1 /*
2 * Copyright (c) 2003, 2012, 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_implementation/parallelScavenge/adjoiningGenerations.hpp"
27 #include "gc_implementation/parallelScavenge/adjoiningVirtualSpaces.hpp"
28 #include "gc_implementation/parallelScavenge/generationSizer.hpp"
29 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
30
31 // If boundary moving is being used, create the young gen and old
32 // gen with ASPSYoungGen and ASPSOldGen, respectively. Revert to
33 // the old behavior otherwise (with PSYoungGen and PSOldGen).
34
35 AdjoiningGenerations::AdjoiningGenerations(ReservedSpace old_young_rs,
36 GenerationSizer* policy,
37 size_t alignment) :
38 _virtual_spaces(old_young_rs, policy->min_gen1_size(),
39 policy->min_gen0_size(), alignment) {
40 size_t init_low_byte_size = policy->initial_gen1_size();
41 size_t min_low_byte_size = policy->min_gen1_size();
42 size_t max_low_byte_size = policy->max_gen1_size();
43 size_t init_high_byte_size = policy->initial_gen0_size();
44 size_t min_high_byte_size = policy->min_gen0_size();
45 size_t max_high_byte_size = policy->max_gen0_size();
46
47 assert(min_low_byte_size <= init_low_byte_size &&
48 init_low_byte_size <= max_low_byte_size, "Parameter check");
49 assert(min_high_byte_size <= init_high_byte_size &&
50 init_high_byte_size <= max_high_byte_size, "Parameter check");
51 // Create the generations differently based on the option to
52 // move the boundary.
53 if (UseAdaptiveGCBoundary) {
54 // Initialize the adjoining virtual spaces. Then pass the
55 // a virtual to each generation for initialization of the
56 // generation.
57
58 // Does the actual creation of the virtual spaces
59 _virtual_spaces.initialize(max_low_byte_size,
60 init_low_byte_size,
61 init_high_byte_size);
62
63 // Place the young gen at the high end. Passes in the virtual space.
64 _young_gen = new ASPSYoungGen(_virtual_spaces.high(),
65 _virtual_spaces.high()->committed_size(),
66 min_high_byte_size,
67 _virtual_spaces.high_byte_size_limit());
68
69 // Place the old gen at the low end. Passes in the virtual space.
70 _old_gen = new ASPSOldGen(_virtual_spaces.low(),
71 _virtual_spaces.low()->committed_size(),
72 min_low_byte_size,
73 _virtual_spaces.low_byte_size_limit(),
74 "old", 1);
75
76 young_gen()->initialize_work();
77 assert(young_gen()->reserved().byte_size() <= young_gen()->gen_size_limit(),
78 "Consistency check");
79 assert(old_young_rs.size() >= young_gen()->gen_size_limit(),
80 "Consistency check");
81
82 old_gen()->initialize_work("old", 1);
83 assert(old_gen()->reserved().byte_size() <= old_gen()->gen_size_limit(),
84 "Consistency check");
85 assert(old_young_rs.size() >= old_gen()->gen_size_limit(),
86 "Consistency check");
87 } else {
88
89 // Layout the reserved space for the generations.
90 ReservedSpace old_rs =
91 virtual_spaces()->reserved_space().first_part(max_low_byte_size);
92 ReservedSpace heap_rs =
93 virtual_spaces()->reserved_space().last_part(max_low_byte_size);
94 ReservedSpace young_rs = heap_rs.first_part(max_high_byte_size);
95 assert(young_rs.size() == heap_rs.size(), "Didn't reserve all of the heap");
96
97 // Create the generations. Virtual spaces are not passed in.
98 _young_gen = new PSYoungGen(init_high_byte_size,
99 min_high_byte_size,
100 max_high_byte_size);
101 _old_gen = new PSOldGen(init_low_byte_size,
102 min_low_byte_size,
103 max_low_byte_size,
104 "old", 1);
105
106 // The virtual spaces are created by the initialization of the gens.
107 _young_gen->initialize(young_rs, alignment);
108 assert(young_gen()->gen_size_limit() == young_rs.size(),
109 "Consistency check");
110 _old_gen->initialize(old_rs, alignment, "old", 1);
111 assert(old_gen()->gen_size_limit() == old_rs.size(), "Consistency check");
112 }
113 }
114
115 size_t AdjoiningGenerations::reserved_byte_size() {
116 return virtual_spaces()->reserved_space().size();
117 }
118
119
120 // Make checks on the current sizes of the generations and
121 // the contraints on the sizes of the generations. Push
122 // up the boundary within the contraints. A partial
123 // push can occur.
124 void AdjoiningGenerations::request_old_gen_expansion(size_t expand_in_bytes) {
125 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
126
127 assert_lock_strong(ExpandHeap_lock);
128 assert_locked_or_safepoint(Heap_lock);
129
130 // These sizes limit the amount the boundaries can move. Effectively,
131 // the generation says how much it is willing to yield to the other
132 // generation.
133 const size_t young_gen_available = young_gen()->available_for_contraction();
134 const size_t old_gen_available = old_gen()->available_for_expansion();
135 const size_t alignment = virtual_spaces()->alignment();
136 size_t change_in_bytes = MIN3(young_gen_available,
137 old_gen_available,
138 align_size_up_(expand_in_bytes, alignment));
139
140 if (change_in_bytes == 0) {
141 return;
142 }
143
144 if (TraceAdaptiveGCBoundary) {
145 gclog_or_tty->print_cr("Before expansion of old gen with boundary move");
146 gclog_or_tty->print_cr(" Requested change: 0x%x Attempted change: 0x%x",
147 expand_in_bytes, change_in_bytes);
148 if (!PrintHeapAtGC) {
149 Universe::print_on(gclog_or_tty);
150 }
151 gclog_or_tty->print_cr(" PSOldGen max size: " SIZE_FORMAT "K",
152 old_gen()->max_gen_size()/K);
153 }
154
155 // Move the boundary between the generations up (smaller young gen).
156 if (virtual_spaces()->adjust_boundary_up(change_in_bytes)) {
157 young_gen()->reset_after_change();
158 old_gen()->reset_after_change();
159 }
160
161 // The total reserved for the generations should match the sum
162 // of the two even if the boundary is moving.
163 assert(reserved_byte_size() ==
164 old_gen()->max_gen_size() + young_gen()->max_size(),
165 "Space is missing");
166 young_gen()->space_invariants();
167 old_gen()->space_invariants();
168
169 if (TraceAdaptiveGCBoundary) {
170 gclog_or_tty->print_cr("After expansion of old gen with boundary move");
171 if (!PrintHeapAtGC) {
172 Universe::print_on(gclog_or_tty);
173 }
174 gclog_or_tty->print_cr(" PSOldGen max size: " SIZE_FORMAT "K",
175 old_gen()->max_gen_size()/K);
176 }
177 }
178
179 // See comments on request_old_gen_expansion()
180 bool AdjoiningGenerations::request_young_gen_expansion(size_t expand_in_bytes) {
181 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
182
183 // If eden is not empty, the boundary can be moved but no advantage
184 // can be made of the move since eden cannot be moved.
185 if (!young_gen()->eden_space()->is_empty()) {
186 return false;
187 }
188
189
190 bool result = false;
191 const size_t young_gen_available = young_gen()->available_for_expansion();
192 const size_t old_gen_available = old_gen()->available_for_contraction();
193 const size_t alignment = virtual_spaces()->alignment();
194 size_t change_in_bytes = MIN3(young_gen_available,
195 old_gen_available,
196 align_size_up_(expand_in_bytes, alignment));
197
198 if (change_in_bytes == 0) {
199 return false;
200 }
201
202 if (TraceAdaptiveGCBoundary) {
203 gclog_or_tty->print_cr("Before expansion of young gen with boundary move");
204 gclog_or_tty->print_cr(" Requested change: 0x%x Attempted change: 0x%x",
205 expand_in_bytes, change_in_bytes);
206 if (!PrintHeapAtGC) {
207 Universe::print_on(gclog_or_tty);
208 }
209 gclog_or_tty->print_cr(" PSYoungGen max size: " SIZE_FORMAT "K",
210 young_gen()->max_size()/K);
211 }
212
213 // Move the boundary between the generations down (smaller old gen).
214 MutexLocker x(ExpandHeap_lock);
215 if (virtual_spaces()->adjust_boundary_down(change_in_bytes)) {
216 young_gen()->reset_after_change();
217 old_gen()->reset_after_change();
218 result = true;
219 }
220
221 // The total reserved for the generations should match the sum
222 // of the two even if the boundary is moving.
223 assert(reserved_byte_size() ==
224 old_gen()->max_gen_size() + young_gen()->max_size(),
225 "Space is missing");
226 young_gen()->space_invariants();
227 old_gen()->space_invariants();
228
229 if (TraceAdaptiveGCBoundary) {
230 gclog_or_tty->print_cr("After expansion of young gen with boundary move");
231 if (!PrintHeapAtGC) {
232 Universe::print_on(gclog_or_tty);
233 }
234 gclog_or_tty->print_cr(" PSYoungGen max size: " SIZE_FORMAT "K",
235 young_gen()->max_size()/K);
236 }
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 }