Mercurial > hg > truffle
view src/share/vm/gc_implementation/g1/g1RemSet.cpp @ 13040:f8b56489e455
Merge
author | mgronlun |
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date | Fri, 01 Nov 2013 17:10:31 +0000 |
parents | 7ec10139bf37 |
children | 46d7652b223c |
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/* * Copyright (c) 2001, 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. * * 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/bufferingOopClosure.hpp" #include "gc_implementation/g1/concurrentG1Refine.hpp" #include "gc_implementation/g1/concurrentG1RefineThread.hpp" #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp" #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" #include "gc_implementation/g1/g1CollectorPolicy.hpp" #include "gc_implementation/g1/g1HotCardCache.hpp" #include "gc_implementation/g1/g1GCPhaseTimes.hpp" #include "gc_implementation/g1/g1OopClosures.inline.hpp" #include "gc_implementation/g1/g1RemSet.inline.hpp" #include "gc_implementation/g1/heapRegionSeq.inline.hpp" #include "gc_implementation/g1/heapRegionRemSet.hpp" #include "memory/iterator.hpp" #include "oops/oop.inline.hpp" #include "utilities/intHisto.hpp" #define CARD_REPEAT_HISTO 0 #if CARD_REPEAT_HISTO static size_t ct_freq_sz; static jbyte* ct_freq = NULL; void init_ct_freq_table(size_t heap_sz_bytes) { if (ct_freq == NULL) { ct_freq_sz = heap_sz_bytes/CardTableModRefBS::card_size; ct_freq = new jbyte[ct_freq_sz]; for (size_t j = 0; j < ct_freq_sz; j++) ct_freq[j] = 0; } } void ct_freq_note_card(size_t index) { assert(0 <= index && index < ct_freq_sz, "Bounds error."); if (ct_freq[index] < 100) { ct_freq[index]++; } } static IntHistogram card_repeat_count(10, 10); void ct_freq_update_histo_and_reset() { for (size_t j = 0; j < ct_freq_sz; j++) { card_repeat_count.add_entry(ct_freq[j]); ct_freq[j] = 0; } } #endif G1RemSet::G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs) : _g1(g1), _conc_refine_cards(0), _ct_bs(ct_bs), _g1p(_g1->g1_policy()), _cg1r(g1->concurrent_g1_refine()), _cset_rs_update_cl(NULL), _cards_scanned(NULL), _total_cards_scanned(0), _prev_period_summary() { _seq_task = new SubTasksDone(NumSeqTasks); guarantee(n_workers() > 0, "There should be some workers"); _cset_rs_update_cl = NEW_C_HEAP_ARRAY(OopsInHeapRegionClosure*, n_workers(), mtGC); for (uint i = 0; i < n_workers(); i++) { _cset_rs_update_cl[i] = NULL; } if (G1SummarizeRSetStats) { _prev_period_summary.initialize(this); } } G1RemSet::~G1RemSet() { delete _seq_task; for (uint i = 0; i < n_workers(); i++) { assert(_cset_rs_update_cl[i] == NULL, "it should be"); } FREE_C_HEAP_ARRAY(OopsInHeapRegionClosure*, _cset_rs_update_cl, mtGC); } void CountNonCleanMemRegionClosure::do_MemRegion(MemRegion mr) { if (_g1->is_in_g1_reserved(mr.start())) { _n += (int) ((mr.byte_size() / CardTableModRefBS::card_size)); if (_start_first == NULL) _start_first = mr.start(); } } class ScanRSClosure : public HeapRegionClosure { size_t _cards_done, _cards; G1CollectedHeap* _g1h; OopsInHeapRegionClosure* _oc; CodeBlobToOopClosure* _code_root_cl; G1BlockOffsetSharedArray* _bot_shared; G1SATBCardTableModRefBS *_ct_bs; double _strong_code_root_scan_time_sec; int _worker_i; int _block_size; bool _try_claimed; public: ScanRSClosure(OopsInHeapRegionClosure* oc, CodeBlobToOopClosure* code_root_cl, int worker_i) : _oc(oc), _code_root_cl(code_root_cl), _strong_code_root_scan_time_sec(0.0), _cards(0), _cards_done(0), _worker_i(worker_i), _try_claimed(false) { _g1h = G1CollectedHeap::heap(); _bot_shared = _g1h->bot_shared(); _ct_bs = _g1h->g1_barrier_set(); _block_size = MAX2<int>(G1RSetScanBlockSize, 1); } void set_try_claimed() { _try_claimed = true; } void scanCard(size_t index, HeapRegion *r) { // Stack allocate the DirtyCardToOopClosure instance HeapRegionDCTOC cl(_g1h, r, _oc, CardTableModRefBS::Precise, HeapRegionDCTOC::IntoCSFilterKind); // Set the "from" region in the closure. _oc->set_region(r); HeapWord* card_start = _bot_shared->address_for_index(index); HeapWord* card_end = card_start + G1BlockOffsetSharedArray::N_words; Space *sp = SharedHeap::heap()->space_containing(card_start); MemRegion sm_region = sp->used_region_at_save_marks(); MemRegion mr = sm_region.intersection(MemRegion(card_start,card_end)); if (!mr.is_empty() && !_ct_bs->is_card_claimed(index)) { // We make the card as "claimed" lazily (so races are possible // but they're benign), which reduces the number of duplicate // scans (the rsets of the regions in the cset can intersect). _ct_bs->set_card_claimed(index); _cards_done++; cl.do_MemRegion(mr); } } void printCard(HeapRegion* card_region, size_t card_index, HeapWord* card_start) { gclog_or_tty->print_cr("T %d Region [" PTR_FORMAT ", " PTR_FORMAT ") " "RS names card %p: " "[" PTR_FORMAT ", " PTR_FORMAT ")", _worker_i, card_region->bottom(), card_region->end(), card_index, card_start, card_start + G1BlockOffsetSharedArray::N_words); } void scan_strong_code_roots(HeapRegion* r) { double scan_start = os::elapsedTime(); r->strong_code_roots_do(_code_root_cl); _strong_code_root_scan_time_sec += (os::elapsedTime() - scan_start); } bool doHeapRegion(HeapRegion* r) { assert(r->in_collection_set(), "should only be called on elements of CS."); HeapRegionRemSet* hrrs = r->rem_set(); if (hrrs->iter_is_complete()) return false; // All done. if (!_try_claimed && !hrrs->claim_iter()) return false; // If we ever free the collection set concurrently, we should also // clear the card table concurrently therefore we won't need to // add regions of the collection set to the dirty cards region. _g1h->push_dirty_cards_region(r); // If we didn't return above, then // _try_claimed || r->claim_iter() // is true: either we're supposed to work on claimed-but-not-complete // regions, or we successfully claimed the region. HeapRegionRemSetIterator iter(hrrs); size_t card_index; // We claim cards in block so as to recude the contention. The block size is determined by // the G1RSetScanBlockSize parameter. size_t jump_to_card = hrrs->iter_claimed_next(_block_size); for (size_t current_card = 0; iter.has_next(card_index); current_card++) { if (current_card >= jump_to_card + _block_size) { jump_to_card = hrrs->iter_claimed_next(_block_size); } if (current_card < jump_to_card) continue; HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index); #if 0 gclog_or_tty->print("Rem set iteration yielded card [" PTR_FORMAT ", " PTR_FORMAT ").\n", card_start, card_start + CardTableModRefBS::card_size_in_words); #endif HeapRegion* card_region = _g1h->heap_region_containing(card_start); assert(card_region != NULL, "Yielding cards not in the heap?"); _cards++; if (!card_region->is_on_dirty_cards_region_list()) { _g1h->push_dirty_cards_region(card_region); } // If the card is dirty, then we will scan it during updateRS. if (!card_region->in_collection_set() && !_ct_bs->is_card_dirty(card_index)) { scanCard(card_index, card_region); } } if (!_try_claimed) { // Scan the strong code root list attached to the current region scan_strong_code_roots(r); hrrs->set_iter_complete(); } return false; } double strong_code_root_scan_time_sec() { return _strong_code_root_scan_time_sec; } size_t cards_done() { return _cards_done;} size_t cards_looked_up() { return _cards;} }; void G1RemSet::scanRS(OopsInHeapRegionClosure* oc, CodeBlobToOopClosure* code_root_cl, int worker_i) { double rs_time_start = os::elapsedTime(); HeapRegion *startRegion = _g1->start_cset_region_for_worker(worker_i); ScanRSClosure scanRScl(oc, code_root_cl, worker_i); _g1->collection_set_iterate_from(startRegion, &scanRScl); scanRScl.set_try_claimed(); _g1->collection_set_iterate_from(startRegion, &scanRScl); double scan_rs_time_sec = (os::elapsedTime() - rs_time_start) - scanRScl.strong_code_root_scan_time_sec(); assert(_cards_scanned != NULL, "invariant"); _cards_scanned[worker_i] = scanRScl.cards_done(); _g1p->phase_times()->record_scan_rs_time(worker_i, scan_rs_time_sec * 1000.0); _g1p->phase_times()->record_strong_code_root_scan_time(worker_i, scanRScl.strong_code_root_scan_time_sec() * 1000.0); } // Closure used for updating RSets and recording references that // point into the collection set. Only called during an // evacuation pause. class RefineRecordRefsIntoCSCardTableEntryClosure: public CardTableEntryClosure { G1RemSet* _g1rs; DirtyCardQueue* _into_cset_dcq; public: RefineRecordRefsIntoCSCardTableEntryClosure(G1CollectedHeap* g1h, DirtyCardQueue* into_cset_dcq) : _g1rs(g1h->g1_rem_set()), _into_cset_dcq(into_cset_dcq) {} bool do_card_ptr(jbyte* card_ptr, int worker_i) { // The only time we care about recording cards that // contain references that point into the collection set // is during RSet updating within an evacuation pause. // In this case worker_i should be the id of a GC worker thread. assert(SafepointSynchronize::is_at_safepoint(), "not during an evacuation pause"); assert(worker_i < (int) (ParallelGCThreads == 0 ? 1 : ParallelGCThreads), "should be a GC worker"); if (_g1rs->refine_card(card_ptr, worker_i, true)) { // 'card_ptr' contains references that point into the collection // set. We need to record the card in the DCQS // (G1CollectedHeap::into_cset_dirty_card_queue_set()) // that's used for that purpose. // // Enqueue the card _into_cset_dcq->enqueue(card_ptr); } return true; } }; void G1RemSet::updateRS(DirtyCardQueue* into_cset_dcq, int worker_i) { double start = os::elapsedTime(); // Apply the given closure to all remaining log entries. RefineRecordRefsIntoCSCardTableEntryClosure into_cset_update_rs_cl(_g1, into_cset_dcq); _g1->iterate_dirty_card_closure(&into_cset_update_rs_cl, into_cset_dcq, false, worker_i); // Now there should be no dirty cards. if (G1RSLogCheckCardTable) { CountNonCleanMemRegionClosure cl(_g1); _ct_bs->mod_card_iterate(&cl); // XXX This isn't true any more: keeping cards of young regions // marked dirty broke it. Need some reasonable fix. guarantee(cl.n() == 0, "Card table should be clean."); } _g1p->phase_times()->record_update_rs_time(worker_i, (os::elapsedTime() - start) * 1000.0); } void G1RemSet::cleanupHRRS() { HeapRegionRemSet::cleanup(); } void G1RemSet::oops_into_collection_set_do(OopsInHeapRegionClosure* oc, CodeBlobToOopClosure* code_root_cl, int worker_i) { #if CARD_REPEAT_HISTO ct_freq_update_histo_and_reset(); #endif // We cache the value of 'oc' closure into the appropriate slot in the // _cset_rs_update_cl for this worker assert(worker_i < (int)n_workers(), "sanity"); _cset_rs_update_cl[worker_i] = oc; // A DirtyCardQueue that is used to hold cards containing references // that point into the collection set. This DCQ is associated with a // special DirtyCardQueueSet (see g1CollectedHeap.hpp). Under normal // circumstances (i.e. the pause successfully completes), these cards // are just discarded (there's no need to update the RSets of regions // that were in the collection set - after the pause these regions // are wholly 'free' of live objects. In the event of an evacuation // failure the cards/buffers in this queue set are: // * passed to the DirtyCardQueueSet that is used to manage deferred // RSet updates, or // * scanned for references that point into the collection set // and the RSet of the corresponding region in the collection set // is updated immediately. DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set()); assert((ParallelGCThreads > 0) || worker_i == 0, "invariant"); // The two flags below were introduced temporarily to serialize // the updating and scanning of remembered sets. There are some // race conditions when these two operations are done in parallel // and they are causing failures. When we resolve said race // conditions, we'll revert back to parallel remembered set // updating and scanning. See CRs 6677707 and 6677708. if (G1UseParallelRSetUpdating || (worker_i == 0)) { updateRS(&into_cset_dcq, worker_i); } else { _g1p->phase_times()->record_update_rs_processed_buffers(worker_i, 0); _g1p->phase_times()->record_update_rs_time(worker_i, 0.0); } if (G1UseParallelRSetScanning || (worker_i == 0)) { scanRS(oc, code_root_cl, worker_i); } else { _g1p->phase_times()->record_scan_rs_time(worker_i, 0.0); } // We now clear the cached values of _cset_rs_update_cl for this worker _cset_rs_update_cl[worker_i] = NULL; } void G1RemSet::prepare_for_oops_into_collection_set_do() { cleanupHRRS(); ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine(); _g1->set_refine_cte_cl_concurrency(false); DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); dcqs.concatenate_logs(); if (G1CollectedHeap::use_parallel_gc_threads()) { // Don't set the number of workers here. It will be set // when the task is run // _seq_task->set_n_termination((int)n_workers()); } guarantee( _cards_scanned == NULL, "invariant" ); _cards_scanned = NEW_C_HEAP_ARRAY(size_t, n_workers(), mtGC); for (uint i = 0; i < n_workers(); ++i) { _cards_scanned[i] = 0; } _total_cards_scanned = 0; } // This closure, applied to a DirtyCardQueueSet, is used to immediately // update the RSets for the regions in the CSet. For each card it iterates // through the oops which coincide with that card. It scans the reference // fields in each oop; when it finds an oop that points into the collection // set, the RSet for the region containing the referenced object is updated. class UpdateRSetCardTableEntryIntoCSetClosure: public CardTableEntryClosure { G1CollectedHeap* _g1; CardTableModRefBS* _ct_bs; public: UpdateRSetCardTableEntryIntoCSetClosure(G1CollectedHeap* g1, CardTableModRefBS* bs): _g1(g1), _ct_bs(bs) { } bool do_card_ptr(jbyte* card_ptr, int worker_i) { // Construct the region representing the card. HeapWord* start = _ct_bs->addr_for(card_ptr); // And find the region containing it. HeapRegion* r = _g1->heap_region_containing(start); assert(r != NULL, "unexpected null"); // Scan oops in the card looking for references into the collection set // Don't use addr_for(card_ptr + 1) which can ask for // a card beyond the heap. This is not safe without a perm // gen. HeapWord* end = start + CardTableModRefBS::card_size_in_words; MemRegion scanRegion(start, end); UpdateRSetImmediate update_rs_cl(_g1->g1_rem_set()); FilterIntoCSClosure update_rs_cset_oop_cl(NULL, _g1, &update_rs_cl); FilterOutOfRegionClosure filter_then_update_rs_cset_oop_cl(r, &update_rs_cset_oop_cl); // We can pass false as the "filter_young" parameter here as: // * we should be in a STW pause, // * the DCQS to which this closure is applied is used to hold // references that point into the collection set from the prior // RSet updating, // * the post-write barrier shouldn't be logging updates to young // regions (but there is a situation where this can happen - see // the comment in G1RemSet::refine_card() below - // that should not be applicable here), and // * during actual RSet updating, the filtering of cards in young // regions in HeapRegion::oops_on_card_seq_iterate_careful is // employed. // As a result, when this closure is applied to "refs into cset" // DCQS, we shouldn't see any cards in young regions. update_rs_cl.set_region(r); HeapWord* stop_point = r->oops_on_card_seq_iterate_careful(scanRegion, &filter_then_update_rs_cset_oop_cl, false /* filter_young */, NULL /* card_ptr */); // Since this is performed in the event of an evacuation failure, we // we shouldn't see a non-null stop point assert(stop_point == NULL, "saw an unallocated region"); return true; } }; void G1RemSet::cleanup_after_oops_into_collection_set_do() { guarantee( _cards_scanned != NULL, "invariant" ); _total_cards_scanned = 0; for (uint i = 0; i < n_workers(); ++i) { _total_cards_scanned += _cards_scanned[i]; } FREE_C_HEAP_ARRAY(size_t, _cards_scanned, mtGC); _cards_scanned = NULL; // Cleanup after copy _g1->set_refine_cte_cl_concurrency(true); // Set all cards back to clean. _g1->cleanUpCardTable(); DirtyCardQueueSet& into_cset_dcqs = _g1->into_cset_dirty_card_queue_set(); int into_cset_n_buffers = into_cset_dcqs.completed_buffers_num(); if (_g1->evacuation_failed()) { // Restore remembered sets for the regions pointing into the collection set. if (G1DeferredRSUpdate) { // If deferred RS updates are enabled then we just need to transfer // the completed buffers from (a) the DirtyCardQueueSet used to hold // cards that contain references that point into the collection set // to (b) the DCQS used to hold the deferred RS updates _g1->dirty_card_queue_set().merge_bufferlists(&into_cset_dcqs); } else { CardTableModRefBS* bs = (CardTableModRefBS*)_g1->barrier_set(); UpdateRSetCardTableEntryIntoCSetClosure update_rs_cset_immediate(_g1, bs); int n_completed_buffers = 0; while (into_cset_dcqs.apply_closure_to_completed_buffer(&update_rs_cset_immediate, 0, 0, true)) { n_completed_buffers++; } assert(n_completed_buffers == into_cset_n_buffers, "missed some buffers"); } } // Free any completed buffers in the DirtyCardQueueSet used to hold cards // which contain references that point into the collection. _g1->into_cset_dirty_card_queue_set().clear(); assert(_g1->into_cset_dirty_card_queue_set().completed_buffers_num() == 0, "all buffers should be freed"); _g1->into_cset_dirty_card_queue_set().clear_n_completed_buffers(); } class ScrubRSClosure: public HeapRegionClosure { G1CollectedHeap* _g1h; BitMap* _region_bm; BitMap* _card_bm; CardTableModRefBS* _ctbs; public: ScrubRSClosure(BitMap* region_bm, BitMap* card_bm) : _g1h(G1CollectedHeap::heap()), _region_bm(region_bm), _card_bm(card_bm), _ctbs(_g1h->g1_barrier_set()) {} bool doHeapRegion(HeapRegion* r) { if (!r->continuesHumongous()) { r->rem_set()->scrub(_ctbs, _region_bm, _card_bm); } return false; } }; void G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm) { ScrubRSClosure scrub_cl(region_bm, card_bm); _g1->heap_region_iterate(&scrub_cl); } void G1RemSet::scrub_par(BitMap* region_bm, BitMap* card_bm, uint worker_num, int claim_val) { ScrubRSClosure scrub_cl(region_bm, card_bm); _g1->heap_region_par_iterate_chunked(&scrub_cl, worker_num, n_workers(), claim_val); } G1TriggerClosure::G1TriggerClosure() : _triggered(false) { } G1InvokeIfNotTriggeredClosure::G1InvokeIfNotTriggeredClosure(G1TriggerClosure* t_cl, OopClosure* oop_cl) : _trigger_cl(t_cl), _oop_cl(oop_cl) { } G1Mux2Closure::G1Mux2Closure(OopClosure *c1, OopClosure *c2) : _c1(c1), _c2(c2) { } G1UpdateRSOrPushRefOopClosure:: G1UpdateRSOrPushRefOopClosure(G1CollectedHeap* g1h, G1RemSet* rs, OopsInHeapRegionClosure* push_ref_cl, bool record_refs_into_cset, int worker_i) : _g1(g1h), _g1_rem_set(rs), _from(NULL), _record_refs_into_cset(record_refs_into_cset), _push_ref_cl(push_ref_cl), _worker_i(worker_i) { } // Returns true if the given card contains references that point // into the collection set, if we're checking for such references; // false otherwise. bool G1RemSet::refine_card(jbyte* card_ptr, int worker_i, bool check_for_refs_into_cset) { // If the card is no longer dirty, nothing to do. if (*card_ptr != CardTableModRefBS::dirty_card_val()) { // No need to return that this card contains refs that point // into the collection set. return false; } // Construct the region representing the card. HeapWord* start = _ct_bs->addr_for(card_ptr); // And find the region containing it. HeapRegion* r = _g1->heap_region_containing(start); if (r == NULL) { // Again no need to return that this card contains refs that // point into the collection set. return false; // Not in the G1 heap (might be in perm, for example.) } // Why do we have to check here whether a card is on a young region, // given that we dirty young regions and, as a result, the // post-barrier is supposed to filter them out and never to enqueue // them? When we allocate a new region as the "allocation region" we // actually dirty its cards after we release the lock, since card // dirtying while holding the lock was a performance bottleneck. So, // as a result, it is possible for other threads to actually // allocate objects in the region (after the acquire the lock) // before all the cards on the region are dirtied. This is unlikely, // and it doesn't happen often, but it can happen. So, the extra // check below filters out those cards. if (r->is_young()) { return false; } // While we are processing RSet buffers during the collection, we // actually don't want to scan any cards on the collection set, // since we don't want to update remebered 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 deals with a reliability issue which // involves scanning a card in the collection set and coming across // an array that was being chunked and looking malformed. Note, // however, that if evacuation fails, we have to scan any objects // that were not moved and create any missing entries. if (r->in_collection_set()) { return false; } // The result from the hot card cache insert call is either: // * pointer to the current card // (implying that the current card is not 'hot'), // * null // (meaning we had inserted the card ptr into the "hot" card cache, // which had some headroom), // * a pointer to a "hot" card that was evicted from the "hot" cache. // G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache(); if (hot_card_cache->use_cache()) { assert(!check_for_refs_into_cset, "sanity"); assert(!SafepointSynchronize::is_at_safepoint(), "sanity"); card_ptr = hot_card_cache->insert(card_ptr); if (card_ptr == NULL) { // There was no eviction. Nothing to do. return false; } start = _ct_bs->addr_for(card_ptr); r = _g1->heap_region_containing(start); if (r == NULL) { // Not in the G1 heap return false; } // Checking whether the region we got back from the cache // is young here is inappropriate. The region could have been // freed, reallocated and tagged as young while in the cache. // Hence we could see its young type change at any time. } // Don't use addr_for(card_ptr + 1) which can ask for // a card beyond the heap. This is not safe without a perm // gen at the upper end of the heap. HeapWord* end = start + CardTableModRefBS::card_size_in_words; MemRegion dirtyRegion(start, end); #if CARD_REPEAT_HISTO init_ct_freq_table(_g1->max_capacity()); ct_freq_note_card(_ct_bs->index_for(start)); #endif OopsInHeapRegionClosure* oops_in_heap_closure = NULL; if (check_for_refs_into_cset) { // ConcurrentG1RefineThreads have worker numbers larger than what // _cset_rs_update_cl[] is set up to handle. But those threads should // only be active outside of a collection which means that when they // reach here they should have check_for_refs_into_cset == false. assert((size_t)worker_i < n_workers(), "index of worker larger than _cset_rs_update_cl[].length"); oops_in_heap_closure = _cset_rs_update_cl[worker_i]; } G1UpdateRSOrPushRefOopClosure update_rs_oop_cl(_g1, _g1->g1_rem_set(), oops_in_heap_closure, check_for_refs_into_cset, worker_i); update_rs_oop_cl.set_from(r); G1TriggerClosure trigger_cl; FilterIntoCSClosure into_cs_cl(NULL, _g1, &trigger_cl); G1InvokeIfNotTriggeredClosure invoke_cl(&trigger_cl, &into_cs_cl); G1Mux2Closure mux(&invoke_cl, &update_rs_oop_cl); FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r, (check_for_refs_into_cset ? (OopClosure*)&mux : (OopClosure*)&update_rs_oop_cl)); // The region for the current card may be a young region. The // current card may have been a card that was evicted from the // card cache. When the card was inserted into the cache, we had // determined that its region was non-young. While in the cache, // the region may have been freed during a cleanup pause, reallocated // and tagged as young. // // We wish to filter out cards for such a region but the current // thread, if we're running concurrently, may "see" the young type // change at any time (so an earlier "is_young" check may pass or // fail arbitrarily). We tell the iteration code to perform this // filtering when it has been determined that there has been an actual // allocation in this region and making it safe to check the young type. bool filter_young = true; HeapWord* stop_point = r->oops_on_card_seq_iterate_careful(dirtyRegion, &filter_then_update_rs_oop_cl, filter_young, card_ptr); // If stop_point is non-null, then we encountered an unallocated region // (perhaps the unfilled portion of a TLAB.) For now, we'll dirty the // card and re-enqueue: if we put off the card until a GC pause, then the // unallocated portion will be filled in. Alternatively, we might try // the full complexity of the technique used in "regular" precleaning. if (stop_point != NULL) { // The card might have gotten re-dirtied and re-enqueued while we // worked. (In fact, it's pretty likely.) if (*card_ptr != CardTableModRefBS::dirty_card_val()) { *card_ptr = CardTableModRefBS::dirty_card_val(); MutexLockerEx x(Shared_DirtyCardQ_lock, Mutex::_no_safepoint_check_flag); DirtyCardQueue* sdcq = JavaThread::dirty_card_queue_set().shared_dirty_card_queue(); sdcq->enqueue(card_ptr); } } else { _conc_refine_cards++; } // This gets set to true if the card being refined has // references that point into the collection set. bool has_refs_into_cset = trigger_cl.triggered(); // We should only be detecting that the card contains references // that point into the collection set if the current thread is // a GC worker thread. assert(!has_refs_into_cset || SafepointSynchronize::is_at_safepoint(), "invalid result at non safepoint"); return has_refs_into_cset; } void G1RemSet::print_periodic_summary_info(const char* header) { G1RemSetSummary current; current.initialize(this); _prev_period_summary.subtract_from(¤t); print_summary_info(&_prev_period_summary, header); _prev_period_summary.set(¤t); } void G1RemSet::print_summary_info() { G1RemSetSummary current; current.initialize(this); print_summary_info(¤t, " Cumulative RS summary"); } void G1RemSet::print_summary_info(G1RemSetSummary * summary, const char * header) { assert(summary != NULL, "just checking"); if (header != NULL) { gclog_or_tty->print_cr("%s", header); } #if CARD_REPEAT_HISTO gclog_or_tty->print_cr("\nG1 card_repeat count histogram: "); gclog_or_tty->print_cr(" # of repeats --> # of cards with that number."); card_repeat_count.print_on(gclog_or_tty); #endif summary->print_on(gclog_or_tty); } void G1RemSet::prepare_for_verify() { if (G1HRRSFlushLogBuffersOnVerify && (VerifyBeforeGC || VerifyAfterGC) && (!_g1->full_collection() || G1VerifyRSetsDuringFullGC)) { cleanupHRRS(); _g1->set_refine_cte_cl_concurrency(false); if (SafepointSynchronize::is_at_safepoint()) { DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); dcqs.concatenate_logs(); } G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache(); bool use_hot_card_cache = hot_card_cache->use_cache(); hot_card_cache->set_use_cache(false); DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set()); updateRS(&into_cset_dcq, 0); _g1->into_cset_dirty_card_queue_set().clear(); hot_card_cache->set_use_cache(use_hot_card_cache); assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed"); } }