1/*
2 * Copyright (c) 2001, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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24
25#ifndef SHARE_GC_G1_G1COLLECTIONSETCHOOSER_HPP
26#define SHARE_GC_G1_G1COLLECTIONSETCHOOSER_HPP
27
28#include "gc/g1/heapRegion.hpp"
29#include "memory/allocation.hpp"
30#include "runtime/globals.hpp"
31
32class G1CollectionSetCandidates;
33class WorkGang;
34
35// Helper class to calculate collection set candidates, and containing some related
36// methods.
37class G1CollectionSetChooser : public AllStatic {
38 static uint calculate_work_chunk_size(uint num_workers, uint num_regions);
39public:
40
41 static size_t mixed_gc_live_threshold_bytes() {
42 return HeapRegion::GrainBytes * (size_t) G1MixedGCLiveThresholdPercent / 100;
43 }
44
45 static bool region_occupancy_low_enough_for_evac(size_t live_bytes) {
46 return live_bytes < mixed_gc_live_threshold_bytes();
47 }
48
49 // Determine whether to add the given region to the collection set candidates or
50 // not. Currently, we skip pinned regions and regions whose live
51 // bytes are over the threshold. Humongous regions may be reclaimed during cleanup.
52 // Regions also need a complete remembered set to be a candidate.
53 static bool should_add(HeapRegion* hr);
54
55 // Build and return set of collection set candidates sorted by decreasing gc
56 // efficiency.
57 static G1CollectionSetCandidates* build(WorkGang* workers, uint max_num_regions);
58};
59
60#endif // SHARE_GC_G1_G1COLLECTIONSETCHOOSER_HPP
61