1717 lines
65 KiB
C++
1717 lines
65 KiB
C++
/*
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* Copyright (c) 2001, 2020, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#include "precompiled.hpp"
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#include "gc/g1/g1BarrierSet.hpp"
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#include "gc/g1/g1BlockOffsetTable.inline.hpp"
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#include "gc/g1/g1CardTable.inline.hpp"
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#include "gc/g1/g1CardTableEntryClosure.hpp"
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#include "gc/g1/g1CollectedHeap.inline.hpp"
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#include "gc/g1/g1ConcurrentRefine.hpp"
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#include "gc/g1/g1DirtyCardQueue.hpp"
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#include "gc/g1/g1FromCardCache.hpp"
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#include "gc/g1/g1GCParPhaseTimesTracker.hpp"
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#include "gc/g1/g1GCPhaseTimes.hpp"
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#include "gc/g1/g1HotCardCache.hpp"
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#include "gc/g1/g1OopClosures.inline.hpp"
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#include "gc/g1/g1RootClosures.hpp"
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#include "gc/g1/g1RemSet.hpp"
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#include "gc/g1/g1SharedDirtyCardQueue.hpp"
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#include "gc/g1/heapRegion.inline.hpp"
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#include "gc/g1/heapRegionManager.inline.hpp"
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#include "gc/g1/heapRegionRemSet.inline.hpp"
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#include "gc/g1/sparsePRT.hpp"
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#include "gc/shared/gcTraceTime.inline.hpp"
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#include "gc/shared/ptrQueue.hpp"
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#include "gc/shared/suspendibleThreadSet.hpp"
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#include "jfr/jfrEvents.hpp"
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#include "memory/iterator.hpp"
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#include "memory/resourceArea.hpp"
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#include "oops/access.inline.hpp"
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#include "oops/oop.inline.hpp"
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#include "runtime/atomic.hpp"
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#include "runtime/os.hpp"
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#include "utilities/align.hpp"
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#include "utilities/globalDefinitions.hpp"
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#include "utilities/stack.inline.hpp"
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#include "utilities/ticks.hpp"
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// Collects information about the overall heap root scan progress during an evacuation.
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//
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// Scanning the remembered sets works by first merging all sources of cards to be
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// scanned (log buffers, hcc, remembered sets) into a single data structure to remove
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// duplicates and simplify work distribution.
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//
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// During the following card scanning we not only scan this combined set of cards, but
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// also remember that these were completely scanned. The following evacuation passes
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// do not scan these cards again, and so need to be preserved across increments.
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//
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// The representation for all the cards to scan is the card table: cards can have
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// one of three states during GC:
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// - clean: these cards will not be scanned in this pass
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// - dirty: these cards will be scanned in this pass
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// - scanned: these cards have already been scanned in a previous pass
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//
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// After all evacuation is done, we reset the card table to clean.
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//
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// Work distribution occurs on "chunk" basis, i.e. contiguous ranges of cards. As an
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// additional optimization, during card merging we remember which regions and which
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// chunks actually contain cards to be scanned. Threads iterate only across these
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// regions, and only compete for chunks containing any cards.
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//
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// Within these chunks, a worker scans the card table on "blocks" of cards, i.e.
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// contiguous ranges of dirty cards to be scanned. These blocks are converted to actual
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// memory ranges and then passed on to actual scanning.
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class G1RemSetScanState : public CHeapObj<mtGC> {
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class G1DirtyRegions;
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size_t _max_regions;
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// Has this region that is part of the regions in the collection set been processed yet.
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typedef bool G1RemsetIterState;
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G1RemsetIterState volatile* _collection_set_iter_state;
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// Card table iteration claim for each heap region, from 0 (completely unscanned)
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// to (>=) HeapRegion::CardsPerRegion (completely scanned).
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uint volatile* _card_table_scan_state;
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// Return "optimal" number of chunks per region we want to use for claiming areas
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// within a region to claim. Dependent on the region size as proxy for the heap
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// size, we limit the total number of chunks to limit memory usage and maintenance
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// effort of that table vs. granularity of distributing scanning work.
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// Testing showed that 8 for 1M/2M region, 16 for 4M/8M regions, 32 for 16/32M regions
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// seems to be such a good trade-off.
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static uint get_chunks_per_region(uint log_region_size) {
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// Limit the expected input values to current known possible values of the
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// (log) region size. Adjust as necessary after testing if changing the permissible
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// values for region size.
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assert(log_region_size >= 20 && log_region_size <= 25,
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"expected value in [20,25], but got %u", log_region_size);
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return 1u << (log_region_size / 2 - 7);
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}
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uint _scan_chunks_per_region; // Number of chunks per region.
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uint8_t _log_scan_chunks_per_region; // Log of number of chunks per region.
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bool* _region_scan_chunks;
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size_t _num_total_scan_chunks; // Total number of elements in _region_scan_chunks.
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uint8_t _scan_chunks_shift; // For conversion between card index and chunk index.
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public:
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uint scan_chunk_size() const { return (uint)1 << _scan_chunks_shift; }
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// Returns whether the chunk corresponding to the given region/card in region contain a
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// dirty card, i.e. actually needs scanning.
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bool chunk_needs_scan(uint const region_idx, uint const card_in_region) const {
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size_t const idx = ((size_t)region_idx << _log_scan_chunks_per_region) + (card_in_region >> _scan_chunks_shift);
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assert(idx < _num_total_scan_chunks, "Index " SIZE_FORMAT " out of bounds " SIZE_FORMAT,
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idx, _num_total_scan_chunks);
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return _region_scan_chunks[idx];
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}
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private:
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// The complete set of regions which card table needs to be cleared at the end of GC because
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// we scribbled all over them.
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G1DirtyRegions* _all_dirty_regions;
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// The set of regions which card table needs to be scanned for new dirty cards
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// in the current evacuation pass.
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G1DirtyRegions* _next_dirty_regions;
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// Set of (unique) regions that can be added to concurrently.
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class G1DirtyRegions : public CHeapObj<mtGC> {
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uint* _buffer;
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uint _cur_idx;
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size_t _max_regions;
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bool* _contains;
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public:
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G1DirtyRegions(size_t max_regions) :
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_buffer(NEW_C_HEAP_ARRAY(uint, max_regions, mtGC)),
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_cur_idx(0),
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_max_regions(max_regions),
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_contains(NEW_C_HEAP_ARRAY(bool, max_regions, mtGC)) {
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reset();
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}
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static size_t chunk_size() { return M; }
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~G1DirtyRegions() {
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FREE_C_HEAP_ARRAY(uint, _buffer);
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FREE_C_HEAP_ARRAY(bool, _contains);
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}
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void reset() {
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_cur_idx = 0;
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::memset(_contains, false, _max_regions * sizeof(bool));
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}
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uint size() const { return _cur_idx; }
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uint at(uint idx) const {
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assert(idx < _cur_idx, "Index %u beyond valid regions", idx);
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return _buffer[idx];
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}
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void add_dirty_region(uint region) {
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if (_contains[region]) {
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return;
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}
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bool marked_as_dirty = Atomic::cmpxchg(&_contains[region], false, true) == false;
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if (marked_as_dirty) {
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uint allocated = Atomic::fetch_and_add(&_cur_idx, 1u);
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_buffer[allocated] = region;
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}
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}
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// Creates the union of this and the other G1DirtyRegions.
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void merge(const G1DirtyRegions* other) {
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for (uint i = 0; i < other->size(); i++) {
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uint region = other->at(i);
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if (!_contains[region]) {
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_buffer[_cur_idx++] = region;
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_contains[region] = true;
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}
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}
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}
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};
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// For each region, contains the maximum top() value to be used during this garbage
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// collection. Subsumes common checks like filtering out everything but old and
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// humongous regions outside the collection set.
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// This is valid because we are not interested in scanning stray remembered set
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// entries from free or archive regions.
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HeapWord** _scan_top;
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class G1ClearCardTableTask : public AbstractGangTask {
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G1CollectedHeap* _g1h;
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G1DirtyRegions* _regions;
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uint _chunk_length;
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uint volatile _cur_dirty_regions;
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G1RemSetScanState* _scan_state;
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public:
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G1ClearCardTableTask(G1CollectedHeap* g1h,
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G1DirtyRegions* regions,
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uint chunk_length,
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G1RemSetScanState* scan_state) :
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AbstractGangTask("G1 Clear Card Table Task"),
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_g1h(g1h),
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_regions(regions),
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_chunk_length(chunk_length),
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_cur_dirty_regions(0),
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_scan_state(scan_state) {
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assert(chunk_length > 0, "must be");
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}
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static uint chunk_size() { return M; }
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void work(uint worker_id) {
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while (_cur_dirty_regions < _regions->size()) {
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uint next = Atomic::fetch_and_add(&_cur_dirty_regions, _chunk_length);
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uint max = MIN2(next + _chunk_length, _regions->size());
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for (uint i = next; i < max; i++) {
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HeapRegion* r = _g1h->region_at(_regions->at(i));
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if (!r->is_survivor()) {
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r->clear_cardtable();
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}
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}
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}
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}
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};
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// Clear the card table of "dirty" regions.
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void clear_card_table(WorkGang* workers) {
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uint num_regions = _all_dirty_regions->size();
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if (num_regions == 0) {
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return;
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}
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uint const num_chunks = (uint)(align_up((size_t)num_regions << HeapRegion::LogCardsPerRegion, G1ClearCardTableTask::chunk_size()) / G1ClearCardTableTask::chunk_size());
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uint const num_workers = MIN2(num_chunks, workers->active_workers());
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uint const chunk_length = G1ClearCardTableTask::chunk_size() / (uint)HeapRegion::CardsPerRegion;
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// Iterate over the dirty cards region list.
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G1ClearCardTableTask cl(G1CollectedHeap::heap(), _all_dirty_regions, chunk_length, this);
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log_debug(gc, ergo)("Running %s using %u workers for %u "
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"units of work for %u regions.",
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cl.name(), num_workers, num_chunks, num_regions);
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workers->run_task(&cl, num_workers);
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#ifndef PRODUCT
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G1CollectedHeap::heap()->verifier()->verify_card_table_cleanup();
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#endif
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}
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public:
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G1RemSetScanState() :
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_max_regions(0),
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_collection_set_iter_state(NULL),
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_card_table_scan_state(NULL),
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_scan_chunks_per_region(get_chunks_per_region(HeapRegion::LogOfHRGrainBytes)),
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_log_scan_chunks_per_region(log2_uint(_scan_chunks_per_region)),
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_region_scan_chunks(NULL),
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_num_total_scan_chunks(0),
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_scan_chunks_shift(0),
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_all_dirty_regions(NULL),
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_next_dirty_regions(NULL),
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_scan_top(NULL) {
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}
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~G1RemSetScanState() {
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FREE_C_HEAP_ARRAY(G1RemsetIterState, _collection_set_iter_state);
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FREE_C_HEAP_ARRAY(uint, _card_table_scan_state);
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FREE_C_HEAP_ARRAY(bool, _region_scan_chunks);
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FREE_C_HEAP_ARRAY(HeapWord*, _scan_top);
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}
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void initialize(size_t max_regions) {
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assert(_collection_set_iter_state == NULL, "Must not be initialized twice");
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_max_regions = max_regions;
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_collection_set_iter_state = NEW_C_HEAP_ARRAY(G1RemsetIterState, max_regions, mtGC);
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_card_table_scan_state = NEW_C_HEAP_ARRAY(uint, max_regions, mtGC);
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_num_total_scan_chunks = max_regions * _scan_chunks_per_region;
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_region_scan_chunks = NEW_C_HEAP_ARRAY(bool, _num_total_scan_chunks, mtGC);
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_scan_chunks_shift = (uint8_t)log2_intptr(HeapRegion::CardsPerRegion / _scan_chunks_per_region);
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_scan_top = NEW_C_HEAP_ARRAY(HeapWord*, max_regions, mtGC);
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}
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void prepare() {
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// Reset the claim and clear scan top for all regions, including
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// regions currently not available or free. Since regions might
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// become used during the collection these values must be valid
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// for those regions as well.
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for (size_t i = 0; i < _max_regions; i++) {
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reset_region_claim((uint)i);
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clear_scan_top((uint)i);
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}
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_all_dirty_regions = new G1DirtyRegions(_max_regions);
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_next_dirty_regions = new G1DirtyRegions(_max_regions);
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}
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void prepare_for_merge_heap_roots() {
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_all_dirty_regions->merge(_next_dirty_regions);
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_next_dirty_regions->reset();
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for (size_t i = 0; i < _max_regions; i++) {
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_card_table_scan_state[i] = 0;
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}
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::memset(_region_scan_chunks, false, _num_total_scan_chunks * sizeof(*_region_scan_chunks));
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}
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// Returns whether the given region contains cards we need to scan. The remembered
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// set and other sources may contain cards that
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// - are in uncommitted regions
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// - are located in the collection set
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// - are located in free regions
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// as we do not clean up remembered sets before merging heap roots.
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bool contains_cards_to_process(uint const region_idx) const {
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HeapRegion* hr = G1CollectedHeap::heap()->region_at_or_null(region_idx);
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return (hr != NULL && !hr->in_collection_set() && hr->is_old_or_humongous_or_archive());
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}
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size_t num_visited_cards() const {
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size_t result = 0;
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for (uint i = 0; i < _num_total_scan_chunks; i++) {
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if (_region_scan_chunks[i]) {
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result++;
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}
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}
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return result * (HeapRegion::CardsPerRegion / _scan_chunks_per_region);
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}
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size_t num_cards_in_dirty_regions() const {
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return _next_dirty_regions->size() * HeapRegion::CardsPerRegion;
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}
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void set_chunk_region_dirty(size_t const region_card_idx) {
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size_t chunk_idx = region_card_idx >> _scan_chunks_shift;
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for (uint i = 0; i < _scan_chunks_per_region; i++) {
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_region_scan_chunks[chunk_idx++] = true;
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}
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}
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void set_chunk_dirty(size_t const card_idx) {
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assert((card_idx >> _scan_chunks_shift) < _num_total_scan_chunks,
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"Trying to access index " SIZE_FORMAT " out of bounds " SIZE_FORMAT,
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card_idx >> _scan_chunks_shift, _num_total_scan_chunks);
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size_t const chunk_idx = card_idx >> _scan_chunks_shift;
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if (!_region_scan_chunks[chunk_idx]) {
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_region_scan_chunks[chunk_idx] = true;
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}
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}
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void cleanup(WorkGang* workers) {
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_all_dirty_regions->merge(_next_dirty_regions);
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clear_card_table(workers);
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delete _all_dirty_regions;
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_all_dirty_regions = NULL;
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delete _next_dirty_regions;
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_next_dirty_regions = NULL;
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}
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void iterate_dirty_regions_from(HeapRegionClosure* cl, uint worker_id) {
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uint num_regions = _next_dirty_regions->size();
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if (num_regions == 0) {
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return;
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}
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G1CollectedHeap* g1h = G1CollectedHeap::heap();
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WorkGang* workers = g1h->workers();
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uint const max_workers = workers->active_workers();
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uint const start_pos = num_regions * worker_id / max_workers;
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uint cur = start_pos;
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do {
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bool result = cl->do_heap_region(g1h->region_at(_next_dirty_regions->at(cur)));
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guarantee(!result, "Not allowed to ask for early termination.");
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cur++;
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if (cur == _next_dirty_regions->size()) {
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cur = 0;
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}
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} while (cur != start_pos);
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}
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void reset_region_claim(uint region_idx) {
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_collection_set_iter_state[region_idx] = false;
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}
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// Attempt to claim the given region in the collection set for iteration. Returns true
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// if this call caused the transition from Unclaimed to Claimed.
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inline bool claim_collection_set_region(uint region) {
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assert(region < _max_regions, "Tried to access invalid region %u", region);
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if (_collection_set_iter_state[region]) {
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return false;
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}
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return !Atomic::cmpxchg(&_collection_set_iter_state[region], false, true);
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}
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bool has_cards_to_scan(uint region) {
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assert(region < _max_regions, "Tried to access invalid region %u", region);
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return _card_table_scan_state[region] < HeapRegion::CardsPerRegion;
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}
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uint claim_cards_to_scan(uint region, uint increment) {
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assert(region < _max_regions, "Tried to access invalid region %u", region);
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return Atomic::fetch_and_add(&_card_table_scan_state[region], increment);
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}
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void add_dirty_region(uint const region) {
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#ifdef ASSERT
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HeapRegion* hr = G1CollectedHeap::heap()->region_at(region);
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assert(!hr->in_collection_set() && hr->is_old_or_humongous_or_archive(),
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"Region %u is not suitable for scanning, is %sin collection set or %s",
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hr->hrm_index(), hr->in_collection_set() ? "" : "not ", hr->get_short_type_str());
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#endif
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_next_dirty_regions->add_dirty_region(region);
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}
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void add_all_dirty_region(uint region) {
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#ifdef ASSERT
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HeapRegion* hr = G1CollectedHeap::heap()->region_at(region);
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assert(hr->in_collection_set(),
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"Only add young regions to all dirty regions directly but %u is %s",
|
|
hr->hrm_index(), hr->get_short_type_str());
|
|
#endif
|
|
_all_dirty_regions->add_dirty_region(region);
|
|
}
|
|
|
|
void set_scan_top(uint region_idx, HeapWord* value) {
|
|
_scan_top[region_idx] = value;
|
|
}
|
|
|
|
HeapWord* scan_top(uint region_idx) const {
|
|
return _scan_top[region_idx];
|
|
}
|
|
|
|
void clear_scan_top(uint region_idx) {
|
|
set_scan_top(region_idx, NULL);
|
|
}
|
|
};
|
|
|
|
G1RemSet::G1RemSet(G1CollectedHeap* g1h,
|
|
G1CardTable* ct,
|
|
G1HotCardCache* hot_card_cache) :
|
|
_scan_state(new G1RemSetScanState()),
|
|
_prev_period_summary(false),
|
|
_g1h(g1h),
|
|
_ct(ct),
|
|
_g1p(_g1h->policy()),
|
|
_hot_card_cache(hot_card_cache) {
|
|
}
|
|
|
|
G1RemSet::~G1RemSet() {
|
|
delete _scan_state;
|
|
}
|
|
|
|
uint G1RemSet::num_par_rem_sets() {
|
|
return G1DirtyCardQueueSet::num_par_ids() + G1ConcurrentRefine::max_num_threads() + MAX2(ConcGCThreads, ParallelGCThreads);
|
|
}
|
|
|
|
void G1RemSet::initialize(size_t capacity, uint max_regions) {
|
|
G1FromCardCache::initialize(num_par_rem_sets(), max_regions);
|
|
_scan_state->initialize(max_regions);
|
|
}
|
|
|
|
// Helper class to scan and detect ranges of cards that need to be scanned on the
|
|
// card table.
|
|
class G1CardTableScanner : public StackObj {
|
|
public:
|
|
typedef CardTable::CardValue CardValue;
|
|
|
|
private:
|
|
CardValue* const _base_addr;
|
|
|
|
CardValue* _cur_addr;
|
|
CardValue* const _end_addr;
|
|
|
|
static const size_t ToScanMask = G1CardTable::g1_card_already_scanned;
|
|
static const size_t ExpandedToScanMask = G1CardTable::WordAlreadyScanned;
|
|
|
|
bool cur_addr_aligned() const {
|
|
return ((uintptr_t)_cur_addr) % sizeof(size_t) == 0;
|
|
}
|
|
|
|
bool cur_card_is_dirty() const {
|
|
CardValue value = *_cur_addr;
|
|
return (value & ToScanMask) == 0;
|
|
}
|
|
|
|
bool cur_word_of_cards_contains_any_dirty_card() const {
|
|
assert(cur_addr_aligned(), "Current address should be aligned");
|
|
size_t const value = *(size_t*)_cur_addr;
|
|
return (~value & ExpandedToScanMask) != 0;
|
|
}
|
|
|
|
bool cur_word_of_cards_all_dirty_cards() const {
|
|
size_t const value = *(size_t*)_cur_addr;
|
|
return value == G1CardTable::WordAllDirty;
|
|
}
|
|
|
|
size_t get_and_advance_pos() {
|
|
_cur_addr++;
|
|
return pointer_delta(_cur_addr, _base_addr, sizeof(CardValue)) - 1;
|
|
}
|
|
|
|
public:
|
|
G1CardTableScanner(CardValue* start_card, size_t size) :
|
|
_base_addr(start_card),
|
|
_cur_addr(start_card),
|
|
_end_addr(start_card + size) {
|
|
|
|
assert(is_aligned(start_card, sizeof(size_t)), "Unaligned start addr " PTR_FORMAT, p2i(start_card));
|
|
assert(is_aligned(size, sizeof(size_t)), "Unaligned size " SIZE_FORMAT, size);
|
|
}
|
|
|
|
size_t find_next_dirty() {
|
|
while (!cur_addr_aligned()) {
|
|
if (cur_card_is_dirty()) {
|
|
return get_and_advance_pos();
|
|
}
|
|
_cur_addr++;
|
|
}
|
|
|
|
assert(cur_addr_aligned(), "Current address should be aligned now.");
|
|
while (_cur_addr != _end_addr) {
|
|
if (cur_word_of_cards_contains_any_dirty_card()) {
|
|
for (size_t i = 0; i < sizeof(size_t); i++) {
|
|
if (cur_card_is_dirty()) {
|
|
return get_and_advance_pos();
|
|
}
|
|
_cur_addr++;
|
|
}
|
|
assert(false, "Should not reach here given we detected a dirty card in the word.");
|
|
}
|
|
_cur_addr += sizeof(size_t);
|
|
}
|
|
return get_and_advance_pos();
|
|
}
|
|
|
|
size_t find_next_non_dirty() {
|
|
assert(_cur_addr <= _end_addr, "Not allowed to search for marks after area.");
|
|
|
|
while (!cur_addr_aligned()) {
|
|
if (!cur_card_is_dirty()) {
|
|
return get_and_advance_pos();
|
|
}
|
|
_cur_addr++;
|
|
}
|
|
|
|
assert(cur_addr_aligned(), "Current address should be aligned now.");
|
|
while (_cur_addr != _end_addr) {
|
|
if (!cur_word_of_cards_all_dirty_cards()) {
|
|
for (size_t i = 0; i < sizeof(size_t); i++) {
|
|
if (!cur_card_is_dirty()) {
|
|
return get_and_advance_pos();
|
|
}
|
|
_cur_addr++;
|
|
}
|
|
assert(false, "Should not reach here given we detected a non-dirty card in the word.");
|
|
}
|
|
_cur_addr += sizeof(size_t);
|
|
}
|
|
return get_and_advance_pos();
|
|
}
|
|
};
|
|
|
|
// Helper class to claim dirty chunks within the card table.
|
|
class G1CardTableChunkClaimer {
|
|
G1RemSetScanState* _scan_state;
|
|
uint _region_idx;
|
|
uint _cur_claim;
|
|
|
|
public:
|
|
G1CardTableChunkClaimer(G1RemSetScanState* scan_state, uint region_idx) :
|
|
_scan_state(scan_state),
|
|
_region_idx(region_idx),
|
|
_cur_claim(0) {
|
|
guarantee(size() <= HeapRegion::CardsPerRegion, "Should not claim more space than possible.");
|
|
}
|
|
|
|
bool has_next() {
|
|
while (true) {
|
|
_cur_claim = _scan_state->claim_cards_to_scan(_region_idx, size());
|
|
if (_cur_claim >= HeapRegion::CardsPerRegion) {
|
|
return false;
|
|
}
|
|
if (_scan_state->chunk_needs_scan(_region_idx, _cur_claim)) {
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
|
|
uint value() const { return _cur_claim; }
|
|
uint size() const { return _scan_state->scan_chunk_size(); }
|
|
};
|
|
|
|
// Scans a heap region for dirty cards.
|
|
class G1ScanHRForRegionClosure : public HeapRegionClosure {
|
|
G1CollectedHeap* _g1h;
|
|
G1CardTable* _ct;
|
|
G1BlockOffsetTable* _bot;
|
|
|
|
G1ParScanThreadState* _pss;
|
|
|
|
G1RemSetScanState* _scan_state;
|
|
|
|
G1GCPhaseTimes::GCParPhases _phase;
|
|
|
|
uint _worker_id;
|
|
|
|
size_t _cards_scanned;
|
|
size_t _blocks_scanned;
|
|
size_t _chunks_claimed;
|
|
|
|
Tickspan _rem_set_root_scan_time;
|
|
Tickspan _rem_set_trim_partially_time;
|
|
|
|
// The address to which this thread already scanned (walked the heap) up to during
|
|
// card scanning (exclusive).
|
|
HeapWord* _scanned_to;
|
|
|
|
HeapWord* scan_memregion(uint region_idx_for_card, MemRegion mr) {
|
|
HeapRegion* const card_region = _g1h->region_at(region_idx_for_card);
|
|
G1ScanCardClosure card_cl(_g1h, _pss);
|
|
|
|
HeapWord* const scanned_to = card_region->oops_on_memregion_seq_iterate_careful<true>(mr, &card_cl);
|
|
assert(scanned_to != NULL, "Should be able to scan range");
|
|
assert(scanned_to >= mr.end(), "Scanned to " PTR_FORMAT " less than range " PTR_FORMAT, p2i(scanned_to), p2i(mr.end()));
|
|
|
|
_pss->trim_queue_partially();
|
|
return scanned_to;
|
|
}
|
|
|
|
void do_claimed_block(uint const region_idx_for_card, size_t const first_card, size_t const num_cards) {
|
|
HeapWord* const card_start = _bot->address_for_index_raw(first_card);
|
|
#ifdef ASSERT
|
|
HeapRegion* hr = _g1h->region_at_or_null(region_idx_for_card);
|
|
assert(hr == NULL || hr->is_in_reserved(card_start),
|
|
"Card start " PTR_FORMAT " to scan outside of region %u", p2i(card_start), _g1h->region_at(region_idx_for_card)->hrm_index());
|
|
#endif
|
|
HeapWord* const top = _scan_state->scan_top(region_idx_for_card);
|
|
if (card_start >= top) {
|
|
return;
|
|
}
|
|
|
|
HeapWord* scan_end = MIN2(card_start + (num_cards << BOTConstants::LogN_words), top);
|
|
if (_scanned_to >= scan_end) {
|
|
return;
|
|
}
|
|
MemRegion mr(MAX2(card_start, _scanned_to), scan_end);
|
|
_scanned_to = scan_memregion(region_idx_for_card, mr);
|
|
|
|
_cards_scanned += num_cards;
|
|
}
|
|
|
|
ALWAYSINLINE void do_card_block(uint const region_idx, size_t const first_card, size_t const num_cards) {
|
|
_ct->mark_as_scanned(first_card, num_cards);
|
|
do_claimed_block(region_idx, first_card, num_cards);
|
|
_blocks_scanned++;
|
|
}
|
|
|
|
void scan_heap_roots(HeapRegion* r) {
|
|
EventGCPhaseParallel event;
|
|
uint const region_idx = r->hrm_index();
|
|
|
|
ResourceMark rm;
|
|
|
|
G1CardTableChunkClaimer claim(_scan_state, region_idx);
|
|
|
|
// Set the current scan "finger" to NULL for every heap region to scan. Since
|
|
// the claim value is monotonically increasing, the check to not scan below this
|
|
// will filter out objects spanning chunks within the region too then, as opposed
|
|
// to resetting this value for every claim.
|
|
_scanned_to = NULL;
|
|
|
|
while (claim.has_next()) {
|
|
size_t const region_card_base_idx = ((size_t)region_idx << HeapRegion::LogCardsPerRegion) + claim.value();
|
|
CardTable::CardValue* const base_addr = _ct->byte_for_index(region_card_base_idx);
|
|
|
|
G1CardTableScanner scan(base_addr, claim.size());
|
|
|
|
size_t first_scan_idx = scan.find_next_dirty();
|
|
while (first_scan_idx != claim.size()) {
|
|
assert(*_ct->byte_for_index(region_card_base_idx + first_scan_idx) <= 0x1, "is %d at region %u idx " SIZE_FORMAT, *_ct->byte_for_index(region_card_base_idx + first_scan_idx), region_idx, first_scan_idx);
|
|
|
|
size_t const last_scan_idx = scan.find_next_non_dirty();
|
|
size_t const len = last_scan_idx - first_scan_idx;
|
|
|
|
do_card_block(region_idx, region_card_base_idx + first_scan_idx, len);
|
|
|
|
if (last_scan_idx == claim.size()) {
|
|
break;
|
|
}
|
|
|
|
first_scan_idx = scan.find_next_dirty();
|
|
}
|
|
_chunks_claimed++;
|
|
}
|
|
|
|
event.commit(GCId::current(), _worker_id, G1GCPhaseTimes::phase_name(G1GCPhaseTimes::ScanHR));
|
|
}
|
|
|
|
public:
|
|
G1ScanHRForRegionClosure(G1RemSetScanState* scan_state,
|
|
G1ParScanThreadState* pss,
|
|
uint worker_id,
|
|
G1GCPhaseTimes::GCParPhases phase) :
|
|
_g1h(G1CollectedHeap::heap()),
|
|
_ct(_g1h->card_table()),
|
|
_bot(_g1h->bot()),
|
|
_pss(pss),
|
|
_scan_state(scan_state),
|
|
_phase(phase),
|
|
_worker_id(worker_id),
|
|
_cards_scanned(0),
|
|
_blocks_scanned(0),
|
|
_chunks_claimed(0),
|
|
_rem_set_root_scan_time(),
|
|
_rem_set_trim_partially_time(),
|
|
_scanned_to(NULL) {
|
|
}
|
|
|
|
bool do_heap_region(HeapRegion* r) {
|
|
assert(!r->in_collection_set() && r->is_old_or_humongous_or_archive(),
|
|
"Should only be called on old gen non-collection set regions but region %u is not.",
|
|
r->hrm_index());
|
|
uint const region_idx = r->hrm_index();
|
|
|
|
if (_scan_state->has_cards_to_scan(region_idx)) {
|
|
G1EvacPhaseWithTrimTimeTracker timer(_pss, _rem_set_root_scan_time, _rem_set_trim_partially_time);
|
|
scan_heap_roots(r);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
Tickspan rem_set_root_scan_time() const { return _rem_set_root_scan_time; }
|
|
Tickspan rem_set_trim_partially_time() const { return _rem_set_trim_partially_time; }
|
|
|
|
size_t cards_scanned() const { return _cards_scanned; }
|
|
size_t blocks_scanned() const { return _blocks_scanned; }
|
|
size_t chunks_claimed() const { return _chunks_claimed; }
|
|
};
|
|
|
|
void G1RemSet::scan_heap_roots(G1ParScanThreadState* pss,
|
|
uint worker_id,
|
|
G1GCPhaseTimes::GCParPhases scan_phase,
|
|
G1GCPhaseTimes::GCParPhases objcopy_phase) {
|
|
G1ScanHRForRegionClosure cl(_scan_state, pss, worker_id, scan_phase);
|
|
_scan_state->iterate_dirty_regions_from(&cl, worker_id);
|
|
|
|
G1GCPhaseTimes* p = _g1p->phase_times();
|
|
|
|
p->record_or_add_time_secs(objcopy_phase, worker_id, cl.rem_set_trim_partially_time().seconds());
|
|
|
|
p->record_or_add_time_secs(scan_phase, worker_id, cl.rem_set_root_scan_time().seconds());
|
|
p->record_or_add_thread_work_item(scan_phase, worker_id, cl.cards_scanned(), G1GCPhaseTimes::ScanHRScannedCards);
|
|
p->record_or_add_thread_work_item(scan_phase, worker_id, cl.blocks_scanned(), G1GCPhaseTimes::ScanHRScannedBlocks);
|
|
p->record_or_add_thread_work_item(scan_phase, worker_id, cl.chunks_claimed(), G1GCPhaseTimes::ScanHRClaimedChunks);
|
|
}
|
|
|
|
// Heap region closure to be applied to all regions in the current collection set
|
|
// increment to fix up non-card related roots.
|
|
class G1ScanCollectionSetRegionClosure : public HeapRegionClosure {
|
|
G1ParScanThreadState* _pss;
|
|
G1RemSetScanState* _scan_state;
|
|
|
|
G1GCPhaseTimes::GCParPhases _scan_phase;
|
|
G1GCPhaseTimes::GCParPhases _code_roots_phase;
|
|
|
|
uint _worker_id;
|
|
|
|
size_t _opt_refs_scanned;
|
|
size_t _opt_refs_memory_used;
|
|
|
|
Tickspan _strong_code_root_scan_time;
|
|
Tickspan _strong_code_trim_partially_time;
|
|
|
|
Tickspan _rem_set_opt_root_scan_time;
|
|
Tickspan _rem_set_opt_trim_partially_time;
|
|
|
|
void scan_opt_rem_set_roots(HeapRegion* r) {
|
|
EventGCPhaseParallel event;
|
|
|
|
G1OopStarChunkedList* opt_rem_set_list = _pss->oops_into_optional_region(r);
|
|
|
|
G1ScanCardClosure scan_cl(G1CollectedHeap::heap(), _pss);
|
|
G1ScanRSForOptionalClosure cl(G1CollectedHeap::heap(), &scan_cl);
|
|
_opt_refs_scanned += opt_rem_set_list->oops_do(&cl, _pss->closures()->strong_oops());
|
|
_opt_refs_memory_used += opt_rem_set_list->used_memory();
|
|
|
|
event.commit(GCId::current(), _worker_id, G1GCPhaseTimes::phase_name(_scan_phase));
|
|
}
|
|
|
|
public:
|
|
G1ScanCollectionSetRegionClosure(G1RemSetScanState* scan_state,
|
|
G1ParScanThreadState* pss,
|
|
uint worker_id,
|
|
G1GCPhaseTimes::GCParPhases scan_phase,
|
|
G1GCPhaseTimes::GCParPhases code_roots_phase) :
|
|
_pss(pss),
|
|
_scan_state(scan_state),
|
|
_scan_phase(scan_phase),
|
|
_code_roots_phase(code_roots_phase),
|
|
_worker_id(worker_id),
|
|
_opt_refs_scanned(0),
|
|
_opt_refs_memory_used(0),
|
|
_strong_code_root_scan_time(),
|
|
_strong_code_trim_partially_time(),
|
|
_rem_set_opt_root_scan_time(),
|
|
_rem_set_opt_trim_partially_time() { }
|
|
|
|
bool do_heap_region(HeapRegion* r) {
|
|
uint const region_idx = r->hrm_index();
|
|
|
|
// The individual references for the optional remembered set are per-worker, so we
|
|
// always need to scan them.
|
|
if (r->has_index_in_opt_cset()) {
|
|
G1EvacPhaseWithTrimTimeTracker timer(_pss, _rem_set_opt_root_scan_time, _rem_set_opt_trim_partially_time);
|
|
scan_opt_rem_set_roots(r);
|
|
}
|
|
|
|
if (_scan_state->claim_collection_set_region(region_idx)) {
|
|
EventGCPhaseParallel event;
|
|
|
|
G1EvacPhaseWithTrimTimeTracker timer(_pss, _strong_code_root_scan_time, _strong_code_trim_partially_time);
|
|
// Scan the strong code root list attached to the current region
|
|
r->strong_code_roots_do(_pss->closures()->weak_codeblobs());
|
|
|
|
event.commit(GCId::current(), _worker_id, G1GCPhaseTimes::phase_name(_code_roots_phase));
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
Tickspan strong_code_root_scan_time() const { return _strong_code_root_scan_time; }
|
|
Tickspan strong_code_root_trim_partially_time() const { return _strong_code_trim_partially_time; }
|
|
|
|
Tickspan rem_set_opt_root_scan_time() const { return _rem_set_opt_root_scan_time; }
|
|
Tickspan rem_set_opt_trim_partially_time() const { return _rem_set_opt_trim_partially_time; }
|
|
|
|
size_t opt_refs_scanned() const { return _opt_refs_scanned; }
|
|
size_t opt_refs_memory_used() const { return _opt_refs_memory_used; }
|
|
};
|
|
|
|
void G1RemSet::scan_collection_set_regions(G1ParScanThreadState* pss,
|
|
uint worker_id,
|
|
G1GCPhaseTimes::GCParPhases scan_phase,
|
|
G1GCPhaseTimes::GCParPhases coderoots_phase,
|
|
G1GCPhaseTimes::GCParPhases objcopy_phase) {
|
|
G1ScanCollectionSetRegionClosure cl(_scan_state, pss, worker_id, scan_phase, coderoots_phase);
|
|
_g1h->collection_set_iterate_increment_from(&cl, worker_id);
|
|
|
|
G1GCPhaseTimes* p = _g1h->phase_times();
|
|
|
|
p->record_or_add_time_secs(scan_phase, worker_id, cl.rem_set_opt_root_scan_time().seconds());
|
|
p->record_or_add_time_secs(scan_phase, worker_id, cl.rem_set_opt_trim_partially_time().seconds());
|
|
|
|
p->record_or_add_time_secs(coderoots_phase, worker_id, cl.strong_code_root_scan_time().seconds());
|
|
p->add_time_secs(objcopy_phase, worker_id, cl.strong_code_root_trim_partially_time().seconds());
|
|
|
|
// At this time we record some metrics only for the evacuations after the initial one.
|
|
if (scan_phase == G1GCPhaseTimes::OptScanHR) {
|
|
p->record_or_add_thread_work_item(scan_phase, worker_id, cl.opt_refs_scanned(), G1GCPhaseTimes::ScanHRScannedOptRefs);
|
|
p->record_or_add_thread_work_item(scan_phase, worker_id, cl.opt_refs_memory_used(), G1GCPhaseTimes::ScanHRUsedMemory);
|
|
}
|
|
}
|
|
|
|
void G1RemSet::prepare_region_for_scan(HeapRegion* region) {
|
|
uint hrm_index = region->hrm_index();
|
|
|
|
if (region->in_collection_set()) {
|
|
// Young regions had their card table marked as young at their allocation;
|
|
// we need to make sure that these marks are cleared at the end of GC, *but*
|
|
// they should not be scanned for cards.
|
|
// So directly add them to the "all_dirty_regions".
|
|
// Same for regions in the (initial) collection set: they may contain cards from
|
|
// the log buffers, make sure they are cleaned.
|
|
_scan_state->add_all_dirty_region(hrm_index);
|
|
} else if (region->is_old_or_humongous_or_archive()) {
|
|
_scan_state->set_scan_top(hrm_index, region->top());
|
|
} else {
|
|
assert(region->is_free(), "Should only be free region at this point %s", region->get_type_str());
|
|
}
|
|
}
|
|
|
|
void G1RemSet::prepare_for_scan_heap_roots() {
|
|
_scan_state->prepare();
|
|
}
|
|
|
|
class G1MergeHeapRootsTask : public AbstractGangTask {
|
|
|
|
// Visitor for remembered sets, dropping entries onto the card table.
|
|
class G1MergeCardSetClosure : public HeapRegionClosure {
|
|
G1RemSetScanState* _scan_state;
|
|
G1CardTable* _ct;
|
|
|
|
uint _merged_sparse;
|
|
uint _merged_fine;
|
|
uint _merged_coarse;
|
|
|
|
size_t _cards_dirty;
|
|
|
|
// Returns if the region contains cards we need to scan. If so, remember that
|
|
// region in the current set of dirty regions.
|
|
bool remember_if_interesting(uint const region_idx) {
|
|
if (!_scan_state->contains_cards_to_process(region_idx)) {
|
|
return false;
|
|
}
|
|
_scan_state->add_dirty_region(region_idx);
|
|
return true;
|
|
}
|
|
public:
|
|
G1MergeCardSetClosure(G1RemSetScanState* scan_state) :
|
|
_scan_state(scan_state),
|
|
_ct(G1CollectedHeap::heap()->card_table()),
|
|
_merged_sparse(0),
|
|
_merged_fine(0),
|
|
_merged_coarse(0),
|
|
_cards_dirty(0) { }
|
|
|
|
void next_coarse_prt(uint const region_idx) {
|
|
if (!remember_if_interesting(region_idx)) {
|
|
return;
|
|
}
|
|
|
|
_merged_coarse++;
|
|
|
|
size_t region_base_idx = (size_t)region_idx << HeapRegion::LogCardsPerRegion;
|
|
_cards_dirty += _ct->mark_region_dirty(region_base_idx, HeapRegion::CardsPerRegion);
|
|
_scan_state->set_chunk_region_dirty(region_base_idx);
|
|
}
|
|
|
|
void next_fine_prt(uint const region_idx, BitMap* bm) {
|
|
if (!remember_if_interesting(region_idx)) {
|
|
return;
|
|
}
|
|
|
|
_merged_fine++;
|
|
|
|
size_t const region_base_idx = (size_t)region_idx << HeapRegion::LogCardsPerRegion;
|
|
BitMap::idx_t cur = bm->get_next_one_offset(0);
|
|
while (cur != bm->size()) {
|
|
_cards_dirty += _ct->mark_clean_as_dirty(region_base_idx + cur);
|
|
_scan_state->set_chunk_dirty(region_base_idx + cur);
|
|
cur = bm->get_next_one_offset(cur + 1);
|
|
}
|
|
}
|
|
|
|
void next_sparse_prt(uint const region_idx, SparsePRTEntry::card_elem_t* cards, uint const num_cards) {
|
|
if (!remember_if_interesting(region_idx)) {
|
|
return;
|
|
}
|
|
|
|
_merged_sparse++;
|
|
|
|
size_t const region_base_idx = (size_t)region_idx << HeapRegion::LogCardsPerRegion;
|
|
for (uint i = 0; i < num_cards; i++) {
|
|
size_t card_idx = region_base_idx + cards[i];
|
|
_cards_dirty += _ct->mark_clean_as_dirty(card_idx);
|
|
_scan_state->set_chunk_dirty(card_idx);
|
|
}
|
|
}
|
|
|
|
virtual bool do_heap_region(HeapRegion* r) {
|
|
assert(r->in_collection_set() || r->is_starts_humongous(), "must be");
|
|
|
|
HeapRegionRemSet* rem_set = r->rem_set();
|
|
if (!rem_set->is_empty()) {
|
|
rem_set->iterate_prts(*this);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
size_t merged_sparse() const { return _merged_sparse; }
|
|
size_t merged_fine() const { return _merged_fine; }
|
|
size_t merged_coarse() const { return _merged_coarse; }
|
|
|
|
size_t cards_dirty() const { return _cards_dirty; }
|
|
};
|
|
|
|
// Visitor for the remembered sets of humongous candidate regions to merge their
|
|
// remembered set into the card table.
|
|
class G1FlushHumongousCandidateRemSets : public HeapRegionClosure {
|
|
G1MergeCardSetClosure _cl;
|
|
|
|
public:
|
|
G1FlushHumongousCandidateRemSets(G1RemSetScanState* scan_state) : _cl(scan_state) { }
|
|
|
|
virtual bool do_heap_region(HeapRegion* r) {
|
|
G1CollectedHeap* g1h = G1CollectedHeap::heap();
|
|
|
|
if (!r->is_starts_humongous() ||
|
|
!g1h->region_attr(r->hrm_index()).is_humongous() ||
|
|
r->rem_set()->is_empty()) {
|
|
return false;
|
|
}
|
|
|
|
guarantee(r->rem_set()->occupancy_less_or_equal_than(G1RSetSparseRegionEntries),
|
|
"Found a not-small remembered set here. This is inconsistent with previous assumptions.");
|
|
|
|
_cl.do_heap_region(r);
|
|
|
|
// We should only clear the card based remembered set here as we will not
|
|
// implicitly rebuild anything else during eager reclaim. Note that at the moment
|
|
// (and probably never) we do not enter this path if there are other kind of
|
|
// remembered sets for this region.
|
|
r->rem_set()->clear_locked(true /* only_cardset */);
|
|
// Clear_locked() above sets the state to Empty. However we want to continue
|
|
// collecting remembered set entries for humongous regions that were not
|
|
// reclaimed.
|
|
r->rem_set()->set_state_complete();
|
|
#ifdef ASSERT
|
|
G1HeapRegionAttr region_attr = g1h->region_attr(r->hrm_index());
|
|
assert(region_attr.needs_remset_update(), "must be");
|
|
#endif
|
|
assert(r->rem_set()->is_empty(), "At this point any humongous candidate remembered set must be empty.");
|
|
|
|
return false;
|
|
}
|
|
|
|
size_t merged_sparse() const { return _cl.merged_sparse(); }
|
|
size_t merged_fine() const { return _cl.merged_fine(); }
|
|
size_t merged_coarse() const { return _cl.merged_coarse(); }
|
|
|
|
size_t cards_dirty() const { return _cl.cards_dirty(); }
|
|
};
|
|
|
|
// Visitor for the log buffer entries to merge them into the card table.
|
|
class G1MergeLogBufferCardsClosure : public G1CardTableEntryClosure {
|
|
G1RemSetScanState* _scan_state;
|
|
G1CardTable* _ct;
|
|
|
|
size_t _cards_dirty;
|
|
size_t _cards_skipped;
|
|
public:
|
|
G1MergeLogBufferCardsClosure(G1CollectedHeap* g1h, G1RemSetScanState* scan_state) :
|
|
_scan_state(scan_state), _ct(g1h->card_table()), _cards_dirty(0), _cards_skipped(0)
|
|
{}
|
|
|
|
void do_card_ptr(CardValue* card_ptr, uint worker_id) {
|
|
// 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_id should be the id of a GC worker thread.
|
|
assert(SafepointSynchronize::is_at_safepoint(), "not during an evacuation pause");
|
|
|
|
uint const region_idx = _ct->region_idx_for(card_ptr);
|
|
|
|
// The second clause must come after - the log buffers might contain cards to uncommited
|
|
// regions.
|
|
// This code may count duplicate entries in the log buffers (even if rare) multiple
|
|
// times.
|
|
if (_scan_state->contains_cards_to_process(region_idx) && (*card_ptr == G1CardTable::dirty_card_val())) {
|
|
_scan_state->add_dirty_region(region_idx);
|
|
_scan_state->set_chunk_dirty(_ct->index_for_cardvalue(card_ptr));
|
|
_cards_dirty++;
|
|
} else {
|
|
// We may have had dirty cards in the (initial) collection set (or the
|
|
// young regions which are always in the initial collection set). We do
|
|
// not fix their cards here: we already added these regions to the set of
|
|
// regions to clear the card table at the end during the prepare() phase.
|
|
_cards_skipped++;
|
|
}
|
|
}
|
|
|
|
size_t cards_dirty() const { return _cards_dirty; }
|
|
size_t cards_skipped() const { return _cards_skipped; }
|
|
};
|
|
|
|
HeapRegionClaimer _hr_claimer;
|
|
G1RemSetScanState* _scan_state;
|
|
BufferNode::Stack _dirty_card_buffers;
|
|
bool _initial_evacuation;
|
|
|
|
volatile bool _fast_reclaim_handled;
|
|
|
|
void apply_closure_to_dirty_card_buffers(G1MergeLogBufferCardsClosure* cl, uint worker_id) {
|
|
G1DirtyCardQueueSet& dcqs = G1BarrierSet::dirty_card_queue_set();
|
|
size_t buffer_size = dcqs.buffer_size();
|
|
while (BufferNode* node = _dirty_card_buffers.pop()) {
|
|
cl->apply_to_buffer(node, buffer_size, worker_id);
|
|
dcqs.deallocate_buffer(node);
|
|
}
|
|
}
|
|
|
|
public:
|
|
G1MergeHeapRootsTask(G1RemSetScanState* scan_state, uint num_workers, bool initial_evacuation) :
|
|
AbstractGangTask("G1 Merge Heap Roots"),
|
|
_hr_claimer(num_workers),
|
|
_scan_state(scan_state),
|
|
_dirty_card_buffers(),
|
|
_initial_evacuation(initial_evacuation),
|
|
_fast_reclaim_handled(false)
|
|
{
|
|
if (initial_evacuation) {
|
|
G1DirtyCardQueueSet& dcqs = G1BarrierSet::dirty_card_queue_set();
|
|
G1BufferNodeList buffers = dcqs.take_all_completed_buffers();
|
|
if (buffers._entry_count != 0) {
|
|
_dirty_card_buffers.prepend(*buffers._head, *buffers._tail);
|
|
}
|
|
}
|
|
}
|
|
|
|
virtual void work(uint worker_id) {
|
|
G1CollectedHeap* g1h = G1CollectedHeap::heap();
|
|
G1GCPhaseTimes* p = g1h->phase_times();
|
|
|
|
G1GCPhaseTimes::GCParPhases merge_remset_phase = _initial_evacuation ?
|
|
G1GCPhaseTimes::MergeRS :
|
|
G1GCPhaseTimes::OptMergeRS;
|
|
|
|
// We schedule flushing the remembered sets of humongous fast reclaim candidates
|
|
// onto the card table first to allow the remaining parallelized tasks hide it.
|
|
if (_initial_evacuation &&
|
|
p->fast_reclaim_humongous_candidates() > 0 &&
|
|
!_fast_reclaim_handled &&
|
|
!Atomic::cmpxchg(&_fast_reclaim_handled, false, true)) {
|
|
|
|
G1GCParPhaseTimesTracker x(p, G1GCPhaseTimes::MergeER, worker_id);
|
|
|
|
G1FlushHumongousCandidateRemSets cl(_scan_state);
|
|
g1h->heap_region_iterate(&cl);
|
|
|
|
p->record_or_add_thread_work_item(merge_remset_phase, worker_id, cl.merged_sparse(), G1GCPhaseTimes::MergeRSMergedSparse);
|
|
p->record_or_add_thread_work_item(merge_remset_phase, worker_id, cl.merged_fine(), G1GCPhaseTimes::MergeRSMergedFine);
|
|
p->record_or_add_thread_work_item(merge_remset_phase, worker_id, cl.merged_coarse(), G1GCPhaseTimes::MergeRSMergedCoarse);
|
|
p->record_or_add_thread_work_item(merge_remset_phase, worker_id, cl.cards_dirty(), G1GCPhaseTimes::MergeRSDirtyCards);
|
|
}
|
|
|
|
// Merge remembered sets of current candidates.
|
|
{
|
|
G1GCParPhaseTimesTracker x(p, merge_remset_phase, worker_id, _initial_evacuation /* must_record */);
|
|
G1MergeCardSetClosure cl(_scan_state);
|
|
g1h->collection_set_iterate_increment_from(&cl, &_hr_claimer, worker_id);
|
|
|
|
p->record_or_add_thread_work_item(merge_remset_phase, worker_id, cl.merged_sparse(), G1GCPhaseTimes::MergeRSMergedSparse);
|
|
p->record_or_add_thread_work_item(merge_remset_phase, worker_id, cl.merged_fine(), G1GCPhaseTimes::MergeRSMergedFine);
|
|
p->record_or_add_thread_work_item(merge_remset_phase, worker_id, cl.merged_coarse(), G1GCPhaseTimes::MergeRSMergedCoarse);
|
|
p->record_or_add_thread_work_item(merge_remset_phase, worker_id, cl.cards_dirty(), G1GCPhaseTimes::MergeRSDirtyCards);
|
|
}
|
|
|
|
// Apply closure to log entries in the HCC.
|
|
if (_initial_evacuation && G1HotCardCache::default_use_cache()) {
|
|
assert(merge_remset_phase == G1GCPhaseTimes::MergeRS, "Wrong merge phase");
|
|
G1GCParPhaseTimesTracker x(p, G1GCPhaseTimes::MergeHCC, worker_id);
|
|
G1MergeLogBufferCardsClosure cl(g1h, _scan_state);
|
|
g1h->iterate_hcc_closure(&cl, worker_id);
|
|
|
|
p->record_thread_work_item(G1GCPhaseTimes::MergeHCC, worker_id, cl.cards_dirty(), G1GCPhaseTimes::MergeHCCDirtyCards);
|
|
p->record_thread_work_item(G1GCPhaseTimes::MergeHCC, worker_id, cl.cards_skipped(), G1GCPhaseTimes::MergeHCCSkippedCards);
|
|
}
|
|
|
|
// Now apply the closure to all remaining log entries.
|
|
if (_initial_evacuation) {
|
|
assert(merge_remset_phase == G1GCPhaseTimes::MergeRS, "Wrong merge phase");
|
|
G1GCParPhaseTimesTracker x(p, G1GCPhaseTimes::MergeLB, worker_id);
|
|
|
|
G1MergeLogBufferCardsClosure cl(g1h, _scan_state);
|
|
apply_closure_to_dirty_card_buffers(&cl, worker_id);
|
|
|
|
p->record_thread_work_item(G1GCPhaseTimes::MergeLB, worker_id, cl.cards_dirty(), G1GCPhaseTimes::MergeLBDirtyCards);
|
|
p->record_thread_work_item(G1GCPhaseTimes::MergeLB, worker_id, cl.cards_skipped(), G1GCPhaseTimes::MergeLBSkippedCards);
|
|
}
|
|
}
|
|
};
|
|
|
|
void G1RemSet::print_merge_heap_roots_stats() {
|
|
size_t num_visited_cards = _scan_state->num_visited_cards();
|
|
|
|
size_t total_dirty_region_cards = _scan_state->num_cards_in_dirty_regions();
|
|
|
|
G1CollectedHeap* g1h = G1CollectedHeap::heap();
|
|
size_t total_old_region_cards =
|
|
(g1h->num_regions() - (g1h->num_free_regions() - g1h->collection_set()->cur_length())) * HeapRegion::CardsPerRegion;
|
|
|
|
log_debug(gc,remset)("Visited cards " SIZE_FORMAT " Total dirty " SIZE_FORMAT " (%.2lf%%) Total old " SIZE_FORMAT " (%.2lf%%)",
|
|
num_visited_cards,
|
|
total_dirty_region_cards,
|
|
percent_of(num_visited_cards, total_dirty_region_cards),
|
|
total_old_region_cards,
|
|
percent_of(num_visited_cards, total_old_region_cards));
|
|
}
|
|
|
|
void G1RemSet::merge_heap_roots(bool initial_evacuation) {
|
|
G1CollectedHeap* g1h = G1CollectedHeap::heap();
|
|
|
|
{
|
|
Ticks start = Ticks::now();
|
|
|
|
_scan_state->prepare_for_merge_heap_roots();
|
|
|
|
Tickspan total = Ticks::now() - start;
|
|
if (initial_evacuation) {
|
|
g1h->phase_times()->record_prepare_merge_heap_roots_time(total.seconds() * 1000.0);
|
|
} else {
|
|
g1h->phase_times()->record_or_add_optional_prepare_merge_heap_roots_time(total.seconds() * 1000.0);
|
|
}
|
|
}
|
|
|
|
WorkGang* workers = g1h->workers();
|
|
size_t const increment_length = g1h->collection_set()->increment_length();
|
|
|
|
uint const num_workers = initial_evacuation ? workers->active_workers() :
|
|
MIN2(workers->active_workers(), (uint)increment_length);
|
|
|
|
{
|
|
G1MergeHeapRootsTask cl(_scan_state, num_workers, initial_evacuation);
|
|
log_debug(gc, ergo)("Running %s using %u workers for " SIZE_FORMAT " regions",
|
|
cl.name(), num_workers, increment_length);
|
|
workers->run_task(&cl, num_workers);
|
|
}
|
|
|
|
if (log_is_enabled(Debug, gc, remset)) {
|
|
print_merge_heap_roots_stats();
|
|
}
|
|
}
|
|
|
|
void G1RemSet::exclude_region_from_scan(uint region_idx) {
|
|
_scan_state->clear_scan_top(region_idx);
|
|
}
|
|
|
|
void G1RemSet::cleanup_after_scan_heap_roots() {
|
|
G1GCPhaseTimes* phase_times = _g1h->phase_times();
|
|
|
|
// Set all cards back to clean.
|
|
double start = os::elapsedTime();
|
|
_scan_state->cleanup(_g1h->workers());
|
|
phase_times->record_clear_ct_time((os::elapsedTime() - start) * 1000.0);
|
|
}
|
|
|
|
inline void check_card_ptr(CardTable::CardValue* card_ptr, G1CardTable* ct) {
|
|
#ifdef ASSERT
|
|
G1CollectedHeap* g1h = G1CollectedHeap::heap();
|
|
assert(g1h->is_in_exact(ct->addr_for(card_ptr)),
|
|
"Card at " PTR_FORMAT " index " SIZE_FORMAT " representing heap at " PTR_FORMAT " (%u) must be in committed heap",
|
|
p2i(card_ptr),
|
|
ct->index_for(ct->addr_for(card_ptr)),
|
|
p2i(ct->addr_for(card_ptr)),
|
|
g1h->addr_to_region(ct->addr_for(card_ptr)));
|
|
#endif
|
|
}
|
|
|
|
bool G1RemSet::clean_card_before_refine(CardValue** const card_ptr_addr) {
|
|
assert(!_g1h->is_gc_active(), "Only call concurrently");
|
|
|
|
CardValue* card_ptr = *card_ptr_addr;
|
|
// Find the start address represented by the card.
|
|
HeapWord* start = _ct->addr_for(card_ptr);
|
|
// And find the region containing it.
|
|
HeapRegion* r = _g1h->heap_region_containing_or_null(start);
|
|
|
|
// If this is a (stale) card into an uncommitted region, exit.
|
|
if (r == NULL) {
|
|
return false;
|
|
}
|
|
|
|
check_card_ptr(card_ptr, _ct);
|
|
|
|
// If the card is no longer dirty, nothing to do.
|
|
// We cannot load the card value before the "r == NULL" check, because G1
|
|
// could uncommit parts of the card table covering uncommitted regions.
|
|
if (*card_ptr != G1CardTable::dirty_card_val()) {
|
|
return false;
|
|
}
|
|
|
|
// This check is needed for some uncommon cases where we should
|
|
// ignore the card.
|
|
//
|
|
// The region could be young. Cards for young regions are
|
|
// distinctly marked (set to g1_young_gen), so the post-barrier will
|
|
// filter them out. However, that marking is performed
|
|
// concurrently. A write to a young object could occur before the
|
|
// card has been marked young, slipping past the filter.
|
|
//
|
|
// The card could be stale, because the region has been freed since
|
|
// the card was recorded. In this case the region type could be
|
|
// anything. If (still) free or (reallocated) young, just ignore
|
|
// it. If (reallocated) old or humongous, the later card trimming
|
|
// and additional checks in iteration may detect staleness. At
|
|
// worst, we end up processing a stale card unnecessarily.
|
|
//
|
|
// In the normal (non-stale) case, the synchronization between the
|
|
// enqueueing of the card and processing it here will have ensured
|
|
// we see the up-to-date region type here.
|
|
if (!r->is_old_or_humongous_or_archive()) {
|
|
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.
|
|
//
|
|
|
|
if (_hot_card_cache->use_cache()) {
|
|
assert(!SafepointSynchronize::is_at_safepoint(), "sanity");
|
|
|
|
const CardValue* orig_card_ptr = card_ptr;
|
|
card_ptr = _hot_card_cache->insert(card_ptr);
|
|
if (card_ptr == NULL) {
|
|
// There was no eviction. Nothing to do.
|
|
return false;
|
|
} else if (card_ptr != orig_card_ptr) {
|
|
// Original card was inserted and an old card was evicted.
|
|
start = _ct->addr_for(card_ptr);
|
|
r = _g1h->heap_region_containing(start);
|
|
|
|
// Check whether the region formerly in the cache should be
|
|
// ignored, as discussed earlier for the original card. The
|
|
// region could have been freed while in the cache.
|
|
if (!r->is_old_or_humongous_or_archive()) {
|
|
return false;
|
|
}
|
|
*card_ptr_addr = card_ptr;
|
|
} // Else we still have the original card.
|
|
}
|
|
|
|
// Trim the region designated by the card to what's been allocated
|
|
// in the region. The card could be stale, or the card could cover
|
|
// (part of) an object at the end of the allocated space and extend
|
|
// beyond the end of allocation.
|
|
|
|
// Non-humongous objects are either allocated in the old regions during GC,
|
|
// or mapped in archive regions during startup. So if region is old or
|
|
// archive then top is stable.
|
|
// Humongous object allocation sets top last; if top has not yet been set,
|
|
// this is a stale card and we'll end up with an empty intersection.
|
|
// If this is not a stale card, the synchronization between the
|
|
// enqueuing of the card and processing it here will have ensured
|
|
// we see the up-to-date top here.
|
|
HeapWord* scan_limit = r->top();
|
|
|
|
if (scan_limit <= start) {
|
|
// If the trimmed region is empty, the card must be stale.
|
|
return false;
|
|
}
|
|
|
|
// Okay to clean and process the card now. There are still some
|
|
// stale card cases that may be detected by iteration and dealt with
|
|
// as iteration failure.
|
|
*const_cast<volatile CardValue*>(card_ptr) = G1CardTable::clean_card_val();
|
|
|
|
return true;
|
|
}
|
|
|
|
void G1RemSet::refine_card_concurrently(CardValue* const card_ptr,
|
|
const uint worker_id) {
|
|
assert(!_g1h->is_gc_active(), "Only call concurrently");
|
|
check_card_ptr(card_ptr, _ct);
|
|
|
|
// Construct the MemRegion representing the card.
|
|
HeapWord* start = _ct->addr_for(card_ptr);
|
|
// And find the region containing it.
|
|
HeapRegion* r = _g1h->heap_region_containing(start);
|
|
// This reload of the top is safe even though it happens after the full
|
|
// fence, because top is stable for old, archive and unfiltered humongous
|
|
// regions, so it must return the same value as the previous load when
|
|
// cleaning the card. Also cleaning the card and refinement of the card
|
|
// cannot span across safepoint, so we don't need to worry about top being
|
|
// changed during safepoint.
|
|
HeapWord* scan_limit = r->top();
|
|
assert(scan_limit > start, "sanity");
|
|
|
|
// Don't use addr_for(card_ptr + 1) which can ask for
|
|
// a card beyond the heap.
|
|
HeapWord* end = start + G1CardTable::card_size_in_words;
|
|
MemRegion dirty_region(start, MIN2(scan_limit, end));
|
|
assert(!dirty_region.is_empty(), "sanity");
|
|
|
|
G1ConcurrentRefineOopClosure conc_refine_cl(_g1h, worker_id);
|
|
if (r->oops_on_memregion_seq_iterate_careful<false>(dirty_region, &conc_refine_cl) != NULL) {
|
|
return;
|
|
}
|
|
|
|
// If unable to process the card then we encountered an unparsable
|
|
// part of the heap (e.g. a partially allocated object, so only
|
|
// temporarily a problem) while processing a stale card. Despite
|
|
// the card being stale, we can't simply ignore it, because we've
|
|
// already marked the card cleaned, so taken responsibility for
|
|
// ensuring the card gets scanned.
|
|
//
|
|
// However, the card might have gotten re-dirtied and re-enqueued
|
|
// while we worked. (In fact, it's pretty likely.)
|
|
if (*card_ptr == G1CardTable::dirty_card_val()) {
|
|
return;
|
|
}
|
|
|
|
// Re-dirty the card and enqueue in the *shared* queue. Can't use
|
|
// the thread-local queue, because that might be the queue that is
|
|
// being processed by us; we could be a Java thread conscripted to
|
|
// perform refinement on our queue's current buffer.
|
|
*card_ptr = G1CardTable::dirty_card_val();
|
|
G1BarrierSet::shared_dirty_card_queue().enqueue(card_ptr);
|
|
}
|
|
|
|
void G1RemSet::print_periodic_summary_info(const char* header, uint period_count) {
|
|
if ((G1SummarizeRSetStatsPeriod > 0) && log_is_enabled(Trace, gc, remset) &&
|
|
(period_count % G1SummarizeRSetStatsPeriod == 0)) {
|
|
|
|
G1RemSetSummary current;
|
|
_prev_period_summary.subtract_from(¤t);
|
|
|
|
Log(gc, remset) log;
|
|
log.trace("%s", header);
|
|
ResourceMark rm;
|
|
LogStream ls(log.trace());
|
|
_prev_period_summary.print_on(&ls);
|
|
|
|
_prev_period_summary.set(¤t);
|
|
}
|
|
}
|
|
|
|
void G1RemSet::print_summary_info() {
|
|
Log(gc, remset, exit) log;
|
|
if (log.is_trace()) {
|
|
log.trace(" Cumulative RS summary");
|
|
G1RemSetSummary current;
|
|
ResourceMark rm;
|
|
LogStream ls(log.trace());
|
|
current.print_on(&ls);
|
|
}
|
|
}
|
|
|
|
class G1RebuildRemSetTask: public AbstractGangTask {
|
|
// Aggregate the counting data that was constructed concurrently
|
|
// with marking.
|
|
class G1RebuildRemSetHeapRegionClosure : public HeapRegionClosure {
|
|
G1ConcurrentMark* _cm;
|
|
G1RebuildRemSetClosure _update_cl;
|
|
|
|
// Applies _update_cl to the references of the given object, limiting objArrays
|
|
// to the given MemRegion. Returns the amount of words actually scanned.
|
|
size_t scan_for_references(oop const obj, MemRegion mr) {
|
|
size_t const obj_size = obj->size();
|
|
// All non-objArrays and objArrays completely within the mr
|
|
// can be scanned without passing the mr.
|
|
if (!obj->is_objArray() || mr.contains(MemRegion(cast_from_oop<HeapWord*>(obj), obj_size))) {
|
|
obj->oop_iterate(&_update_cl);
|
|
return obj_size;
|
|
}
|
|
// This path is for objArrays crossing the given MemRegion. Only scan the
|
|
// area within the MemRegion.
|
|
obj->oop_iterate(&_update_cl, mr);
|
|
return mr.intersection(MemRegion(cast_from_oop<HeapWord*>(obj), obj_size)).word_size();
|
|
}
|
|
|
|
// A humongous object is live (with respect to the scanning) either
|
|
// a) it is marked on the bitmap as such
|
|
// b) its TARS is larger than TAMS, i.e. has been allocated during marking.
|
|
bool is_humongous_live(oop const humongous_obj, const G1CMBitMap* const bitmap, HeapWord* tams, HeapWord* tars) const {
|
|
return bitmap->is_marked(humongous_obj) || (tars > tams);
|
|
}
|
|
|
|
// Iterator over the live objects within the given MemRegion.
|
|
class LiveObjIterator : public StackObj {
|
|
const G1CMBitMap* const _bitmap;
|
|
const HeapWord* _tams;
|
|
const MemRegion _mr;
|
|
HeapWord* _current;
|
|
|
|
bool is_below_tams() const {
|
|
return _current < _tams;
|
|
}
|
|
|
|
bool is_live(HeapWord* obj) const {
|
|
return !is_below_tams() || _bitmap->is_marked(obj);
|
|
}
|
|
|
|
HeapWord* bitmap_limit() const {
|
|
return MIN2(const_cast<HeapWord*>(_tams), _mr.end());
|
|
}
|
|
|
|
void move_if_below_tams() {
|
|
if (is_below_tams() && has_next()) {
|
|
_current = _bitmap->get_next_marked_addr(_current, bitmap_limit());
|
|
}
|
|
}
|
|
public:
|
|
LiveObjIterator(const G1CMBitMap* const bitmap, const HeapWord* tams, const MemRegion mr, HeapWord* first_oop_into_mr) :
|
|
_bitmap(bitmap),
|
|
_tams(tams),
|
|
_mr(mr),
|
|
_current(first_oop_into_mr) {
|
|
|
|
assert(_current <= _mr.start(),
|
|
"First oop " PTR_FORMAT " should extend into mr [" PTR_FORMAT ", " PTR_FORMAT ")",
|
|
p2i(first_oop_into_mr), p2i(mr.start()), p2i(mr.end()));
|
|
|
|
// Step to the next live object within the MemRegion if needed.
|
|
if (is_live(_current)) {
|
|
// Non-objArrays were scanned by the previous part of that region.
|
|
if (_current < mr.start() && !oop(_current)->is_objArray()) {
|
|
_current += oop(_current)->size();
|
|
// We might have positioned _current on a non-live object. Reposition to the next
|
|
// live one if needed.
|
|
move_if_below_tams();
|
|
}
|
|
} else {
|
|
// The object at _current can only be dead if below TAMS, so we can use the bitmap.
|
|
// immediately.
|
|
_current = _bitmap->get_next_marked_addr(_current, bitmap_limit());
|
|
assert(_current == _mr.end() || is_live(_current),
|
|
"Current " PTR_FORMAT " should be live (%s) or beyond the end of the MemRegion (" PTR_FORMAT ")",
|
|
p2i(_current), BOOL_TO_STR(is_live(_current)), p2i(_mr.end()));
|
|
}
|
|
}
|
|
|
|
void move_to_next() {
|
|
_current += next()->size();
|
|
move_if_below_tams();
|
|
}
|
|
|
|
oop next() const {
|
|
oop result = oop(_current);
|
|
assert(is_live(_current),
|
|
"Object " PTR_FORMAT " must be live TAMS " PTR_FORMAT " below %d mr " PTR_FORMAT " " PTR_FORMAT " outside %d",
|
|
p2i(_current), p2i(_tams), _tams > _current, p2i(_mr.start()), p2i(_mr.end()), _mr.contains(result));
|
|
return result;
|
|
}
|
|
|
|
bool has_next() const {
|
|
return _current < _mr.end();
|
|
}
|
|
};
|
|
|
|
// Rebuild remembered sets in the part of the region specified by mr and hr.
|
|
// Objects between the bottom of the region and the TAMS are checked for liveness
|
|
// using the given bitmap. Objects between TAMS and TARS are assumed to be live.
|
|
// Returns the number of live words between bottom and TAMS.
|
|
size_t rebuild_rem_set_in_region(const G1CMBitMap* const bitmap,
|
|
HeapWord* const top_at_mark_start,
|
|
HeapWord* const top_at_rebuild_start,
|
|
HeapRegion* hr,
|
|
MemRegion mr) {
|
|
size_t marked_words = 0;
|
|
|
|
if (hr->is_humongous()) {
|
|
oop const humongous_obj = oop(hr->humongous_start_region()->bottom());
|
|
if (is_humongous_live(humongous_obj, bitmap, top_at_mark_start, top_at_rebuild_start)) {
|
|
// We need to scan both [bottom, TAMS) and [TAMS, top_at_rebuild_start);
|
|
// however in case of humongous objects it is sufficient to scan the encompassing
|
|
// area (top_at_rebuild_start is always larger or equal to TAMS) as one of the
|
|
// two areas will be zero sized. I.e. TAMS is either
|
|
// the same as bottom or top(_at_rebuild_start). There is no way TAMS has a different
|
|
// value: this would mean that TAMS points somewhere into the object.
|
|
assert(hr->top() == top_at_mark_start || hr->top() == top_at_rebuild_start,
|
|
"More than one object in the humongous region?");
|
|
humongous_obj->oop_iterate(&_update_cl, mr);
|
|
return top_at_mark_start != hr->bottom() ? mr.intersection(MemRegion(cast_from_oop<HeapWord*>(humongous_obj), humongous_obj->size())).byte_size() : 0;
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
for (LiveObjIterator it(bitmap, top_at_mark_start, mr, hr->block_start(mr.start())); it.has_next(); it.move_to_next()) {
|
|
oop obj = it.next();
|
|
size_t scanned_size = scan_for_references(obj, mr);
|
|
if (cast_from_oop<HeapWord*>(obj) < top_at_mark_start) {
|
|
marked_words += scanned_size;
|
|
}
|
|
}
|
|
|
|
return marked_words * HeapWordSize;
|
|
}
|
|
public:
|
|
G1RebuildRemSetHeapRegionClosure(G1CollectedHeap* g1h,
|
|
G1ConcurrentMark* cm,
|
|
uint worker_id) :
|
|
HeapRegionClosure(),
|
|
_cm(cm),
|
|
_update_cl(g1h, worker_id) { }
|
|
|
|
bool do_heap_region(HeapRegion* hr) {
|
|
if (_cm->has_aborted()) {
|
|
return true;
|
|
}
|
|
|
|
uint const region_idx = hr->hrm_index();
|
|
DEBUG_ONLY(HeapWord* const top_at_rebuild_start_check = _cm->top_at_rebuild_start(region_idx);)
|
|
assert(top_at_rebuild_start_check == NULL ||
|
|
top_at_rebuild_start_check > hr->bottom(),
|
|
"A TARS (" PTR_FORMAT ") == bottom() (" PTR_FORMAT ") indicates the old region %u is empty (%s)",
|
|
p2i(top_at_rebuild_start_check), p2i(hr->bottom()), region_idx, hr->get_type_str());
|
|
|
|
size_t total_marked_bytes = 0;
|
|
size_t const chunk_size_in_words = G1RebuildRemSetChunkSize / HeapWordSize;
|
|
|
|
HeapWord* const top_at_mark_start = hr->prev_top_at_mark_start();
|
|
|
|
HeapWord* cur = hr->bottom();
|
|
while (cur < hr->end()) {
|
|
// After every iteration (yield point) we need to check whether the region's
|
|
// TARS changed due to e.g. eager reclaim.
|
|
HeapWord* const top_at_rebuild_start = _cm->top_at_rebuild_start(region_idx);
|
|
if (top_at_rebuild_start == NULL) {
|
|
return false;
|
|
}
|
|
|
|
MemRegion next_chunk = MemRegion(hr->bottom(), top_at_rebuild_start).intersection(MemRegion(cur, chunk_size_in_words));
|
|
if (next_chunk.is_empty()) {
|
|
break;
|
|
}
|
|
|
|
const Ticks start = Ticks::now();
|
|
size_t marked_bytes = rebuild_rem_set_in_region(_cm->prev_mark_bitmap(),
|
|
top_at_mark_start,
|
|
top_at_rebuild_start,
|
|
hr,
|
|
next_chunk);
|
|
Tickspan time = Ticks::now() - start;
|
|
|
|
log_trace(gc, remset, tracking)("Rebuilt region %u "
|
|
"live " SIZE_FORMAT " "
|
|
"time %.3fms "
|
|
"marked bytes " SIZE_FORMAT " "
|
|
"bot " PTR_FORMAT " "
|
|
"TAMS " PTR_FORMAT " "
|
|
"TARS " PTR_FORMAT,
|
|
region_idx,
|
|
_cm->liveness(region_idx) * HeapWordSize,
|
|
time.seconds() * 1000.0,
|
|
marked_bytes,
|
|
p2i(hr->bottom()),
|
|
p2i(top_at_mark_start),
|
|
p2i(top_at_rebuild_start));
|
|
|
|
if (marked_bytes > 0) {
|
|
total_marked_bytes += marked_bytes;
|
|
}
|
|
cur += chunk_size_in_words;
|
|
|
|
_cm->do_yield_check();
|
|
if (_cm->has_aborted()) {
|
|
return true;
|
|
}
|
|
}
|
|
// In the final iteration of the loop the region might have been eagerly reclaimed.
|
|
// Simply filter out those regions. We can not just use region type because there
|
|
// might have already been new allocations into these regions.
|
|
DEBUG_ONLY(HeapWord* const top_at_rebuild_start = _cm->top_at_rebuild_start(region_idx);)
|
|
assert(top_at_rebuild_start == NULL ||
|
|
total_marked_bytes == hr->marked_bytes(),
|
|
"Marked bytes " SIZE_FORMAT " for region %u (%s) in [bottom, TAMS) do not match calculated marked bytes " SIZE_FORMAT " "
|
|
"(" PTR_FORMAT " " PTR_FORMAT " " PTR_FORMAT ")",
|
|
total_marked_bytes, hr->hrm_index(), hr->get_type_str(), hr->marked_bytes(),
|
|
p2i(hr->bottom()), p2i(top_at_mark_start), p2i(top_at_rebuild_start));
|
|
// Abort state may have changed after the yield check.
|
|
return _cm->has_aborted();
|
|
}
|
|
};
|
|
|
|
HeapRegionClaimer _hr_claimer;
|
|
G1ConcurrentMark* _cm;
|
|
|
|
uint _worker_id_offset;
|
|
public:
|
|
G1RebuildRemSetTask(G1ConcurrentMark* cm,
|
|
uint n_workers,
|
|
uint worker_id_offset) :
|
|
AbstractGangTask("G1 Rebuild Remembered Set"),
|
|
_hr_claimer(n_workers),
|
|
_cm(cm),
|
|
_worker_id_offset(worker_id_offset) {
|
|
}
|
|
|
|
void work(uint worker_id) {
|
|
SuspendibleThreadSetJoiner sts_join;
|
|
|
|
G1CollectedHeap* g1h = G1CollectedHeap::heap();
|
|
|
|
G1RebuildRemSetHeapRegionClosure cl(g1h, _cm, _worker_id_offset + worker_id);
|
|
g1h->heap_region_par_iterate_from_worker_offset(&cl, &_hr_claimer, worker_id);
|
|
}
|
|
};
|
|
|
|
void G1RemSet::rebuild_rem_set(G1ConcurrentMark* cm,
|
|
WorkGang* workers,
|
|
uint worker_id_offset) {
|
|
uint num_workers = workers->active_workers();
|
|
|
|
G1RebuildRemSetTask cl(cm,
|
|
num_workers,
|
|
worker_id_offset);
|
|
workers->run_task(&cl, num_workers);
|
|
}
|