0N/A

0N/A#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1EVACFAILURE_HPP

0N/A#define SHARE_VM_GC_IMPLEMENTATION_G1_G1EVACFAILURE_HPP

0N/A

0N/A#include "gc_implementation/g1/concurrentMark.inline.hpp"

0N/A#include "gc_implementation/g1/dirtyCardQueue.hpp"

0N/A#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"

0N/A#include "gc_implementation/g1/g1_globals.hpp"

0N/A#include "gc_implementation/g1/g1OopClosures.inline.hpp"

0N/A#include "gc_implementation/g1/heapRegion.hpp"

0N/A#include "gc_implementation/g1/heapRegionRemSet.hpp"

0N/A#include "utilities/workgroup.hpp"

0N/A

0N/A

0N/Aclass UpdateRSetDeferred : public OopsInHeapRegionClosure {

0N/Aprivate:

0N/A G1CollectedHeap* _g1;

0N/A DirtyCardQueue *_dcq;

0N/A CardTableModRefBS* _ct_bs;

0N/A

0N/Apublic:

0N/A UpdateRSetDeferred(G1CollectedHeap* g1, DirtyCardQueue* dcq) :

0N/A _g1(g1), _ct_bs((CardTableModRefBS*)_g1->barrier_set()), _dcq(dcq) {}

0N/A

0N/A virtual void do_oop(narrowOop* p) { do_oop_work(p); }

0N/A virtual void do_oop( oop* p) { do_oop_work(p); }

0N/A template <class T> void do_oop_work(T* p) {

0N/A assert(_from->is_in_reserved(p), "paranoia");

0N/A if (!_from->is_in_reserved(oopDesc::load_decode_heap_oop(p)) &&

0N/A !_from->is_survivor()) {

0N/A size_t card_index = _ct_bs->index_for(p);

0N/A if (_ct_bs->mark_card_deferred(card_index)) {

0N/A _dcq->enqueue((jbyte*)_ct_bs->byte_for_index(card_index));

0N/A }

0N/A }

0N/A }

0N/A};

0N/A

0N/Aclass RemoveSelfForwardPtrObjClosure: public ObjectClosure {

0N/Aprivate:

0N/A G1CollectedHeap* _g1;

0N/A ConcurrentMark* _cm;

0N/A HeapRegion* _hr;

0N/A size_t _marked_bytes;

0N/A OopsInHeapRegionClosure *_update_rset_cl;

0N/A bool _during_initial_mark;

0N/A bool _during_conc_mark;

0N/A uint _worker_id;

0N/A

0N/Apublic:

0N/A RemoveSelfForwardPtrObjClosure(G1CollectedHeap* g1, ConcurrentMark* cm,

0N/A HeapRegion* hr,

0N/A OopsInHeapRegionClosure* update_rset_cl,

0N/A bool during_initial_mark,

0N/A bool during_conc_mark,

0N/A uint worker_id) :

0N/A _g1(g1), _cm(cm), _hr(hr), _marked_bytes(0),

0N/A _update_rset_cl(update_rset_cl),

0N/A _during_initial_mark(during_initial_mark),

0N/A _during_conc_mark(during_conc_mark),

0N/A _worker_id(worker_id) { }

0N/A

0N/A size_t marked_bytes() { return _marked_bytes; }

0N/A

0N/A // <original comment>

0N/A // The original idea here was to coalesce evacuated and dead objects.

0N/A // However that caused complications with the block offset table (BOT).

0N/A // In particular if there were two TLABs, one of them partially refined.

0N/A // |----- TLAB_1--------|----TLAB_2-~~~(partially refined part)~~~|

0N/A // The BOT entries of the unrefined part of TLAB_2 point to the start

0N/A // of TLAB_2. If the last object of the TLAB_1 and the first object

0N/A // of TLAB_2 are coalesced, then the cards of the unrefined part

0N/A // would point into middle of the filler object.

0N/A // The current approach is to not coalesce and leave the BOT contents intact.

0N/A // </original comment>

0N/A //

0N/A // We now reset the BOT when we start the object iteration over the

0N/A // region and refine its entries for every object we come across. So

0N/A // the above comment is not really relevant and we should be able

0N/A // to coalesce dead objects if we want to.

0N/A void do_object(oop obj) {

0N/A HeapWord* obj_addr = (HeapWord*) obj;

0N/A assert(_hr->is_in(obj_addr), "sanity");

0N/A size_t obj_size = obj->size();

0N/A _hr->update_bot_for_object(obj_addr, obj_size);

0N/A

0N/A if (obj->is_forwarded() && obj->forwardee() == obj) {

0N/A // The object failed to move.

0N/A

0N/A // We consider all objects that we find self-forwarded to be

0N/A // live. What we'll do is that we'll update the prev marking

0N/A // info so that they are all under PTAMS and explicitly marked.

0N/A _cm->markPrev(obj);

0N/A if (_during_initial_mark) {

0N/A // For the next marking info we'll only mark the

0N/A // self-forwarded objects explicitly if we are during

0N/A // initial-mark (since, normally, we only mark objects pointed

0N/A // to by roots if we succeed in copying them). By marking all

0N/A // self-forwarded objects we ensure that we mark any that are

0N/A // still pointed to be roots. During concurrent marking, and

0N/A // after initial-mark, we don't need to mark any objects

0N/A // explicitly and all objects in the CSet are considered

0N/A // (implicitly) live. So, we won't mark them explicitly and

0N/A // we'll leave them over NTAMS.

0N/A _cm->grayRoot(obj, obj_size, _worker_id, _hr);

0N/A }

0N/A _marked_bytes += (obj_size * HeapWordSize);

0N/A obj->set_mark(markOopDesc::prototype());

0N/A

0N/A // While we were processing RSet buffers during the collection,

0N/A // we actually didn't scan any cards on the collection set,

0N/A // since we didn't want to update remembered sets with entries

0N/A // that point into the collection set, given that live objects

0N/A // from the collection set are about to move and such entries

0N/A // will be stale very soon.

0N/A // This change also dealt with a reliability issue which

0N/A // involved scanning a card in the collection set and coming

0N/A // across an array that was being chunked and looking malformed.

0N/A // The problem is that, if evacuation fails, we might have

0N/A // remembered set entries missing given that we skipped cards on

0N/A // the collection set. So, we'll recreate such entries now.

0N/A obj->oop_iterate(_update_rset_cl);

0N/A assert(_cm->isPrevMarked(obj), "Should be marked!");

0N/A } else {

0N/A // The object has been either evacuated or is dead. Fill it with a

0N/A // dummy object.

0N/A MemRegion mr((HeapWord*) obj, obj_size);

0N/A CollectedHeap::fill_with_object(mr);

0N/A }

0N/A }

0N/A};

0N/A

0N/Aclass RemoveSelfForwardPtrHRClosure: public HeapRegionClosure {

0N/A G1CollectedHeap* _g1h;

0N/A ConcurrentMark* _cm;

0N/A OopsInHeapRegionClosure *_update_rset_cl;

0N/A uint _worker_id;

0N/A

0N/Apublic:

0N/A RemoveSelfForwardPtrHRClosure(G1CollectedHeap* g1h,

0N/A OopsInHeapRegionClosure* update_rset_cl,

0N/A uint worker_id) :

0N/A _g1h(g1h), _update_rset_cl(update_rset_cl),

0N/A _worker_id(worker_id), _cm(_g1h->concurrent_mark()) { }

0N/A

0N/A bool doHeapRegion(HeapRegion *hr) {

0N/A bool during_initial_mark = _g1h->g1_policy()->during_initial_mark_pause();

0N/A bool during_conc_mark = _g1h->mark_in_progress();

0N/A

0N/A assert(!hr->isHumongous(), "sanity");

assert(hr->in_collection_set(), "bad CS");

if (hr->claimHeapRegion(HeapRegion::ParEvacFailureClaimValue)) {

if (hr->evacuation_failed()) {

RemoveSelfForwardPtrObjClosure rspc(_g1h, _cm, hr, _update_rset_cl,

during_initial_mark,

during_conc_mark,

_worker_id);

MemRegion mr(hr->bottom(), hr->end());

// We'll recreate the prev marking info so we'll first clear

// the prev bitmap range for this region. We never mark any

// CSet objects explicitly so the next bitmap range should be

// cleared anyway.

_cm->clearRangePrevBitmap(mr);

hr->note_self_forwarding_removal_start(during_initial_mark,

during_conc_mark);

// 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->note_self_forwarding_removal_end(during_initial_mark,

during_conc_mark,

rspc.marked_bytes());

}

}

return false;

}

};

class G1ParRemoveSelfForwardPtrsTask: public AbstractGangTask {

protected:

G1CollectedHeap* _g1h;

public:

G1ParRemoveSelfForwardPtrsTask(G1CollectedHeap* g1h) :

AbstractGangTask("G1 Remove Self-forwarding Pointers"),

_g1h(g1h) { }

void work(uint worker_id) {

UpdateRSetImmediate immediate_update(_g1h->g1_rem_set());

DirtyCardQueue dcq(&_g1h->dirty_card_queue_set());

UpdateRSetDeferred deferred_update(_g1h, &dcq);

OopsInHeapRegionClosure *update_rset_cl = &deferred_update;

if (!G1DeferredRSUpdate) {

update_rset_cl = &immediate_update;

}

RemoveSelfForwardPtrHRClosure rsfp_cl(_g1h, update_rset_cl, worker_id);

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