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