void G1MarkSweep::mark_sweep_phase1(bool& marked_for_unloading,
bool clear_all_softrefs) {
// Recursively traverse all live objects and mark them
GCTraceTime(Info, gc, phases) tm("Phase 1: Mark live objects", gc_timer());
G1CollectedHeap* g1h = G1CollectedHeap::heap();
// Need cleared claim bits for the roots processing
ClassLoaderDataGraph::clear_claimed_marks();
MarkingCodeBlobClosure follow_code_closure(&GenMarkSweep::follow_root_closure, !CodeBlobToOopClosure::FixRelocations);
{
G1RootProcessor root_processor(g1h, 1);
if (ClassUnloading) {
root_processor.process_strong_roots(&GenMarkSweep::follow_root_closure,
&GenMarkSweep::follow_cld_closure,
&follow_code_closure);
} else {
root_processor.process_all_roots_no_string_table(
&GenMarkSweep::follow_root_closure,
&GenMarkSweep::follow_cld_closure,
&follow_code_closure);
}
}
{
GCTraceTime(Debug, gc, phases) trace("Reference Processing", gc_timer());
// Process reference objects found during marking
ReferenceProcessor* rp = GenMarkSweep::ref_processor();
assert(rp == g1h->ref_processor_stw(), "Sanity");
rp->setup_policy(clear_all_softrefs);
const ReferenceProcessorStats& stats =
rp->process_discovered_references(&GenMarkSweep::is_alive,
&GenMarkSweep::keep_alive,
&GenMarkSweep::follow_stack_closure,
NULL,
gc_timer());
gc_tracer()->report_gc_reference_stats(stats);
}
// This is the point where the entire marking should have completed.
assert(GenMarkSweep::_marking_stack.is_empty(), "Marking should have completed");
if (ClassUnloading) {
GCTraceTime(Debug, gc, phases) trace("Class Unloading", gc_timer());
// Unload classes and purge the SystemDictionary.
bool purged_class = SystemDictionary::do_unloading(&GenMarkSweep::is_alive);
// Unload nmethods.
CodeCache::do_unloading(&GenMarkSweep::is_alive, purged_class);
// Prune dead klasses from subklass/sibling/implementor lists.
Klass::clean_weak_klass_links(&GenMarkSweep::is_alive);
}
{
GCTraceTime(Debug, gc, phases) trace("Scrub String and Symbol Tables", gc_timer());
// Delete entries for dead interned string and clean up unreferenced symbols in symbol table.
g1h->unlink_string_and_symbol_table(&GenMarkSweep::is_alive);
}
if (G1StringDedup::is_enabled()) {
GCTraceTime(Debug, gc, phases) trace("String Deduplication Unlink", gc_timer());
G1StringDedup::unlink(&GenMarkSweep::is_alive);
}
if (VerifyDuringGC) {
HandleMark hm; // handle scope
#if defined(COMPILER2) || INCLUDE_JVMCI
DerivedPointerTableDeactivate dpt_deact;
#endif
g1h->prepare_for_verify();
// Note: we can verify only the heap here. When an object is
// marked, the previous value of the mark word (including
// identity hash values, ages, etc) is preserved, and the mark
// word is set to markOop::marked_value - effectively removing
// any hash values from the mark word. These hash values are
// used when verifying the dictionaries and so removing them
// from the mark word can make verification of the dictionaries
// fail. At the end of the GC, the original mark word values
// (including hash values) are restored to the appropriate
// objects.
GCTraceTime(Info, gc, verify)("During GC (full)");
g1h->verify(VerifyOption_G1UseMarkWord);
}
gc_tracer()->report_object_count_after_gc(&GenMarkSweep::is_alive);
}
void G1MarkSweep::mark_sweep_phase1(bool& marked_for_unloading,
bool clear_all_softrefs) {
// Recursively traverse all live objects and mark them
GCTraceTime tm("phase 1", G1Log::fine() && Verbose, true, gc_timer(), gc_tracer()->gc_id());
GenMarkSweep::trace(" 1");
G1CollectedHeap* g1h = G1CollectedHeap::heap();
// Need cleared claim bits for the roots processing
ClassLoaderDataGraph::clear_claimed_marks();
MarkingCodeBlobClosure follow_code_closure(&GenMarkSweep::follow_root_closure, !CodeBlobToOopClosure::FixRelocations);
{
G1RootProcessor root_processor(g1h);
root_processor.process_strong_roots(&GenMarkSweep::follow_root_closure,
&GenMarkSweep::follow_cld_closure,
&follow_code_closure);
}
// Process reference objects found during marking
ReferenceProcessor* rp = GenMarkSweep::ref_processor();
assert(rp == g1h->ref_processor_stw(), "Sanity");
rp->setup_policy(clear_all_softrefs);
const ReferenceProcessorStats& stats =
rp->process_discovered_references(&GenMarkSweep::is_alive,
&GenMarkSweep::keep_alive,
&GenMarkSweep::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(GenMarkSweep::_marking_stack.is_empty(), "Marking should have completed");
// Unload classes and purge the SystemDictionary.
bool purged_class = SystemDictionary::do_unloading(&GenMarkSweep::is_alive);
// Unload nmethods.
CodeCache::do_unloading(&GenMarkSweep::is_alive, purged_class);
// Prune dead klasses from subklass/sibling/implementor lists.
Klass::clean_weak_klass_links(&GenMarkSweep::is_alive);
// Delete entries for dead interned string and clean up unreferenced symbols in symbol table.
G1CollectedHeap::heap()->unlink_string_and_symbol_table(&GenMarkSweep::is_alive);
if (VerifyDuringGC) {
HandleMark hm; // handle scope
COMPILER2_PRESENT(DerivedPointerTableDeactivate dpt_deact);
Universe::heap()->prepare_for_verify();
// Note: we can verify only the heap here. When an object is
// marked, the previous value of the mark word (including
// identity hash values, ages, etc) is preserved, and the mark
// word is set to markOop::marked_value - effectively removing
// any hash values from the mark word. These hash values are
// used when verifying the dictionaries and so removing them
// from the mark word can make verification of the dictionaries
// fail. At the end of the GC, the orginal mark word values
// (including hash values) are restored to the appropriate
// objects.
if (!VerifySilently) {
gclog_or_tty->print(" VerifyDuringGC:(full)[Verifying ");
}
Universe::heap()->verify(VerifySilently, VerifyOption_G1UseMarkWord);
if (!VerifySilently) {
gclog_or_tty->print_cr("]");
}
}
gc_tracer()->report_object_count_after_gc(&GenMarkSweep::is_alive);
}
