1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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24
25 #ifndef SHARE_GC_G1_HETEROGENEOUSHEAPREGIONMANAGER_HPP
26 #define SHARE_GC_G1_HETEROGENEOUSHEAPREGIONMANAGER_HPP
27
28 #include "gc/g1/heapRegionManager.hpp"
29
30 // This class manages heap regions on heterogenous memory comprising of dram and nv-dimm.
31 // Regions in dram (dram_set) are used for young objects and archive regions (CDS).
32 // Regions in nv-dimm (nvdimm_set) are used for old objects and humongous objects.
33 // At any point there are some regions committed on dram and some on nv-dimm with the following guarantees:
34 // 1. The total number of regions committed in dram and nv-dimm equals the current size of heap.
35 // 2. Consequently, total number of regions committed is less than or equal to Xmx.
36 // 3. To maintain the guarantee stated by 1., whenever one set grows (new regions committed), the other set shrinks (regions un-committed).
37 // 3a. If more dram regions are needed (young generation expansion), corresponding number of regions in nv-dimm are un-committed.
38 // 3b. When old generation or humongous set grows, and new regions need to be committed to nv-dimm, corresponding number of regions
39 // are un-committed in dram.
40 class HeterogeneousHeapRegionManager : public HeapRegionManager {
41 const uint _max_regions;
42 uint _max_dram_regions;
43 uint _max_nvdimm_regions;
44 uint _start_index_of_nvdimm;
45 uint _total_commited_before_full_gc;
46 uint _no_borrowed_regions;
47
48 uint total_regions_committed() const;
49 uint num_committed_dram() const;
50 uint num_committed_nvdimm() const;
51
52 // Similar to find_unavailable_from_idx() function from base class, difference is this function searches in range [start, end].
53 uint find_unavailable_in_range(uint start_idx, uint end_idx, uint* res_idx) const;
54
55 // Expand into dram. Maintains the invariant that total number of committed regions is less than current heap size.
56 uint expand_dram(uint num_regions, WorkGang* pretouch_workers);
57
58 // Expand into nv-dimm.
59 uint expand_nvdimm(uint num_regions, WorkGang* pretouch_workers);
60
61 // Expand by finding unavailable regions in [start, end] range.
62 uint expand_in_range(uint start, uint end, uint num_regions, WorkGang* pretouch_workers);
63
64 // Shrink dram set of regions.
65 uint shrink_dram(uint num_regions, bool update_free_list = true);
66
67 // Shrink nv-dimm set of regions.
68 uint shrink_nvdimm(uint num_regions, bool update_free_list = true);
69
70 // Shrink regions from [start, end] range.
71 uint shrink_in_range(uint start, uint end, uint num_regions, bool update_free_list = true);
72
73 // Similar to find_empty_from_idx_reverse() in base class. Only here it searches in a range.
74 uint find_empty_in_range_reverse(uint start_idx, uint end_idx, uint* res_idx);
75
76 // Similar to find_contiguous() in base class, with [start, end] range
77 uint find_contiguous(size_t start, size_t end, size_t num, bool empty_only);
78
79 // This function is called when there are no free nv-dimm regions.
80 // It borrows a region from the set of unavailable regions in nv-dimm for GC purpose.
81 HeapRegion* borrow_old_region_for_gc();
82
83 uint free_list_dram_length() const;
84 uint free_list_nvdimm_length() const;
85
86 // is region with given index in nv-dimm?
87 bool is_in_nvdimm(uint index) const;
88 bool is_in_dram(uint index) const;
89
90 public:
91
92 // Empty constructor, we'll initialize it with the initialize() method.
93 HeterogeneousHeapRegionManager(uint num_regions) : _max_regions(num_regions), _max_dram_regions(0),
94 _max_nvdimm_regions(0), _start_index_of_nvdimm(0),
95 _total_commited_before_full_gc(0), _no_borrowed_regions(0)
96 {}
97
98 static HeterogeneousHeapRegionManager* manager();
99
100 virtual void initialize(G1RegionToSpaceMapper* heap_storage,
101 G1RegionToSpaceMapper* prev_bitmap,
102 G1RegionToSpaceMapper* next_bitmap,
103 G1RegionToSpaceMapper* bot,
104 G1RegionToSpaceMapper* cardtable,
105 G1RegionToSpaceMapper* card_counts);
106
107 uint start_index_of_nvdimm() const;
108 uint start_index_of_dram() const;
109 uint end_index_of_nvdimm() const;
110 uint end_index_of_dram() const;
111
112 // Override.
113 HeapRegion* get_dummy_region();
114
115 // Adjust dram_set to provision 'expected_num_regions' regions.
116 void adjust_dram_regions(uint expected_num_regions, WorkGang* pretouch_workers);
117
118 // Prepare heap regions before and after full collection.
119 void prepare_for_full_collection_start();
120 void prepare_for_full_collection_end();
121
122 virtual HeapRegion* allocate_free_region(HeapRegionType type, uint node_index);
123
124 // Return maximum number of regions that heap can expand to.
125 uint max_expandable_length() const;
126
127 // Override. Expand in nv-dimm.
128 uint expand_by(uint num_regions, WorkGang* pretouch_workers);
129
130 // Override.
131 uint expand_at(uint start, uint num_regions, WorkGang* pretouch_workers);
132
133 // Override. This function is called for humongous allocation, so we need to find empty regions in nv-dimm.
134 uint find_contiguous_only_empty(size_t num);
135
136 // Override. This function is called for humongous allocation, so we need to find empty or unavailable regions in nv-dimm.
137 uint find_contiguous_empty_or_unavailable(size_t num);
138
139 // Overrides base class implementation to find highest free region in dram.
140 uint find_highest_free(bool* expanded);
141
142 // Override. This fuction is called to shrink the heap, we shrink in dram first then in nv-dimm.
143 uint shrink_by(uint num_regions_to_remove);
144
145 bool has_borrowed_regions() const;
146
147 void verify();
148 };
149
150 #endif // SHARE_GC_G1_HETEROGENEOUSHEAPREGIONMANAGER_HPP