1 /*
2 * Copyright (c) 2014, 2017, 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 free_buckets();
80 for (BasicHashtableEntry<mtGC>* e = new_entry_free_list(); e != NULL; e = new_entry_free_list()) {
81 FREE_C_HEAP_ARRAY(char, e);
82 }
83 }
84
85 bool G1CodeRootSetTable::add(nmethod* nm) {
86 if (!contains(nm)) {
87 Entry* e = new_entry(nm);
88 int index = hash_to_index(e->hash());
89 add_entry(index, e);
90 return true;
91 }
92 return false;
93 }
94
95 bool G1CodeRootSetTable::contains(nmethod* nm) {
96 int index = hash_to_index(compute_hash(nm));
97 for (Entry* e = bucket(index); e != NULL; e = e->next()) {
98 if (e->literal() == nm) {
99 return true;
100 }
101 }
102 return false;
103 }
104
105 bool G1CodeRootSetTable::remove(nmethod* nm) {
106 int index = hash_to_index(compute_hash(nm));
107 Entry* previous = NULL;
108 for (Entry* e = bucket(index); e != NULL; previous = e, e = e->next()) {
109 if (e->literal() == nm) {
110 remove_entry(e, previous);
111 return true;
112 }
113 }
114 return false;
115 }
116
117 void G1CodeRootSetTable::copy_to(G1CodeRootSetTable* new_table) {
118 for (int index = 0; index < table_size(); ++index) {
119 for (Entry* e = bucket(index); e != NULL; e = e->next()) {
120 new_table->add(e->literal());
121 }
122 }
123 new_table->copy_freelist(this);
124 }
125
126 void G1CodeRootSetTable::nmethods_do(CodeBlobClosure* blk) {
127 for (int index = 0; index < table_size(); ++index) {
128 for (Entry* e = bucket(index); e != NULL; e = e->next()) {
129 blk->do_code_blob(e->literal());
130 }
131 }
132 }
133
134 template<typename CB>
135 int G1CodeRootSetTable::remove_if(CB& should_remove) {
136 int num_removed = 0;
137 for (int index = 0; index < table_size(); ++index) {
138 Entry* previous = NULL;
139 Entry* e = bucket(index);
140 while (e != NULL) {
141 Entry* next = e->next();
142 if (should_remove(e->literal())) {
143 remove_entry(e, previous);
144 ++num_removed;
145 } else {
146 previous = e;
147 }
148 e = next;
149 }
150 }
151 return num_removed;
152 }
153
154 G1CodeRootSet::~G1CodeRootSet() {
155 delete _table;
156 }
157
158 G1CodeRootSetTable* G1CodeRootSet::load_acquire_table() {
159 return OrderAccess::load_acquire(&_table);
160 }
161
162 void G1CodeRootSet::allocate_small_table() {
163 G1CodeRootSetTable* temp = new G1CodeRootSetTable(SmallSize);
164
165 OrderAccess::release_store(&_table, temp);
166 }
167
168 void G1CodeRootSetTable::purge_list_append(G1CodeRootSetTable* table) {
169 for (;;) {
170 table->_purge_next = _purge_list;
171 G1CodeRootSetTable* old = Atomic::cmpxchg(table, &_purge_list, table->_purge_next);
172 if (old == table->_purge_next) {
173 break;
174 }
175 }
176 }
177
178 void G1CodeRootSetTable::purge() {
179 G1CodeRootSetTable* table = _purge_list;
180 _purge_list = NULL;
181 while (table != NULL) {
182 G1CodeRootSetTable* to_purge = table;
183 table = table->_purge_next;
184 delete to_purge;
185 }
186 }
187
188 void G1CodeRootSet::move_to_large() {
189 G1CodeRootSetTable* temp = new G1CodeRootSetTable(LargeSize);
190
191 _table->copy_to(temp);
192
193 G1CodeRootSetTable::purge_list_append(_table);
194
195 OrderAccess::release_store(&_table, temp);
196 }
197
198 void G1CodeRootSet::purge() {
199 G1CodeRootSetTable::purge();
200 }
201
202 size_t G1CodeRootSet::static_mem_size() {
203 return G1CodeRootSetTable::static_mem_size();
204 }
205
206 void G1CodeRootSet::add(nmethod* method) {
207 bool added = false;
208 if (is_empty()) {
209 allocate_small_table();
210 }
211 added = _table->add(method);
212 if (added) {
213 if (_length == Threshold) {
214 move_to_large();
215 }
216 ++_length;
217 }
218 assert(_length == (size_t)_table->number_of_entries(), "sizes should match");
219 }
220
221 bool G1CodeRootSet::remove(nmethod* method) {
222 bool removed = false;
223 if (_table != NULL) {
224 removed = _table->remove(method);
225 }
226 if (removed) {
227 _length--;
228 if (_length == 0) {
229 clear();
230 }
231 }
232 assert((_length == 0 && _table == NULL) ||
233 (_length == (size_t)_table->number_of_entries()), "sizes should match");
234 return removed;
235 }
236
237 bool G1CodeRootSet::contains(nmethod* method) {
238 G1CodeRootSetTable* table = load_acquire_table(); // contains() may be called outside of lock, so ensure mem sync.
239 if (table != NULL) {
240 return table->contains(method);
241 }
242 return false;
243 }
244
245 void G1CodeRootSet::clear() {
246 delete _table;
247 _table = NULL;
248 _length = 0;
249 }
250
251 size_t G1CodeRootSet::mem_size() {
252 return sizeof(*this) + (_table != NULL ? _table->mem_size() : 0);
253 }
254
255 void G1CodeRootSet::nmethods_do(CodeBlobClosure* blk) const {
256 if (_table != NULL) {
257 _table->nmethods_do(blk);
258 }
259 }
260
261 class CleanCallback : public StackObj {
262 class PointsIntoHRDetectionClosure : public OopClosure {
263 HeapRegion* _hr;
264 public:
265 bool _points_into;
266 PointsIntoHRDetectionClosure(HeapRegion* hr) : _hr(hr), _points_into(false) {}
267
268 void do_oop(narrowOop* o) {
269 do_oop_work(o);
270 }
271
272 void do_oop(oop* o) {
273 do_oop_work(o);
274 }
275
276 template <typename T>
277 void do_oop_work(T* p) {
278 if (_hr->is_in(RawAccess<>::oop_load(p))) {
279 _points_into = true;
280 }
281 }
282 };
283
284 PointsIntoHRDetectionClosure _detector;
285 CodeBlobToOopClosure _blobs;
286
287 public:
288 CleanCallback(HeapRegion* hr) : _detector(hr), _blobs(&_detector, !CodeBlobToOopClosure::FixRelocations) {}
289
290 bool operator() (nmethod* nm) {
291 _detector._points_into = false;
292 _blobs.do_code_blob(nm);
293 return !_detector._points_into;
294 }
295 };
296
297 void G1CodeRootSet::clean(HeapRegion* owner) {
298 CleanCallback should_clean(owner);
299 if (_table != NULL) {
300 int removed = _table->remove_if(should_clean);
301 assert((size_t)removed <= _length, "impossible");
302 _length -= removed;
303 }
304 if (_length == 0) {
305 clear();
306 }
307 }