1 /*
2 * Copyright (c) 2014, 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 "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/oop.inline.hpp"
34 #include "utilities/hashtable.inline.hpp"
35 #include "utilities/stack.inline.hpp"
36
37 G1CodeRootSetTable* volatile G1CodeRootSetTable::_purge_list = NULL;
38
39 size_t G1CodeRootSetTable::mem_size() {
40 return sizeof(G1CodeRootSetTable) + (entry_size() * number_of_entries()) + (sizeof(HashtableBucket<mtGC>) * table_size());
41 }
42
43 G1CodeRootSetTable::Entry* G1CodeRootSetTable::new_entry(nmethod* nm) {
44 unsigned int hash = compute_hash(nm);
45 Entry* entry = (Entry*) new_entry_free_list();
46 if (entry == NULL) {
47 entry = (Entry*) NEW_C_HEAP_ARRAY2(char, entry_size(), mtGC, CURRENT_PC);
48 }
49 entry->set_next(NULL);
50 entry->set_hash(hash);
51 entry->set_literal(nm);
52 return entry;
53 }
54
55 void G1CodeRootSetTable::remove_entry(Entry* e, Entry* previous) {
56 int index = hash_to_index(e->hash());
57 assert((e == bucket(index)) == (previous == NULL), "if e is the first entry then previous should be null");
58
59 if (previous == NULL) {
60 set_entry(index, e->next());
61 } else {
62 previous->set_next(e->next());
63 }
64 free_entry(e);
65 }
66
67 G1CodeRootSetTable::~G1CodeRootSetTable() {
68 for (int index = 0; index < table_size(); ++index) {
69 for (Entry* e = bucket(index); e != NULL; ) {
70 Entry* to_remove = e;
71 // read next before freeing.
72 e = e->next();
73 unlink_entry(to_remove);
74 FREE_C_HEAP_ARRAY(char, to_remove);
75 }
76 }
77 assert(number_of_entries() == 0, "should have removed all entries");
78 free_buckets();
79 for (BasicHashtableEntry<mtGC>* e = new_entry_free_list(); e != NULL; e = new_entry_free_list()) {
80 FREE_C_HEAP_ARRAY(char, e);
81 }
82 }
83
84 bool G1CodeRootSetTable::add(nmethod* nm) {
85 if (!contains(nm)) {
86 Entry* e = new_entry(nm);
87 int index = hash_to_index(e->hash());
88 add_entry(index, e);
89 return true;
90 }
91 return false;
92 }
93
94 bool G1CodeRootSetTable::contains(nmethod* nm) {
95 int index = hash_to_index(compute_hash(nm));
96 for (Entry* e = bucket(index); e != NULL; e = e->next()) {
97 if (e->literal() == nm) {
98 return true;
99 }
100 }
101 return false;
102 }
103
104 bool G1CodeRootSetTable::remove(nmethod* nm) {
105 int index = hash_to_index(compute_hash(nm));
106 Entry* previous = NULL;
107 for (Entry* e = bucket(index); e != NULL; previous = e, e = e->next()) {
108 if (e->literal() == nm) {
109 remove_entry(e, previous);
110 return true;
111 }
112 }
113 return false;
114 }
115
116 void G1CodeRootSetTable::copy_to(G1CodeRootSetTable* new_table) {
117 for (int index = 0; index < table_size(); ++index) {
118 for (Entry* e = bucket(index); e != NULL; e = e->next()) {
119 new_table->add(e->literal());
120 }
121 }
122 new_table->copy_freelist(this);
123 }
124
125 void G1CodeRootSetTable::nmethods_do(CodeBlobClosure* blk) {
126 for (int index = 0; index < table_size(); ++index) {
127 for (Entry* e = bucket(index); e != NULL; e = e->next()) {
128 blk->do_code_blob(e->literal());
129 }
130 }
131 }
132
133 template<typename CB>
134 int G1CodeRootSetTable::remove_if(CB& should_remove) {
135 int num_removed = 0;
136 for (int index = 0; index < table_size(); ++index) {
137 Entry* previous = NULL;
138 Entry* e = bucket(index);
139 while (e != NULL) {
140 Entry* next = e->next();
141 if (should_remove(e->literal())) {
142 remove_entry(e, previous);
143 ++num_removed;
144 } else {
145 previous = e;
146 }
147 e = next;
148 }
149 }
150 return num_removed;
151 }
152
153 G1CodeRootSet::~G1CodeRootSet() {
154 delete _table;
155 }
156
157 G1CodeRootSetTable* G1CodeRootSet::load_acquire_table() {
158 return (G1CodeRootSetTable*) OrderAccess::load_ptr_acquire(&_table);
159 }
160
161 void G1CodeRootSet::allocate_small_table() {
162 G1CodeRootSetTable* temp = new G1CodeRootSetTable(SmallSize);
163
164 OrderAccess::release_store_ptr(&_table, temp);
165 }
166
167 void G1CodeRootSetTable::purge_list_append(G1CodeRootSetTable* table) {
168 for (;;) {
169 table->_purge_next = _purge_list;
170 G1CodeRootSetTable* old = (G1CodeRootSetTable*) Atomic::cmpxchg_ptr(table, &_purge_list, table->_purge_next);
171 if (old == table->_purge_next) {
172 break;
173 }
174 }
175 }
176
177 void G1CodeRootSetTable::purge() {
178 G1CodeRootSetTable* table = _purge_list;
179 _purge_list = NULL;
180 while (table != NULL) {
181 G1CodeRootSetTable* to_purge = table;
182 table = table->_purge_next;
183 delete to_purge;
184 }
185 }
186
187 void G1CodeRootSet::move_to_large() {
188 G1CodeRootSetTable* temp = new G1CodeRootSetTable(LargeSize);
189
190 _table->copy_to(temp);
191
192 G1CodeRootSetTable::purge_list_append(_table);
193
194 OrderAccess::release_store_ptr(&_table, temp);
195 }
196
197 void G1CodeRootSet::purge() {
198 G1CodeRootSetTable::purge();
199 }
200
201 size_t G1CodeRootSet::static_mem_size() {
202 return G1CodeRootSetTable::static_mem_size();
203 }
204
205 void G1CodeRootSet::add(nmethod* method) {
206 bool added = false;
207 if (is_empty()) {
208 allocate_small_table();
209 }
210 added = _table->add(method);
211 if (added) {
212 if (_length == Threshold) {
213 move_to_large();
214 }
215 ++_length;
216 }
217 assert(_length == (size_t)_table->number_of_entries(), "sizes should match");
218 }
219
220 bool G1CodeRootSet::remove(nmethod* method) {
221 bool removed = false;
222 if (_table != NULL) {
223 removed = _table->remove(method);
224 }
225 if (removed) {
226 _length--;
227 if (_length == 0) {
228 clear();
229 }
230 }
231 assert((_length == 0 && _table == NULL) ||
232 (_length == (size_t)_table->number_of_entries()), "sizes should match");
233 return removed;
234 }
235
236 bool G1CodeRootSet::contains(nmethod* method) {
237 G1CodeRootSetTable* table = load_acquire_table(); // contains() may be called outside of lock, so ensure mem sync.
238 if (table != NULL) {
239 return table->contains(method);
240 }
241 return false;
242 }
243
244 void G1CodeRootSet::clear() {
245 delete _table;
246 _table = NULL;
247 _length = 0;
248 }
249
250 size_t G1CodeRootSet::mem_size() {
251 return sizeof(*this) + (_table != NULL ? _table->mem_size() : 0);
252 }
253
254 void G1CodeRootSet::nmethods_do(CodeBlobClosure* blk) const {
255 if (_table != NULL) {
256 _table->nmethods_do(blk);
257 }
258 }
259
260 class CleanCallback : public StackObj {
261 class PointsIntoHRDetectionClosure : public OopClosure {
262 HeapRegion* _hr;
263 public:
264 bool _points_into;
265 PointsIntoHRDetectionClosure(HeapRegion* hr) : _hr(hr), _points_into(false) {}
266
267 void do_oop(narrowOop* o) {
268 do_oop_work(o);
269 }
270
271 void do_oop(oop* o) {
272 do_oop_work(o);
273 }
274
275 template <typename T>
276 void do_oop_work(T* p) {
277 if (_hr->is_in(oopDesc::load_decode_heap_oop(p))) {
278 _points_into = true;
279 }
280 }
281 };
282
283 PointsIntoHRDetectionClosure _detector;
284 CodeBlobToOopClosure _blobs;
285
286 public:
287 CleanCallback(HeapRegion* hr) : _detector(hr), _blobs(&_detector, !CodeBlobToOopClosure::FixRelocations) {}
288
289 bool operator() (nmethod* nm) {
290 _detector._points_into = false;
291 _blobs.do_code_blob(nm);
292 return !_detector._points_into;
293 }
294 };
295
296 void G1CodeRootSet::clean(HeapRegion* owner) {
297 CleanCallback should_clean(owner);
298 if (_table != NULL) {
299 int removed = _table->remove_if(should_clean);
300 assert((size_t)removed <= _length, "impossible");
301 _length -= removed;
302 }
303 if (_length == 0) {
304 clear();
305 }
306 }