--- a/src/hotspot/share/gc/g1/g1MarkSweep.cpp Mon Oct 30 08:34:54 2017 +0100
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,387 +0,0 @@
-/*
- * Copyright (c) 2001, 2017, 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 "classfile/javaClasses.hpp"
-#include "classfile/symbolTable.hpp"
-#include "classfile/systemDictionary.hpp"
-#include "classfile/vmSymbols.hpp"
-#include "code/codeCache.hpp"
-#include "code/icBuffer.hpp"
-#include "gc/g1/g1FullGCScope.hpp"
-#include "gc/g1/g1MarkSweep.hpp"
-#include "gc/g1/g1RootProcessor.hpp"
-#include "gc/g1/g1StringDedup.hpp"
-#include "gc/serial/markSweep.inline.hpp"
-#include "gc/shared/gcHeapSummary.hpp"
-#include "gc/shared/gcLocker.hpp"
-#include "gc/shared/gcTimer.hpp"
-#include "gc/shared/gcTrace.hpp"
-#include "gc/shared/gcTraceTime.inline.hpp"
-#include "gc/shared/genCollectedHeap.hpp"
-#include "gc/shared/modRefBarrierSet.hpp"
-#include "gc/shared/referencePolicy.hpp"
-#include "gc/shared/space.hpp"
-#include "gc/shared/weakProcessor.hpp"
-#include "oops/instanceRefKlass.hpp"
-#include "oops/oop.inline.hpp"
-#include "prims/jvmtiExport.hpp"
-#include "runtime/atomic.hpp"
-#include "runtime/biasedLocking.hpp"
-#include "runtime/synchronizer.hpp"
-#include "runtime/thread.hpp"
-#include "runtime/vmThread.hpp"
-#include "utilities/copy.hpp"
-#include "utilities/events.hpp"
-
-class HeapRegion;
-
-void G1MarkSweep::invoke_at_safepoint(ReferenceProcessor* rp,
- bool clear_all_softrefs) {
- assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
- HandleMark hm; // Discard invalid handles created during gc
-
-#if COMPILER2_OR_JVMCI
- DerivedPointerTable::clear();
-#endif
-#ifdef ASSERT
- if (G1CollectedHeap::heap()->collector_policy()->should_clear_all_soft_refs()) {
- assert(clear_all_softrefs, "Policy should have been checked earler");
- }
-#endif
- // hook up weak ref data so it can be used during Mark-Sweep
- assert(GenMarkSweep::ref_processor() == NULL, "no stomping");
- assert(rp != NULL, "should be non-NULL");
- assert(rp == G1CollectedHeap::heap()->ref_processor_stw(), "Precondition");
-
- GenMarkSweep::set_ref_processor(rp);
- rp->setup_policy(clear_all_softrefs);
-
- // When collecting the permanent generation Method*s may be moving,
- // so we either have to flush all bcp data or convert it into bci.
- CodeCache::gc_prologue();
-
- bool marked_for_unloading = false;
-
- allocate_stacks();
-
- // We should save the marks of the currently locked biased monitors.
- // The marking doesn't preserve the marks of biased objects.
- BiasedLocking::preserve_marks();
-
- // Process roots and do the marking.
- mark_sweep_phase1(marked_for_unloading, clear_all_softrefs);
-
- // Prepare compaction.
- mark_sweep_phase2();
-
-#if COMPILER2_OR_JVMCI
- // Don't add any more derived pointers during phase3
- DerivedPointerTable::set_active(false);
-#endif
-
- // Adjust all pointers.
- mark_sweep_phase3();
-
- // Do the actual compaction.
- mark_sweep_phase4();
-
- GenMarkSweep::restore_marks();
- BiasedLocking::restore_marks();
- GenMarkSweep::deallocate_stacks();
-
-#if COMPILER2_OR_JVMCI
- // Now update the derived pointers.
- DerivedPointerTable::update_pointers();
-#endif
-
- CodeCache::gc_epilogue();
- JvmtiExport::gc_epilogue();
-
- // refs processing: clean slate
- GenMarkSweep::set_ref_processor(NULL);
-}
-
-STWGCTimer* G1MarkSweep::gc_timer() {
- return G1FullGCScope::instance()->timer();
-}
-
-SerialOldTracer* G1MarkSweep::gc_tracer() {
- return G1FullGCScope::instance()->tracer();
-}
-
-void G1MarkSweep::allocate_stacks() {
- GenMarkSweep::_preserved_count_max = 0;
- GenMarkSweep::_preserved_marks = NULL;
- GenMarkSweep::_preserved_count = 0;
-}
-
-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);
- ReferenceProcessorPhaseTimes pt(gc_timer(), rp->num_q());
-
- const ReferenceProcessorStats& stats =
- rp->process_discovered_references(&GenMarkSweep::is_alive,
- &GenMarkSweep::keep_alive,
- &GenMarkSweep::follow_stack_closure,
- NULL,
- &pt);
- gc_tracer()->report_gc_reference_stats(stats);
- pt.print_all_references();
- }
-
- // This is the point where the entire marking should have completed.
- assert(GenMarkSweep::_marking_stack.is_empty(), "Marking should have completed");
-
- {
- GCTraceTime(Debug, gc, phases) trace("Weak Processing", gc_timer());
- WeakProcessor::weak_oops_do(&GenMarkSweep::is_alive, &do_nothing_cl);
- }
-
- 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, gc_timer());
-
- g1h->complete_cleaning(&GenMarkSweep::is_alive, purged_class);
- } else {
- GCTraceTime(Debug, gc, phases) trace("Cleanup", gc_timer());
- g1h->partial_cleaning(&GenMarkSweep::is_alive, true, true, G1StringDedup::is_enabled());
- }
-
- if (VerifyDuringGC) {
- HandleMark hm; // handle scope
-#if COMPILER2_OR_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_phase2() {
- // 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.
-
- GCTraceTime(Info, gc, phases) tm("Phase 2: Compute new object addresses", gc_timer());
-
- prepare_compaction();
-}
-
-class G1AdjustPointersClosure: public HeapRegionClosure {
- public:
- bool doHeapRegion(HeapRegion* r) {
- if (r->is_humongous()) {
- if (r->is_starts_humongous()) {
- // We must adjust the pointers on the single H object.
- oop obj = oop(r->bottom());
- // point all the oops to the new location
- MarkSweep::adjust_pointers(obj);
- }
- } else if (!r->is_closed_archive()) {
- // This really ought to be "as_CompactibleSpace"...
- r->adjust_pointers();
- }
- return false;
- }
-};
-
-void G1MarkSweep::mark_sweep_phase3() {
- G1CollectedHeap* g1h = G1CollectedHeap::heap();
-
- // Adjust the pointers to reflect the new locations
- GCTraceTime(Info, gc, phases) tm("Phase 3: Adjust pointers", gc_timer());
-
- // Need cleared claim bits for the roots processing
- ClassLoaderDataGraph::clear_claimed_marks();
-
- CodeBlobToOopClosure adjust_code_closure(&GenMarkSweep::adjust_pointer_closure, CodeBlobToOopClosure::FixRelocations);
- {
- G1RootProcessor root_processor(g1h, 1);
- root_processor.process_all_roots(&GenMarkSweep::adjust_pointer_closure,
- &GenMarkSweep::adjust_cld_closure,
- &adjust_code_closure);
- }
-
- assert(GenMarkSweep::ref_processor() == g1h->ref_processor_stw(), "Sanity");
- g1h->ref_processor_stw()->weak_oops_do(&GenMarkSweep::adjust_pointer_closure);
-
- // Now adjust pointers in remaining weak roots. (All of which should
- // have been cleared if they pointed to non-surviving objects.)
- WeakProcessor::oops_do(&GenMarkSweep::adjust_pointer_closure);
-
- if (G1StringDedup::is_enabled()) {
- G1StringDedup::oops_do(&GenMarkSweep::adjust_pointer_closure);
- }
-
- GenMarkSweep::adjust_marks();
-
- G1AdjustPointersClosure blk;
- g1h->heap_region_iterate(&blk);
-}
-
-class G1SpaceCompactClosure: public HeapRegionClosure {
-public:
- G1SpaceCompactClosure() {}
-
- bool doHeapRegion(HeapRegion* hr) {
- if (hr->is_humongous()) {
- if (hr->is_starts_humongous()) {
- oop obj = oop(hr->bottom());
- if (obj->is_gc_marked()) {
- obj->init_mark();
- } else {
- assert(hr->is_empty(), "Should have been cleared in phase 2.");
- }
- }
- hr->reset_during_compaction();
- } else if (!hr->is_pinned()) {
- hr->compact();
- }
- return false;
- }
-};
-
-void G1MarkSweep::mark_sweep_phase4() {
- // All pointers are now adjusted, move objects accordingly
-
- // The ValidateMarkSweep live oops tracking expects us to traverse spaces
- // in the same order in phase2, phase3 and phase4. We don't quite do that
- // here (code and comment not fixed for perm removal), so we tell the validate code
- // to use a higher index (saved from phase2) when verifying perm_gen.
- G1CollectedHeap* g1h = G1CollectedHeap::heap();
-
- GCTraceTime(Info, gc, phases) tm("Phase 4: Move objects", gc_timer());
-
- G1SpaceCompactClosure blk;
- g1h->heap_region_iterate(&blk);
-
-}
-
-void G1MarkSweep::prepare_compaction_work(G1PrepareCompactClosure* blk) {
- G1CollectedHeap* g1h = G1CollectedHeap::heap();
- g1h->heap_region_iterate(blk);
- blk->update_sets();
-}
-
-void G1PrepareCompactClosure::free_humongous_region(HeapRegion* hr) {
- HeapWord* end = hr->end();
- FreeRegionList dummy_free_list("Dummy Free List for G1MarkSweep");
-
- hr->set_containing_set(NULL);
- _humongous_regions_removed++;
-
- _g1h->free_humongous_region(hr, &dummy_free_list, false /* skip_remset */);
- prepare_for_compaction(hr, end);
- dummy_free_list.remove_all();
-}
-
-void G1PrepareCompactClosure::prepare_for_compaction(HeapRegion* hr, HeapWord* end) {
- // If this is the first live region that we came across which we can compact,
- // initialize the CompactPoint.
- if (!is_cp_initialized()) {
- _cp.space = hr;
- _cp.threshold = hr->initialize_threshold();
- }
- prepare_for_compaction_work(&_cp, hr, end);
-}
-
-void G1PrepareCompactClosure::prepare_for_compaction_work(CompactPoint* cp,
- HeapRegion* hr,
- HeapWord* end) {
- hr->prepare_for_compaction(cp);
- // Also clear the part of the card table that will be unused after
- // compaction.
- _mrbs->clear(MemRegion(hr->compaction_top(), end));
-}
-
-void G1PrepareCompactClosure::update_sets() {
- // We'll recalculate total used bytes and recreate the free list
- // at the end of the GC, so no point in updating those values here.
- _g1h->remove_from_old_sets(0, _humongous_regions_removed);
-}
-
-bool G1PrepareCompactClosure::doHeapRegion(HeapRegion* hr) {
- if (hr->is_humongous()) {
- oop obj = oop(hr->humongous_start_region()->bottom());
- if (hr->is_starts_humongous() && obj->is_gc_marked()) {
- obj->forward_to(obj);
- }
- if (!obj->is_gc_marked()) {
- free_humongous_region(hr);
- }
- } else if (!hr->is_pinned()) {
- prepare_for_compaction(hr, hr->end());
- }
- return false;
-}