100 lines
3.6 KiB
C++
100 lines
3.6 KiB
C++
/*
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* Copyright (c) 2019, 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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#ifndef SHARE_GC_G1_G1COLLECTIONSETCANDIDATES_HPP
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#define SHARE_GC_G1_G1COLLECTIONSETCANDIDATES_HPP
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#include "gc/g1/g1CollectionSetCandidates.hpp"
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#include "gc/shared/workgroup.hpp"
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#include "memory/allocation.hpp"
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#include "runtime/globals.hpp"
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class HeapRegion;
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class HeapRegionClosure;
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// Set of collection set candidates, i.e. all old gen regions we consider worth
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// collecting in the remainder of the current mixed phase. Regions are sorted by decreasing
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// gc efficiency.
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// Maintains a cursor into the list that specifies the next collection set candidate
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// to put into the current collection set.
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class G1CollectionSetCandidates : public CHeapObj<mtGC> {
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HeapRegion** _regions;
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uint _num_regions; // Total number of regions in the collection set candidate set.
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// The sum of bytes that can be reclaimed in the remaining set of collection
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// set candidates.
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size_t _remaining_reclaimable_bytes;
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// The index of the next candidate old region to be considered for
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// addition to the current collection set.
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uint _front_idx;
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public:
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G1CollectionSetCandidates(HeapRegion** regions, uint num_regions, size_t remaining_reclaimable_bytes) :
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_regions(regions),
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_num_regions(num_regions),
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_remaining_reclaimable_bytes(remaining_reclaimable_bytes),
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_front_idx(0) { }
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~G1CollectionSetCandidates() {
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FREE_C_HEAP_ARRAY(HeapRegion*, _regions);
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}
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// Returns the total number of collection set candidate old regions added.
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uint num_regions() { return _num_regions; }
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// Return the candidate region at the cursor position to be considered for collection without
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// removing it.
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HeapRegion* peek_front() {
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HeapRegion* res = NULL;
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if (_front_idx < _num_regions) {
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res = _regions[_front_idx];
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assert(res != NULL, "Unexpected NULL HeapRegion at index %u", _front_idx);
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}
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return res;
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}
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// Remove the given region from the candidates set and move the cursor to the next one.
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HeapRegion* pop_front();
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// Add the given HeapRegion to the front of the collection set candidate set again.
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void push_front(HeapRegion* hr);
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// Iterate over all remaining collection set candidate regions.
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void iterate(HeapRegionClosure* cl);
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// Return the number of candidate regions remaining.
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uint num_remaining() { return _num_regions - _front_idx; }
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bool is_empty() { return num_remaining() == 0; }
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// Return the amount of reclaimable bytes that may be collected by the remaining
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// candidate regions.
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size_t remaining_reclaimable_bytes() { return _remaining_reclaimable_bytes; }
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void verify() const PRODUCT_RETURN;
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};
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#endif /* SHARE_GC_G1_G1COLLECTIONSETCANDIDATES_HPP */
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