1 /*
2 * Copyright (c) 2003, 2010, 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/parallelScavengeHeap.hpp"
29 #include "gc_implementation/parallelScavenge/psPermGen.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 size_t init_low_byte_size,
37 size_t min_low_byte_size,
38 size_t max_low_byte_size,
39 size_t init_high_byte_size,
40 size_t min_high_byte_size,
41 size_t max_high_byte_size,
42 size_t alignment) :
43 _virtual_spaces(old_young_rs, min_low_byte_size,
44 min_high_byte_size, alignment) {
45 assert(min_low_byte_size <= init_low_byte_size &&
46 init_low_byte_size <= max_low_byte_size, "Parameter check");
47 assert(min_high_byte_size <= init_high_byte_size &&
48 init_high_byte_size <= max_high_byte_size, "Parameter check");
49 // Create the generations differently based on the option to
50 // move the boundary.
51 if (UseAdaptiveGCBoundary) {
52 // Initialize the adjoining virtual spaces. Then pass the
53 // a virtual to each generation for initialization of the
54 // generation.
55
56 // Does the actual creation of the virtual spaces
57 _virtual_spaces.initialize(max_low_byte_size,
58 init_low_byte_size,
59 init_high_byte_size);
60
61 // Place the young gen at the high end. Passes in the virtual space.
62 _young_gen = new ASPSYoungGen(_virtual_spaces.high(),
63 _virtual_spaces.high()->committed_size(),
64 min_high_byte_size,
65 _virtual_spaces.high_byte_size_limit());
66
67 // Place the old gen at the low end. Passes in the virtual space.
68 _old_gen = new ASPSOldGen(_virtual_spaces.low(),
69 _virtual_spaces.low()->committed_size(),
70 min_low_byte_size,
71 _virtual_spaces.low_byte_size_limit(),
72 "old", 1);
73
74 young_gen()->initialize_work();
75 assert(young_gen()->reserved().byte_size() <= young_gen()->gen_size_limit(),
76 "Consistency check");
77 assert(old_young_rs.size() >= young_gen()->gen_size_limit(),
78 "Consistency check");
79
80 old_gen()->initialize_work("old", 1);
81 assert(old_gen()->reserved().byte_size() <= old_gen()->gen_size_limit(),
82 "Consistency check");
83 assert(old_young_rs.size() >= old_gen()->gen_size_limit(),
84 "Consistency check");
85 } else {
86
87 // Layout the reserved space for the generations.
88 ReservedSpace old_rs =
89 virtual_spaces()->reserved_space().first_part(max_low_byte_size);
90 ReservedSpace heap_rs =
91 virtual_spaces()->reserved_space().last_part(max_low_byte_size);
92 ReservedSpace young_rs = heap_rs.first_part(max_high_byte_size);
93 assert(young_rs.size() == heap_rs.size(), "Didn't reserve all of the heap");
94
95 // Create the generations. Virtual spaces are not passed in.
96 _young_gen = new PSYoungGen(init_high_byte_size,
97 min_high_byte_size,
98 max_high_byte_size);
99 _old_gen = new PSOldGen(init_low_byte_size,
100 min_low_byte_size,
101 max_low_byte_size,
102 "old", 1);
103
104 // The virtual spaces are created by the initialization of the gens.
105 _young_gen->initialize(young_rs, alignment);
106 assert(young_gen()->gen_size_limit() == young_rs.size(),
107 "Consistency check");
108 _old_gen->initialize(old_rs, alignment, "old", 1);
109 assert(old_gen()->gen_size_limit() == old_rs.size(), "Consistency check");
110 }
111 }
112
113 size_t AdjoiningGenerations::reserved_byte_size() {
114 return virtual_spaces()->reserved_space().size();
115 }
116
117
118 // Make checks on the current sizes of the generations and
119 // the contraints on the sizes of the generations. Push
120 // up the boundary within the contraints. A partial
121 // push can occur.
122 void AdjoiningGenerations::request_old_gen_expansion(size_t expand_in_bytes) {
123 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
124
125 assert_lock_strong(ExpandHeap_lock);
126 assert_locked_or_safepoint(Heap_lock);
127
128 // These sizes limit the amount the boundaries can move. Effectively,
129 // the generation says how much it is willing to yield to the other
130 // generation.
131 const size_t young_gen_available = young_gen()->available_for_contraction();
132 const size_t old_gen_available = old_gen()->available_for_expansion();
133 const size_t alignment = virtual_spaces()->alignment();
134 size_t change_in_bytes = MIN3(young_gen_available,
135 old_gen_available,
136 align_size_up_(expand_in_bytes, alignment));
137
138 if (change_in_bytes == 0) {
139 return;
140 }
141
142 if (TraceAdaptiveGCBoundary) {
143 gclog_or_tty->print_cr("Before expansion of old gen with boundary move");
144 gclog_or_tty->print_cr(" Requested change: 0x%x Attempted change: 0x%x",
145 expand_in_bytes, change_in_bytes);
146 if (!PrintHeapAtGC) {
147 Universe::print_on(gclog_or_tty);
148 }
149 gclog_or_tty->print_cr(" PSOldGen max size: " SIZE_FORMAT "K",
150 old_gen()->max_gen_size()/K);
151 }
152
153 // Move the boundary between the generations up (smaller young gen).
154 if (virtual_spaces()->adjust_boundary_up(change_in_bytes)) {
155 young_gen()->reset_after_change();
156 old_gen()->reset_after_change();
157 }
158
159 // The total reserved for the generations should match the sum
160 // of the two even if the boundary is moving.
161 assert(reserved_byte_size() ==
162 old_gen()->max_gen_size() + young_gen()->max_size(),
163 "Space is missing");
164 young_gen()->space_invariants();
165 old_gen()->space_invariants();
166
167 if (TraceAdaptiveGCBoundary) {
168 gclog_or_tty->print_cr("After expansion of old gen with boundary move");
169 if (!PrintHeapAtGC) {
170 Universe::print_on(gclog_or_tty);
171 }
172 gclog_or_tty->print_cr(" PSOldGen max size: " SIZE_FORMAT "K",
173 old_gen()->max_gen_size()/K);
174 }
175 }
176
177 // See comments on request_old_gen_expansion()
178 bool AdjoiningGenerations::request_young_gen_expansion(size_t expand_in_bytes) {
179 assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
180
181 // If eden is not empty, the boundary can be moved but no advantage
182 // can be made of the move since eden cannot be moved.
183 if (!young_gen()->eden_space()->is_empty()) {
184 return false;
185 }
186
187
188 bool result = false;
189 const size_t young_gen_available = young_gen()->available_for_expansion();
190 const size_t old_gen_available = old_gen()->available_for_contraction();
191 const size_t alignment = virtual_spaces()->alignment();
192 size_t change_in_bytes = MIN3(young_gen_available,
193 old_gen_available,
194 align_size_up_(expand_in_bytes, alignment));
195
196 if (change_in_bytes == 0) {
197 return false;
198 }
199
200 if (TraceAdaptiveGCBoundary) {
201 gclog_or_tty->print_cr("Before expansion of young gen with boundary move");
202 gclog_or_tty->print_cr(" Requested change: 0x%x Attempted change: 0x%x",
203 expand_in_bytes, change_in_bytes);
204 if (!PrintHeapAtGC) {
205 Universe::print_on(gclog_or_tty);
206 }
207 gclog_or_tty->print_cr(" PSYoungGen max size: " SIZE_FORMAT "K",
208 young_gen()->max_size()/K);
209 }
210
211 // Move the boundary between the generations down (smaller old gen).
212 MutexLocker x(ExpandHeap_lock);
213 if (virtual_spaces()->adjust_boundary_down(change_in_bytes)) {
214 young_gen()->reset_after_change();
215 old_gen()->reset_after_change();
216 result = true;
217 }
218
219 // The total reserved for the generations should match the sum
220 // of the two even if the boundary is moving.
221 assert(reserved_byte_size() ==
222 old_gen()->max_gen_size() + young_gen()->max_size(),
223 "Space is missing");
224 young_gen()->space_invariants();
225 old_gen()->space_invariants();
226
227 if (TraceAdaptiveGCBoundary) {
228 gclog_or_tty->print_cr("After expansion of young gen with boundary move");
229 if (!PrintHeapAtGC) {
230 Universe::print_on(gclog_or_tty);
231 }
232 gclog_or_tty->print_cr(" PSYoungGen max size: " SIZE_FORMAT "K",
233 young_gen()->max_size()/K);
234 }
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 }