1 /*
2 * Copyright (c) 2003, 2018, 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/parallel/adjoiningGenerations.hpp"
27 #include "gc/parallel/adjoiningVirtualSpaces.hpp"
28 #include "gc/parallel/generationSizer.hpp"
29 #include "gc/parallel/parallelScavengeHeap.hpp"
30 #include "logging/log.hpp"
31 #include "logging/logStream.hpp"
32 #include "memory/resourceArea.hpp"
33 #include "utilities/align.hpp"
34 #include "utilities/ostream.hpp"
35
36 // If boundary moving is being used, create the young gen and old
37 // gen with ASPSYoungGen and ASPSOldGen, respectively. Revert to
38 // the old behavior otherwise (with PSYoungGen and PSOldGen).
39
40 AdjoiningGenerations::AdjoiningGenerations(ReservedSpace old_young_rs,
41 GenerationSizer* policy,
42 size_t alignment) :
43 _virtual_spaces(new AdjoiningVirtualSpaces(old_young_rs, policy->min_old_size(),
44 policy->min_young_size(), alignment)) {
45 size_t init_low_byte_size = policy->initial_old_size();
46 size_t min_low_byte_size = policy->min_old_size();
47 size_t max_low_byte_size = policy->max_old_size();
48 size_t init_high_byte_size = policy->initial_young_size();
49 size_t min_high_byte_size = policy->min_young_size();
50 size_t max_high_byte_size = policy->max_young_size();
51
52 assert(min_low_byte_size <= init_low_byte_size &&
53 init_low_byte_size <= max_low_byte_size, "Parameter check");
54 assert(min_high_byte_size <= init_high_byte_size &&
55 init_high_byte_size <= max_high_byte_size, "Parameter check");
56 // Create the generations differently based on the option to
57 // move the boundary.
58 if (UseAdaptiveGCBoundary) {
59 // Initialize the adjoining virtual spaces. Then pass the
60 // a virtual to each generation for initialization of the
61 // generation.
62
63 // Does the actual creation of the virtual spaces
64 _virtual_spaces->initialize(max_low_byte_size,
65 init_low_byte_size,
66 init_high_byte_size);
67
68 // Place the young gen at the high end. Passes in the virtual space.
69 _young_gen = new ASPSYoungGen(_virtual_spaces->high(),
70 _virtual_spaces->high()->committed_size(),
71 min_high_byte_size,
72 _virtual_spaces->high_byte_size_limit());
73
74 // Place the old gen at the low end. Passes in the virtual space.
75 _old_gen = new ASPSOldGen(_virtual_spaces->low(),
76 _virtual_spaces->low()->committed_size(),
77 min_low_byte_size,
78 _virtual_spaces->low_byte_size_limit(),
79 "old", 1);
80
81 young_gen()->initialize_work();
82 assert(young_gen()->reserved().byte_size() <= young_gen()->gen_size_limit(),
83 "Consistency check");
84 assert(old_young_rs.size() >= young_gen()->gen_size_limit(),
85 "Consistency check");
86
87 old_gen()->initialize_work("old", 1);
88 assert(old_gen()->reserved().byte_size() <= old_gen()->gen_size_limit(),
89 "Consistency check");
90 assert(old_young_rs.size() >= old_gen()->gen_size_limit(),
91 "Consistency check");
92 } else {
93
94 // Layout the reserved space for the generations.
95 // If OldGen is allocated on nv-dimm, we need to split the reservation (this is required for windows).
96 ReservedSpace old_rs =
97 virtual_spaces()->reserved_space().first_part(max_low_byte_size, AllocateOldGenAt != NULL /* split */);
98 ReservedSpace heap_rs =
99 virtual_spaces()->reserved_space().last_part(max_low_byte_size);
100 ReservedSpace young_rs = heap_rs.first_part(max_high_byte_size);
101 assert(young_rs.size() == heap_rs.size(), "Didn't reserve all of the heap");
102
103 // Create the generations. Virtual spaces are not passed in.
104 _young_gen = new PSYoungGen(init_high_byte_size,
105 min_high_byte_size,
106 max_high_byte_size);
107 _old_gen = new PSOldGen(init_low_byte_size,
108 min_low_byte_size,
109 max_low_byte_size,
110 "old", 1);
111
112 // The virtual spaces are created by the initialization of the gens.
113 _young_gen->initialize(young_rs, alignment);
114 assert(young_gen()->gen_size_limit() == young_rs.size(),
115 "Consistency check");
116 _old_gen->initialize(old_rs, alignment, "old", 1);
117 assert(old_gen()->gen_size_limit() == old_rs.size(), "Consistency check");
118 }
119 }
120
121 AdjoiningGenerations::AdjoiningGenerations() { }
122
123 size_t AdjoiningGenerations::reserved_byte_size() {
124 return virtual_spaces()->reserved_space().size();
125 }
126
127 void log_before_expansion(bool old, size_t expand_in_bytes, size_t change_in_bytes, size_t max_size) {
128 Log(heap, ergo) log;
129 if (!log.is_debug()) {
130 return;
131 }
132 log.debug("Before expansion of %s gen with boundary move", old ? "old" : "young");
133 log.debug(" Requested change: " SIZE_FORMAT_HEX " Attempted change: " SIZE_FORMAT_HEX,
134 expand_in_bytes, change_in_bytes);
135 ResourceMark rm;
136 LogStream ls(log.debug());
137 ParallelScavengeHeap::heap()->print_on(&ls);
138 log.debug(" PS%sGen max size: " SIZE_FORMAT "K", old ? "Old" : "Young", max_size/K);
139 }
140
141 void log_after_expansion(bool old, size_t max_size) {
142 Log(heap, ergo) log;
143 if (!log.is_debug()) {
144 return;
145 }
146 log.debug("After expansion of %s gen with boundary move", old ? "old" : "young");
147 ResourceMark rm;
148 LogStream ls(log.debug());
149 ParallelScavengeHeap::heap()->print_on(&ls);
150 log.debug(" PS%sGen max size: " SIZE_FORMAT "K", old ? "Old" : "Young", max_size/K);
151 }
152
153 // Make checks on the current sizes of the generations and
154 // the constraints on the sizes of the generations. Push
155 // up the boundary within the constraints. A partial
156 // push can occur.
157 void AdjoiningGenerations::request_old_gen_expansion(size_t expand_in_bytes) {
158 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
159
160 assert_lock_strong(ExpandHeap_lock);
161 assert_locked_or_safepoint(Heap_lock);
162
163 // These sizes limit the amount the boundaries can move. Effectively,
164 // the generation says how much it is willing to yield to the other
165 // generation.
166 const size_t young_gen_available = young_gen()->available_for_contraction();
167 const size_t old_gen_available = old_gen()->available_for_expansion();
168 const size_t alignment = virtual_spaces()->alignment();
169 size_t change_in_bytes = MIN3(young_gen_available,
170 old_gen_available,
171 align_up(expand_in_bytes, alignment));
172
173 if (change_in_bytes == 0) {
174 return;
175 }
176
177 log_before_expansion(true, expand_in_bytes, change_in_bytes, old_gen()->max_gen_size());
178
179 // Move the boundary between the generations up (smaller young gen).
180 if (virtual_spaces()->adjust_boundary_up(change_in_bytes)) {
181 young_gen()->reset_after_change();
182 old_gen()->reset_after_change();
183 }
184
185 // The total reserved for the generations should match the sum
186 // of the two even if the boundary is moving.
187 assert(reserved_byte_size() ==
188 old_gen()->max_gen_size() + young_gen()->max_size(),
189 "Space is missing");
190 young_gen()->space_invariants();
191 old_gen()->space_invariants();
192
193 log_after_expansion(true, old_gen()->max_gen_size());
194 }
195
196 // See comments on request_old_gen_expansion()
197 bool AdjoiningGenerations::request_young_gen_expansion(size_t expand_in_bytes) {
198 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
199
200 // If eden is not empty, the boundary can be moved but no advantage
201 // can be made of the move since eden cannot be moved.
202 if (!young_gen()->eden_space()->is_empty()) {
203 return false;
204 }
205
206
207 bool result = false;
208 const size_t young_gen_available = young_gen()->available_for_expansion();
209 const size_t old_gen_available = old_gen()->available_for_contraction();
210 const size_t alignment = virtual_spaces()->alignment();
211 size_t change_in_bytes = MIN3(young_gen_available,
212 old_gen_available,
213 align_up(expand_in_bytes, alignment));
214
215 if (change_in_bytes == 0) {
216 return false;
217 }
218
219 log_before_expansion(false, expand_in_bytes, change_in_bytes, young_gen()->max_size());
220
221 // Move the boundary between the generations down (smaller old gen).
222 MutexLocker x(ExpandHeap_lock);
223 if (virtual_spaces()->adjust_boundary_down(change_in_bytes)) {
224 young_gen()->reset_after_change();
225 old_gen()->reset_after_change();
226 result = true;
227 }
228
229 // The total reserved for the generations should match the sum
230 // of the two even if the boundary is moving.
231 assert(reserved_byte_size() ==
232 old_gen()->max_gen_size() + young_gen()->max_size(),
233 "Space is missing");
234 young_gen()->space_invariants();
235 old_gen()->space_invariants();
236
237 log_after_expansion(false, young_gen()->max_size());
238
239 return result;
240 }
241
242 // Additional space is needed in the old generation. Try to move the boundary
243 // up to meet the need. Moves boundary up only
244 void AdjoiningGenerations::adjust_boundary_for_old_gen_needs(
245 size_t desired_free_space) {
246 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
247
248 // Stress testing.
249 if (PSAdaptiveSizePolicyResizeVirtualSpaceAlot == 1) {
250 MutexLocker x(ExpandHeap_lock);
251 request_old_gen_expansion(virtual_spaces()->alignment() * 3 / 2);
252 }
253
254 // Expand only if the entire generation is already committed.
255 if (old_gen()->virtual_space()->uncommitted_size() == 0) {
256 if (old_gen()->free_in_bytes() < desired_free_space) {
257 MutexLocker x(ExpandHeap_lock);
258 request_old_gen_expansion(desired_free_space);
259 }
260 }
261 }
262
263 // See comment on adjust_boundary_for_old_gen_needss().
264 // Adjust boundary down only.
265 void AdjoiningGenerations::adjust_boundary_for_young_gen_needs(size_t eden_size,
266 size_t survivor_size) {
267
268 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
269
270 // Stress testing.
271 if (PSAdaptiveSizePolicyResizeVirtualSpaceAlot == 0) {
272 request_young_gen_expansion(virtual_spaces()->alignment() * 3 / 2);
273 eden_size = young_gen()->eden_space()->capacity_in_bytes();
274 }
275
276 // Expand only if the entire generation is already committed.
277 if (young_gen()->virtual_space()->uncommitted_size() == 0) {
278 size_t desired_size = eden_size + 2 * survivor_size;
279 const size_t committed = young_gen()->virtual_space()->committed_size();
280 if (desired_size > committed) {
281 request_young_gen_expansion(desired_size - committed);
282 }
283 }
284 }