1 /*
2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/g1/g1BiasedArray.hpp"
27 #include "gc/g1/g1RegionToSpaceMapper.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "memory/virtualspace.hpp"
30 #include "services/memTracker.hpp"
31 #include "utilities/align.hpp"
32 #include "utilities/bitMap.inline.hpp"
33
34 G1RegionToSpaceMapper::G1RegionToSpaceMapper(ReservedSpace rs,
35 size_t used_size,
36 size_t page_size,
37 size_t region_granularity,
38 size_t commit_factor,
39 MemoryType type) :
40 _storage(rs, used_size, page_size),
41 _region_granularity(region_granularity),
42 _listener(NULL),
43 _commit_map(rs.size() * commit_factor / region_granularity) {
44 guarantee(is_power_of_2(page_size), "must be");
45 guarantee(is_power_of_2(region_granularity), "must be");
46
47 MemTracker::record_virtual_memory_type((address)rs.base(), type);
48 }
49
50 // G1RegionToSpaceMapper implementation where the region granularity is larger than
51 // or the same as the commit granularity.
52 // Basically, the space corresponding to one region region spans several OS pages.
53 class G1RegionsLargerThanCommitSizeMapper : public G1RegionToSpaceMapper {
54 private:
55 size_t _pages_per_region;
56
57 public:
58 G1RegionsLargerThanCommitSizeMapper(ReservedSpace rs,
59 size_t actual_size,
60 size_t page_size,
61 size_t alloc_granularity,
62 size_t commit_factor,
63 MemoryType type) :
64 G1RegionToSpaceMapper(rs, actual_size, page_size, alloc_granularity, commit_factor, type),
65 _pages_per_region(alloc_granularity / (page_size * commit_factor)) {
66
67 guarantee(alloc_granularity >= page_size, "allocation granularity smaller than commit granularity");
68 }
69
70 virtual void commit_regions(uint start_idx, size_t num_regions, WorkGang* pretouch_gang) {
71 size_t const start_page = (size_t)start_idx * _pages_per_region;
72 bool zero_filled = _storage.commit(start_page, num_regions * _pages_per_region);
73 if (AlwaysPreTouch) {
74 _storage.pretouch(start_page, num_regions * _pages_per_region, pretouch_gang);
75 }
76 _commit_map.set_range(start_idx, start_idx + num_regions);
77 fire_on_commit(start_idx, num_regions, zero_filled);
78 }
79
80 virtual void uncommit_regions(uint start_idx, size_t num_regions) {
81 _storage.uncommit((size_t)start_idx * _pages_per_region, num_regions * _pages_per_region);
82 _commit_map.clear_range(start_idx, start_idx + num_regions);
83 }
84 };
85
86 // G1RegionToSpaceMapper implementation where the region granularity is smaller
87 // than the commit granularity.
88 // Basically, the contents of one OS page span several regions.
89 class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper {
90 private:
91 class CommitRefcountArray : public G1BiasedMappedArray<uint> {
92 protected:
93 virtual uint default_value() const { return 0; }
94 };
95
96 size_t _regions_per_page;
97
98 CommitRefcountArray _refcounts;
99
100 uintptr_t region_idx_to_page_idx(uint region) const {
101 return region / _regions_per_page;
102 }
103
104 public:
105 G1RegionsSmallerThanCommitSizeMapper(ReservedSpace rs,
106 size_t actual_size,
107 size_t page_size,
108 size_t alloc_granularity,
109 size_t commit_factor,
110 MemoryType type) :
111 G1RegionToSpaceMapper(rs, actual_size, page_size, alloc_granularity, commit_factor, type),
112 _regions_per_page((page_size * commit_factor) / alloc_granularity), _refcounts() {
113
114 guarantee((page_size * commit_factor) >= alloc_granularity, "allocation granularity smaller than commit granularity");
115 _refcounts.initialize((HeapWord*)rs.base(), (HeapWord*)(rs.base() + align_up(rs.size(), page_size)), page_size);
116 }
117
118 virtual void commit_regions(uint start_idx, size_t num_regions, WorkGang* pretouch_gang) {
119 size_t const NoPage = ~(size_t)0;
120
121 size_t first_committed = NoPage;
122 size_t num_committed = 0;
123
124 bool all_zero_filled = true;
125
126 for (uint i = start_idx; i < start_idx + num_regions; i++) {
127 assert(!_commit_map.at(i), "Trying to commit storage at region %u that is already committed", i);
128 size_t idx = region_idx_to_page_idx(i);
129 uint old_refcount = _refcounts.get_by_index(idx);
130
131 bool zero_filled = false;
132 if (old_refcount == 0) {
133 if (first_committed == NoPage) {
134 first_committed = idx;
135 num_committed = 1;
136 } else {
137 num_committed++;
138 }
139 zero_filled = _storage.commit(idx, 1);
140 }
141 all_zero_filled &= zero_filled;
142
143 _refcounts.set_by_index(idx, old_refcount + 1);
144 _commit_map.set_bit(i);
145 }
146 if (AlwaysPreTouch && num_committed > 0) {
147 _storage.pretouch(first_committed, num_committed, pretouch_gang);
148 }
149 fire_on_commit(start_idx, num_regions, all_zero_filled);
150 }
151
152 virtual void uncommit_regions(uint start_idx, size_t num_regions) {
153 for (uint i = start_idx; i < start_idx + num_regions; i++) {
154 assert(_commit_map.at(i), "Trying to uncommit storage at region %u that is not committed", i);
155 size_t idx = region_idx_to_page_idx(i);
156 uint old_refcount = _refcounts.get_by_index(idx);
157 assert(old_refcount > 0, "must be");
158 if (old_refcount == 1) {
159 _storage.uncommit(idx, 1);
160 }
161 _refcounts.set_by_index(idx, old_refcount - 1);
162 _commit_map.clear_bit(i);
163 }
164 }
165 };
166
167 void G1RegionToSpaceMapper::fire_on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
168 if (_listener != NULL) {
169 _listener->on_commit(start_idx, num_regions, zero_filled);
170 }
171 }
172
173 G1RegionToSpaceMapper* G1RegionToSpaceMapper::create_mapper(ReservedSpace rs,
174 size_t actual_size,
175 size_t page_size,
176 size_t region_granularity,
177 size_t commit_factor,
178 MemoryType type) {
179
180 if (region_granularity >= (page_size * commit_factor)) {
181 return new G1RegionsLargerThanCommitSizeMapper(rs, actual_size, page_size, region_granularity, commit_factor, type);
182 } else {
183 return new G1RegionsSmallerThanCommitSizeMapper(rs, actual_size, page_size, region_granularity, commit_factor, type);
184 }
185 }