| /* |
| * Copyright (c) 2001, 2012, 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/g1OopClosures.inline.hpp" |
| #include "gc_implementation/g1/g1RemSet.inline.hpp" |
| #include "gc_implementation/g1/heapRegionSeq.inline.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) |
| { |
| _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; |
| } |
| } |
| |
| 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; |
| G1BlockOffsetSharedArray* _bot_shared; |
| CardTableModRefBS *_ct_bs; |
| int _worker_i; |
| int _block_size; |
| bool _try_claimed; |
| public: |
| ScanRSClosure(OopsInHeapRegionClosure* oc, int worker_i) : |
| _oc(oc), |
| _cards(0), |
| _cards_done(0), |
| _worker_i(worker_i), |
| _try_claimed(false) |
| { |
| _g1h = G1CollectedHeap::heap(); |
| _bot_shared = _g1h->bot_shared(); |
| _ct_bs = (CardTableModRefBS*) (_g1h->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); |
| } |
| |
| 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 = _g1h->rem_set_iterator(_worker_i); |
| hrrs->init_iterator(iter); |
| 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) { |
| hrrs->set_iter_complete(); |
| } |
| return false; |
| } |
| size_t cards_done() { return _cards_done;} |
| size_t cards_looked_up() { return _cards;} |
| }; |
| |
| void G1RemSet::scanRS(OopsInHeapRegionClosure* oc, int worker_i) { |
| double rs_time_start = os::elapsedTime(); |
| HeapRegion *startRegion = _g1->start_cset_region_for_worker(worker_i); |
| |
| ScanRSClosure scanRScl(oc, 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; |
| |
| assert( _cards_scanned != NULL, "invariant" ); |
| _cards_scanned[worker_i] = scanRScl.cards_done(); |
| |
| _g1p->record_scan_rs_time(worker_i, scan_rs_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->concurrentRefineOneCard(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->record_update_rs_time(worker_i, (os::elapsedTime() - start) * 1000.0); |
| } |
| |
| class CountRSSizeClosure: public HeapRegionClosure { |
| size_t _n; |
| size_t _tot; |
| size_t _max; |
| HeapRegion* _max_r; |
| enum { |
| N = 20, |
| MIN = 6 |
| }; |
| int _histo[N]; |
| public: |
| CountRSSizeClosure() : _n(0), _tot(0), _max(0), _max_r(NULL) { |
| for (int i = 0; i < N; i++) _histo[i] = 0; |
| } |
| bool doHeapRegion(HeapRegion* r) { |
| if (!r->continuesHumongous()) { |
| size_t occ = r->rem_set()->occupied(); |
| _n++; |
| _tot += occ; |
| if (occ > _max) { |
| _max = occ; |
| _max_r = r; |
| } |
| // Fit it into a histo bin. |
| int s = 1 << MIN; |
| int i = 0; |
| while (occ > (size_t) s && i < (N-1)) { |
| s = s << 1; |
| i++; |
| } |
| _histo[i]++; |
| } |
| return false; |
| } |
| size_t n() { return _n; } |
| size_t tot() { return _tot; } |
| size_t mx() { return _max; } |
| HeapRegion* mxr() { return _max_r; } |
| void print_histo() { |
| int mx = N; |
| while (mx >= 0) { |
| if (_histo[mx-1] > 0) break; |
| mx--; |
| } |
| gclog_or_tty->print_cr("Number of regions with given RS sizes:"); |
| gclog_or_tty->print_cr(" <= %8d %8d", 1 << MIN, _histo[0]); |
| for (int i = 1; i < mx-1; i++) { |
| gclog_or_tty->print_cr(" %8d - %8d %8d", |
| (1 << (MIN + i - 1)) + 1, |
| 1 << (MIN + i), |
| _histo[i]); |
| } |
| gclog_or_tty->print_cr(" > %8d %8d", (1 << (MIN+mx-2))+1, _histo[mx-1]); |
| } |
| }; |
| |
| void G1RemSet::cleanupHRRS() { |
| HeapRegionRemSet::cleanup(); |
| } |
| |
| void G1RemSet::oops_into_collection_set_do(OopsInHeapRegionClosure* oc, |
| int worker_i) { |
| #if CARD_REPEAT_HISTO |
| ct_freq_update_histo_and_reset(); |
| #endif |
| if (worker_i == 0) { |
| _cg1r->clear_and_record_card_counts(); |
| } |
| |
| // Make this into a command-line flag... |
| if (G1RSCountHisto && (ParallelGCThreads == 0 || worker_i == 0)) { |
| CountRSSizeClosure count_cl; |
| _g1->heap_region_iterate(&count_cl); |
| gclog_or_tty->print_cr("Avg of %d RS counts is %f, max is %d, " |
| "max region is " PTR_FORMAT, |
| count_cl.n(), (float)count_cl.tot()/(float)count_cl.n(), |
| count_cl.mx(), count_cl.mxr()); |
| count_cl.print_histo(); |
| } |
| |
| // 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->record_update_rs_processed_buffers(worker_i, 0.0); |
| _g1p->record_update_rs_time(worker_i, 0.0); |
| } |
| if (G1UseParallelRSetScanning || (worker_i == 0)) { |
| scanRS(oc, worker_i); |
| } else { |
| _g1p->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 |
| HeapWord* end = _ct_bs->addr_for(card_ptr + 1); |
| 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::concurrentRefineOneCard 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(NULL) |
| { |
| ModRefBarrierSet* bs = _g1h->mr_bs(); |
| guarantee(bs->is_a(BarrierSet::CardTableModRef), "Precondition"); |
| _ctbs = (CardTableModRefBS*)bs; |
| } |
| |
| 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); |
| } |
| |
| |
| static IntHistogram out_of_histo(50, 50); |
| |
| |
| 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) { } |
| |
| bool G1RemSet::concurrentRefineOneCard_impl(jbyte* card_ptr, int worker_i, |
| bool check_for_refs_into_cset) { |
| // 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"); |
| |
| HeapWord* end = _ct_bs->addr_for(card_ptr + 1); |
| 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 { |
| out_of_histo.add_entry(filter_then_update_rs_oop_cl.out_of_region()); |
| _conc_refine_cards++; |
| } |
| |
| return trigger_cl.triggered(); |
| } |
| |
| bool G1RemSet::concurrentRefineOneCard(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) { |
| guarantee(_g1->is_in_permanent(start), "Or else where?"); |
| // 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; |
| } |
| |
| // Should we defer processing the card? |
| // |
| // Previously the result from the insert_cache call would be |
| // either card_ptr (implying that card_ptr was currently "cold"), |
| // null (meaning we had inserted the card ptr into the "hot" |
| // cache, which had some headroom), or a "hot" card ptr |
| // extracted from the "hot" cache. |
| // |
| // Now that the _card_counts cache in the ConcurrentG1Refine |
| // instance is an evicting hash table, the result we get back |
| // could be from evicting the card ptr in an already occupied |
| // bucket (in which case we have replaced the card ptr in the |
| // bucket with card_ptr and "defer" is set to false). To avoid |
| // having a data structure (updates to which would need a lock) |
| // to hold these unprocessed dirty cards, we need to immediately |
| // process card_ptr. The actions needed to be taken on return |
| // from cache_insert are summarized in the following table: |
| // |
| // res defer action |
| // -------------------------------------------------------------- |
| // null false card evicted from _card_counts & replaced with |
| // card_ptr; evicted ptr added to hot cache. |
| // No need to process res; immediately process card_ptr |
| // |
| // null true card not evicted from _card_counts; card_ptr added |
| // to hot cache. |
| // Nothing to do. |
| // |
| // non-null false card evicted from _card_counts & replaced with |
| // card_ptr; evicted ptr is currently "cold" or |
| // caused an eviction from the hot cache. |
| // Immediately process res; process card_ptr. |
| // |
| // non-null true card not evicted from _card_counts; card_ptr is |
| // currently cold, or caused an eviction from hot |
| // cache. |
| // Immediately process res; no need to process card_ptr. |
| |
| |
| jbyte* res = card_ptr; |
| bool defer = false; |
| |
| // This gets set to true if the card being refined has references |
| // that point into the collection set. |
| bool oops_into_cset = false; |
| |
| if (_cg1r->use_cache()) { |
| jbyte* res = _cg1r->cache_insert(card_ptr, &defer); |
| if (res != NULL && (res != card_ptr || defer)) { |
| start = _ct_bs->addr_for(res); |
| r = _g1->heap_region_containing(start); |
| if (r == NULL) { |
| assert(_g1->is_in_permanent(start), "Or else where?"); |
| } else { |
| // 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. |
| // |
| // Process card pointer we get back from the hot card cache. This |
| // will check whether the region containing the card is young |
| // _after_ checking that the region has been allocated from. |
| oops_into_cset = concurrentRefineOneCard_impl(res, worker_i, |
| false /* check_for_refs_into_cset */); |
| // The above call to concurrentRefineOneCard_impl is only |
| // performed if the hot card cache is enabled. This cache is |
| // disabled during an evacuation pause - which is the only |
| // time when we need know if the card contains references |
| // that point into the collection set. Also when the hot card |
| // cache is enabled, this code is executed by the concurrent |
| // refine threads - rather than the GC worker threads - and |
| // concurrentRefineOneCard_impl will return false. |
| assert(!oops_into_cset, "should not see true here"); |
| } |
| } |
| } |
| |
| if (!defer) { |
| oops_into_cset = |
| concurrentRefineOneCard_impl(card_ptr, worker_i, check_for_refs_into_cset); |
| // 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(!oops_into_cset || SafepointSynchronize::is_at_safepoint(), |
| "invalid result at non safepoint"); |
| } |
| return oops_into_cset; |
| } |
| |
| class HRRSStatsIter: public HeapRegionClosure { |
| size_t _occupied; |
| size_t _total_mem_sz; |
| size_t _max_mem_sz; |
| HeapRegion* _max_mem_sz_region; |
| public: |
| HRRSStatsIter() : |
| _occupied(0), |
| _total_mem_sz(0), |
| _max_mem_sz(0), |
| _max_mem_sz_region(NULL) |
| {} |
| |
| bool doHeapRegion(HeapRegion* r) { |
| if (r->continuesHumongous()) return false; |
| size_t mem_sz = r->rem_set()->mem_size(); |
| if (mem_sz > _max_mem_sz) { |
| _max_mem_sz = mem_sz; |
| _max_mem_sz_region = r; |
| } |
| _total_mem_sz += mem_sz; |
| size_t occ = r->rem_set()->occupied(); |
| _occupied += occ; |
| return false; |
| } |
| size_t total_mem_sz() { return _total_mem_sz; } |
| size_t max_mem_sz() { return _max_mem_sz; } |
| size_t occupied() { return _occupied; } |
| HeapRegion* max_mem_sz_region() { return _max_mem_sz_region; } |
| }; |
| |
| class PrintRSThreadVTimeClosure : public ThreadClosure { |
| public: |
| virtual void do_thread(Thread *t) { |
| ConcurrentG1RefineThread* crt = (ConcurrentG1RefineThread*) t; |
| gclog_or_tty->print(" %5.2f", crt->vtime_accum()); |
| } |
| }; |
| |
| void G1RemSet::print_summary_info() { |
| G1CollectedHeap* g1 = G1CollectedHeap::heap(); |
| |
| #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 |
| |
| if (FILTEROUTOFREGIONCLOSURE_DOHISTOGRAMCOUNT) { |
| gclog_or_tty->print_cr("\nG1 rem-set out-of-region histogram: "); |
| gclog_or_tty->print_cr(" # of CS ptrs --> # of cards with that number."); |
| out_of_histo.print_on(gclog_or_tty); |
| } |
| gclog_or_tty->print_cr("\n Concurrent RS processed %d cards", |
| _conc_refine_cards); |
| DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); |
| jint tot_processed_buffers = |
| dcqs.processed_buffers_mut() + dcqs.processed_buffers_rs_thread(); |
| gclog_or_tty->print_cr(" Of %d completed buffers:", tot_processed_buffers); |
| gclog_or_tty->print_cr(" %8d (%5.1f%%) by conc RS threads.", |
| dcqs.processed_buffers_rs_thread(), |
| 100.0*(float)dcqs.processed_buffers_rs_thread()/ |
| (float)tot_processed_buffers); |
| gclog_or_tty->print_cr(" %8d (%5.1f%%) by mutator threads.", |
| dcqs.processed_buffers_mut(), |
| 100.0*(float)dcqs.processed_buffers_mut()/ |
| (float)tot_processed_buffers); |
| gclog_or_tty->print_cr(" Conc RS threads times(s)"); |
| PrintRSThreadVTimeClosure p; |
| gclog_or_tty->print(" "); |
| g1->concurrent_g1_refine()->threads_do(&p); |
| gclog_or_tty->print_cr(""); |
| |
| HRRSStatsIter blk; |
| g1->heap_region_iterate(&blk); |
| gclog_or_tty->print_cr(" Total heap region rem set sizes = " SIZE_FORMAT "K." |
| " Max = " SIZE_FORMAT "K.", |
| blk.total_mem_sz()/K, blk.max_mem_sz()/K); |
| gclog_or_tty->print_cr(" Static structures = " SIZE_FORMAT "K," |
| " free_lists = " SIZE_FORMAT "K.", |
| HeapRegionRemSet::static_mem_size()/K, |
| HeapRegionRemSet::fl_mem_size()/K); |
| gclog_or_tty->print_cr(" %d occupied cards represented.", |
| blk.occupied()); |
| gclog_or_tty->print_cr(" Max sz region = [" PTR_FORMAT ", " PTR_FORMAT " )" |
| ", cap = " SIZE_FORMAT "K, occ = " SIZE_FORMAT "K.", |
| blk.max_mem_sz_region()->bottom(), blk.max_mem_sz_region()->end(), |
| (blk.max_mem_sz_region()->rem_set()->mem_size() + K - 1)/K, |
| (blk.max_mem_sz_region()->rem_set()->occupied() + K - 1)/K); |
| gclog_or_tty->print_cr(" Did %d coarsenings.", HeapRegionRemSet::n_coarsenings()); |
| } |
| |
| void G1RemSet::prepare_for_verify() { |
| if (G1HRRSFlushLogBuffersOnVerify && |
| (VerifyBeforeGC || VerifyAfterGC) |
| && !_g1->full_collection()) { |
| cleanupHRRS(); |
| _g1->set_refine_cte_cl_concurrency(false); |
| if (SafepointSynchronize::is_at_safepoint()) { |
| DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); |
| dcqs.concatenate_logs(); |
| } |
| bool cg1r_use_cache = _cg1r->use_cache(); |
| _cg1r->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(); |
| _cg1r->set_use_cache(cg1r_use_cache); |
| |
| assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed"); |
| } |
| } |
