1 /*
2 * Copyright (c) 2003, 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/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(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 ReservedSpace old_rs =
96 virtual_spaces()->reserved_space().first_part(max_low_byte_size);
97 ReservedSpace heap_rs =
98 virtual_spaces()->reserved_space().last_part(max_low_byte_size);
99 ReservedSpace young_rs = heap_rs.first_part(max_high_byte_size);
100 assert(young_rs.size() == heap_rs.size(), "Didn't reserve all of the heap");
101
102 // Create the generations. Virtual spaces are not passed in.
103 _young_gen = new PSYoungGen(init_high_byte_size,
104 min_high_byte_size,
105 max_high_byte_size);
106 _old_gen = new PSOldGen(init_low_byte_size,
107 min_low_byte_size,
108 max_low_byte_size,
109 "old", 1);
110
111 // The virtual spaces are created by the initialization of the gens.
112 _young_gen->initialize(young_rs, alignment);
113 assert(young_gen()->gen_size_limit() == young_rs.size(),
114 "Consistency check");
115 _old_gen->initialize(old_rs, alignment, "old", 1);
116 assert(old_gen()->gen_size_limit() == old_rs.size(), "Consistency check");
117 }
118 }
119
120 size_t AdjoiningGenerations::reserved_byte_size() {
121 return virtual_spaces()->reserved_space().size();
122 }
123
124 void log_before_expansion(bool old, size_t expand_in_bytes, size_t change_in_bytes, size_t max_size) {
125 Log(heap, ergo) log;
126 if (!log.is_debug()) {
127 return;
128 }
129 log.debug("Before expansion of %s gen with boundary move", old ? "old" : "young");
130 log.debug(" Requested change: " SIZE_FORMAT_HEX " Attempted change: " SIZE_FORMAT_HEX,
131 expand_in_bytes, change_in_bytes);
132 ResourceMark rm;
133 LogStream ls(log.debug());
134 ParallelScavengeHeap::heap()->print_on(&ls);
135 log.debug(" PS%sGen max size: " SIZE_FORMAT "K", old ? "Old" : "Young", max_size/K);
136 }
137
138 void log_after_expansion(bool old, size_t max_size) {
139 Log(heap, ergo) log;
140 if (!log.is_debug()) {
141 return;
142 }
143 log.debug("After expansion of %s gen with boundary move", old ? "old" : "young");
144 ResourceMark rm;
145 LogStream ls(log.debug());
146 ParallelScavengeHeap::heap()->print_on(&ls);
147 log.debug(" PS%sGen max size: " SIZE_FORMAT "K", old ? "Old" : "Young", max_size/K);
148 }
149
150 // Make checks on the current sizes of the generations and
151 // the constraints on the sizes of the generations. Push
152 // up the boundary within the constraints. A partial
153 // push can occur.
154 void AdjoiningGenerations::request_old_gen_expansion(size_t expand_in_bytes) {
155 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
156
157 assert_lock_strong(ExpandHeap_lock);
158 assert_locked_or_safepoint(Heap_lock);
159
160 // These sizes limit the amount the boundaries can move. Effectively,
161 // the generation says how much it is willing to yield to the other
162 // generation.
163 const size_t young_gen_available = young_gen()->available_for_contraction();
164 const size_t old_gen_available = old_gen()->available_for_expansion();
165 const size_t alignment = virtual_spaces()->alignment();
166 size_t change_in_bytes = MIN3(young_gen_available,
167 old_gen_available,
168 align_up(expand_in_bytes, alignment));
169
170 if (change_in_bytes == 0) {
171 return;
172 }
173
174 log_before_expansion(true, expand_in_bytes, change_in_bytes, old_gen()->max_gen_size());
175
176 // Move the boundary between the generations up (smaller young gen).
177 if (virtual_spaces()->adjust_boundary_up(change_in_bytes)) {
178 young_gen()->reset_after_change();
179 old_gen()->reset_after_change();
180 }
181
182 // The total reserved for the generations should match the sum
183 // of the two even if the boundary is moving.
184 assert(reserved_byte_size() ==
185 old_gen()->max_gen_size() + young_gen()->max_size(),
186 "Space is missing");
187 young_gen()->space_invariants();
188 old_gen()->space_invariants();
189
190 log_after_expansion(true, old_gen()->max_gen_size());
191 }
192
193 // See comments on request_old_gen_expansion()
194 bool AdjoiningGenerations::request_young_gen_expansion(size_t expand_in_bytes) {
195 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
196
197 // If eden is not empty, the boundary can be moved but no advantage
198 // can be made of the move since eden cannot be moved.
199 if (!young_gen()->eden_space()->is_empty()) {
200 return false;
201 }
202
203
204 bool result = false;
205 const size_t young_gen_available = young_gen()->available_for_expansion();
206 const size_t old_gen_available = old_gen()->available_for_contraction();
207 const size_t alignment = virtual_spaces()->alignment();
208 size_t change_in_bytes = MIN3(young_gen_available,
209 old_gen_available,
210 align_up(expand_in_bytes, alignment));
211
212 if (change_in_bytes == 0) {
213 return false;
214 }
215
216 log_before_expansion(false, expand_in_bytes, change_in_bytes, young_gen()->max_size());
217
218 // Move the boundary between the generations down (smaller old gen).
219 MutexLocker x(ExpandHeap_lock);
220 if (virtual_spaces()->adjust_boundary_down(change_in_bytes)) {
221 young_gen()->reset_after_change();
222 old_gen()->reset_after_change();
223 result = true;
224 }
225
226 // The total reserved for the generations should match the sum
227 // of the two even if the boundary is moving.
228 assert(reserved_byte_size() ==
229 old_gen()->max_gen_size() + young_gen()->max_size(),
230 "Space is missing");
231 young_gen()->space_invariants();
232 old_gen()->space_invariants();
233
234 log_after_expansion(false, young_gen()->max_size());
235
236 return result;
237 }
238
239 // Additional space is needed in the old generation. Try to move the boundary
240 // up to meet the need. Moves boundary up only
241 void AdjoiningGenerations::adjust_boundary_for_old_gen_needs(
242 size_t desired_free_space) {
243 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
244
245 // Stress testing.
246 if (PSAdaptiveSizePolicyResizeVirtualSpaceAlot == 1) {
247 MutexLocker x(ExpandHeap_lock);
248 request_old_gen_expansion(virtual_spaces()->alignment() * 3 / 2);
249 }
250
251 // Expand only if the entire generation is already committed.
252 if (old_gen()->virtual_space()->uncommitted_size() == 0) {
253 if (old_gen()->free_in_bytes() < desired_free_space) {
254 MutexLocker x(ExpandHeap_lock);
255 request_old_gen_expansion(desired_free_space);
256 }
257 }
258 }
259
260 // See comment on adjust_boundary_for_old_gen_needss().
261 // Adjust boundary down only.
262 void AdjoiningGenerations::adjust_boundary_for_young_gen_needs(size_t eden_size,
263 size_t survivor_size) {
264
265 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
266
267 // Stress testing.
268 if (PSAdaptiveSizePolicyResizeVirtualSpaceAlot == 0) {
269 request_young_gen_expansion(virtual_spaces()->alignment() * 3 / 2);
270 eden_size = young_gen()->eden_space()->capacity_in_bytes();
271 }
272
273 // Expand only if the entire generation is already committed.
274 if (young_gen()->virtual_space()->uncommitted_size() == 0) {
275 size_t desired_size = eden_size + 2 * survivor_size;
276 const size_t committed = young_gen()->virtual_space()->committed_size();
277 if (desired_size > committed) {
278 request_young_gen_expansion(desired_size - committed);
279 }
280 }
281 }