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