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(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 // Layout the reserved space for the generations.
94 // If OldGen is allocated on nv-dimm, we need to split the reservation (this is required for windows).
95 ReservedSpace old_rs =
96 virtual_spaces()->reserved_space().first_part(max_low_byte_size, AllocateOldGenAt != NULL /* split */);
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 AdjoiningGenerations::AdjoiningGenerations() { }
121
122 size_t AdjoiningGenerations::reserved_byte_size() {
123 return virtual_spaces()->reserved_space().size();
124 }
125
126 void log_before_expansion(bool old, size_t expand_in_bytes, size_t change_in_bytes, size_t max_size) {
127 Log(heap, ergo) log;
128 if (!log.is_debug()) {
129 return;
130 }
131 log.debug("Before expansion of %s gen with boundary move", old ? "old" : "young");
132 log.debug(" Requested change: " SIZE_FORMAT_HEX " Attempted change: " SIZE_FORMAT_HEX,
133 expand_in_bytes, change_in_bytes);
134 ResourceMark rm;
135 LogStream ls(log.debug());
136 ParallelScavengeHeap::heap()->print_on(&ls);
137 log.debug(" PS%sGen max size: " SIZE_FORMAT "K", old ? "Old" : "Young", max_size/K);
138 }
139
140 void log_after_expansion(bool old, size_t max_size) {
141 Log(heap, ergo) log;
142 if (!log.is_debug()) {
143 return;
144 }
145 log.debug("After expansion of %s gen with boundary move", old ? "old" : "young");
146 ResourceMark rm;
147 LogStream ls(log.debug());
148 ParallelScavengeHeap::heap()->print_on(&ls);
149 log.debug(" PS%sGen max size: " SIZE_FORMAT "K", old ? "Old" : "Young", max_size/K);
150 }
151
152 // Make checks on the current sizes of the generations and
153 // the constraints on the sizes of the generations. Push
154 // up the boundary within the constraints. A partial
155 // push can occur.
156 void AdjoiningGenerations::request_old_gen_expansion(size_t expand_in_bytes) {
157 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
158
159 assert_lock_strong(ExpandHeap_lock);
160 assert_locked_or_safepoint(Heap_lock);
161
162 // These sizes limit the amount the boundaries can move. Effectively,
163 // the generation says how much it is willing to yield to the other
164 // generation.
165 const size_t young_gen_available = young_gen()->available_for_contraction();
166 const size_t old_gen_available = old_gen()->available_for_expansion();
167 const size_t alignment = virtual_spaces()->alignment();
168 size_t change_in_bytes = MIN3(young_gen_available,
169 old_gen_available,
170 align_up(expand_in_bytes, alignment));
171
172 if (change_in_bytes == 0) {
173 return;
174 }
175
176 log_before_expansion(true, expand_in_bytes, change_in_bytes, old_gen()->max_gen_size());
177
178 // Move the boundary between the generations up (smaller young gen).
179 if (virtual_spaces()->adjust_boundary_up(change_in_bytes)) {
180 young_gen()->reset_after_change();
181 old_gen()->reset_after_change();
182 }
183
184 // The total reserved for the generations should match the sum
185 // of the two even if the boundary is moving.
186 assert(reserved_byte_size() ==
187 old_gen()->max_gen_size() + young_gen()->max_size(),
188 "Space is missing");
189 young_gen()->space_invariants();
190 old_gen()->space_invariants();
191
192 log_after_expansion(true, old_gen()->max_gen_size());
193 }
194
195 // See comments on request_old_gen_expansion()
196 bool AdjoiningGenerations::request_young_gen_expansion(size_t expand_in_bytes) {
197 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
198
199 // If eden is not empty, the boundary can be moved but no advantage
200 // can be made of the move since eden cannot be moved.
201 if (!young_gen()->eden_space()->is_empty()) {
202 return false;
203 }
204
205
206 bool result = false;
207 const size_t young_gen_available = young_gen()->available_for_expansion();
208 const size_t old_gen_available = old_gen()->available_for_contraction();
209 const size_t alignment = virtual_spaces()->alignment();
210 size_t change_in_bytes = MIN3(young_gen_available,
211 old_gen_available,
212 align_up(expand_in_bytes, alignment));
213
214 if (change_in_bytes == 0) {
215 return false;
216 }
217
218 log_before_expansion(false, expand_in_bytes, change_in_bytes, young_gen()->max_size());
219
220 // Move the boundary between the generations down (smaller old gen).
221 MutexLocker x(ExpandHeap_lock);
222 if (virtual_spaces()->adjust_boundary_down(change_in_bytes)) {
223 young_gen()->reset_after_change();
224 old_gen()->reset_after_change();
225 result = true;
226 }
227
228 // The total reserved for the generations should match the sum
229 // of the two even if the boundary is moving.
230 assert(reserved_byte_size() ==
231 old_gen()->max_gen_size() + young_gen()->max_size(),
232 "Space is missing");
233 young_gen()->space_invariants();
234 old_gen()->space_invariants();
235
236 log_after_expansion(false, young_gen()->max_size());
237
238 return result;
239 }
240
241 // Additional space is needed in the old generation. Try to move the boundary
242 // up to meet the need. Moves boundary up only
243 void AdjoiningGenerations::adjust_boundary_for_old_gen_needs(
244 size_t desired_free_space) {
245 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
246
247 // Stress testing.
248 if (PSAdaptiveSizePolicyResizeVirtualSpaceAlot == 1) {
249 MutexLocker x(ExpandHeap_lock);
250 request_old_gen_expansion(virtual_spaces()->alignment() * 3 / 2);
251 }
252
253 // Expand only if the entire generation is already committed.
254 if (old_gen()->virtual_space()->uncommitted_size() == 0) {
255 if (old_gen()->free_in_bytes() < desired_free_space) {
256 MutexLocker x(ExpandHeap_lock);
257 request_old_gen_expansion(desired_free_space);
258 }
259 }
260 }
261
262 // See comment on adjust_boundary_for_old_gen_needss().
263 // Adjust boundary down only.
264 void AdjoiningGenerations::adjust_boundary_for_young_gen_needs(size_t eden_size,
265 size_t survivor_size) {
266
267 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
268
269 // Stress testing.
270 if (PSAdaptiveSizePolicyResizeVirtualSpaceAlot == 0) {
271 request_young_gen_expansion(virtual_spaces()->alignment() * 3 / 2);
272 eden_size = young_gen()->eden_space()->capacity_in_bytes();
273 }
274
275 // Expand only if the entire generation is already committed.
276 if (young_gen()->virtual_space()->uncommitted_size() == 0) {
277 size_t desired_size = eden_size + 2 * survivor_size;
278 const size_t committed = young_gen()->virtual_space()->committed_size();
279 if (desired_size > committed) {
280 request_young_gen_expansion(desired_size - committed);
281 }
282 }
283 }