Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/g1/ptrQueue.cpp @ 441:da9cb4e97a5f
6770608: G1: Mutator thread can flush barrier and satb queues during safepoint
6660573: G1: BigApps Failure : guarantee(satb_mq_set.completed_buffers_num() == 0,"invariant")
Summary: When exiting a mutator thread is removed from the thread list before it has a chance to flush its SATB and barrier queues. If GC happens at this moment the objects that are refererred from these queues can be moved, which will case a crash. The fix is simply to flush the buffers before removing a thread from the list.
Reviewed-by: jcoomes, tonyp
author | iveresov |
---|---|
date | Fri, 14 Nov 2008 14:23:05 -0800 |
parents | 37f87013dfd8 |
children | ad8c8ca4ab0f |
rev | line source |
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342 | 1 /* |
2 * Copyright 2001-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_ptrQueue.cpp.incl" | |
27 | |
28 PtrQueue::PtrQueue(PtrQueueSet* qset_, bool perm) : | |
29 _qset(qset_), _buf(NULL), _index(0), _active(false), | |
30 _perm(perm), _lock(NULL) | |
31 {} | |
32 | |
441
da9cb4e97a5f
6770608: G1: Mutator thread can flush barrier and satb queues during safepoint
iveresov
parents:
342
diff
changeset
|
33 void PtrQueue::flush() { |
342 | 34 if (!_perm && _buf != NULL) { |
35 if (_index == _sz) { | |
36 // No work to do. | |
37 qset()->deallocate_buffer(_buf); | |
38 } else { | |
39 // We must NULL out the unused entries, then enqueue. | |
40 for (size_t i = 0; i < _index; i += oopSize) { | |
41 _buf[byte_index_to_index((int)i)] = NULL; | |
42 } | |
43 qset()->enqueue_complete_buffer(_buf); | |
44 } | |
441
da9cb4e97a5f
6770608: G1: Mutator thread can flush barrier and satb queues during safepoint
iveresov
parents:
342
diff
changeset
|
45 _buf = NULL; |
da9cb4e97a5f
6770608: G1: Mutator thread can flush barrier and satb queues during safepoint
iveresov
parents:
342
diff
changeset
|
46 _index = 0; |
342 | 47 } |
48 } | |
49 | |
50 | |
51 static int byte_index_to_index(int ind) { | |
52 assert((ind % oopSize) == 0, "Invariant."); | |
53 return ind / oopSize; | |
54 } | |
55 | |
56 static int index_to_byte_index(int byte_ind) { | |
57 return byte_ind * oopSize; | |
58 } | |
59 | |
60 void PtrQueue::enqueue_known_active(void* ptr) { | |
61 assert(0 <= _index && _index <= _sz, "Invariant."); | |
62 assert(_index == 0 || _buf != NULL, "invariant"); | |
63 | |
64 while (_index == 0) { | |
65 handle_zero_index(); | |
66 } | |
67 assert(_index > 0, "postcondition"); | |
68 | |
69 _index -= oopSize; | |
70 _buf[byte_index_to_index((int)_index)] = ptr; | |
71 assert(0 <= _index && _index <= _sz, "Invariant."); | |
72 } | |
73 | |
74 void PtrQueue::locking_enqueue_completed_buffer(void** buf) { | |
75 assert(_lock->owned_by_self(), "Required."); | |
76 _lock->unlock(); | |
77 qset()->enqueue_complete_buffer(buf); | |
78 // We must relock only because the caller will unlock, for the normal | |
79 // case. | |
80 _lock->lock_without_safepoint_check(); | |
81 } | |
82 | |
83 | |
84 PtrQueueSet::PtrQueueSet(bool notify_when_complete) : | |
85 _max_completed_queue(0), | |
86 _cbl_mon(NULL), _fl_lock(NULL), | |
87 _notify_when_complete(notify_when_complete), | |
88 _sz(0), | |
89 _completed_buffers_head(NULL), | |
90 _completed_buffers_tail(NULL), | |
91 _n_completed_buffers(0), | |
92 _process_completed_threshold(0), _process_completed(false), | |
93 _buf_free_list(NULL), _buf_free_list_sz(0) | |
94 {} | |
95 | |
96 void** PtrQueueSet::allocate_buffer() { | |
97 assert(_sz > 0, "Didn't set a buffer size."); | |
98 MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag); | |
99 if (_buf_free_list != NULL) { | |
100 void** res = _buf_free_list; | |
101 _buf_free_list = (void**)_buf_free_list[0]; | |
102 _buf_free_list_sz--; | |
103 // Just override the next pointer with NULL, just in case we scan this part | |
104 // of the buffer. | |
105 res[0] = NULL; | |
106 return res; | |
107 } else { | |
108 return NEW_C_HEAP_ARRAY(void*, _sz); | |
109 } | |
110 } | |
111 | |
112 void PtrQueueSet::deallocate_buffer(void** buf) { | |
113 assert(_sz > 0, "Didn't set a buffer size."); | |
114 MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag); | |
115 buf[0] = (void*)_buf_free_list; | |
116 _buf_free_list = buf; | |
117 _buf_free_list_sz++; | |
118 } | |
119 | |
120 void PtrQueueSet::reduce_free_list() { | |
121 // For now we'll adopt the strategy of deleting half. | |
122 MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag); | |
123 size_t n = _buf_free_list_sz / 2; | |
124 while (n > 0) { | |
125 assert(_buf_free_list != NULL, "_buf_free_list_sz must be wrong."); | |
126 void** head = _buf_free_list; | |
127 _buf_free_list = (void**)_buf_free_list[0]; | |
128 FREE_C_HEAP_ARRAY(void*,head); | |
129 n--; | |
130 } | |
131 } | |
132 | |
133 void PtrQueueSet::enqueue_complete_buffer(void** buf, size_t index, bool ignore_max_completed) { | |
134 // I use explicit locking here because there's a bailout in the middle. | |
135 _cbl_mon->lock_without_safepoint_check(); | |
136 | |
137 Thread* thread = Thread::current(); | |
138 assert( ignore_max_completed || | |
139 thread->is_Java_thread() || | |
140 SafepointSynchronize::is_at_safepoint(), | |
141 "invariant" ); | |
142 ignore_max_completed = ignore_max_completed || !thread->is_Java_thread(); | |
143 | |
144 if (!ignore_max_completed && _max_completed_queue > 0 && | |
145 _n_completed_buffers >= (size_t) _max_completed_queue) { | |
146 _cbl_mon->unlock(); | |
147 bool b = mut_process_buffer(buf); | |
148 if (b) { | |
149 deallocate_buffer(buf); | |
150 return; | |
151 } | |
152 | |
153 // Otherwise, go ahead and enqueue the buffer. Must reaquire the lock. | |
154 _cbl_mon->lock_without_safepoint_check(); | |
155 } | |
156 | |
157 // Here we still hold the _cbl_mon. | |
158 CompletedBufferNode* cbn = new CompletedBufferNode; | |
159 cbn->buf = buf; | |
160 cbn->next = NULL; | |
161 cbn->index = index; | |
162 if (_completed_buffers_tail == NULL) { | |
163 assert(_completed_buffers_head == NULL, "Well-formedness"); | |
164 _completed_buffers_head = cbn; | |
165 _completed_buffers_tail = cbn; | |
166 } else { | |
167 _completed_buffers_tail->next = cbn; | |
168 _completed_buffers_tail = cbn; | |
169 } | |
170 _n_completed_buffers++; | |
171 | |
172 if (!_process_completed && | |
173 _n_completed_buffers == _process_completed_threshold) { | |
174 _process_completed = true; | |
175 if (_notify_when_complete) | |
176 _cbl_mon->notify_all(); | |
177 } | |
178 debug_only(assert_completed_buffer_list_len_correct_locked()); | |
179 _cbl_mon->unlock(); | |
180 } | |
181 | |
182 int PtrQueueSet::completed_buffers_list_length() { | |
183 int n = 0; | |
184 CompletedBufferNode* cbn = _completed_buffers_head; | |
185 while (cbn != NULL) { | |
186 n++; | |
187 cbn = cbn->next; | |
188 } | |
189 return n; | |
190 } | |
191 | |
192 void PtrQueueSet::assert_completed_buffer_list_len_correct() { | |
193 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag); | |
194 assert_completed_buffer_list_len_correct_locked(); | |
195 } | |
196 | |
197 void PtrQueueSet::assert_completed_buffer_list_len_correct_locked() { | |
198 guarantee((size_t)completed_buffers_list_length() == _n_completed_buffers, | |
199 "Completed buffer length is wrong."); | |
200 } | |
201 | |
202 void PtrQueueSet::set_buffer_size(size_t sz) { | |
203 assert(_sz == 0 && sz > 0, "Should be called only once."); | |
204 _sz = sz * oopSize; | |
205 } | |
206 | |
207 void PtrQueueSet::set_process_completed_threshold(size_t sz) { | |
208 _process_completed_threshold = sz; | |
209 } |