// This method iterates over all objects in the young generation,
// unforwarding markOops. It then restores any preserved mark oops,
// and clears the _preserved_mark_stack.
void PSScavenge::clean_up_failed_promotion() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSYoungGen* young_gen = heap->young_gen();
{
ResourceMark rm;
// Unforward all pointers in the young gen.
PSPromotionFailedClosure unforward_closure;
young_gen->object_iterate(&unforward_closure);
if (PrintGC && Verbose) {
gclog_or_tty->print_cr("Restoring %d marks", _preserved_oop_stack.size());
}
// Restore any saved marks.
while (!_preserved_oop_stack.is_empty()) {
oop obj = _preserved_oop_stack.pop();
markOop mark = _preserved_mark_stack.pop();
obj->set_mark(mark);
}
// Clear the preserved mark and oop stack caches.
_preserved_mark_stack.clear(true);
_preserved_oop_stack.clear(true);
}
// Reset the PromotionFailureALot counters.
NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();)
}
void PSYoungGen::compute_initial_space_boundaries() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
// Compute sizes
size_t alignment = heap->intra_heap_alignment();
size_t size = virtual_space()->committed_size();
size_t survivor_size = size / InitialSurvivorRatio;
survivor_size = align_size_down(survivor_size, alignment);
// ... but never less than an alignment
survivor_size = MAX2(survivor_size, alignment);
// Young generation is eden + 2 survivor spaces
size_t eden_size = size - (2 * survivor_size);
// Now go ahead and set 'em.
set_space_boundaries(eden_size, survivor_size);
space_invariants();
if (UsePerfData) {
_eden_counters->update_capacity();
_from_counters->update_capacity();
_to_counters->update_capacity();
}
}
void PSPromotionManager::initialize() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
_old_gen = heap->old_gen();
_young_space = heap->young_gen()->to_space();
assert(_manager_array == NULL, "Attempt to initialize twice");
_manager_array = NEW_C_HEAP_ARRAY(PSPromotionManager*, ParallelGCThreads+1, mtGC);
guarantee(_manager_array != NULL, "Could not initialize promotion manager");
_stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads);
guarantee(_stack_array_depth != NULL, "Cound not initialize promotion manager");
// Create and register the PSPromotionManager(s) for the worker threads.
for(uint i=0; i<ParallelGCThreads; i++) {
_manager_array[i] = new PSPromotionManager();
guarantee(_manager_array[i] != NULL, "Could not create PSPromotionManager");
stack_array_depth()->register_queue(i, _manager_array[i]->claimed_stack_depth());
}
// The VMThread gets its own PSPromotionManager, which is not available
// for work stealing.
_manager_array[ParallelGCThreads] = new PSPromotionManager();
guarantee(_manager_array[ParallelGCThreads] != NULL, "Could not create PSPromotionManager");
}
void PSMarkSweep::mark_sweep_phase2() {
EventMark m("2 compute new addresses");
TraceTime tm("phase 2", PrintGCDetails && Verbose, true, gclog_or_tty);
trace("2");
// Now all live objects are marked, compute the new object addresses.
// It is imperative that we traverse perm_gen LAST. If dead space is
// allowed a range of dead object may get overwritten by a dead int
// array. If perm_gen is not traversed last a klassOop may get
// overwritten. This is fine since it is dead, but if the class has dead
// instances we have to skip them, and in order to find their size we
// need the klassOop!
//
// It is not required that we traverse spaces in the same order in
// phase2, phase3 and phase4, but the ValidateMarkSweep live oops
// tracking expects us to do so. See comment under phase4.
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSOldGen* old_gen = heap->old_gen();
PSPermGen* perm_gen = heap->perm_gen();
// Begin compacting into the old gen
PSMarkSweepDecorator::set_destination_decorator_tenured();
// This will also compact the young gen spaces.
old_gen->precompact();
// Compact the perm gen into the perm gen
PSMarkSweepDecorator::set_destination_decorator_perm_gen();
perm_gen->precompact();
}
void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) {
// Recursively traverse all live objects and mark them
GCTraceTime tm("phase 1", PrintGCDetails && Verbose, true, _gc_timer);
trace(" 1");
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
// General strong roots.
{
ParallelScavengeHeap::ParStrongRootsScope psrs;
Universe::oops_do(mark_and_push_closure());
JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles
CodeBlobToOopClosure each_active_code_blob(mark_and_push_closure(), /*do_marking=*/ true);
Threads::oops_do(mark_and_push_closure(), &each_active_code_blob);
ObjectSynchronizer::oops_do(mark_and_push_closure());
FlatProfiler::oops_do(mark_and_push_closure());
Management::oops_do(mark_and_push_closure());
JvmtiExport::oops_do(mark_and_push_closure());
SystemDictionary::always_strong_oops_do(mark_and_push_closure());
// Do not treat nmethods as strong roots for mark/sweep, since we can unload them.
//CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure()));
}
// Flush marking stack.
follow_stack();
// Process reference objects found during marking
{
ref_processor()->setup_policy(clear_all_softrefs);
const ReferenceProcessorStats& stats =
ref_processor()->process_discovered_references(
is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL, _gc_timer);
gc_tracer()->report_gc_reference_stats(stats);
}
// Follow system dictionary roots and unload classes
bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
// Follow code cache roots
CodeCache::do_unloading(is_alive_closure(), mark_and_push_closure(),
purged_class);
follow_stack(); // Flush marking stack
// Update subklass/sibling/implementor links of live klasses
follow_weak_klass_links();
assert(_marking_stack.is_empty(), "just drained");
// Visit memoized mdo's and clear unmarked weak refs
follow_mdo_weak_refs();
assert(_marking_stack.is_empty(), "just drained");
// Visit interned string tables and delete unmarked oops
StringTable::unlink(is_alive_closure());
// Clean up unreferenced symbols in symbol table.
SymbolTable::unlink();
assert(_marking_stack.is_empty(), "stack should be empty by now");
_gc_tracer->report_object_count_after_gc(is_alive_closure());
}
// This method contains all heap specific policy for invoking scavenge.
// PSScavenge::invoke_no_policy() will do nothing but attempt to
// scavenge. It will not clean up after failed promotions, bail out if
// we've exceeded policy time limits, or any other special behavior.
// All such policy should be placed here.
//
// Note that this method should only be called from the vm_thread while
// at a safepoint!
void PSScavenge::invoke() {
assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
assert(!Universe::heap()->is_gc_active(), "not reentrant");
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSAdaptiveSizePolicy* policy = heap->size_policy();
IsGCActiveMark mark;
bool scavenge_was_done = PSScavenge::invoke_no_policy();
PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
if (UsePerfData)
counters->update_full_follows_scavenge(0);
if (!scavenge_was_done ||
policy->should_full_GC(heap->old_gen()->free_in_bytes())) {
if (UsePerfData)
counters->update_full_follows_scavenge(full_follows_scavenge);
GCCauseSetter gccs(heap, GCCause::_adaptive_size_policy);
CollectorPolicy* cp = heap->collector_policy();
const bool clear_all_softrefs = cp->should_clear_all_soft_refs();
if (UseParallelOldGC) {
PSParallelCompact::invoke_no_policy(clear_all_softrefs);
} else {
PSMarkSweep::invoke_no_policy(clear_all_softrefs);
}
}
}
PSKeepAliveClosure(PSPromotionManager* pm) : _promotion_manager(pm) {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
_to_space = heap->young_gen()->to_space();
assert(_promotion_manager != NULL, "Sanity");
}
void PSMarkSweep::allocate_stacks() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSYoungGen* young_gen = heap->young_gen();
MutableSpace* to_space = young_gen->to_space();
_preserved_marks = (PreservedMark*)to_space->top();
_preserved_count = 0;
// We want to calculate the size in bytes first.
_preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte));
// Now divide by the size of a PreservedMark
_preserved_count_max /= sizeof(PreservedMark);
_preserved_mark_stack = NULL;
_preserved_oop_stack = NULL;
_marking_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true);
int size = SystemDictionary::number_of_classes() * 2;
_revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true);
// (#klass/k)^2, for k ~ 10 appears a better setting, but this will have to do for
// now until we investigate a more optimal setting.
_revisit_mdo_stack = new (ResourceObj::C_HEAP) GrowableArray<DataLayout*>(size*2, true);
}
void PSMarkSweep::mark_sweep_phase1( bool& marked_for_unloading, bool clear_all_softrefs) {
// Recursively traverse all live objects and mark them
EventMark m("1 mark object");
TraceTime tm("phase 1", PrintGC && Verbose, true, gclog_or_tty);
trace(" 1");
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
// General strong roots.
Universe::oops_do(mark_and_push_closure());
JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles
Threads::oops_do(mark_and_push_closure());
ObjectSynchronizer::oops_do(mark_and_push_closure());
FlatProfiler::oops_do(mark_and_push_closure());
SystemDictionary::always_strong_oops_do(mark_and_push_closure());
guarantee(!jvmdi::enabled(), "Should not be used with jvmdi");
vmSymbols::oops_do(mark_and_push_closure());
// Flush marking stack.
follow_stack();
// Process reference objects found during marking
ReferencePolicy *soft_ref_policy;
if (clear_all_softrefs) {
soft_ref_policy = new AlwaysClearPolicy();
} else {
NOT_COMPILER2(soft_ref_policy = new LRUCurrentHeapPolicy();)
COMPILER2_ONLY(soft_ref_policy = new LRUMaxHeapPolicy();)
}
void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) {
// Recursively traverse all live objects and mark them
GCTraceTime tm("phase 1", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id());
trace(" 1");
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
// Need to clear claim bits before the tracing starts.
ClassLoaderDataGraph::clear_claimed_marks();
// General strong roots.
{
ParallelScavengeHeap::ParStrongRootsScope psrs;
Universe::oops_do(mark_and_push_closure());
JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles
CLDToOopClosure mark_and_push_from_cld(mark_and_push_closure());
MarkingCodeBlobClosure each_active_code_blob(mark_and_push_closure(), !CodeBlobToOopClosure::FixRelocations);
Threads::oops_do(mark_and_push_closure(), &mark_and_push_from_cld, &each_active_code_blob);
ObjectSynchronizer::oops_do(mark_and_push_closure());
FlatProfiler::oops_do(mark_and_push_closure());
Management::oops_do(mark_and_push_closure());
JvmtiExport::oops_do(mark_and_push_closure());
SystemDictionary::always_strong_oops_do(mark_and_push_closure());
ClassLoaderDataGraph::always_strong_cld_do(follow_cld_closure());
// Do not treat nmethods as strong roots for mark/sweep, since we can unload them.
//CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure()));
}
// Flush marking stack.
follow_stack();
// Process reference objects found during marking
{
ref_processor()->setup_policy(clear_all_softrefs);
const ReferenceProcessorStats& stats =
ref_processor()->process_discovered_references(
is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL, _gc_timer, _gc_tracer->gc_id());
gc_tracer()->report_gc_reference_stats(stats);
}
// This is the point where the entire marking should have completed.
assert(_marking_stack.is_empty(), "Marking should have completed");
// Unload classes and purge the SystemDictionary.
bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
// Unload nmethods.
CodeCache::do_unloading(is_alive_closure(), purged_class);
// Prune dead klasses from subklass/sibling/implementor lists.
Klass::clean_weak_klass_links(is_alive_closure());
// Delete entries for dead interned strings.
StringTable::unlink(is_alive_closure());
// Clean up unreferenced symbols in symbol table.
SymbolTable::unlink();
_gc_tracer->report_object_count_after_gc(is_alive_closure());
}
CheckForUnmarkedObjects() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
_young_gen = heap->young_gen();
_card_table = (CardTableExtension*)heap->barrier_set();
// No point in asserting barrier set type here. Need to make CardTableExtension
// a unique barrier set type.
}
bool PSScavenge::should_attempt_scavenge() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
if (UsePerfData) {
counters->update_scavenge_skipped(not_skipped);
}
PSYoungGen* young_gen = heap->young_gen();
PSOldGen* old_gen = heap->old_gen();
if (!ScavengeWithObjectsInToSpace) {
// Do not attempt to promote unless to_space is empty
if (!young_gen->to_space()->is_empty()) {
_consecutive_skipped_scavenges++;
if (UsePerfData) {
counters->update_scavenge_skipped(to_space_not_empty);
}
return false;
}
}
// Test to see if the scavenge will likely fail.
PSAdaptiveSizePolicy* policy = heap->size_policy();
// A similar test is done in the policy's should_full_GC(). If this is
// changed, decide if that test should also be changed.
size_t avg_promoted = (size_t) policy->padded_average_promoted_in_bytes();
size_t promotion_estimate = MIN2(avg_promoted, young_gen->used_in_bytes());
bool result = promotion_estimate < old_gen->free_in_bytes();
if (PrintGCDetails && Verbose) {
gclog_or_tty->print(result ? " do scavenge: " : " skip scavenge: ");
gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT
" padded_average_promoted " SIZE_FORMAT
" free in old gen " SIZE_FORMAT,
(size_t) policy->average_promoted_in_bytes(),
(size_t) policy->padded_average_promoted_in_bytes(),
old_gen->free_in_bytes());
if (young_gen->used_in_bytes() <
(size_t) policy->padded_average_promoted_in_bytes()) {
gclog_or_tty->print_cr(" padded_promoted_average is greater"
" than maximum promotion = " SIZE_FORMAT, young_gen->used_in_bytes());
}
}
if (result) {
_consecutive_skipped_scavenges = 0;
} else {
_consecutive_skipped_scavenges++;
if (UsePerfData) {
counters->update_scavenge_skipped(promoted_too_large);
}
}
return result;
}
void PSPromotionManager::pre_scavenge() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
_young_space = heap->young_gen()->to_space();
for(uint i=0; i<ParallelGCThreads+1; i++) {
manager_array(i)->reset();
}
}
void PSOldGen::precompact() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
// Reset start array first.
_start_array.reset();
object_mark_sweep()->precompact();
// Now compact the young gen
heap->young_gen()->precompact();
}
bool PSYoungPromotionLAB::lab_is_valid(MemRegion lab) {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
MutableSpace* to_space = heap->young_gen()->to_space();
MemRegion used = to_space->used_region();
if (used.contains(lab)) {
return true;
}
return false;
}
// Static method
bool ParallelScavengeHeap::is_in_young(oop* p) {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap,
"Must be ParallelScavengeHeap");
PSYoungGen* young_gen = heap->young_gen();
if (young_gen->is_in(p)) {
return true;
}
return false;
}
ParCompactionManager::ParCompactionManager() :
_action(CopyAndUpdate),
_region_stack(NULL),
_region_stack_index((uint)max_uintx) {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
_old_gen = heap->old_gen();
_start_array = old_gen()->start_array();
marking_stack()->initialize();
_objarray_stack.initialize();
}
bool PSOldPromotionLAB::lab_is_valid(MemRegion lab) {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
assert(_start_array->covered_region().contains(lab), "Sanity");
PSOldGen* old_gen = heap->old_gen();
MemRegion used = old_gen->object_space()->used_region();
if (used.contains(lab)) {
return true;
}
return false;
}
void PSMarkSweep::allocate_stacks() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSYoungGen* young_gen = heap->young_gen();
MutableSpace* to_space = young_gen->to_space();
_preserved_marks = (PreservedMark*)to_space->top();
_preserved_count = 0;
// We want to calculate the size in bytes first.
_preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte));
// Now divide by the size of a PreservedMark
_preserved_count_max /= sizeof(PreservedMark);
}
void PSMarkSweep::mark_sweep_phase4() {
EventMark m("4 compact heap");
TraceTime tm("phase 4", PrintGCDetails && Verbose, true, gclog_or_tty);
trace("4");
// All pointers are now adjusted, move objects accordingly
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSYoungGen* young_gen = heap->young_gen();
PSOldGen* old_gen = heap->old_gen();
old_gen->compact();
young_gen->compact();
}
void PSScavenge::initialize() {
// Arguments must have been parsed
if (AlwaysTenure) {
_tenuring_threshold = 0;
} else if (NeverTenure) {
_tenuring_threshold = markOopDesc::max_age + 1;
} else {
// We want to smooth out our startup times for the AdaptiveSizePolicy
_tenuring_threshold = (UseAdaptiveSizePolicy) ? InitialTenuringThreshold :
MaxTenuringThreshold;
}
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSYoungGen* young_gen = heap->young_gen();
PSOldGen* old_gen = heap->old_gen();
PSPermGen* perm_gen = heap->perm_gen();
// Set boundary between young_gen and old_gen
assert(perm_gen->reserved().end() <= old_gen->object_space()->bottom(),
"perm above old");
assert(old_gen->reserved().end() <= young_gen->eden_space()->bottom(),
"old above young");
_young_generation_boundary = young_gen->eden_space()->bottom();
// Initialize ref handling object for scavenging.
MemRegion mr = young_gen->reserved();
_ref_processor =
new ReferenceProcessor(mr, // span
ParallelRefProcEnabled && (ParallelGCThreads > 1), // mt processing
(int) ParallelGCThreads, // mt processing degree
true, // mt discovery
(int) ParallelGCThreads, // mt discovery degree
true, // atomic_discovery
NULL, // header provides liveness info
false); // next field updates do not need write barrier
// Cache the cardtable
BarrierSet* bs = Universe::heap()->barrier_set();
assert(bs->kind() == BarrierSet::CardTableModRef, "Wrong barrier set kind");
_card_table = (CardTableExtension*)bs;
_counters = new CollectorCounters("PSScavenge", 0);
}
// Static method
bool ParallelScavengeHeap::is_in_old_or_perm(oop* p) {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap,
"Must be ParallelScavengeHeap");
PSOldGen* old_gen = heap->old_gen();
PSPermGen* perm_gen = heap->perm_gen();
if (old_gen->is_in(p)) {
return true;
}
if (perm_gen->is_in(p)) {
return true;
}
return false;
}
void PSMarkSweep::mark_sweep_phase3() {
// Adjust the pointers to reflect the new locations
EventMark m("3 adjust pointers");
TraceTime tm("phase 3", PrintGCDetails && Verbose, true, gclog_or_tty);
trace("3");
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSYoungGen* young_gen = heap->young_gen();
PSOldGen* old_gen = heap->old_gen();
PSPermGen* perm_gen = heap->perm_gen();
// General strong roots.
Universe::oops_do(adjust_root_pointer_closure());
ReferenceProcessor::oops_do(adjust_root_pointer_closure());
JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles
Threads::oops_do(adjust_root_pointer_closure(), NULL);
ObjectSynchronizer::oops_do(adjust_root_pointer_closure());
FlatProfiler::oops_do(adjust_root_pointer_closure());
Management::oops_do(adjust_root_pointer_closure());
JvmtiExport::oops_do(adjust_root_pointer_closure());
// SO_AllClasses
SystemDictionary::oops_do(adjust_root_pointer_closure());
vmSymbols::oops_do(adjust_root_pointer_closure());
//CodeCache::scavenge_root_nmethods_oops_do(adjust_root_pointer_closure());
// Now adjust pointers in remaining weak roots. (All of which should
// have been cleared if they pointed to non-surviving objects.)
// Global (weak) JNI handles
JNIHandles::weak_oops_do(&always_true, adjust_root_pointer_closure());
CodeCache::oops_do(adjust_pointer_closure());
SymbolTable::oops_do(adjust_root_pointer_closure());
StringTable::oops_do(adjust_root_pointer_closure());
ref_processor()->weak_oops_do(adjust_root_pointer_closure());
PSScavenge::reference_processor()->weak_oops_do(adjust_root_pointer_closure());
adjust_marks();
young_gen->adjust_pointers();
old_gen->adjust_pointers();
perm_gen->adjust_pointers();
}
void PSMarkSweep::mark_sweep_phase3() {
// Adjust the pointers to reflect the new locations
GCTraceTime tm("phase 3", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id());
trace("3");
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSYoungGen* young_gen = heap->young_gen();
PSOldGen* old_gen = heap->old_gen();
// Need to clear claim bits before the tracing starts.
ClassLoaderDataGraph::clear_claimed_marks();
// General strong roots.
Universe::oops_do(adjust_pointer_closure());
JNIHandles::oops_do(adjust_pointer_closure()); // Global (strong) JNI handles
CLDToOopClosure adjust_from_cld(adjust_pointer_closure());
Threads::oops_do(adjust_pointer_closure(), &adjust_from_cld, NULL);
ObjectSynchronizer::oops_do(adjust_pointer_closure());
FlatProfiler::oops_do(adjust_pointer_closure());
Management::oops_do(adjust_pointer_closure());
JvmtiExport::oops_do(adjust_pointer_closure());
SystemDictionary::oops_do(adjust_pointer_closure());
ClassLoaderDataGraph::cld_do(adjust_cld_closure());
// Now adjust pointers in remaining weak roots. (All of which should
// have been cleared if they pointed to non-surviving objects.)
// Global (weak) JNI handles
JNIHandles::weak_oops_do(&always_true, adjust_pointer_closure());
CodeBlobToOopClosure adjust_from_blobs(adjust_pointer_closure(), CodeBlobToOopClosure::FixRelocations);
CodeCache::blobs_do(&adjust_from_blobs);
StringTable::oops_do(adjust_pointer_closure());
ref_processor()->weak_oops_do(adjust_pointer_closure());
PSScavenge::reference_processor()->weak_oops_do(adjust_pointer_closure());
adjust_marks();
young_gen->adjust_pointers();
old_gen->adjust_pointers();
}
void PSMarkSweepDecorator::advance_destination_decorator() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
assert(_destination_decorator != NULL, "Sanity");
PSMarkSweepDecorator* first = heap->old_gen()->object_mark_sweep();
PSMarkSweepDecorator* second = heap->young_gen()->eden_mark_sweep();
PSMarkSweepDecorator* third = heap->young_gen()->from_mark_sweep();
PSMarkSweepDecorator* fourth = heap->young_gen()->to_mark_sweep();
if ( _destination_decorator == first ) {
_destination_decorator = second;
} else if ( _destination_decorator == second ) {
_destination_decorator = third;
} else if ( _destination_decorator == third ) {
_destination_decorator = fourth;
} else {
fatal("PSMarkSweep attempting to advance past last compaction area");
}
}
void PSMarkSweep::mark_sweep_phase2() {
TraceTime tm("phase 2", PrintGCDetails && Verbose, true, gclog_or_tty);
trace("2");
// Now all live objects are marked, compute the new object addresses.
// It is not required that we traverse spaces in the same order in
// phase2, phase3 and phase4, but the ValidateMarkSweep live oops
// tracking expects us to do so. See comment under phase4.
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSOldGen* old_gen = heap->old_gen();
// Begin compacting into the old gen
PSMarkSweepDecorator::set_destination_decorator_tenured();
// This will also compact the young gen spaces.
old_gen->precompact();
}
void PSMarkSweep::mark_sweep_phase4() {
EventMark m("4 compact heap");
TraceTime tm("phase 4", PrintGCDetails && Verbose, true, gclog_or_tty);
trace("4");
// All pointers are now adjusted, move objects accordingly
// It is imperative that we traverse perm_gen first in phase4. All
// classes must be allocated earlier than their instances, and traversing
// perm_gen first makes sure that all klassOops have moved to their new
// location before any instance does a dispatch through it's klass!
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSYoungGen* young_gen = heap->young_gen();
PSOldGen* old_gen = heap->old_gen();
PSPermGen* perm_gen = heap->perm_gen();
perm_gen->compact();
old_gen->compact();
young_gen->compact();
}
// This method iterates over all objects in the young generation,
// unforwarding markWords. It then restores any preserved mark oops,
// and clears the _preserved_mark_stack.
void PSScavenge::clean_up_failed_promotion() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
assert(promotion_failed(), "Sanity");
PSYoungGen* young_gen = heap->young_gen();
{
ResourceMark rm;
// Unforward all pointers in the young gen.
PSPromotionFailedClosure unforward_closure;
young_gen->object_iterate(&unforward_closure);
if (PrintGC && Verbose) {
gclog_or_tty->print_cr("Restoring %d marks",
_preserved_oop_stack->length());
}
// Restore any saved marks.
for (int i=0; i < _preserved_oop_stack->length(); i++) {
oop obj = _preserved_oop_stack->at(i);
markWord*mark=_preserved_mark_stack->at(i);
obj->set_mark(mark);
}
// Deallocate the preserved mark and oop stacks.
// The stacks were allocated as CHeap objects, so
// we must call delete to prevent mem leaks.
delete _preserved_mark_stack;
_preserved_mark_stack = NULL;
delete _preserved_oop_stack;
_preserved_oop_stack = NULL;
}
// Reset the PromotionFailureALot counters.
NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();)
}
void PSMarkSweep::allocate_stacks() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSYoungGen* young_gen = heap->young_gen();
MutableSpace* to_space = young_gen->to_space();
_preserved_marks = (PreservedMark*)to_space->top();
_preserved_count = 0;
// We want to calculate the size in bytes first.
_preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte));
// Now divide by the size of a PreservedMark
_preserved_count_max /= sizeof(PreservedMark);
_preserved_mark_stack = NULL;
_preserved_oop_stack = NULL;
_marking_stack = new GrowableArray<oop>(4000, true);
int size = SystemDictionary::number_of_classes() * 2;
_revisit_klass_stack = new GrowableArray<Klass*>(size, true);
}
void PSOldGen::resize(size_t desired_free_space) {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
const size_t alignment = heap->min_alignment();
const size_t size_before = _virtual_space.committed_size();
size_t new_size = used_in_bytes() + desired_free_space;
new_size = align_size_up(new_size, alignment);
assert(_max_gen_size == reserved().byte_size(), "max new size problem?");
// Adjust according to our min and max
new_size = MAX2(MIN2(new_size, _max_gen_size), _min_gen_size);
const size_t current_size = capacity_in_bytes();
if (new_size == current_size) {
// No change requested
return;
}
if (new_size > current_size) {
size_t change_bytes = new_size - current_size;
expand(change_bytes);
} else {
size_t change_bytes = current_size - new_size;
// shrink doesn't grab this lock, expand does. Is that right?
MutexLocker x(ExpandHeap_lock);
shrink(change_bytes);
}
if (PrintAdaptiveSizePolicy) {
gclog_or_tty->print_cr("AdaptiveSizePolicy::old generation size: "
"collection: %d "
"(" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
heap->total_collections(),
size_before, _virtual_space.committed_size());
}
}