--- old/src/share/vm/gc_implementation/g1/g1EvacFailure.cpp 2015-05-13 13:55:42.939299887 +0200 +++ /dev/null 2015-03-18 17:10:38.111854831 +0100 @@ -1,239 +0,0 @@ -/* - * 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. - * - * 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 "gc_implementation/g1/concurrentMark.inline.hpp" -#include "gc_implementation/g1/dirtyCardQueue.hpp" -#include "gc_implementation/g1/g1CollectedHeap.inline.hpp" -#include "gc_implementation/g1/g1EvacFailure.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" - -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; - } -}; - -G1ParRemoveSelfForwardPtrsTask::G1ParRemoveSelfForwardPtrsTask(G1CollectedHeap* g1h) : - AbstractGangTask("G1 Remove Self-forwarding Pointers"), _g1h(g1h), - _hrclaimer(g1h->workers()->active_workers()) {} - -void G1ParRemoveSelfForwardPtrsTask::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); -} --- /dev/null 2015-03-18 17:10:38.111854831 +0100 +++ new/src/share/vm/gc/g1/g1EvacFailure.cpp 2015-05-13 13:55:42.761292501 +0200 @@ -0,0 +1,239 @@ +/* + * 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. + * + * 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 "gc/g1/concurrentMark.inline.hpp" +#include "gc/g1/dirtyCardQueue.hpp" +#include "gc/g1/g1CollectedHeap.inline.hpp" +#include "gc/g1/g1EvacFailure.hpp" +#include "gc/g1/g1OopClosures.inline.hpp" +#include "gc/g1/g1_globals.hpp" +#include "gc/g1/heapRegion.hpp" +#include "gc/g1/heapRegionRemSet.hpp" + +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; + } +}; + +G1ParRemoveSelfForwardPtrsTask::G1ParRemoveSelfForwardPtrsTask(G1CollectedHeap* g1h) : + AbstractGangTask("G1 Remove Self-forwarding Pointers"), _g1h(g1h), + _hrclaimer(g1h->workers()->active_workers()) {} + +void G1ParRemoveSelfForwardPtrsTask::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); +}