--- old/src/share/vm/gc_implementation/g1/g1EvacFailure.hpp 2015-02-11 13:49:28.737611466 +0100 +++ new/src/share/vm/gc_implementation/g1/g1EvacFailure.hpp 2015-02-11 13:49:28.625607719 +0100 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2012, 2015, 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 @@ -25,229 +25,24 @@ #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1EVACFAILURE_HPP #define SHARE_VM_GC_IMPLEMENTATION_G1_G1EVACFAILURE_HPP -#include "gc_implementation/g1/concurrentMark.inline.hpp" -#include "gc_implementation/g1/dirtyCardQueue.hpp" -#include "gc_implementation/g1/g1CollectedHeap.inline.hpp" -#include "gc_implementation/g1/g1_globals.hpp" -#include "gc_implementation/g1/g1OopClosures.inline.hpp" -#include "gc_implementation/g1/heapRegion.hpp" -#include "gc_implementation/g1/heapRegionRemSet.hpp" +#include "gc_implementation/g1/g1OopClosures.hpp" +#include "gc_implementation/g1/heapRegionManager.hpp" +#include "utilities/globalDefinitions.hpp" #include "utilities/workgroup.hpp" -// Closures and tasks associated with any self-forwarding pointers -// installed as a result of an evacuation failure. - -class UpdateRSetDeferred : public OopsInHeapRegionClosure { -private: - G1CollectedHeap* _g1; - DirtyCardQueue *_dcq; - G1SATBCardTableModRefBS* _ct_bs; - -public: - UpdateRSetDeferred(G1CollectedHeap* g1, DirtyCardQueue* dcq) : - _g1(g1), _ct_bs(_g1->g1_barrier_set()), _dcq(dcq) {} - - virtual void do_oop(narrowOop* p) { do_oop_work(p); } - virtual void do_oop( oop* p) { do_oop_work(p); } - template void do_oop_work(T* p) { - assert(_from->is_in_reserved(p), "paranoia"); - if (!_from->is_in_reserved(oopDesc::load_decode_heap_oop(p)) && - !_from->is_survivor()) { - size_t card_index = _ct_bs->index_for(p); - if (_ct_bs->mark_card_deferred(card_index)) { - _dcq->enqueue((jbyte*)_ct_bs->byte_for_index(card_index)); - } - } - } -}; - -class RemoveSelfForwardPtrObjClosure: public ObjectClosure { -private: - G1CollectedHeap* _g1; - ConcurrentMark* _cm; - HeapRegion* _hr; - size_t _marked_bytes; - OopsInHeapRegionClosure *_update_rset_cl; - bool _during_initial_mark; - bool _during_conc_mark; - uint _worker_id; - HeapWord* _end_of_last_gap; - HeapWord* _last_gap_threshold; - HeapWord* _last_obj_threshold; - -public: - RemoveSelfForwardPtrObjClosure(G1CollectedHeap* g1, ConcurrentMark* cm, - HeapRegion* hr, - OopsInHeapRegionClosure* update_rset_cl, - bool during_initial_mark, - bool during_conc_mark, - uint worker_id) : - _g1(g1), _cm(cm), _hr(hr), _marked_bytes(0), - _update_rset_cl(update_rset_cl), - _during_initial_mark(during_initial_mark), - _during_conc_mark(during_conc_mark), - _worker_id(worker_id), - _end_of_last_gap(hr->bottom()), - _last_gap_threshold(hr->bottom()), - _last_obj_threshold(hr->bottom()) { } - - size_t marked_bytes() { return _marked_bytes; } - - // - // The original idea here was to coalesce evacuated and dead objects. - // However that caused complications with the block offset table (BOT). - // In particular if there were two TLABs, one of them partially refined. - // |----- TLAB_1--------|----TLAB_2-~~~(partially refined part)~~~| - // The BOT entries of the unrefined part of TLAB_2 point to the start - // of TLAB_2. If the last object of the TLAB_1 and the first object - // of TLAB_2 are coalesced, then the cards of the unrefined part - // would point into middle of the filler object. - // The current approach is to not coalesce and leave the BOT contents intact. - // - // - // We now reset the BOT when we start the object iteration over the - // region and refine its entries for every object we come across. So - // the above comment is not really relevant and we should be able - // to coalesce dead objects if we want to. - void do_object(oop obj) { - HeapWord* obj_addr = (HeapWord*) obj; - assert(_hr->is_in(obj_addr), "sanity"); - size_t obj_size = obj->size(); - HeapWord* obj_end = obj_addr + obj_size; - - if (_end_of_last_gap != obj_addr) { - // there was a gap before obj_addr - _last_gap_threshold = _hr->cross_threshold(_end_of_last_gap, obj_addr); - } - - if (obj->is_forwarded() && obj->forwardee() == obj) { - // The object failed to move. - - // We consider all objects that we find self-forwarded to be - // live. What we'll do is that we'll update the prev marking - // info so that they are all under PTAMS and explicitly marked. - if (!_cm->isPrevMarked(obj)) { - _cm->markPrev(obj); - } - if (_during_initial_mark) { - // For the next marking info we'll only mark the - // self-forwarded objects explicitly if we are during - // initial-mark (since, normally, we only mark objects pointed - // to by roots if we succeed in copying them). By marking all - // self-forwarded objects we ensure that we mark any that are - // still pointed to be roots. During concurrent marking, and - // after initial-mark, we don't need to mark any objects - // explicitly and all objects in the CSet are considered - // (implicitly) live. So, we won't mark them explicitly and - // we'll leave them over NTAMS. - _cm->grayRoot(obj, obj_size, _worker_id, _hr); - } - _marked_bytes += (obj_size * HeapWordSize); - obj->set_mark(markOopDesc::prototype()); - - // While we were processing RSet buffers during the collection, - // we actually didn't scan any cards on the collection set, - // since we didn't want to update remembered sets with entries - // that point into the collection set, given that live objects - // from the collection set are about to move and such entries - // will be stale very soon. - // This change also dealt with a reliability issue which - // involved scanning a card in the collection set and coming - // across an array that was being chunked and looking malformed. - // The problem is that, if evacuation fails, we might have - // remembered set entries missing given that we skipped cards on - // the collection set. So, we'll recreate such entries now. - obj->oop_iterate(_update_rset_cl); - } else { - - // The object has been either evacuated or is dead. Fill it with a - // dummy object. - MemRegion mr(obj_addr, obj_size); - CollectedHeap::fill_with_object(mr); - - // must nuke all dead objects which we skipped when iterating over the region - _cm->clearRangePrevBitmap(MemRegion(_end_of_last_gap, obj_end)); - } - _end_of_last_gap = obj_end; - _last_obj_threshold = _hr->cross_threshold(obj_addr, obj_end); - } -}; - -class RemoveSelfForwardPtrHRClosure: public HeapRegionClosure { - G1CollectedHeap* _g1h; - ConcurrentMark* _cm; - uint _worker_id; - HeapRegionClaimer* _hrclaimer; - - DirtyCardQueue _dcq; - UpdateRSetDeferred _update_rset_cl; - -public: - RemoveSelfForwardPtrHRClosure(G1CollectedHeap* g1h, - uint worker_id, - HeapRegionClaimer* hrclaimer) : - _g1h(g1h), _dcq(&g1h->dirty_card_queue_set()), _update_rset_cl(g1h, &_dcq), - _worker_id(worker_id), _cm(_g1h->concurrent_mark()), _hrclaimer(hrclaimer) { - } - - bool doHeapRegion(HeapRegion *hr) { - bool during_initial_mark = _g1h->g1_policy()->during_initial_mark_pause(); - bool during_conc_mark = _g1h->mark_in_progress(); - - assert(!hr->is_humongous(), "sanity"); - assert(hr->in_collection_set(), "bad CS"); - - if (_hrclaimer->claim_region(hr->hrm_index())) { - if (hr->evacuation_failed()) { - RemoveSelfForwardPtrObjClosure rspc(_g1h, _cm, hr, &_update_rset_cl, - during_initial_mark, - during_conc_mark, - _worker_id); - - hr->note_self_forwarding_removal_start(during_initial_mark, - during_conc_mark); - _g1h->check_bitmaps("Self-Forwarding Ptr Removal", hr); - - // In the common case (i.e. when there is no evacuation - // failure) we make sure that the following is done when - // the region is freed so that it is "ready-to-go" when it's - // re-allocated. However, when evacuation failure happens, a - // region will remain in the heap and might ultimately be added - // to a CSet in the future. So we have to be careful here and - // make sure the region's RSet is ready for parallel iteration - // whenever this might be required in the future. - hr->rem_set()->reset_for_par_iteration(); - hr->reset_bot(); - _update_rset_cl.set_region(hr); - hr->object_iterate(&rspc); - - hr->rem_set()->clean_strong_code_roots(hr); - - hr->note_self_forwarding_removal_end(during_initial_mark, - during_conc_mark, - rspc.marked_bytes()); - } - } - return false; - } -}; +class G1CollectedHeap; +// Task to fixup self-forwarding pointers +// installed as a result of an evacuation failure. class G1ParRemoveSelfForwardPtrsTask: public AbstractGangTask { protected: G1CollectedHeap* _g1h; HeapRegionClaimer _hrclaimer; public: - G1ParRemoveSelfForwardPtrsTask(G1CollectedHeap* g1h) : - AbstractGangTask("G1 Remove Self-forwarding Pointers"), _g1h(g1h), - _hrclaimer(g1h->workers()->active_workers()) {} - - void work(uint worker_id) { - RemoveSelfForwardPtrHRClosure rsfp_cl(_g1h, worker_id, &_hrclaimer); - - HeapRegion* hr = _g1h->start_cset_region_for_worker(worker_id); - _g1h->collection_set_iterate_from(hr, &rsfp_cl); - } + G1ParRemoveSelfForwardPtrsTask(G1CollectedHeap* g1h); + + void work(uint worker_id); }; #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1EVACFAILURE_HPP