/* * Copyright 2001-2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. * */ #include "incls/_precompiled.incl" #include "incls/_g1RemSet.cpp.incl" #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 class IntoCSOopClosure: public OopsInHeapRegionClosure { OopsInHeapRegionClosure* _blk; G1CollectedHeap* _g1; public: IntoCSOopClosure(G1CollectedHeap* g1, OopsInHeapRegionClosure* blk) : _g1(g1), _blk(blk) {} void set_region(HeapRegion* from) { _blk->set_region(from); } virtual void do_oop(narrowOop* p) { guarantee(false, "NYI"); } virtual void do_oop(oop* p) { oop obj = *p; if (_g1->obj_in_cs(obj)) _blk->do_oop(p); } bool apply_to_weak_ref_discovered_field() { return true; } bool idempotent() { return true; } }; class IntoCSRegionClosure: public HeapRegionClosure { IntoCSOopClosure _blk; G1CollectedHeap* _g1; public: IntoCSRegionClosure(G1CollectedHeap* g1, OopsInHeapRegionClosure* blk) : _g1(g1), _blk(g1, blk) {} bool doHeapRegion(HeapRegion* r) { if (!r->in_collection_set()) { _blk.set_region(r); if (r->isHumongous()) { if (r->startsHumongous()) { oop obj = oop(r->bottom()); obj->oop_iterate(&_blk); } } else { r->oop_before_save_marks_iterate(&_blk); } } return false; } }; void StupidG1RemSet::oops_into_collection_set_do(OopsInHeapRegionClosure* oc, int worker_i) { IntoCSRegionClosure rc(_g1, oc); _g1->heap_region_iterate(&rc); } class UpdateRSOutOfRegionClosure: public HeapRegionClosure { G1CollectedHeap* _g1h; ModRefBarrierSet* _mr_bs; UpdateRSOopClosure _cl; int _worker_i; public: UpdateRSOutOfRegionClosure(G1CollectedHeap* g1, int worker_i = 0) : _cl(g1->g1_rem_set()->as_HRInto_G1RemSet(), worker_i), _mr_bs(g1->mr_bs()), _worker_i(worker_i), _g1h(g1) {} bool doHeapRegion(HeapRegion* r) { if (!r->in_collection_set() && !r->continuesHumongous()) { _cl.set_from(r); r->set_next_filter_kind(HeapRegionDCTOC::OutOfRegionFilterKind); _mr_bs->mod_oop_in_space_iterate(r, &_cl, true, true); } return false; } }; class VerifyRSCleanCardOopClosure: public OopClosure { G1CollectedHeap* _g1; public: VerifyRSCleanCardOopClosure(G1CollectedHeap* g1) : _g1(g1) {} virtual void do_oop(narrowOop* p) { guarantee(false, "NYI"); } virtual void do_oop(oop* p) { oop obj = *p; HeapRegion* to = _g1->heap_region_containing(obj); guarantee(to == NULL || !to->in_collection_set(), "Missed a rem set member."); } }; HRInto_G1RemSet::HRInto_G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs) : G1RemSet(g1), _ct_bs(ct_bs), _g1p(_g1->g1_policy()), _cg1r(g1->concurrent_g1_refine()), _par_traversal_in_progress(false), _new_refs(NULL), _cards_scanned(NULL), _total_cards_scanned(0) { _seq_task = new SubTasksDone(NumSeqTasks); guarantee(n_workers() > 0, "There should be some workers"); _new_refs = NEW_C_HEAP_ARRAY(GrowableArray*, n_workers()); for (uint i = 0; i < n_workers(); i++) { _new_refs[i] = new (ResourceObj::C_HEAP) GrowableArray(8192,true); } } HRInto_G1RemSet::~HRInto_G1RemSet() { delete _seq_task; for (uint i = 0; i < n_workers(); i++) { delete _new_refs[i]; } FREE_C_HEAP_ARRAY(GrowableArray*, _new_refs); } 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; bool _try_claimed; size_t _min_skip_distance, _max_skip_distance; 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()); _min_skip_distance = 16; _max_skip_distance = 2 * _g1h->n_par_threads() * _min_skip_distance; } void set_try_claimed() { _try_claimed = true; } void scanCard(size_t index, HeapRegion *r) { _cards_done++; DirtyCardToOopClosure* cl = r->new_dcto_closure(_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; if (ParallelGCThreads > 0) { // first find the used area sm_region = sp->used_region_at_save_marks(); } else { // The closure is not idempotent. We shouldn't look at objects // allocated during the GC. sm_region = sp->used_region_at_save_marks(); } MemRegion mr = sm_region.intersection(MemRegion(card_start,card_end)); if (!mr.is_empty()) { 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 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; size_t skip_distance = 0, current_card = 0, jump_to_card = 0; while (iter->has_next(card_index)) { if (current_card < jump_to_card) { ++current_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 the card is dirty, then we will scan it during updateRS. if (!card_region->in_collection_set() && !_ct_bs->is_card_dirty(card_index)) { if (!_ct_bs->is_card_claimed(card_index) && _ct_bs->claim_card(card_index)) { scanCard(card_index, card_region); } else if (_try_claimed) { if (jump_to_card == 0 || jump_to_card != current_card) { // We did some useful work in the previous iteration. // Decrease the distance. skip_distance = MAX2(skip_distance >> 1, _min_skip_distance); } else { // Previous iteration resulted in a claim failure. // Increase the distance. skip_distance = MIN2(skip_distance << 1, _max_skip_distance); } jump_to_card = current_card + skip_distance; } } ++current_card; } if (!_try_claimed) { hrrs->set_iter_complete(); } return false; } // Set all cards back to clean. void cleanup() {_g1h->cleanUpCardTable();} size_t cards_done() { return _cards_done;} size_t cards_looked_up() { return _cards;} }; // We want the parallel threads to start their scanning at // different collection set regions to avoid contention. // If we have: // n collection set regions // p threads // Then thread t will start at region t * floor (n/p) HeapRegion* HRInto_G1RemSet::calculateStartRegion(int worker_i) { HeapRegion* result = _g1p->collection_set(); if (ParallelGCThreads > 0) { size_t cs_size = _g1p->collection_set_size(); int n_workers = _g1->workers()->total_workers(); size_t cs_spans = cs_size / n_workers; size_t ind = cs_spans * worker_i; for (size_t i = 0; i < ind; i++) result = result->next_in_collection_set(); } return result; } void HRInto_G1RemSet::scanRS(OopsInHeapRegionClosure* oc, int worker_i) { double rs_time_start = os::elapsedTime(); HeapRegion *startRegion = calculateStartRegion(worker_i); BufferingOopsInHeapRegionClosure boc(oc); ScanRSClosure scanRScl(&boc, worker_i); _g1->collection_set_iterate_from(startRegion, &scanRScl); scanRScl.set_try_claimed(); _g1->collection_set_iterate_from(startRegion, &scanRScl); boc.done(); double closure_app_time_sec = boc.closure_app_seconds(); double scan_rs_time_sec = (os::elapsedTime() - rs_time_start) - closure_app_time_sec; double closure_app_time_ms = closure_app_time_sec * 1000.0; assert( _cards_scanned != NULL, "invariant" ); _cards_scanned[worker_i] = scanRScl.cards_done(); _g1p->record_scan_rs_start_time(worker_i, rs_time_start * 1000.0); _g1p->record_scan_rs_time(worker_i, scan_rs_time_sec * 1000.0); double scan_new_refs_time_ms = _g1p->get_scan_new_refs_time(worker_i); if (scan_new_refs_time_ms > 0.0) { closure_app_time_ms += scan_new_refs_time_ms; } _g1p->record_obj_copy_time(worker_i, closure_app_time_ms); } void HRInto_G1RemSet::updateRS(int worker_i) { ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine(); double start = os::elapsedTime(); _g1p->record_update_rs_start_time(worker_i, start * 1000.0); if (G1RSBarrierUseQueue && !cg1r->do_traversal()) { // Apply the appropriate closure to all remaining log entries. _g1->iterate_dirty_card_closure(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."); } } else { UpdateRSOutOfRegionClosure update_rs(_g1, worker_i); _g1->heap_region_iterate(&update_rs); // We did a traversal; no further one is necessary. if (G1RSBarrierUseQueue) { assert(cg1r->do_traversal(), "Or we shouldn't have gotten here."); cg1r->set_pya_cancel(); } if (_cg1r->use_cache()) { _cg1r->clear_and_record_card_counts(); _cg1r->clear_hot_cache(); } } _g1p->record_update_rs_time(worker_i, (os::elapsedTime() - start) * 1000.0); } #ifndef PRODUCT class PrintRSClosure : public HeapRegionClosure { int _count; public: PrintRSClosure() : _count(0) {} bool doHeapRegion(HeapRegion* r) { HeapRegionRemSet* hrrs = r->rem_set(); _count += (int) hrrs->occupied(); if (hrrs->occupied() == 0) { gclog_or_tty->print("Heap Region [" PTR_FORMAT ", " PTR_FORMAT ") " "has no remset entries\n", r->bottom(), r->end()); } else { gclog_or_tty->print("Printing rem set for heap region [" PTR_FORMAT ", " PTR_FORMAT ")\n", r->bottom(), r->end()); r->print(); hrrs->print(); gclog_or_tty->print("\nDone printing rem set\n"); } return false; } int occupied() {return _count;} }; #endif 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 HRInto_G1RemSet::scanNewRefsRS(OopsInHeapRegionClosure* oc, int worker_i) { double scan_new_refs_start_sec = os::elapsedTime(); G1CollectedHeap* g1h = G1CollectedHeap::heap(); CardTableModRefBS* ct_bs = (CardTableModRefBS*) (g1h->barrier_set()); for (int i = 0; i < _new_refs[worker_i]->length(); i++) { oop* p = _new_refs[worker_i]->at(i); oop obj = *p; // *p was in the collection set when p was pushed on "_new_refs", but // another thread may have processed this location from an RS, so it // might not point into the CS any longer. If so, it's obviously been // processed, and we don't need to do anything further. if (g1h->obj_in_cs(obj)) { HeapRegion* r = g1h->heap_region_containing(p); DEBUG_ONLY(HeapRegion* to = g1h->heap_region_containing(obj)); oc->set_region(r); // If "p" has already been processed concurrently, this is // idempotent. oc->do_oop(p); } } _g1p->record_scan_new_refs_time(worker_i, (os::elapsedTime() - scan_new_refs_start_sec) * 1000.0); } void HRInto_G1RemSet::set_par_traversal(bool b) { _par_traversal_in_progress = b; HeapRegionRemSet::set_par_traversal(b); } void HRInto_G1RemSet::cleanupHRRS() { HeapRegionRemSet::cleanup(); } void HRInto_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(); } if (ParallelGCThreads > 0) { // 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 (G1ParallelRSetUpdatingEnabled || (worker_i == 0)) { updateRS(worker_i); scanNewRefsRS(oc, worker_i); } else { _g1p->record_update_rs_start_time(worker_i, os::elapsedTime()); _g1p->record_update_rs_processed_buffers(worker_i, 0.0); _g1p->record_update_rs_time(worker_i, 0.0); _g1p->record_scan_new_refs_time(worker_i, 0.0); } if (G1ParallelRSetScanningEnabled || (worker_i == 0)) { scanRS(oc, worker_i); } else { _g1p->record_scan_rs_start_time(worker_i, os::elapsedTime()); _g1p->record_scan_rs_time(worker_i, 0.0); } } else { assert(worker_i == 0, "invariant"); updateRS(0); scanNewRefsRS(oc, 0); scanRS(oc, 0); } } void HRInto_G1RemSet:: prepare_for_oops_into_collection_set_do() { #if G1_REM_SET_LOGGING PrintRSClosure cl; _g1->collection_set_iterate(&cl); #endif cleanupHRRS(); ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine(); _g1->set_refine_cte_cl_concurrency(false); DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); dcqs.concatenate_logs(); assert(!_par_traversal_in_progress, "Invariant between iterations."); if (ParallelGCThreads > 0) { set_par_traversal(true); _seq_task->set_par_threads((int)n_workers()); if (cg1r->do_traversal()) { updateRS(0); // Have to do this again after updaters cleanupHRRS(); } } guarantee( _cards_scanned == NULL, "invariant" ); _cards_scanned = NEW_C_HEAP_ARRAY(size_t, n_workers()); for (uint i = 0; i < n_workers(); ++i) { _cards_scanned[i] = 0; } _total_cards_scanned = 0; } class cleanUpIteratorsClosure : public HeapRegionClosure { bool doHeapRegion(HeapRegion *r) { HeapRegionRemSet* hrrs = r->rem_set(); hrrs->init_for_par_iteration(); return false; } }; class UpdateRSetOopsIntoCSImmediate : public OopClosure { G1CollectedHeap* _g1; public: UpdateRSetOopsIntoCSImmediate(G1CollectedHeap* g1) : _g1(g1) { } virtual void do_oop(narrowOop* p) { guarantee(false, "NYI"); } virtual void do_oop(oop* p) { HeapRegion* to = _g1->heap_region_containing(*p); if (to->in_collection_set()) { to->rem_set()->add_reference(p, 0); } } }; class UpdateRSetOopsIntoCSDeferred : public OopClosure { G1CollectedHeap* _g1; CardTableModRefBS* _ct_bs; DirtyCardQueue* _dcq; public: UpdateRSetOopsIntoCSDeferred(G1CollectedHeap* g1, DirtyCardQueue* dcq) : _g1(g1), _ct_bs((CardTableModRefBS*)_g1->barrier_set()), _dcq(dcq) { } virtual void do_oop(narrowOop* p) { guarantee(false, "NYI"); } virtual void do_oop(oop* p) { oop obj = *p; if (_g1->obj_in_cs(obj)) { size_t card_index = _ct_bs->index_for(p); if (_ct_bs->mark_card_deferred(card_index)) { _dcq->enqueue((jbyte*)_ct_bs->byte_for_index(card_index)); } } } }; void HRInto_G1RemSet::new_refs_iterate(OopClosure* cl) { for (size_t i = 0; i < n_workers(); i++) { for (int j = 0; j < _new_refs[i]->length(); j++) { oop* p = _new_refs[i]->at(j); cl->do_oop(p); } } } void HRInto_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 #if G1_REM_SET_LOGGING PrintRSClosure cl; _g1->heap_region_iterate(&cl); #endif _g1->set_refine_cte_cl_concurrency(true); cleanUpIteratorsClosure iterClosure; _g1->collection_set_iterate(&iterClosure); // Set all cards back to clean. _g1->cleanUpCardTable(); if (ParallelGCThreads > 0) { ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine(); if (cg1r->do_traversal()) { cg1r->cg1rThread()->set_do_traversal(false); } set_par_traversal(false); } if (_g1->evacuation_failed()) { // Restore remembered sets for the regions pointing into // the collection set. if (G1DeferredRSUpdate) { DirtyCardQueue dcq(&_g1->dirty_card_queue_set()); UpdateRSetOopsIntoCSDeferred deferred_update(_g1, &dcq); new_refs_iterate(&deferred_update); } else { UpdateRSetOopsIntoCSImmediate immediate_update(_g1); new_refs_iterate(&immediate_update); } } for (uint i = 0; i < n_workers(); i++) { _new_refs[i]->clear(); } assert(!_par_traversal_in_progress, "Invariant between iterations."); } class UpdateRSObjectClosure: public ObjectClosure { UpdateRSOopClosure* _update_rs_oop_cl; public: UpdateRSObjectClosure(UpdateRSOopClosure* update_rs_oop_cl) : _update_rs_oop_cl(update_rs_oop_cl) {} void do_object(oop obj) { obj->oop_iterate(_update_rs_oop_cl); } }; 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 HRInto_G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm) { ScrubRSClosure scrub_cl(region_bm, card_bm); _g1->heap_region_iterate(&scrub_cl); } void HRInto_G1RemSet::scrub_par(BitMap* region_bm, BitMap* card_bm, int worker_num, int claim_val) { ScrubRSClosure scrub_cl(region_bm, card_bm); _g1->heap_region_par_iterate_chunked(&scrub_cl, worker_num, claim_val); } class ConcRefineRegionClosure: public HeapRegionClosure { G1CollectedHeap* _g1h; CardTableModRefBS* _ctbs; ConcurrentGCThread* _cgc_thrd; ConcurrentG1Refine* _cg1r; unsigned _cards_processed; UpdateRSOopClosure _update_rs_oop_cl; public: ConcRefineRegionClosure(CardTableModRefBS* ctbs, ConcurrentG1Refine* cg1r, HRInto_G1RemSet* g1rs) : _ctbs(ctbs), _cg1r(cg1r), _cgc_thrd(cg1r->cg1rThread()), _update_rs_oop_cl(g1rs), _cards_processed(0), _g1h(G1CollectedHeap::heap()) {} bool doHeapRegion(HeapRegion* r) { if (!r->in_collection_set() && !r->continuesHumongous() && !r->is_young()) { _update_rs_oop_cl.set_from(r); UpdateRSObjectClosure update_rs_obj_cl(&_update_rs_oop_cl); // For each run of dirty card in the region: // 1) Clear the cards. // 2) Process the range corresponding to the run, adding any // necessary RS entries. // 1 must precede 2, so that a concurrent modification redirties the // card. If a processing attempt does not succeed, because it runs // into an unparseable region, we will do binary search to find the // beginning of the next parseable region. HeapWord* startAddr = r->bottom(); HeapWord* endAddr = r->used_region().end(); HeapWord* lastAddr; HeapWord* nextAddr; for (nextAddr = lastAddr = startAddr; nextAddr < endAddr; nextAddr = lastAddr) { MemRegion dirtyRegion; // Get and clear dirty region from card table MemRegion next_mr(nextAddr, endAddr); dirtyRegion = _ctbs->dirty_card_range_after_reset( next_mr, true, CardTableModRefBS::clean_card_val()); assert(dirtyRegion.start() >= nextAddr, "returned region inconsistent?"); if (!dirtyRegion.is_empty()) { HeapWord* stop_point = r->object_iterate_mem_careful(dirtyRegion, &update_rs_obj_cl); if (stop_point == NULL) { lastAddr = dirtyRegion.end(); _cards_processed += (int) (dirtyRegion.word_size() / CardTableModRefBS::card_size_in_words); } else { // We're going to skip one or more cards that we can't parse. HeapWord* next_parseable_card = r->next_block_start_careful(stop_point); // Round this up to a card boundary. next_parseable_card = _ctbs->addr_for(_ctbs->byte_after_const(next_parseable_card)); // Now we invalidate the intervening cards so we'll see them // again. MemRegion remaining_dirty = MemRegion(stop_point, dirtyRegion.end()); MemRegion skipped = MemRegion(stop_point, next_parseable_card); _ctbs->invalidate(skipped.intersection(remaining_dirty)); // Now start up again where we can parse. lastAddr = next_parseable_card; // Count how many we did completely. _cards_processed += (stop_point - dirtyRegion.start()) / CardTableModRefBS::card_size_in_words; } // Allow interruption at regular intervals. // (Might need to make them more regular, if we get big // dirty regions.) if (_cgc_thrd != NULL) { if (_cgc_thrd->should_yield()) { _cgc_thrd->yield(); switch (_cg1r->get_pya()) { case PYA_continue: // This may have changed: re-read. endAddr = r->used_region().end(); continue; case PYA_restart: case PYA_cancel: return true; } } } } else { break; } } } // A good yield opportunity. if (_cgc_thrd != NULL) { if (_cgc_thrd->should_yield()) { _cgc_thrd->yield(); switch (_cg1r->get_pya()) { case PYA_restart: case PYA_cancel: return true; default: break; } } } return false; } unsigned cards_processed() { return _cards_processed; } }; void HRInto_G1RemSet::concurrentRefinementPass(ConcurrentG1Refine* cg1r) { ConcRefineRegionClosure cr_cl(ct_bs(), cg1r, this); _g1->heap_region_iterate(&cr_cl); _conc_refine_traversals++; _conc_refine_cards += cr_cl.cards_processed(); } static IntHistogram out_of_histo(50, 50); void HRInto_G1RemSet::concurrentRefineOneCard(jbyte* card_ptr, int worker_i) { // If the card is no longer dirty, nothing to do. if (*card_ptr != CardTableModRefBS::dirty_card_val()) return; // 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?"); return; // 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; } // 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; } // Should we defer it? if (_cg1r->use_cache()) { card_ptr = _cg1r->cache_insert(card_ptr); // If it was not an eviction, nothing to do. if (card_ptr == NULL) return; // OK, we have to reset the card start, region, etc. start = _ct_bs->addr_for(card_ptr); r = _g1->heap_region_containing(start); if (r == NULL) { guarantee(_g1->is_in_permanent(start), "Or else where?"); return; // Not in the G1 heap (might be in perm, for example.) } guarantee(!r->is_young(), "It was evicted in the current minor cycle."); } HeapWord* end = _ct_bs->addr_for(card_ptr + 1); MemRegion dirtyRegion(start, end); #if CARD_REPEAT_HISTO init_ct_freq_table(_g1->g1_reserved_obj_bytes()); ct_freq_note_card(_ct_bs->index_for(start)); #endif UpdateRSOopClosure update_rs_oop_cl(this, worker_i); update_rs_oop_cl.set_from(r); FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r, &update_rs_oop_cl); // Undirty the card. *card_ptr = CardTableModRefBS::clean_card_val(); // We must complete this write before we do any of the reads below. OrderAccess::storeload(); // And process it, being careful of unallocated portions of TLAB's. HeapWord* stop_point = r->oops_on_card_seq_iterate_careful(dirtyRegion, &filter_then_update_rs_oop_cl); // 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++; } } 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; } }; void HRInto_G1RemSet::print_summary_info() { G1CollectedHeap* g1 = G1CollectedHeap::heap(); ConcurrentG1RefineThread* cg1r_thrd = g1->concurrent_g1_refine()->cg1rThread(); #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 in " "%5.2fs.", _conc_refine_cards, cg1r_thrd->vtime_accum()); 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 thread.", 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(" Did %d concurrent refinement traversals.", _conc_refine_traversals); if (!G1RSBarrierUseQueue) { gclog_or_tty->print_cr(" Scanned %8.2f cards/traversal.", _conc_refine_traversals > 0 ? (float)_conc_refine_cards/(float)_conc_refine_traversals : 0); } gclog_or_tty->print_cr(""); if (G1UseHRIntoRS) { 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 HRInto_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); updateRS(0); _cg1r->set_use_cache(cg1r_use_cache); assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed"); } }