1 /*
2 * Copyright (c) 2001, 2016, 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 "oops/oop.inline.hpp"
29 #include "runtime/atomic.hpp"
30 #include "runtime/safepoint.hpp"
31 #include "runtime/thread.hpp"
32 #include "utilities/align.hpp"
33 #include "utilities/macros.hpp"
34
35 MutableSpace::MutableSpace(size_t alignment): ImmutableSpace(), _top(NULL), _alignment(alignment) {
36 assert(MutableSpace::alignment() % os::vm_page_size() == 0,
37 "Space should be aligned");
38 _mangler = new MutableSpaceMangler(this);
39 }
40
41 MutableSpace::~MutableSpace() {
42 delete _mangler;
43 }
44
45 void MutableSpace::numa_setup_pages(MemRegion mr, bool clear_space) {
46 if (!mr.is_empty()) {
47 size_t page_size = UseLargePages ? alignment() : os::vm_page_size();
48 HeapWord *start = align_up(mr.start(), page_size);
49 HeapWord *end = align_down(mr.end(), page_size);
50 if (end > start) {
51 size_t size = pointer_delta(end, start, sizeof(char));
52 if (clear_space) {
53 // Prefer page reallocation to migration.
54 os::free_memory((char*)start, size, page_size);
55 }
56 os::numa_make_global((char*)start, size);
57 }
58 }
59 }
60
61 void MutableSpace::pretouch_pages(MemRegion mr) {
62 os::pretouch_memory(mr.start(), mr.end());
63 }
64
65 void MutableSpace::initialize(MemRegion mr,
66 bool clear_space,
67 bool mangle_space,
68 bool setup_pages) {
69
70 assert(Universe::on_page_boundary(mr.start()) && Universe::on_page_boundary(mr.end()),
71 "invalid space boundaries");
72
73 if (setup_pages && (UseNUMA || AlwaysPreTouch)) {
74 // The space may move left and right or expand/shrink.
75 // We'd like to enforce the desired page placement.
76 MemRegion head, tail;
77 if (last_setup_region().is_empty()) {
78 // If it's the first initialization don't limit the amount of work.
79 head = mr;
80 tail = MemRegion(mr.end(), mr.end());
81 } else {
82 // Is there an intersection with the address space?
83 MemRegion intersection = last_setup_region().intersection(mr);
84 if (intersection.is_empty()) {
85 intersection = MemRegion(mr.end(), mr.end());
86 }
87 // All the sizes below are in words.
88 size_t head_size = 0, tail_size = 0;
89 if (mr.start() <= intersection.start()) {
90 head_size = pointer_delta(intersection.start(), mr.start());
91 }
92 if(intersection.end() <= mr.end()) {
93 tail_size = pointer_delta(mr.end(), intersection.end());
94 }
95 // Limit the amount of page manipulation if necessary.
96 if (NUMASpaceResizeRate > 0 && !AlwaysPreTouch) {
97 const size_t change_size = head_size + tail_size;
98 const float setup_rate_words = NUMASpaceResizeRate >> LogBytesPerWord;
99 head_size = MIN2((size_t)(setup_rate_words * head_size / change_size),
100 head_size);
101 tail_size = MIN2((size_t)(setup_rate_words * tail_size / change_size),
102 tail_size);
103 }
104 head = MemRegion(intersection.start() - head_size, intersection.start());
105 tail = MemRegion(intersection.end(), intersection.end() + tail_size);
106 }
107 assert(mr.contains(head) && mr.contains(tail), "Sanity");
108
109 if (UseNUMA) {
110 numa_setup_pages(head, clear_space);
111 numa_setup_pages(tail, clear_space);
112 }
113
114 if (AlwaysPreTouch) {
115 pretouch_pages(head);
116 pretouch_pages(tail);
117 }
118
119 // Remember where we stopped so that we can continue later.
120 set_last_setup_region(MemRegion(head.start(), tail.end()));
121 }
122
123 set_bottom(mr.start());
124 set_end(mr.end());
125
126 if (clear_space) {
127 clear(mangle_space);
128 }
129 }
130
131 void MutableSpace::clear(bool mangle_space) {
132 set_top(bottom());
133 if (ZapUnusedHeapArea && mangle_space) {
134 mangle_unused_area();
135 }
136 }
137
138 #ifndef PRODUCT
139 void MutableSpace::check_mangled_unused_area(HeapWord* limit) {
140 mangler()->check_mangled_unused_area(limit);
141 }
142
143 void MutableSpace::check_mangled_unused_area_complete() {
144 mangler()->check_mangled_unused_area_complete();
145 }
146
147 // Mangle only the unused space that has not previously
148 // been mangled and that has not been allocated since being
149 // mangled.
150 void MutableSpace::mangle_unused_area() {
151 mangler()->mangle_unused_area();
152 }
153
154 void MutableSpace::mangle_unused_area_complete() {
155 mangler()->mangle_unused_area_complete();
156 }
157
158 void MutableSpace::mangle_region(MemRegion mr) {
159 SpaceMangler::mangle_region(mr);
160 }
161
162 void MutableSpace::set_top_for_allocations(HeapWord* v) {
163 mangler()->set_top_for_allocations(v);
164 }
165
166 void MutableSpace::set_top_for_allocations() {
167 mangler()->set_top_for_allocations(top());
168 }
169 #endif
170
171 // This version requires locking. */
172 HeapWord* MutableSpace::allocate(size_t size) {
173 assert(Heap_lock->owned_by_self() ||
174 (SafepointSynchronize::is_at_safepoint() &&
175 Thread::current()->is_VM_thread()),
176 "not locked");
177 HeapWord* obj = top();
178 if (pointer_delta(end(), obj) >= size) {
179 HeapWord* new_top = obj + size;
180 set_top(new_top);
181 assert(is_object_aligned(obj) && is_object_aligned(new_top),
182 "checking alignment");
183 return obj;
184 } else {
185 return NULL;
186 }
187 }
188
189 // This version is lock-free.
190 HeapWord* MutableSpace::cas_allocate(size_t size) {
191 do {
192 HeapWord* obj = top();
193 if (pointer_delta(end(), obj) >= size) {
194 HeapWord* new_top = obj + size;
195 HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj);
196 // result can be one of two:
197 // the old top value: the exchange succeeded
198 // otherwise: the new value of the top is returned.
199 if (result != obj) {
200 continue; // another thread beat us to the allocation, try again
201 }
202 assert(is_object_aligned(obj) && is_object_aligned(new_top),
203 "checking alignment");
204 return obj;
205 } else {
206 return NULL;
207 }
208 } while (true);
209 }
210
211 // Try to deallocate previous allocation. Returns true upon success.
212 bool MutableSpace::cas_deallocate(HeapWord *obj, size_t size) {
213 HeapWord* expected_top = obj + size;
214 return (HeapWord*)Atomic::cmpxchg_ptr(obj, top_addr(), expected_top) == expected_top;
215 }
216
217 void MutableSpace::oop_iterate_no_header(OopClosure* cl) {
218 HeapWord* obj_addr = bottom();
219 HeapWord* t = top();
220 // Could call objects iterate, but this is easier.
221 while (obj_addr < t) {
222 obj_addr += oop(obj_addr)->oop_iterate_no_header(cl);
223 }
224 }
225
226 void MutableSpace::object_iterate(ObjectClosure* cl) {
227 HeapWord* p = bottom();
228 while (p < top()) {
229 cl->do_object(oop(p));
230 p += oop(p)->size();
231 }
232 }
233
234 void MutableSpace::print_short() const { print_short_on(tty); }
235 void MutableSpace::print_short_on( outputStream* st) const {
236 st->print(" space " SIZE_FORMAT "K, %d%% used", capacity_in_bytes() / K,
237 (int) ((double) used_in_bytes() * 100 / capacity_in_bytes()));
238 }
239
240 void MutableSpace::print() const { print_on(tty); }
241 void MutableSpace::print_on(outputStream* st) const {
242 MutableSpace::print_short_on(st);
243 st->print_cr(" [" INTPTR_FORMAT "," INTPTR_FORMAT "," INTPTR_FORMAT ")",
244 p2i(bottom()), p2i(top()), p2i(end()));
245 }
246
247 void MutableSpace::verify() {
248 HeapWord* p = bottom();
249 HeapWord* t = top();
250 HeapWord* prev_p = NULL;
251 while (p < t) {
252 oop(p)->verify();
253 prev_p = p;
254 p += oop(p)->size();
255 }
256 guarantee(p == top(), "end of last object must match end of space");
257 }