382 lines
13 KiB
C++
382 lines
13 KiB
C++
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/*
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* Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*
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*/
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#include "incls/_precompiled.incl"
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#include "incls/_g1MarkSweep.cpp.incl"
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class HeapRegion;
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void G1MarkSweep::invoke_at_safepoint(ReferenceProcessor* rp,
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bool clear_all_softrefs) {
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assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
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// hook up weak ref data so it can be used during Mark-Sweep
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assert(GenMarkSweep::ref_processor() == NULL, "no stomping");
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GenMarkSweep::_ref_processor = rp;
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assert(rp != NULL, "should be non-NULL");
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// When collecting the permanent generation methodOops may be moving,
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// so we either have to flush all bcp data or convert it into bci.
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CodeCache::gc_prologue();
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Threads::gc_prologue();
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// Increment the invocation count for the permanent generation, since it is
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// implicitly collected whenever we do a full mark sweep collection.
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SharedHeap* sh = SharedHeap::heap();
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sh->perm_gen()->stat_record()->invocations++;
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bool marked_for_unloading = false;
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allocate_stacks();
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mark_sweep_phase1(marked_for_unloading, clear_all_softrefs);
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if (G1VerifyConcMark) {
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G1CollectedHeap* g1h = G1CollectedHeap::heap();
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g1h->checkConcurrentMark();
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}
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mark_sweep_phase2();
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// Don't add any more derived pointers during phase3
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COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
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mark_sweep_phase3();
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mark_sweep_phase4();
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GenMarkSweep::restore_marks();
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GenMarkSweep::deallocate_stacks();
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// We must invalidate the perm-gen rs, so that it gets rebuilt.
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GenRemSet* rs = sh->rem_set();
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rs->invalidate(sh->perm_gen()->used_region(), true /*whole_heap*/);
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// "free at last gc" is calculated from these.
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// CHF: cheating for now!!!
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// Universe::set_heap_capacity_at_last_gc(Universe::heap()->capacity());
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// Universe::set_heap_used_at_last_gc(Universe::heap()->used());
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Threads::gc_epilogue();
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CodeCache::gc_epilogue();
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// refs processing: clean slate
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GenMarkSweep::_ref_processor = NULL;
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}
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void G1MarkSweep::allocate_stacks() {
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GenMarkSweep::_preserved_count_max = 0;
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GenMarkSweep::_preserved_marks = NULL;
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GenMarkSweep::_preserved_count = 0;
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GenMarkSweep::_preserved_mark_stack = NULL;
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GenMarkSweep::_preserved_oop_stack = NULL;
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GenMarkSweep::_marking_stack =
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new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true);
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size_t size = SystemDictionary::number_of_classes() * 2;
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GenMarkSweep::_revisit_klass_stack =
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new (ResourceObj::C_HEAP) GrowableArray<Klass*>((int)size, true);
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}
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void G1MarkSweep::mark_sweep_phase1(bool& marked_for_unloading,
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bool clear_all_softrefs) {
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// Recursively traverse all live objects and mark them
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EventMark m("1 mark object");
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TraceTime tm("phase 1", PrintGC && Verbose, true, gclog_or_tty);
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GenMarkSweep::trace(" 1");
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SharedHeap* sh = SharedHeap::heap();
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sh->process_strong_roots(true, // Collecting permanent generation.
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SharedHeap::SO_SystemClasses,
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&GenMarkSweep::follow_root_closure,
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&GenMarkSweep::follow_root_closure);
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// Process reference objects found during marking
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ReferencePolicy *soft_ref_policy;
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if (clear_all_softrefs) {
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soft_ref_policy = new AlwaysClearPolicy();
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} else {
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#ifdef COMPILER2
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soft_ref_policy = new LRUMaxHeapPolicy();
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#else
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soft_ref_policy = new LRUCurrentHeapPolicy();
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#endif
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}
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assert(soft_ref_policy != NULL,"No soft reference policy");
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GenMarkSweep::ref_processor()->process_discovered_references(
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soft_ref_policy,
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&GenMarkSweep::is_alive,
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&GenMarkSweep::keep_alive,
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&GenMarkSweep::follow_stack_closure,
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NULL);
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// Follow system dictionary roots and unload classes
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bool purged_class = SystemDictionary::do_unloading(&GenMarkSweep::is_alive);
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assert(GenMarkSweep::_marking_stack->is_empty(),
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"stack should be empty by now");
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// Follow code cache roots (has to be done after system dictionary,
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// assumes all live klasses are marked)
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CodeCache::do_unloading(&GenMarkSweep::is_alive,
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&GenMarkSweep::keep_alive,
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purged_class);
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GenMarkSweep::follow_stack();
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// Update subklass/sibling/implementor links of live klasses
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GenMarkSweep::follow_weak_klass_links();
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assert(GenMarkSweep::_marking_stack->is_empty(),
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"stack should be empty by now");
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// Visit symbol and interned string tables and delete unmarked oops
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SymbolTable::unlink(&GenMarkSweep::is_alive);
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StringTable::unlink(&GenMarkSweep::is_alive);
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assert(GenMarkSweep::_marking_stack->is_empty(),
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"stack should be empty by now");
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}
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class G1PrepareCompactClosure: public HeapRegionClosure {
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ModRefBarrierSet* _mrbs;
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CompactPoint _cp;
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bool _popular_only;
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void free_humongous_region(HeapRegion* hr) {
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HeapWord* bot = hr->bottom();
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HeapWord* end = hr->end();
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assert(hr->startsHumongous(),
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"Only the start of a humongous region should be freed.");
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G1CollectedHeap::heap()->free_region(hr);
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hr->prepare_for_compaction(&_cp);
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// Also clear the part of the card table that will be unused after
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// compaction.
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_mrbs->clear(MemRegion(hr->compaction_top(), hr->end()));
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}
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public:
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G1PrepareCompactClosure(CompactibleSpace* cs, bool popular_only) :
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_cp(NULL, cs, cs->initialize_threshold()),
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_mrbs(G1CollectedHeap::heap()->mr_bs()),
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_popular_only(popular_only)
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{}
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bool doHeapRegion(HeapRegion* hr) {
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if (_popular_only && !hr->popular())
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return true; // terminate early
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else if (!_popular_only && hr->popular())
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return false; // skip this one.
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if (hr->isHumongous()) {
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if (hr->startsHumongous()) {
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oop obj = oop(hr->bottom());
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if (obj->is_gc_marked()) {
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obj->forward_to(obj);
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} else {
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free_humongous_region(hr);
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}
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} else {
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assert(hr->continuesHumongous(), "Invalid humongous.");
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}
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} else {
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hr->prepare_for_compaction(&_cp);
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// Also clear the part of the card table that will be unused after
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// compaction.
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_mrbs->clear(MemRegion(hr->compaction_top(), hr->end()));
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}
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return false;
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}
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};
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// Stolen verbatim from g1CollectedHeap.cpp
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class FindFirstRegionClosure: public HeapRegionClosure {
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HeapRegion* _a_region;
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bool _find_popular;
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public:
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FindFirstRegionClosure(bool find_popular) :
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_a_region(NULL), _find_popular(find_popular) {}
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bool doHeapRegion(HeapRegion* r) {
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if (r->popular() == _find_popular) {
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_a_region = r;
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return true;
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} else {
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return false;
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}
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}
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HeapRegion* result() { return _a_region; }
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};
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void G1MarkSweep::mark_sweep_phase2() {
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// Now all live objects are marked, compute the new object addresses.
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// It is imperative that we traverse perm_gen LAST. If dead space is
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// allowed a range of dead object may get overwritten by a dead int
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// array. If perm_gen is not traversed last a klassOop may get
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// overwritten. This is fine since it is dead, but if the class has dead
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// instances we have to skip them, and in order to find their size we
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// need the klassOop!
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//
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// It is not required that we traverse spaces in the same order in
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// phase2, phase3 and phase4, but the ValidateMarkSweep live oops
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// tracking expects us to do so. See comment under phase4.
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G1CollectedHeap* g1h = G1CollectedHeap::heap();
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Generation* pg = g1h->perm_gen();
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EventMark m("2 compute new addresses");
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TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty);
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GenMarkSweep::trace("2");
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// First we compact the popular regions.
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if (G1NumPopularRegions > 0) {
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CompactibleSpace* sp = g1h->first_compactible_space();
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FindFirstRegionClosure cl(true /*find_popular*/);
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g1h->heap_region_iterate(&cl);
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HeapRegion *r = cl.result();
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assert(r->popular(), "should have found a popular region.");
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assert(r == sp, "first popular heap region should "
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"== first compactible space");
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G1PrepareCompactClosure blk(sp, true/*popular_only*/);
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g1h->heap_region_iterate(&blk);
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}
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// Now we do the regular regions.
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FindFirstRegionClosure cl(false /*find_popular*/);
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g1h->heap_region_iterate(&cl);
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HeapRegion *r = cl.result();
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assert(!r->popular(), "should have founda non-popular region.");
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CompactibleSpace* sp = r;
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if (r->isHumongous() && oop(r->bottom())->is_gc_marked()) {
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sp = r->next_compaction_space();
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}
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G1PrepareCompactClosure blk(sp, false/*popular_only*/);
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g1h->heap_region_iterate(&blk);
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CompactPoint perm_cp(pg, NULL, NULL);
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pg->prepare_for_compaction(&perm_cp);
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}
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class G1AdjustPointersClosure: public HeapRegionClosure {
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public:
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bool doHeapRegion(HeapRegion* r) {
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if (r->isHumongous()) {
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if (r->startsHumongous()) {
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// We must adjust the pointers on the single H object.
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oop obj = oop(r->bottom());
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debug_only(GenMarkSweep::track_interior_pointers(obj));
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// point all the oops to the new location
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obj->adjust_pointers();
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debug_only(GenMarkSweep::check_interior_pointers());
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}
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} else {
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// This really ought to be "as_CompactibleSpace"...
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r->adjust_pointers();
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}
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return false;
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}
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};
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void G1MarkSweep::mark_sweep_phase3() {
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G1CollectedHeap* g1h = G1CollectedHeap::heap();
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Generation* pg = g1h->perm_gen();
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// Adjust the pointers to reflect the new locations
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EventMark m("3 adjust pointers");
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TraceTime tm("phase 3", PrintGC && Verbose, true, gclog_or_tty);
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GenMarkSweep::trace("3");
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SharedHeap* sh = SharedHeap::heap();
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sh->process_strong_roots(true, // Collecting permanent generation.
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SharedHeap::SO_AllClasses,
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&GenMarkSweep::adjust_root_pointer_closure,
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&GenMarkSweep::adjust_pointer_closure);
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g1h->ref_processor()->weak_oops_do(&GenMarkSweep::adjust_root_pointer_closure);
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// Now adjust pointers in remaining weak roots. (All of which should
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// have been cleared if they pointed to non-surviving objects.)
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g1h->g1_process_weak_roots(&GenMarkSweep::adjust_root_pointer_closure,
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&GenMarkSweep::adjust_pointer_closure);
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GenMarkSweep::adjust_marks();
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G1AdjustPointersClosure blk;
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g1h->heap_region_iterate(&blk);
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pg->adjust_pointers();
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}
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class G1SpaceCompactClosure: public HeapRegionClosure {
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public:
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G1SpaceCompactClosure() {}
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bool doHeapRegion(HeapRegion* hr) {
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if (hr->isHumongous()) {
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if (hr->startsHumongous()) {
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oop obj = oop(hr->bottom());
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if (obj->is_gc_marked()) {
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obj->init_mark();
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} else {
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assert(hr->is_empty(), "Should have been cleared in phase 2.");
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}
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hr->reset_during_compaction();
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}
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} else {
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hr->compact();
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}
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return false;
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}
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};
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void G1MarkSweep::mark_sweep_phase4() {
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// All pointers are now adjusted, move objects accordingly
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// It is imperative that we traverse perm_gen first in phase4. All
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// 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!
|
||
|
|
|
||
|
|
// 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 (perm_gen first rather than last), so we tell the validate code
|
||
|
|
// to use a higher index (saved from phase2) when verifying perm_gen.
|
||
|
|
G1CollectedHeap* g1h = G1CollectedHeap::heap();
|
||
|
|
Generation* pg = g1h->perm_gen();
|
||
|
|
|
||
|
|
EventMark m("4 compact heap");
|
||
|
|
TraceTime tm("phase 4", PrintGC && Verbose, true, gclog_or_tty);
|
||
|
|
GenMarkSweep::trace("4");
|
||
|
|
|
||
|
|
pg->compact();
|
||
|
|
|
||
|
|
G1SpaceCompactClosure blk;
|
||
|
|
g1h->heap_region_iterate(&blk);
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
// Local Variables: ***
|
||
|
|
// c-indentation-style: gnu ***
|
||
|
|
// End: ***
|