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src/share/vm/gc_implementation/g1/g1EvacFailure.hpp
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*** 1,7 ****
/*
! * Copyright (c) 2012, 2013, 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.
--- 1,7 ----
/*
! * 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*** 23,253 ****
*/
#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 "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 <class T> 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; }
!
! // <original comment>
! // 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.
! // </original comment>
! //
! // 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 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);
! }
};
#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1EVACFAILURE_HPP
--- 23,48 ----
*/
#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1EVACFAILURE_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_G1EVACFAILURE_HPP
! #include "gc_implementation/g1/g1OopClosures.hpp"
! #include "gc_implementation/g1/heapRegionManager.hpp"
! #include "utilities/globalDefinitions.hpp"
#include "utilities/workgroup.hpp"
! 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);
!
! void work(uint worker_id);
};
#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1EVACFAILURE_HPP
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