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
37G1CodeRootSetTable* volatile G1CodeRootSetTable::_purge_list = NULL;
38
39size_t G1CodeRootSetTable::mem_size() {
40  return sizeof(G1CodeRootSetTable) + (entry_size() * number_of_entries()) + (sizeof(HashtableBucket<mtGC>) * table_size());
41}
42
43G1CodeRootSetTable::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
55void 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
67G1CodeRootSetTable::~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
84bool 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
94bool 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
104bool 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
116void 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
125void 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
133template<typename CB>
134int 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
153G1CodeRootSet::~G1CodeRootSet() {
154  delete _table;
155}
156
157G1CodeRootSetTable* G1CodeRootSet::load_acquire_table() {
158  return (G1CodeRootSetTable*) OrderAccess::load_ptr_acquire(&_table);
159}
160
161void G1CodeRootSet::allocate_small_table() {
162  G1CodeRootSetTable* temp = new G1CodeRootSetTable(SmallSize);
163
164  OrderAccess::release_store_ptr(&_table, temp);
165}
166
167void 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
177void 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
187void 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
197void G1CodeRootSet::purge() {
198  G1CodeRootSetTable::purge();
199}
200
201size_t G1CodeRootSet::static_mem_size() {
202  return G1CodeRootSetTable::static_mem_size();
203}
204
205void 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
220bool 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
236bool 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
244void G1CodeRootSet::clear() {
245  delete _table;
246  _table = NULL;
247  _length = 0;
248}
249
250size_t G1CodeRootSet::mem_size() {
251  return sizeof(*this) + (_table != NULL ? _table->mem_size() : 0);
252}
253
254void G1CodeRootSet::nmethods_do(CodeBlobClosure* blk) const {
255  if (_table != NULL) {
256    _table->nmethods_do(blk);
257  }
258}
259
260class 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
296void 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}
307