1 /*
2 * Copyright (c) 2001, 2018, 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/parallel/mutableSpace.hpp"
27 #include "gc/shared/spaceDecorator.hpp"
28 #include "memory/iterator.inline.hpp"
29 #include "memory/universe.hpp"
30 #include "oops/oop.inline.hpp"
31 #include "runtime/atomic.hpp"
32 #include "runtime/safepoint.hpp"
33 #include "runtime/thread.hpp"
34 #include "utilities/align.hpp"
35 #include "utilities/macros.hpp"
36
37 MutableSpace::MutableSpace(size_t alignment): ImmutableSpace(), _alignment(alignment), _top(NULL) {
38 assert(MutableSpace::alignment() % os::vm_page_size() == 0,
39 "Space should be aligned");
40 _mangler = new MutableSpaceMangler(this);
41 }
42
43 MutableSpace::~MutableSpace() {
44 delete _mangler;
45 }
46
47 void MutableSpace::numa_setup_pages(MemRegion mr, bool clear_space) {
48 if (!mr.is_empty()) {
49 size_t page_size = UseLargePages ? alignment() : os::vm_page_size();
50 HeapWord *start = align_up(mr.start(), page_size);
51 HeapWord *end = align_down(mr.end(), page_size);
52 if (end > start) {
53 size_t size = pointer_delta(end, start, sizeof(char));
54 if (clear_space) {
55 // Prefer page reallocation to migration.
56 os::free_memory((char*)start, size, page_size);
57 }
58 os::numa_make_global((char*)start, size);
59 }
60 }
61 }
62
63 void MutableSpace::pretouch_pages(MemRegion mr) {
64 os::pretouch_memory(mr.start(), mr.end());
65 }
66
67 void MutableSpace::initialize(MemRegion mr,
68 bool clear_space,
69 bool mangle_space,
70 bool setup_pages) {
71
72 assert(Universe::on_page_boundary(mr.start()) && Universe::on_page_boundary(mr.end()),
73 "invalid space boundaries");
74
75 if (setup_pages && (UseNUMA || AlwaysPreTouch)) {
76 // The space may move left and right or expand/shrink.
77 // We'd like to enforce the desired page placement.
78 MemRegion head, tail;
79 if (last_setup_region().is_empty()) {
80 // If it's the first initialization don't limit the amount of work.
81 head = mr;
82 tail = MemRegion(mr.end(), mr.end());
83 } else {
84 // Is there an intersection with the address space?
85 MemRegion intersection = last_setup_region().intersection(mr);
86 if (intersection.is_empty()) {
87 intersection = MemRegion(mr.end(), mr.end());
88 }
89 // All the sizes below are in words.
90 size_t head_size = 0, tail_size = 0;
91 if (mr.start() <= intersection.start()) {
92 head_size = pointer_delta(intersection.start(), mr.start());
93 }
94 if(intersection.end() <= mr.end()) {
95 tail_size = pointer_delta(mr.end(), intersection.end());
96 }
97 // Limit the amount of page manipulation if necessary.
98 if (NUMASpaceResizeRate > 0 && !AlwaysPreTouch) {
99 const size_t change_size = head_size + tail_size;
100 const float setup_rate_words = NUMASpaceResizeRate >> LogBytesPerWord;
101 head_size = MIN2((size_t)(setup_rate_words * head_size / change_size),
102 head_size);
103 tail_size = MIN2((size_t)(setup_rate_words * tail_size / change_size),
104 tail_size);
105 }
106 head = MemRegion(intersection.start() - head_size, intersection.start());
107 tail = MemRegion(intersection.end(), intersection.end() + tail_size);
108 }
109 assert(mr.contains(head) && mr.contains(tail), "Sanity");
110
111 if (UseNUMA) {
112 numa_setup_pages(head, clear_space);
113 numa_setup_pages(tail, clear_space);
114 }
115
116 if (AlwaysPreTouch) {
117 pretouch_pages(head);
118 pretouch_pages(tail);
119 }
120
121 // Remember where we stopped so that we can continue later.
122 set_last_setup_region(MemRegion(head.start(), tail.end()));
123 }
124
125 set_bottom(mr.start());
126 set_end(mr.end());
127
128 if (clear_space) {
129 clear(mangle_space);
130 }
131 }
132
133 void MutableSpace::clear(bool mangle_space) {
134 set_top(bottom());
135 if (ZapUnusedHeapArea && mangle_space) {
136 mangle_unused_area();
137 }
138 }
139
140 #ifndef PRODUCT
141 void MutableSpace::check_mangled_unused_area(HeapWord* limit) {
142 mangler()->check_mangled_unused_area(limit);
143 }
144
145 void MutableSpace::check_mangled_unused_area_complete() {
146 mangler()->check_mangled_unused_area_complete();
147 }
148
149 // Mangle only the unused space that has not previously
150 // been mangled and that has not been allocated since being
151 // mangled.
152 void MutableSpace::mangle_unused_area() {
153 mangler()->mangle_unused_area();
154 }
155
156 void MutableSpace::mangle_unused_area_complete() {
157 mangler()->mangle_unused_area_complete();
158 }
159
160 void MutableSpace::mangle_region(MemRegion mr) {
161 SpaceMangler::mangle_region(mr);
162 }
163
164 void MutableSpace::set_top_for_allocations(HeapWord* v) {
165 mangler()->set_top_for_allocations(v);
166 }
167
168 void MutableSpace::set_top_for_allocations() {
169 mangler()->set_top_for_allocations(top());
170 }
171 #endif
172
173 // This version requires locking. */
174 HeapWord* MutableSpace::allocate(size_t size) {
175 assert(Heap_lock->owned_by_self() ||
176 (SafepointSynchronize::is_at_safepoint() &&
177 Thread::current()->is_VM_thread()),
178 "not locked");
179 HeapWord* obj = top();
180 if (pointer_delta(end(), obj) >= size) {
181 HeapWord* new_top = obj + size;
182 set_top(new_top);
183 assert(is_object_aligned(obj) && is_object_aligned(new_top),
184 "checking alignment");
185 return obj;
186 } else {
187 return NULL;
188 }
189 }
190
191 // This version is lock-free.
192 HeapWord* MutableSpace::cas_allocate(size_t size) {
193 do {
194 HeapWord* obj = top();
195 if (pointer_delta(end(), obj) >= size) {
196 HeapWord* new_top = obj + size;
197 HeapWord* result = Atomic::cmpxchg(new_top, top_addr(), obj);
198 // result can be one of two:
199 // the old top value: the exchange succeeded
200 // otherwise: the new value of the top is returned.
201 if (result != obj) {
202 continue; // another thread beat us to the allocation, try again
203 }
204 assert(is_object_aligned(obj) && is_object_aligned(new_top),
205 "checking alignment");
206 return obj;
207 } else {
208 return NULL;
209 }
210 } while (true);
211 }
212
213 // Try to deallocate previous allocation. Returns true upon success.
214 bool MutableSpace::cas_deallocate(HeapWord *obj, size_t size) {
215 HeapWord* expected_top = obj + size;
216 return Atomic::cmpxchg(obj, top_addr(), expected_top) == expected_top;
217 }
218
219 void MutableSpace::oop_iterate(OopIterateClosure* cl) {
220 HeapWord* obj_addr = bottom();
221 HeapWord* t = top();
222 // Could call objects iterate, but this is easier.
223 while (obj_addr < t) {
224 obj_addr += oop(obj_addr)->oop_iterate_size(cl);
225 }
226 }
227
228 void MutableSpace::object_iterate(ObjectClosure* cl) {
229 HeapWord* p = bottom();
230 while (p < top()) {
231 cl->do_object(oop(p));
232 p += oop(p)->size();
233 }
234 }
235
236 void MutableSpace::print_short() const { print_short_on(tty); }
237 void MutableSpace::print_short_on( outputStream* st) const {
238 st->print(" space " SIZE_FORMAT "K, %d%% used", capacity_in_bytes() / K,
239 (int) ((double) used_in_bytes() * 100 / capacity_in_bytes()));
240 }
241
242 void MutableSpace::print() const { print_on(tty); }
243 void MutableSpace::print_on(outputStream* st) const {
244 MutableSpace::print_short_on(st);
245 st->print_cr(" [" INTPTR_FORMAT "," INTPTR_FORMAT "," INTPTR_FORMAT ")",
246 p2i(bottom()), p2i(top()), p2i(end()));
247 }
248
249 void MutableSpace::verify() {
250 HeapWord* p = bottom();
251 HeapWord* t = top();
252 HeapWord* prev_p = NULL;
253 while (p < t) {
254 oopDesc::verify(oop(p));
255 prev_p = p;
256 p += oop(p)->size();
257 }
258 guarantee(p == top(), "end of last object must match end of space");
259 }