (GenCollectedHeap::heap()->collector_policy()->has_soft_ended_eden()) {

_eden_space = new ConcEdenSpace(this);

} else {

_eden_space = new EdenSpace(this);

}

_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()->min_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

// Generation counters -- generation 0, 3 subspaces

_gen_counters = new GenerationCounters("new", 0, 3, &_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()->min_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::object_iterate_since_last_GC(ObjectClosure* cl) {

// $$$ This may be wrong in case of "scavenge failure"?

eden()->object_iterate(cl);

}

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()->min_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());

}

HeapWord* DefNewGeneration::allocate_from_space(size_t size) {

HeapWord* result = NULL;

if (Verbose && PrintGCDetails) {

gclog_or_tty->print("DefNewGeneration::allocate_from_space(%u):"

" 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::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(os::elapsed_counter());

DefNewTracer gc_tracer;

gc_tracer.report_gc_start(gch->gc_cause(), _gc_timer->gc_start());

_next_gen = gch->next_gen(this);

assert(_next_gen != NULL,

"This must be the youngest gen, and not the only gen");

// 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);

// 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);

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_strong_roots(_level,

true, // Process younger gens, if any,

// as strong roots.

true, // activate StrongRootsScope

false, // not collecting perm generation.

SharedHeap::SO_AllClasses,

&fsc_with_no_gc_barrier,

true, // walk *all* scavengable nmethods

&fsc_with_gc_barrier);

// "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.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");

// Set the desired survivor size to half the real survivor space

_tenuring_threshold =

age_table()->compute_tenuring_threshold(to()->capacity()/HeapWordSize);

// 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();

if (PrintGC && !PrintGCDetails) {

gch->print_heap_change(gch_prev_used);

}

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();)

}

// 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_timer->register_gc_end(os::elapsed_counter());

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 = " SIZE_FORMAT ") ",

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(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.

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);

assert(_next_gen != NULL,

"This must be the youngest gen, and not the only gen");

}

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";

}

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) {

return result;

}

do {

HeapWord* old_limit = eden()->soft_end();

if (old_limit < eden()->end()) {

// Tell the next generation we reached a limit.

HeapWord* new_limit =

next_gen()->allocation_limit_reached(eden(), eden()->top(), word_size);

if (new_limit != NULL) {

Atomic::cmpxchg_ptr(new_limit, eden()->soft_end_addr(), old_limit);

} else {

assert(eden()->soft_end() == eden()->end(),

"invalid state after allocation_limit_reached returned null");

}

} else {

// The allocation failed and the soft limit is equal to the hard limit,

// there are no reasons to do an attempt to allocate

assert(old_limit == eden()->end(), "sanity check");

break;

}

// Try to allocate until succeeded or the soft limit can't be adjusted

result = eden()->par_allocate(word_size);

} while (result == NULL);

// 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.

if (result == NULL) {

result = allocate_from_space(word_size);

}

return result;

}

HeapWord* DefNewGeneration::par_allocate(size_t word_size,

bool is_tlab) {

return eden()->par_allocate(word_size);

}

void DefNewGeneration::gc_prologue(bool full) {

// Ensure that _end and _soft_end are the same in eden space.

eden()->set_soft_end(eden()->end());

}

size_t DefNewGeneration::tlab_capacity() const {

return eden()->capacity();

}

size_t DefNewGeneration::unsafe_max_tlab_alloc() const {

return unsafe_max_alloc_nogc();

}