1 /*
2 * Copyright (c) 2014, 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 "code/codeCache.hpp"
27 #include "code/nmethod.hpp"
28 #include "gc/g1/g1CodeRootSetTable.hpp"
29 #include "gc/g1/g1CodeCacheRemSet.hpp"
30 #include "gc/g1/heapRegion.hpp"
31 #include "memory/heap.hpp"
32 #include "memory/iterator.hpp"
33 #include "oops/access.inline.hpp"
34 #include "oops/oop.inline.hpp"
35 #include "utilities/hashtable.inline.hpp"
36 #include "utilities/stack.inline.hpp"
37
38 G1CodeRootSetTable* volatile G1CodeRootSetTable::_purge_list = NULL;
39
40 size_t G1CodeRootSetTable::mem_size() {
41 return sizeof(G1CodeRootSetTable) + (entry_size() * number_of_entries()) + (sizeof(HashtableBucket<mtGC>) * table_size());
42 }
43
44 G1CodeRootSetTable::Entry* G1CodeRootSetTable::new_entry(nmethod* nm) {
45 unsigned int hash = compute_hash(nm);
46 Entry* entry = (Entry*) new_entry_free_list();
47 if (entry == NULL) {
48 entry = (Entry*) NEW_C_HEAP_ARRAY2(char, entry_size(), mtGC, CURRENT_PC);
49 }
50 entry->set_next(NULL);
51 entry->set_hash(hash);
52 entry->set_literal(nm);
53 return entry;
54 }
55
56 void G1CodeRootSetTable::remove_entry(Entry* e, Entry* previous) {
57 int index = hash_to_index(e->hash());
58 assert((e == bucket(index)) == (previous == NULL), "if e is the first entry then previous should be null");
59
60 if (previous == NULL) {
61 set_entry(index, e->next());
62 } else {
63 previous->set_next(e->next());
64 }
65 free_entry(e);
66 }
67
68 G1CodeRootSetTable::~G1CodeRootSetTable() {
69 for (int index = 0; index < table_size(); ++index) {
70 for (Entry* e = bucket(index); e != NULL; ) {
71 Entry* to_remove = e;
72 // read next before freeing.
73 e = e->next();
74 unlink_entry(to_remove);
75 FREE_C_HEAP_ARRAY(char, to_remove);
76 }
77 }
78 assert(number_of_entries() == 0, "should have removed all entries");
79 // Each of the entries in new_entry_free_list() have been allocated in
80 // G1CodeRootSetTable::new_entry(). We never call the block allocator
81 // in BasicHashtable::new_entry().
82 for (BasicHashtableEntry<mtGC>* e = new_entry_free_list(); e != NULL; e = new_entry_free_list()) {
83 FREE_C_HEAP_ARRAY(char, e);
84 }
85 }
86
87 bool G1CodeRootSetTable::add(nmethod* nm) {
88 if (!contains(nm)) {
89 Entry* e = new_entry(nm);
90 int index = hash_to_index(e->hash());
91 add_entry(index, e);
92 return true;
93 }
94 return false;
95 }
96
97 bool G1CodeRootSetTable::contains(nmethod* nm) {
98 int index = hash_to_index(compute_hash(nm));
99 for (Entry* e = bucket(index); e != NULL; e = e->next()) {
100 if (e->literal() == nm) {
101 return true;
102 }
103 }
104 return false;
105 }
106
107 bool G1CodeRootSetTable::remove(nmethod* nm) {
108 int index = hash_to_index(compute_hash(nm));
109 Entry* previous = NULL;
110 for (Entry* e = bucket(index); e != NULL; previous = e, e = e->next()) {
111 if (e->literal() == nm) {
112 remove_entry(e, previous);
113 return true;
114 }
115 }
116 return false;
117 }
118
119 void G1CodeRootSetTable::copy_to(G1CodeRootSetTable* new_table) {
120 for (int index = 0; index < table_size(); ++index) {
121 for (Entry* e = bucket(index); e != NULL; e = e->next()) {
122 new_table->add(e->literal());
123 }
124 }
125 new_table->copy_freelist(this);
126 }
127
128 void G1CodeRootSetTable::nmethods_do(CodeBlobClosure* blk) {
129 for (int index = 0; index < table_size(); ++index) {
130 for (Entry* e = bucket(index); e != NULL; e = e->next()) {
131 blk->do_code_blob(e->literal());
132 }
133 }
134 }
135
136 template<typename CB>
137 int G1CodeRootSetTable::remove_if(CB& should_remove) {
138 int num_removed = 0;
139 for (int index = 0; index < table_size(); ++index) {
140 Entry* previous = NULL;
141 Entry* e = bucket(index);
142 while (e != NULL) {
143 Entry* next = e->next();
144 if (should_remove(e->literal())) {
145 remove_entry(e, previous);
146 ++num_removed;
147 } else {
148 previous = e;
149 }
150 e = next;
151 }
152 }
153 return num_removed;
154 }
155
156 G1CodeRootSet::~G1CodeRootSet() {
157 delete _table;
158 }
159
160 G1CodeRootSetTable* G1CodeRootSet::load_acquire_table() {
161 return Atomic::load_acquire(&_table);
162 }
163
164 void G1CodeRootSet::allocate_small_table() {
165 G1CodeRootSetTable* temp = new G1CodeRootSetTable(SmallSize);
166
167 Atomic::release_store(&_table, temp);
168 }
169
170 void G1CodeRootSetTable::purge_list_append(G1CodeRootSetTable* table) {
171 for (;;) {
172 table->_purge_next = _purge_list;
173 G1CodeRootSetTable* old = Atomic::cmpxchg(table, &_purge_list, table->_purge_next);
174 if (old == table->_purge_next) {
175 break;
176 }
177 }
178 }
179
180 void G1CodeRootSetTable::purge() {
181 G1CodeRootSetTable* table = _purge_list;
182 _purge_list = NULL;
183 while (table != NULL) {
184 G1CodeRootSetTable* to_purge = table;
185 table = table->_purge_next;
186 delete to_purge;
187 }
188 }
189
190 void G1CodeRootSet::move_to_large() {
191 G1CodeRootSetTable* temp = new G1CodeRootSetTable(LargeSize);
192
193 _table->copy_to(temp);
194
195 G1CodeRootSetTable::purge_list_append(_table);
196
197 Atomic::release_store(&_table, temp);
198 }
199
200 void G1CodeRootSet::purge() {
201 G1CodeRootSetTable::purge();
202 }
203
204 size_t G1CodeRootSet::static_mem_size() {
205 return G1CodeRootSetTable::static_mem_size();
206 }
207
208 void G1CodeRootSet::add(nmethod* method) {
209 bool added = false;
210 if (is_empty()) {
211 allocate_small_table();
212 }
213 added = _table->add(method);
214 if (added) {
215 if (_length == Threshold) {
216 move_to_large();
217 }
218 ++_length;
219 }
220 assert(_length == (size_t)_table->number_of_entries(), "sizes should match");
221 }
222
223 bool G1CodeRootSet::remove(nmethod* method) {
224 bool removed = false;
225 if (_table != NULL) {
226 removed = _table->remove(method);
227 }
228 if (removed) {
229 _length--;
230 if (_length == 0) {
231 clear();
232 }
233 }
234 assert((_length == 0 && _table == NULL) ||
235 (_length == (size_t)_table->number_of_entries()), "sizes should match");
236 return removed;
237 }
238
239 bool G1CodeRootSet::contains(nmethod* method) {
240 G1CodeRootSetTable* table = load_acquire_table(); // contains() may be called outside of lock, so ensure mem sync.
241 if (table != NULL) {
242 return table->contains(method);
243 }
244 return false;
245 }
246
247 void G1CodeRootSet::clear() {
248 delete _table;
249 _table = NULL;
250 _length = 0;
251 }
252
253 size_t G1CodeRootSet::mem_size() {
254 return sizeof(*this) + (_table != NULL ? _table->mem_size() : 0);
255 }
256
257 void G1CodeRootSet::nmethods_do(CodeBlobClosure* blk) const {
258 if (_table != NULL) {
259 _table->nmethods_do(blk);
260 }
261 }
262
263 class CleanCallback : public StackObj {
264 class PointsIntoHRDetectionClosure : public OopClosure {
265 HeapRegion* _hr;
266 public:
267 bool _points_into;
268 PointsIntoHRDetectionClosure(HeapRegion* hr) : _hr(hr), _points_into(false) {}
269
270 void do_oop(narrowOop* o) {
271 do_oop_work(o);
272 }
273
274 void do_oop(oop* o) {
275 do_oop_work(o);
276 }
277
278 template <typename T>
279 void do_oop_work(T* p) {
280 if (_hr->is_in(RawAccess<>::oop_load(p))) {
281 _points_into = true;
282 }
283 }
284 };
285
286 PointsIntoHRDetectionClosure _detector;
287 CodeBlobToOopClosure _blobs;
288
289 public:
290 CleanCallback(HeapRegion* hr) : _detector(hr), _blobs(&_detector, !CodeBlobToOopClosure::FixRelocations) {}
291
292 bool operator() (nmethod* nm) {
293 _detector._points_into = false;
294 _blobs.do_code_blob(nm);
295 return !_detector._points_into;
296 }
297 };
298
299 void G1CodeRootSet::clean(HeapRegion* owner) {
300 CleanCallback should_clean(owner);
301 if (_table != NULL) {
302 int removed = _table->remove_if(should_clean);
303 assert((size_t)removed <= _length, "impossible");
304 _length -= removed;
305 }
306 if (_length == 0) {
307 clear();
308 }
309 }