diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/gc/g1/g1RemSet.hpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/hotspot/share/gc/g1/g1RemSet.hpp Tue Sep 12 19:03:39 2017 +0200 @@ -0,0 +1,215 @@ +/* + * Copyright (c) 2001, 2017, 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. + * + */ + +#ifndef SHARE_VM_GC_G1_G1REMSET_HPP +#define SHARE_VM_GC_G1_G1REMSET_HPP + +#include "gc/g1/dirtyCardQueue.hpp" +#include "gc/g1/g1CardLiveData.hpp" +#include "gc/g1/g1RemSetSummary.hpp" +#include "gc/g1/heapRegion.hpp" +#include "memory/allocation.hpp" +#include "memory/iterator.hpp" + +// A G1RemSet provides ways of iterating over pointers into a selected +// collection set. + +class BitMap; +class CardTableModRefBS; +class G1BlockOffsetTable; +class CodeBlobClosure; +class G1CollectedHeap; +class G1HotCardCache; +class G1RemSetScanState; +class G1ParScanThreadState; +class G1Policy; +class G1SATBCardTableModRefBS; +class G1ScanObjsDuringScanRSClosure; +class G1ScanObjsDuringUpdateRSClosure; +class HeapRegionClaimer; + +// A G1RemSet in which each heap region has a rem set that records the +// external heap references into it. Uses a mod ref bs to track updates, +// so that they can be used to update the individual region remsets. +class G1RemSet: public CHeapObj { +private: + G1RemSetScanState* _scan_state; + G1CardLiveData _card_live_data; + + G1RemSetSummary _prev_period_summary; + + // Scan all remembered sets of the collection set for references into the collection + // set. + void scan_rem_set(G1ParScanThreadState* pss, + CodeBlobClosure* heap_region_codeblobs, + uint worker_i); + + // Flush remaining refinement buffers for cross-region references to either evacuate references + // into the collection set or update the remembered set. + void update_rem_set(G1ParScanThreadState* pss, uint worker_i); + + G1CollectedHeap* _g1; + size_t _num_conc_refined_cards; // Number of cards refined concurrently to the mutator. + + CardTableModRefBS* _ct_bs; + G1Policy* _g1p; + G1HotCardCache* _hot_card_cache; + +public: + // Gives an approximation on how many threads can be expected to add records to + // a remembered set in parallel. This can be used for sizing data structures to + // decrease performance losses due to data structure sharing. + // Examples for quantities that influence this value are the maximum number of + // mutator threads, maximum number of concurrent refinement or GC threads. + static uint num_par_rem_sets(); + + // Initialize data that depends on the heap size being known. + void initialize(size_t capacity, uint max_regions); + + // This is called to reset dual hash tables after the gc pause + // is finished and the initial hash table is no longer being + // scanned. + void cleanupHRRS(); + + G1RemSet(G1CollectedHeap* g1, + CardTableModRefBS* ct_bs, + G1HotCardCache* hot_card_cache); + ~G1RemSet(); + + // Process all oops in the collection set from the cards in the refinement buffers and + // remembered sets using pss. + // + // Further applies heap_region_codeblobs on the oops of the unmarked nmethods on the strong code + // roots list for each region in the collection set. + void oops_into_collection_set_do(G1ParScanThreadState* pss, + CodeBlobClosure* heap_region_codeblobs, + uint worker_i); + + // Prepare for and cleanup after an oops_into_collection_set_do + // call. Must call each of these once before and after (in sequential + // code) any thread calls oops_into_collection_set_do. + void prepare_for_oops_into_collection_set_do(); + void cleanup_after_oops_into_collection_set_do(); + + G1RemSetScanState* scan_state() const { return _scan_state; } + + // Record, if necessary, the fact that *p (where "p" is in region "from", + // which is required to be non-NULL) has changed to a new non-NULL value. + template void par_write_ref(HeapRegion* from, T* p, uint tid); + + // Eliminates any remembered set entries that correspond to dead heap ranges. + void scrub(uint worker_num, HeapRegionClaimer* hrclaimer); + + // Refine the card corresponding to "card_ptr". Safe to be called concurrently + // to the mutator. + void refine_card_concurrently(jbyte* card_ptr, + uint worker_i); + + // Refine the card corresponding to "card_ptr", applying the given closure to + // all references found. Must only be called during gc. + // Returns whether the card has been scanned. + bool refine_card_during_gc(jbyte* card_ptr, G1ScanObjsDuringUpdateRSClosure* update_rs_cl); + + // Print accumulated summary info from the start of the VM. + void print_summary_info(); + + // Print accumulated summary info from the last time called. + void print_periodic_summary_info(const char* header, uint period_count); + + size_t num_conc_refined_cards() const { return _num_conc_refined_cards; } + + void create_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap); + void finalize_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap); + + // Verify that the liveness count data created concurrently matches one created + // during this safepoint. + void verify_card_live_data(WorkGang* workers, G1CMBitMap* actual_bitmap); + + void clear_card_live_data(WorkGang* workers); + +#ifdef ASSERT + void verify_card_live_data_is_clear(); +#endif +}; + +class G1ScanRSForRegionClosure : public HeapRegionClosure { + G1RemSetScanState* _scan_state; + + size_t _cards_scanned; + size_t _cards_claimed; + size_t _cards_skipped; + + G1CollectedHeap* _g1h; + + G1ScanObjsDuringScanRSClosure* _scan_objs_on_card_cl; + CodeBlobClosure* _code_root_cl; + + G1BlockOffsetTable* _bot; + G1SATBCardTableModRefBS *_ct_bs; + + double _strong_code_root_scan_time_sec; + uint _worker_i; + + void claim_card(size_t card_index, const uint region_idx_for_card); + void scan_card(MemRegion mr, uint region_idx_for_card); + void scan_strong_code_roots(HeapRegion* r); +public: + G1ScanRSForRegionClosure(G1RemSetScanState* scan_state, + G1ScanObjsDuringScanRSClosure* scan_obj_on_card, + CodeBlobClosure* code_root_cl, + uint worker_i); + + bool doHeapRegion(HeapRegion* r); + + double strong_code_root_scan_time_sec() { + return _strong_code_root_scan_time_sec; + } + + size_t cards_scanned() const { return _cards_scanned; } + size_t cards_claimed() const { return _cards_claimed; } + size_t cards_skipped() const { return _cards_skipped; } +}; + +class RebuildRSOopClosure: public ExtendedOopClosure { + HeapRegion* _from; + G1RemSet* _rs; + uint _worker_i; + + template void do_oop_work(T* p); + +public: + RebuildRSOopClosure(G1RemSet* rs, uint worker_i = 0) : + _from(NULL), _rs(rs), _worker_i(worker_i) + {} + + void set_from(HeapRegion* from) { + assert(from != NULL, "from region must be non-NULL"); + _from = from; + } + + virtual void do_oop(narrowOop* p) { do_oop_work(p); } + virtual void do_oop(oop* p) { do_oop_work(p); } +}; + +#endif // SHARE_VM_GC_G1_G1REMSET_HPP