1 /*
2 * Copyright (c) 2001, 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 "runtime/atomic.inline.hpp"
27 #include "utilities/macros.hpp"
28 #if INCLUDE_ALL_GCS
29 #include "gc/shared/mutableSpace.hpp"
30 #include "gc/shared/spaceDecorator.hpp"
31 #include "oops/oop.inline.hpp"
32 #include "runtime/safepoint.hpp"
33 #include "runtime/thread.hpp"
34 #endif // INCLUDE_ALL_GCS
35
36 MutableSpace::MutableSpace(size_t alignment): ImmutableSpace(), _top(NULL), _alignment(alignment) {
37 assert(MutableSpace::alignment() % os::vm_page_size() == 0,
38 "Space should be aligned");
39 _mangler = new MutableSpaceMangler(this);
40 }
41
42 MutableSpace::~MutableSpace() {
43 delete _mangler;
44 }
45
46 void MutableSpace::numa_setup_pages(MemRegion mr, bool clear_space) {
47 if (!mr.is_empty()) {
48 size_t page_size = UseLargePages ? alignment() : os::vm_page_size();
49 HeapWord *start = (HeapWord*)round_to((intptr_t) mr.start(), page_size);
50 HeapWord *end = (HeapWord*)round_down((intptr_t) mr.end(), page_size);
51 if (end > start) {
52 size_t size = pointer_delta(end, start, sizeof(char));
53 if (clear_space) {
54 // Prefer page reallocation to migration.
55 os::free_memory((char*)start, size, page_size);
56 }
57 os::numa_make_global((char*)start, size);
58 }
59 }
60 }
61
62 void MutableSpace::pretouch_pages(MemRegion mr) {
63 os::pretouch_memory((char*)mr.start(), (char*)mr.end());
64 }
65
66 void MutableSpace::initialize(MemRegion mr,
67 bool clear_space,
68 bool mangle_space,
69 bool setup_pages) {
70
71 assert(Universe::on_page_boundary(mr.start()) && Universe::on_page_boundary(mr.end()),
72 "invalid space boundaries");
73
74 if (setup_pages && (UseNUMA || AlwaysPreTouch)) {
75 // The space may move left and right or expand/shrink.
76 // We'd like to enforce the desired page placement.
77 MemRegion head, tail;
78 if (last_setup_region().is_empty()) {
79 // If it's the first initialization don't limit the amount of work.
80 head = mr;
81 tail = MemRegion(mr.end(), mr.end());
82 } else {
83 // Is there an intersection with the address space?
84 MemRegion intersection = last_setup_region().intersection(mr);
85 if (intersection.is_empty()) {
86 intersection = MemRegion(mr.end(), mr.end());
87 }
88 // All the sizes below are in words.
89 size_t head_size = 0, tail_size = 0;
90 if (mr.start() <= intersection.start()) {
91 head_size = pointer_delta(intersection.start(), mr.start());
92 }
93 if(intersection.end() <= mr.end()) {
94 tail_size = pointer_delta(mr.end(), intersection.end());
95 }
96 // Limit the amount of page manipulation if necessary.
97 if (NUMASpaceResizeRate > 0 && !AlwaysPreTouch) {
98 const size_t change_size = head_size + tail_size;
99 const float setup_rate_words = NUMASpaceResizeRate >> LogBytesPerWord;
100 head_size = MIN2((size_t)(setup_rate_words * head_size / change_size),
101 head_size);
102 tail_size = MIN2((size_t)(setup_rate_words * tail_size / change_size),
103 tail_size);
104 }
105 head = MemRegion(intersection.start() - head_size, intersection.start());
106 tail = MemRegion(intersection.end(), intersection.end() + tail_size);
107 }
108 assert(mr.contains(head) && mr.contains(tail), "Sanity");
109
110 if (UseNUMA) {
111 numa_setup_pages(head, clear_space);
112 numa_setup_pages(tail, clear_space);
113 }
114
115 if (AlwaysPreTouch) {
116 pretouch_pages(head);
117 pretouch_pages(tail);
118 }
119
120 // Remember where we stopped so that we can continue later.
121 set_last_setup_region(MemRegion(head.start(), tail.end()));
122 }
123
124 set_bottom(mr.start());
125 set_end(mr.end());
126
127 if (clear_space) {
128 clear(mangle_space);
129 }
130 }
131
132 void MutableSpace::clear(bool mangle_space) {
133 set_top(bottom());
134 if (ZapUnusedHeapArea && mangle_space) {
135 mangle_unused_area();
136 }
137 }
138
139 #ifndef PRODUCT
140 void MutableSpace::check_mangled_unused_area(HeapWord* limit) {
141 mangler()->check_mangled_unused_area(limit);
142 }
143
144 void MutableSpace::check_mangled_unused_area_complete() {
145 mangler()->check_mangled_unused_area_complete();
146 }
147
148 // Mangle only the unused space that has not previously
149 // been mangled and that has not been allocated since being
150 // mangled.
151 void MutableSpace::mangle_unused_area() {
152 mangler()->mangle_unused_area();
153 }
154
155 void MutableSpace::mangle_unused_area_complete() {
156 mangler()->mangle_unused_area_complete();
157 }
158
159 void MutableSpace::mangle_region(MemRegion mr) {
160 SpaceMangler::mangle_region(mr);
161 }
162
163 void MutableSpace::set_top_for_allocations(HeapWord* v) {
164 mangler()->set_top_for_allocations(v);
165 }
166
167 void MutableSpace::set_top_for_allocations() {
168 mangler()->set_top_for_allocations(top());
169 }
170 #endif
171
172 // This version requires locking. */
173 HeapWord* MutableSpace::allocate(size_t size) {
174 assert(Heap_lock->owned_by_self() ||
175 (SafepointSynchronize::is_at_safepoint() &&
176 Thread::current()->is_VM_thread()),
177 "not locked");
178 HeapWord* obj = top();
179 if (pointer_delta(end(), obj) >= size) {
180 HeapWord* new_top = obj + size;
181 set_top(new_top);
182 assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
183 "checking alignment");
184 return obj;
185 } else {
186 return NULL;
187 }
188 }
189
190 // This version is lock-free.
191 HeapWord* MutableSpace::cas_allocate(size_t size) {
192 do {
193 HeapWord* obj = top();
194 if (pointer_delta(end(), obj) >= size) {
195 HeapWord* new_top = obj + size;
196 HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj);
197 // result can be one of two:
198 // the old top value: the exchange succeeded
199 // otherwise: the new value of the top is returned.
200 if (result != obj) {
201 continue; // another thread beat us to the allocation, try again
202 }
203 assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
204 "checking alignment");
205 return obj;
206 } else {
207 return NULL;
208 }
209 } while (true);
210 }
211
212 // Try to deallocate previous allocation. Returns true upon success.
213 bool MutableSpace::cas_deallocate(HeapWord *obj, size_t size) {
214 HeapWord* expected_top = obj + size;
215 return (HeapWord*)Atomic::cmpxchg_ptr(obj, top_addr(), expected_top) == expected_top;
216 }
217
218 void MutableSpace::oop_iterate(ExtendedOopClosure* cl) {
219 HeapWord* obj_addr = bottom();
220 HeapWord* t = top();
221 // Could call objects iterate, but this is easier.
222 while (obj_addr < t) {
223 obj_addr += oop(obj_addr)->oop_iterate(cl);
224 }
225 }
226
227 void MutableSpace::oop_iterate_no_header(OopClosure* cl) {
228 HeapWord* obj_addr = bottom();
229 HeapWord* t = top();
230 // Could call objects iterate, but this is easier.
231 while (obj_addr < t) {
232 obj_addr += oop(obj_addr)->oop_iterate_no_header(cl);
233 }
234 }
235
236 void MutableSpace::object_iterate(ObjectClosure* cl) {
237 HeapWord* p = bottom();
238 while (p < top()) {
239 cl->do_object(oop(p));
240 p += oop(p)->size();
241 }
242 }
243
244 void MutableSpace::print_short() const { print_short_on(tty); }
245 void MutableSpace::print_short_on( outputStream* st) const {
246 st->print(" space " SIZE_FORMAT "K, %d%% used", capacity_in_bytes() / K,
247 (int) ((double) used_in_bytes() * 100 / capacity_in_bytes()));
248 }
249
250 void MutableSpace::print() const { print_on(tty); }
251 void MutableSpace::print_on(outputStream* st) const {
252 MutableSpace::print_short_on(st);
253 st->print_cr(" [" INTPTR_FORMAT "," INTPTR_FORMAT "," INTPTR_FORMAT ")",
254 p2i(bottom()), p2i(top()), p2i(end()));
255 }
256
257 void MutableSpace::verify() {
258 HeapWord* p = bottom();
259 HeapWord* t = top();
260 HeapWord* prev_p = NULL;
261 while (p < t) {
262 oop(p)->verify();
263 prev_p = p;
264 p += oop(p)->size();
265 }
266 guarantee(p == top(), "end of last object must match end of space");
267 }