1 /*
2 * Copyright (c) 2001, 2014, 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_implementation/shared/mutableSpace.hpp"
30 #include "gc_implementation/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 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
37
38 MutableSpace::MutableSpace(size_t alignment): ImmutableSpace(), _top(NULL), _alignment(alignment) {
39 assert(MutableSpace::alignment() >= 0 &&
40 MutableSpace::alignment() % os::vm_page_size() == 0,
41 "Space should be aligned");
42 _mangler = new MutableSpaceMangler(this);
43 }
44
45 MutableSpace::~MutableSpace() {
46 delete _mangler;
47 }
48
49 void MutableSpace::numa_setup_pages(MemRegion mr, bool clear_space) {
50 if (!mr.is_empty()) {
51 size_t page_size = UseLargePages ? alignment() : os::vm_page_size();
52 HeapWord *start = (HeapWord*)round_to((intptr_t) mr.start(), page_size);
53 HeapWord *end = (HeapWord*)round_down((intptr_t) mr.end(), page_size);
54 if (end > start) {
55 size_t size = pointer_delta(end, start, sizeof(char));
56 if (clear_space) {
57 // Prefer page reallocation to migration.
58 os::free_memory((char*)start, size, page_size);
59 }
60 os::numa_make_global((char*)start, size);
61 }
62 }
63 }
64
65 void MutableSpace::pretouch_pages(MemRegion mr) {
66 for (volatile char *p = (char*)mr.start(); p < (char*)mr.end(); p += os::vm_page_size()) {
67 char t = *p; *p = t;
68 }
69 }
70
71 void MutableSpace::initialize(MemRegion mr,
72 bool clear_space,
73 bool mangle_space,
74 bool setup_pages) {
75
76 assert(Universe::on_page_boundary(mr.start()) && Universe::on_page_boundary(mr.end()),
77 "invalid space boundaries");
78
79 if (setup_pages && (UseNUMA || AlwaysPreTouch)) {
80 // The space may move left and right or expand/shrink.
81 // We'd like to enforce the desired page placement.
82 MemRegion head, tail;
83 if (last_setup_region().is_empty()) {
84 // If it's the first initialization don't limit the amount of work.
85 head = mr;
86 tail = MemRegion(mr.end(), mr.end());
87 } else {
88 // Is there an intersection with the address space?
89 MemRegion intersection = last_setup_region().intersection(mr);
90 if (intersection.is_empty()) {
91 intersection = MemRegion(mr.end(), mr.end());
92 }
93 // All the sizes below are in words.
94 size_t head_size = 0, tail_size = 0;
95 if (mr.start() <= intersection.start()) {
96 head_size = pointer_delta(intersection.start(), mr.start());
97 }
98 if(intersection.end() <= mr.end()) {
99 tail_size = pointer_delta(mr.end(), intersection.end());
100 }
101 // Limit the amount of page manipulation if necessary.
102 if (NUMASpaceResizeRate > 0 && !AlwaysPreTouch) {
103 const size_t change_size = head_size + tail_size;
104 const float setup_rate_words = NUMASpaceResizeRate >> LogBytesPerWord;
105 head_size = MIN2((size_t)(setup_rate_words * head_size / change_size),
106 head_size);
107 tail_size = MIN2((size_t)(setup_rate_words * tail_size / change_size),
108 tail_size);
109 }
110 head = MemRegion(intersection.start() - head_size, intersection.start());
111 tail = MemRegion(intersection.end(), intersection.end() + tail_size);
112 }
113 assert(mr.contains(head) && mr.contains(tail), "Sanity");
114
115 if (UseNUMA) {
116 numa_setup_pages(head, clear_space);
117 numa_setup_pages(tail, clear_space);
118 }
119
120 if (AlwaysPreTouch) {
121 pretouch_pages(head);
122 pretouch_pages(tail);
123 }
124
125 // Remember where we stopped so that we can continue later.
126 set_last_setup_region(MemRegion(head.start(), tail.end()));
127 }
128
129 set_bottom(mr.start());
130 set_end(mr.end());
131
132 if (clear_space) {
133 clear(mangle_space);
134 }
135 }
136
137 void MutableSpace::clear(bool mangle_space) {
138 set_top(bottom());
139 if (ZapUnusedHeapArea && mangle_space) {
140 mangle_unused_area();
141 }
142 }
143
144 #ifndef PRODUCT
145 void MutableSpace::check_mangled_unused_area(HeapWord* limit) {
146 mangler()->check_mangled_unused_area(limit);
147 }
148
149 void MutableSpace::check_mangled_unused_area_complete() {
150 mangler()->check_mangled_unused_area_complete();
151 }
152
153 // Mangle only the unused space that has not previously
154 // been mangled and that has not been allocated since being
155 // mangled.
156 void MutableSpace::mangle_unused_area() {
157 mangler()->mangle_unused_area();
158 }
159
160 void MutableSpace::mangle_unused_area_complete() {
161 mangler()->mangle_unused_area_complete();
162 }
163
164 void MutableSpace::mangle_region(MemRegion mr) {
165 SpaceMangler::mangle_region(mr);
166 }
167
168 void MutableSpace::set_top_for_allocations(HeapWord* v) {
169 mangler()->set_top_for_allocations(v);
170 }
171
172 void MutableSpace::set_top_for_allocations() {
173 mangler()->set_top_for_allocations(top());
174 }
175 #endif
176
177 // This version requires locking. */
178 HeapWord* MutableSpace::allocate(size_t size) {
179 assert(Heap_lock->owned_by_self() ||
180 (SafepointSynchronize::is_at_safepoint() &&
181 Thread::current()->is_VM_thread()),
182 "not locked");
183 HeapWord* obj = top();
184 if (pointer_delta(end(), obj) >= size) {
185 HeapWord* new_top = obj + size;
186 set_top(new_top);
187 assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
188 "checking alignment");
189 return obj;
190 } else {
191 return NULL;
192 }
193 }
194
195 // This version is lock-free.
196 HeapWord* MutableSpace::cas_allocate(size_t size) {
197 do {
198 HeapWord* obj = top();
199 if (pointer_delta(end(), obj) >= size) {
200 HeapWord* new_top = obj + size;
201 HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj);
202 // result can be one of two:
203 // the old top value: the exchange succeeded
204 // otherwise: the new value of the top is returned.
205 if (result != obj) {
206 continue; // another thread beat us to the allocation, try again
207 }
208 assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
209 "checking alignment");
210 return obj;
211 } else {
212 return NULL;
213 }
214 } while (true);
215 }
216
217 // Try to deallocate previous allocation. Returns true upon success.
218 bool MutableSpace::cas_deallocate(HeapWord *obj, size_t size) {
219 HeapWord* expected_top = obj + size;
220 return (HeapWord*)Atomic::cmpxchg_ptr(obj, top_addr(), expected_top) == expected_top;
221 }
222
223 void MutableSpace::oop_iterate(ExtendedOopClosure* cl) {
224 HeapWord* obj_addr = bottom();
225 HeapWord* t = top();
226 // Could call objects iterate, but this is easier.
227 while (obj_addr < t) {
228 obj_addr += oop(obj_addr)->oop_iterate<false>(cl);
229 }
230 }
231
232 void MutableSpace::oop_iterate_no_header(OopClosure* cl) {
233 HeapWord* obj_addr = bottom();
234 HeapWord* t = top();
235 // Could call objects iterate, but this is easier.
236 while (obj_addr < t) {
237 obj_addr += oop(obj_addr)->oop_iterate_no_header(cl);
238 }
239 }
240
241 void MutableSpace::object_iterate(ObjectClosure* cl) {
242 HeapWord* p = bottom();
243 while (p < top()) {
244 cl->do_object(oop(p));
245 p += oop(p)->size();
246 }
247 }
248
249 void MutableSpace::print_short() const { print_short_on(tty); }
250 void MutableSpace::print_short_on( outputStream* st) const {
251 st->print(" space " SIZE_FORMAT "K, %d%% used", capacity_in_bytes() / K,
252 (int) ((double) used_in_bytes() * 100 / capacity_in_bytes()));
253 }
254
255 void MutableSpace::print() const { print_on(tty); }
256 void MutableSpace::print_on(outputStream* st) const {
257 MutableSpace::print_short_on(st);
258 st->print_cr(" [" INTPTR_FORMAT "," INTPTR_FORMAT "," INTPTR_FORMAT ")",
259 bottom(), top(), end());
260 }
261
262 void MutableSpace::verify() {
263 HeapWord* p = bottom();
264 HeapWord* t = top();
265 HeapWord* prev_p = NULL;
266 while (p < t) {
267 oop(p)->verify();
268 prev_p = p;
269 p += oop(p)->size();
270 }
271 guarantee(p == top(), "end of last object must match end of space");
272 }