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());
}
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());
}
void MarkSweep::follow_weak_klass_links() {
// All klasses on the revisit stack are marked at this point.
// Update and follow all subklass, sibling and implementor links.
for (int i = 0; i < _revisit_klass_stack->length(); i++) {
_revisit_klass_stack->at(i)->follow_weak_klass_links(&is_alive,&keep_alive);
}
follow_stack();
}
void MarkSweep::follow_weak_klass_links() {
// All klasses on the revisit stack are marked at this point.
// Update and follow all subklass, sibling and implementor links.
if (PrintRevisitStats) {
gclog_or_tty->print_cr("#classes in system dictionary = %d", SystemDictionary::number_of_classes());
gclog_or_tty->print_cr("Revisit klass stack length = %d", _revisit_klass_stack->length());
}
for (int i = 0; i < _revisit_klass_stack->length(); i++) {
_revisit_klass_stack->at(i)->follow_weak_klass_links(&is_alive,&keep_alive);
}
follow_stack();
}
template <class T> inline void MarkSweep::follow_root(T* p) {
assert(!Universe::heap()->is_in_reserved(p),
"roots shouldn't be things within the heap");
T heap_oop = oopDesc::load_heap_oop(p);
if (!oopDesc::is_null(heap_oop)) {
oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
if (!obj->mark()->is_marked()) {
mark_object(obj);
follow_object(obj);
}
}
follow_stack();
}
void MarkSweep::follow_mdo_weak_refs() {
// All strongly reachable oops have been marked at this point;
// we can visit and clear any weak references from MDO's which
// we memoized during the strong marking phase.
assert(_marking_stack->is_empty(), "Marking stack should be empty");
if (PrintRevisitStats) {
gclog_or_tty->print_cr("#classes in system dictionary = %d", SystemDictionary::number_of_classes());
gclog_or_tty->print_cr("Revisit MDO stack length = %d", _revisit_mdo_stack->length());
}
for (int i = 0; i < _revisit_mdo_stack->length(); i++) {
_revisit_mdo_stack->at(i)->follow_weak_refs(&is_alive);
}
follow_stack();
}
void MarkSweep::follow_weak_klass_links() {
// All klasses on the revisit stack are marked at this point.
// Update and follow all subklass, sibling and implementor links.
if (PrintRevisitStats) {
gclog_or_tty->print_cr("#classes in system dictionary = %d",
SystemDictionary::number_of_classes());
gclog_or_tty->print_cr("Revisit klass stack size = " SIZE_FORMAT,
_revisit_klass_stack.size());
}
while (!_revisit_klass_stack.is_empty()) {
Klass* const k = _revisit_klass_stack.pop();
k->follow_weak_klass_links(&is_alive, &keep_alive);
}
follow_stack();
}
void MarkSweep::follow_root(oop* p) {
assert(!Universe::heap()->is_in_reserved(p),
"roots shouldn't be things within the heap");
#ifdef VALIDATE_MARK_SWEEP
if (ValidateMarkSweep) {
guarantee(!_root_refs_stack->contains(p), "should only be in here once");
_root_refs_stack->push(p);
}
#endif
oop m = *p;
if (m && !m->mark()->is_marked()) {
mark_object(m);
m->follow_contents(); // Follow contents of the marked object
}
follow_stack();
}
template <class T> inline void MarkSweep::follow_root(T* p) {
assert(!Universe::heap()->is_in_reserved(p),
"roots shouldn't be things within the heap");
#ifdef VALIDATE_MARK_SWEEP
if (ValidateMarkSweep) {
guarantee(!_root_refs_stack->contains(p), "should only be in here once");
_root_refs_stack->push(p);
}
#endif
T heap_oop = oopDesc::load_heap_oop(p);
if (!oopDesc::is_null(heap_oop)) {
oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
if (!obj->mark()->is_marked()) {
mark_object(obj);
obj->follow_contents();
}
}
follow_stack();
}
void MarkSweep::FollowStackClosure::do_void() { follow_stack(); }
