--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/g1/g1RemSet.cpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,649 @@
+/*
+ * Copyright (c) 2001, 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/concurrentG1Refine.hpp"
+#include "gc/g1/concurrentG1RefineThread.hpp"
+#include "gc/g1/g1BlockOffsetTable.inline.hpp"
+#include "gc/g1/g1CollectedHeap.inline.hpp"
+#include "gc/g1/g1CollectorPolicy.hpp"
+#include "gc/g1/g1GCPhaseTimes.hpp"
+#include "gc/g1/g1HotCardCache.hpp"
+#include "gc/g1/g1OopClosures.inline.hpp"
+#include "gc/g1/g1RemSet.inline.hpp"
+#include "gc/g1/heapRegionManager.inline.hpp"
+#include "gc/g1/heapRegionRemSet.hpp"
+#include "memory/iterator.hpp"
+#include "oops/oop.inline.hpp"
+#include "utilities/globalDefinitions.hpp"
+#include "utilities/intHisto.hpp"
+#include "utilities/stack.inline.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()
+{
+ _cset_rs_update_cl = NEW_C_HEAP_ARRAY(G1ParPushHeapRSClosure*, 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() {
+ for (uint i = 0; i < n_workers(); i++) {
+ assert(_cset_rs_update_cl[i] == NULL, "it should be");
+ }
+ FREE_C_HEAP_ARRAY(G1ParPushHeapRSClosure*, _cset_rs_update_cl);
+}
+
+class ScanRSClosure : public HeapRegionClosure {
+ size_t _cards_done, _cards;
+ G1CollectedHeap* _g1h;
+
+ G1ParPushHeapRSClosure* _oc;
+ CodeBlobClosure* _code_root_cl;
+
+ G1BlockOffsetSharedArray* _bot_shared;
+ G1SATBCardTableModRefBS *_ct_bs;
+
+ double _strong_code_root_scan_time_sec;
+ uint _worker_i;
+ size_t _block_size;
+ bool _try_claimed;
+
+public:
+ ScanRSClosure(G1ParPushHeapRSClosure* oc,
+ CodeBlobClosure* code_root_cl,
+ uint 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<size_t>(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);
+
+ // Set the "from" region in the closure.
+ _oc->set_region(r);
+ MemRegion card_region(_bot_shared->address_for_index(index), G1BlockOffsetSharedArray::N_words);
+ MemRegion pre_gc_allocated(r->bottom(), r->scan_top());
+ MemRegion mr = pre_gc_allocated.intersection(card_region);
+ 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 %u Region [" PTR_FORMAT ", " PTR_FORMAT ") "
+ "RS names card " SIZE_FORMAT_HEX ": "
+ "[" PTR_FORMAT ", " PTR_FORMAT ")",
+ _worker_i,
+ p2i(card_region->bottom()), p2i(card_region->end()),
+ card_index,
+ p2i(card_start), p2i(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 reduce 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);
+ _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(G1ParPushHeapRSClosure* oc,
+ CodeBlobClosure* code_root_cl,
+ uint 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_time_secs(G1GCPhaseTimes::ScanRS, worker_i, scan_rs_time_sec);
+ _g1p->phase_times()->record_time_secs(G1GCPhaseTimes::CodeRoots, worker_i, scanRScl.strong_code_root_scan_time_sec());
+}
+
+// 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, uint 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 < 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, uint worker_i) {
+ G1GCParPhaseTimesTracker x(_g1p->phase_times(), G1GCPhaseTimes::UpdateRS, worker_i);
+ // 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);
+}
+
+void G1RemSet::cleanupHRRS() {
+ HeapRegionRemSet::cleanup();
+}
+
+void G1RemSet::oops_into_collection_set_do(G1ParPushHeapRSClosure* oc,
+ CodeBlobClosure* code_root_cl,
+ uint 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 < 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 RSet updates
+ DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set());
+
+ updateRS(&into_cset_dcq, worker_i);
+ scanRS(oc, code_root_cl, worker_i);
+
+ // 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();
+ _g1->set_refine_cte_cl_concurrency(false);
+ DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+ dcqs.concatenate_logs();
+
+ 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;
+}
+
+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);
+ _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()) {
+ double restore_remembered_set_start = os::elapsedTime();
+
+ // Restore remembered sets for the regions pointing into the collection set.
+ // We just need to transfer the completed buffers from the DirtyCardQueueSet
+ // used to hold cards that contain references that point into the collection set
+ // to the DCQS used to hold the deferred RS updates.
+ _g1->dirty_card_queue_set().merge_bufferlists(&into_cset_dcqs);
+ _g1->g1_policy()->phase_times()->record_evac_fail_restore_remsets((os::elapsedTime() - restore_remembered_set_start) * 1000.0);
+ }
+
+ // 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->is_continues_humongous()) {
+ r->rem_set()->scrub(_ctbs, _region_bm, _card_bm);
+ }
+ return false;
+ }
+};
+
+void G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer *hrclaimer) {
+ ScrubRSClosure scrub_cl(region_bm, card_bm);
+ _g1->heap_region_par_iterate(&scrub_cl, worker_num, hrclaimer);
+}
+
+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,
+ G1ParPushHeapRSClosure* push_ref_cl,
+ bool record_refs_into_cset,
+ uint 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, uint worker_i,
+ bool check_for_refs_into_cset) {
+ assert(_g1->is_in_exact(_ct_bs->addr_for(card_ptr)),
+ err_msg("Card at "PTR_FORMAT" index "SIZE_FORMAT" representing heap at "PTR_FORMAT" (%u) must be in committed heap",
+ p2i(card_ptr),
+ _ct_bs->index_for(_ct_bs->addr_for(card_ptr)),
+ p2i(_ct_bs->addr_for(card_ptr)),
+ _g1->addr_to_region(_ct_bs->addr_for(card_ptr))));
+
+ // 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);
+
+ // 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 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 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);
+
+ // 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
+
+ G1ParPushHeapRSClosure* 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");
+ }
+}