Mercurial > hg > truffle
diff src/share/vm/gc_implementation/g1/g1MarkSweep.cpp @ 362:f8199438385b
Merge
author | apetrusenko |
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date | Wed, 17 Sep 2008 16:49:18 +0400 |
parents | 8651a65ac4b4 |
children | c96030fff130 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/g1/g1MarkSweep.cpp Wed Sep 17 16:49:18 2008 +0400 @@ -0,0 +1,385 @@ +/* + * Copyright 2001-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +#include "incls/_precompiled.incl" +#include "incls/_g1MarkSweep.cpp.incl" + +class HeapRegion; + +void G1MarkSweep::invoke_at_safepoint(ReferenceProcessor* rp, + bool clear_all_softrefs) { + assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); + + // hook up weak ref data so it can be used during Mark-Sweep + assert(GenMarkSweep::ref_processor() == NULL, "no stomping"); + GenMarkSweep::_ref_processor = rp; + assert(rp != NULL, "should be non-NULL"); + + // When collecting the permanent generation methodOops may be moving, + // so we either have to flush all bcp data or convert it into bci. + CodeCache::gc_prologue(); + Threads::gc_prologue(); + + // Increment the invocation count for the permanent generation, since it is + // implicitly collected whenever we do a full mark sweep collection. + SharedHeap* sh = SharedHeap::heap(); + sh->perm_gen()->stat_record()->invocations++; + + 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(); + + mark_sweep_phase1(marked_for_unloading, clear_all_softrefs); + + if (G1VerifyConcMark) { + G1CollectedHeap* g1h = G1CollectedHeap::heap(); + g1h->checkConcurrentMark(); + } + + mark_sweep_phase2(); + + // Don't add any more derived pointers during phase3 + COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); + + mark_sweep_phase3(); + + mark_sweep_phase4(); + + GenMarkSweep::restore_marks(); + BiasedLocking::restore_marks(); + GenMarkSweep::deallocate_stacks(); + + // We must invalidate the perm-gen rs, so that it gets rebuilt. + GenRemSet* rs = sh->rem_set(); + rs->invalidate(sh->perm_gen()->used_region(), true /*whole_heap*/); + + // "free at last gc" is calculated from these. + // CHF: cheating for now!!! + // Universe::set_heap_capacity_at_last_gc(Universe::heap()->capacity()); + // Universe::set_heap_used_at_last_gc(Universe::heap()->used()); + + Threads::gc_epilogue(); + CodeCache::gc_epilogue(); + + // refs processing: clean slate + GenMarkSweep::_ref_processor = NULL; +} + + +void G1MarkSweep::allocate_stacks() { + GenMarkSweep::_preserved_count_max = 0; + GenMarkSweep::_preserved_marks = NULL; + GenMarkSweep::_preserved_count = 0; + GenMarkSweep::_preserved_mark_stack = NULL; + GenMarkSweep::_preserved_oop_stack = NULL; + + GenMarkSweep::_marking_stack = + new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true); + + size_t size = SystemDictionary::number_of_classes() * 2; + GenMarkSweep::_revisit_klass_stack = + new (ResourceObj::C_HEAP) GrowableArray<Klass*>((int)size, true); +} + +void G1MarkSweep::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); + GenMarkSweep::trace(" 1"); + + SharedHeap* sh = SharedHeap::heap(); + + sh->process_strong_roots(true, // Collecting permanent generation. + SharedHeap::SO_SystemClasses, + &GenMarkSweep::follow_root_closure, + &GenMarkSweep::follow_root_closure); + + // Process reference objects found during marking + ReferencePolicy *soft_ref_policy; + if (clear_all_softrefs) { + soft_ref_policy = new AlwaysClearPolicy(); + } else { +#ifdef COMPILER2 + soft_ref_policy = new LRUMaxHeapPolicy(); +#else + soft_ref_policy = new LRUCurrentHeapPolicy(); +#endif + } + assert(soft_ref_policy != NULL,"No soft reference policy"); + GenMarkSweep::ref_processor()->process_discovered_references( + soft_ref_policy, + &GenMarkSweep::is_alive, + &GenMarkSweep::keep_alive, + &GenMarkSweep::follow_stack_closure, + NULL); + + // Follow system dictionary roots and unload classes + bool purged_class = SystemDictionary::do_unloading(&GenMarkSweep::is_alive); + assert(GenMarkSweep::_marking_stack->is_empty(), + "stack should be empty by now"); + + // Follow code cache roots (has to be done after system dictionary, + // assumes all live klasses are marked) + CodeCache::do_unloading(&GenMarkSweep::is_alive, + &GenMarkSweep::keep_alive, + purged_class); + GenMarkSweep::follow_stack(); + + // Update subklass/sibling/implementor links of live klasses + GenMarkSweep::follow_weak_klass_links(); + assert(GenMarkSweep::_marking_stack->is_empty(), + "stack should be empty by now"); + + // Visit symbol and interned string tables and delete unmarked oops + SymbolTable::unlink(&GenMarkSweep::is_alive); + StringTable::unlink(&GenMarkSweep::is_alive); + + assert(GenMarkSweep::_marking_stack->is_empty(), + "stack should be empty by now"); +} + +class G1PrepareCompactClosure: public HeapRegionClosure { + ModRefBarrierSet* _mrbs; + CompactPoint _cp; + bool _popular_only; + + void free_humongous_region(HeapRegion* hr) { + HeapWord* bot = hr->bottom(); + HeapWord* end = hr->end(); + assert(hr->startsHumongous(), + "Only the start of a humongous region should be freed."); + G1CollectedHeap::heap()->free_region(hr); + 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(), hr->end())); + } + +public: + G1PrepareCompactClosure(CompactibleSpace* cs, bool popular_only) : + _cp(NULL, cs, cs->initialize_threshold()), + _mrbs(G1CollectedHeap::heap()->mr_bs()), + _popular_only(popular_only) + {} + bool doHeapRegion(HeapRegion* hr) { + if (_popular_only && !hr->popular()) + return true; // terminate early + else if (!_popular_only && hr->popular()) + return false; // skip this one. + + if (hr->isHumongous()) { + if (hr->startsHumongous()) { + oop obj = oop(hr->bottom()); + if (obj->is_gc_marked()) { + obj->forward_to(obj); + } else { + free_humongous_region(hr); + } + } else { + assert(hr->continuesHumongous(), "Invalid humongous."); + } + } else { + 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(), hr->end())); + } + return false; + } +}; +// Stolen verbatim from g1CollectedHeap.cpp +class FindFirstRegionClosure: public HeapRegionClosure { + HeapRegion* _a_region; + bool _find_popular; +public: + FindFirstRegionClosure(bool find_popular) : + _a_region(NULL), _find_popular(find_popular) {} + bool doHeapRegion(HeapRegion* r) { + if (r->popular() == _find_popular) { + _a_region = r; + return true; + } else { + return false; + } + } + HeapRegion* result() { return _a_region; } +}; + +void G1MarkSweep::mark_sweep_phase2() { + // 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. + + G1CollectedHeap* g1h = G1CollectedHeap::heap(); + Generation* pg = g1h->perm_gen(); + + EventMark m("2 compute new addresses"); + TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty); + GenMarkSweep::trace("2"); + + // First we compact the popular regions. + if (G1NumPopularRegions > 0) { + CompactibleSpace* sp = g1h->first_compactible_space(); + FindFirstRegionClosure cl(true /*find_popular*/); + g1h->heap_region_iterate(&cl); + HeapRegion *r = cl.result(); + assert(r->popular(), "should have found a popular region."); + assert(r == sp, "first popular heap region should " + "== first compactible space"); + G1PrepareCompactClosure blk(sp, true/*popular_only*/); + g1h->heap_region_iterate(&blk); + } + + // Now we do the regular regions. + FindFirstRegionClosure cl(false /*find_popular*/); + g1h->heap_region_iterate(&cl); + HeapRegion *r = cl.result(); + assert(!r->popular(), "should have founda non-popular region."); + CompactibleSpace* sp = r; + if (r->isHumongous() && oop(r->bottom())->is_gc_marked()) { + sp = r->next_compaction_space(); + } + + G1PrepareCompactClosure blk(sp, false/*popular_only*/); + g1h->heap_region_iterate(&blk); + + CompactPoint perm_cp(pg, NULL, NULL); + pg->prepare_for_compaction(&perm_cp); +} + +class G1AdjustPointersClosure: public HeapRegionClosure { + public: + bool doHeapRegion(HeapRegion* r) { + if (r->isHumongous()) { + if (r->startsHumongous()) { + // We must adjust the pointers on the single H object. + oop obj = oop(r->bottom()); + debug_only(GenMarkSweep::track_interior_pointers(obj)); + // point all the oops to the new location + obj->adjust_pointers(); + debug_only(GenMarkSweep::check_interior_pointers()); + } + } else { + // This really ought to be "as_CompactibleSpace"... + r->adjust_pointers(); + } + return false; + } +}; + +void G1MarkSweep::mark_sweep_phase3() { + G1CollectedHeap* g1h = G1CollectedHeap::heap(); + Generation* pg = g1h->perm_gen(); + + // Adjust the pointers to reflect the new locations + EventMark m("3 adjust pointers"); + TraceTime tm("phase 3", PrintGC && Verbose, true, gclog_or_tty); + GenMarkSweep::trace("3"); + + SharedHeap* sh = SharedHeap::heap(); + + sh->process_strong_roots(true, // Collecting permanent generation. + SharedHeap::SO_AllClasses, + &GenMarkSweep::adjust_root_pointer_closure, + &GenMarkSweep::adjust_pointer_closure); + + g1h->ref_processor()->weak_oops_do(&GenMarkSweep::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.) + g1h->g1_process_weak_roots(&GenMarkSweep::adjust_root_pointer_closure, + &GenMarkSweep::adjust_pointer_closure); + + GenMarkSweep::adjust_marks(); + + G1AdjustPointersClosure blk; + g1h->heap_region_iterate(&blk); + pg->adjust_pointers(); +} + +class G1SpaceCompactClosure: public HeapRegionClosure { +public: + G1SpaceCompactClosure() {} + + bool doHeapRegion(HeapRegion* hr) { + if (hr->isHumongous()) { + if (hr->startsHumongous()) { + 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 { + hr->compact(); + } + return false; + } +}; + +void G1MarkSweep::mark_sweep_phase4() { + // 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! + + // 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: ***