The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2008 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
Andy McFadden | 581bed7 | 2009-10-15 11:24:54 -0700 | [diff] [blame] | 16 | |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 17 | /* |
| 18 | * Fundamental synchronization mechanisms. |
| 19 | * |
| 20 | * The top part of the file has operations on "monitor" structs; the |
| 21 | * next part has the native calls on objects. |
| 22 | * |
| 23 | * The current implementation uses "thin locking" to avoid allocating |
| 24 | * an Object's full Monitor struct until absolutely necessary (i.e., |
| 25 | * during contention or a call to wait()). |
| 26 | * |
| 27 | * TODO: make improvements to thin locking |
| 28 | * We may be able to improve performance and reduce memory requirements by: |
| 29 | * - reverting to a thin lock once the Monitor is no longer necessary |
| 30 | * - using a pool of monitor objects, with some sort of recycling scheme |
| 31 | * |
| 32 | * TODO: recycle native-level monitors when objects are garbage collected. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 33 | */ |
| 34 | #include "Dalvik.h" |
| 35 | |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 36 | #include <fcntl.h> |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 37 | #include <stdlib.h> |
| 38 | #include <unistd.h> |
| 39 | #include <pthread.h> |
| 40 | #include <time.h> |
| 41 | #include <sys/time.h> |
| 42 | #include <errno.h> |
| 43 | |
| 44 | #define LOG_THIN LOGV |
| 45 | |
| 46 | #ifdef WITH_DEADLOCK_PREDICTION /* fwd */ |
| 47 | static const char* kStartBanner = |
| 48 | "<-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#"; |
| 49 | static const char* kEndBanner = |
| 50 | "#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#->"; |
| 51 | |
| 52 | /* |
| 53 | * Unsorted, expanding list of objects. |
| 54 | * |
| 55 | * This is very similar to PointerSet (which came into existence after this), |
| 56 | * but these are unsorted, uniqueness is not enforced by the "add" function, |
| 57 | * and the base object isn't allocated on the heap. |
| 58 | */ |
| 59 | typedef struct ExpandingObjectList { |
| 60 | u2 alloc; |
| 61 | u2 count; |
| 62 | Object** list; |
| 63 | } ExpandingObjectList; |
| 64 | |
| 65 | /* fwd */ |
| 66 | static void updateDeadlockPrediction(Thread* self, Object* obj); |
| 67 | static void removeCollectedObject(Object* obj); |
| 68 | static void expandObjClear(ExpandingObjectList* pList); |
| 69 | #endif |
| 70 | |
| 71 | /* |
| 72 | * Every Object has a monitor associated with it, but not every Object is |
| 73 | * actually locked. Even the ones that are locked do not need a |
| 74 | * full-fledged monitor until a) there is actual contention or b) wait() |
| 75 | * is called on the Object. |
| 76 | * |
| 77 | * For Dalvik, we have implemented a scheme similar to the one described |
| 78 | * in Bacon et al.'s "Thin locks: featherweight synchronization for Java" |
| 79 | * (ACM 1998). Things are even easier for us, though, because we have |
| 80 | * a full 32 bits to work with. |
| 81 | * |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 82 | * The two states of an Object's lock are referred to as "thin" and |
| 83 | * "fat". A lock may transition from the "thin" state to the "fat" |
| 84 | * state and this transition is referred to as inflation. Once a lock |
| 85 | * has been inflated it remains in the "fat" state indefinitely. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 86 | * |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 87 | * The lock value itself is stored in Object.lock. The LSB of the |
| 88 | * lock encodes its state. When cleared, the lock is in the "thin" |
| 89 | * state and its bits are formatted as follows: |
Carl Shapiro | 7193802 | 2009-12-22 13:49:53 -0800 | [diff] [blame] | 90 | * |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 91 | * [31 ---- 19] [18 ---- 3] [2 ---- 1] [0] |
| 92 | * lock count thread id hash state 0 |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 93 | * |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 94 | * When set, the lock is in the "fat" state and its bits are formatted |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 95 | * as follows: |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 96 | * |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 97 | * [31 ---- 3] [2 ---- 1] [0] |
| 98 | * pointer hash state 1 |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 99 | * |
| 100 | * For an in-depth description of the mechanics of thin-vs-fat locking, |
| 101 | * read the paper referred to above. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 102 | */ |
| 103 | |
| 104 | /* |
| 105 | * Monitors provide: |
| 106 | * - mutually exclusive access to resources |
| 107 | * - a way for multiple threads to wait for notification |
| 108 | * |
| 109 | * In effect, they fill the role of both mutexes and condition variables. |
| 110 | * |
| 111 | * Only one thread can own the monitor at any time. There may be several |
| 112 | * threads waiting on it (the wait call unlocks it). One or more waiting |
| 113 | * threads may be getting interrupted or notified at any given time. |
Carl Shapiro | fa903b3 | 2010-08-31 15:11:46 -0700 | [diff] [blame] | 114 | * |
| 115 | * TODO: the various members of monitor are not SMP-safe. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 116 | */ |
| 117 | struct Monitor { |
| 118 | Thread* owner; /* which thread currently owns the lock? */ |
| 119 | int lockCount; /* owner's recursive lock depth */ |
| 120 | Object* obj; /* what object are we part of [debug only] */ |
| 121 | |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 122 | Thread* waitSet; /* threads currently waiting on this monitor */ |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 123 | |
| 124 | pthread_mutex_t lock; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 125 | |
| 126 | Monitor* next; |
| 127 | |
Carl Shapiro | fa903b3 | 2010-08-31 15:11:46 -0700 | [diff] [blame] | 128 | /* |
| 129 | * Who last acquired this monitor, when lock sampling is enabled. |
| 130 | * Even when enabled, ownerFileName may be NULL. |
| 131 | */ |
| 132 | char* ownerFileName; |
| 133 | u4 ownerLineNumber; |
| 134 | |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 135 | #ifdef WITH_DEADLOCK_PREDICTION |
| 136 | /* |
| 137 | * Objects that have been locked immediately after this one in the |
| 138 | * past. We use an expanding flat array, allocated on first use, to |
| 139 | * minimize allocations. Deletions from the list, expected to be |
| 140 | * infrequent, are crunched down. |
| 141 | */ |
| 142 | ExpandingObjectList historyChildren; |
| 143 | |
| 144 | /* |
| 145 | * We also track parents. This isn't strictly necessary, but it makes |
| 146 | * the cleanup at GC time significantly faster. |
| 147 | */ |
| 148 | ExpandingObjectList historyParents; |
| 149 | |
| 150 | /* used during cycle detection */ |
| 151 | bool historyMark; |
| 152 | |
| 153 | /* stack trace, established the first time we locked the object */ |
| 154 | int historyStackDepth; |
| 155 | int* historyRawStackTrace; |
| 156 | #endif |
| 157 | }; |
| 158 | |
| 159 | |
| 160 | /* |
| 161 | * Create and initialize a monitor. |
| 162 | */ |
| 163 | Monitor* dvmCreateMonitor(Object* obj) |
| 164 | { |
| 165 | Monitor* mon; |
| 166 | |
| 167 | mon = (Monitor*) calloc(1, sizeof(Monitor)); |
| 168 | if (mon == NULL) { |
| 169 | LOGE("Unable to allocate monitor\n"); |
| 170 | dvmAbort(); |
| 171 | } |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 172 | if (((u4)mon & 7) != 0) { |
| 173 | LOGE("Misaligned monitor: %p\n", mon); |
| 174 | dvmAbort(); |
| 175 | } |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 176 | mon->obj = obj; |
| 177 | dvmInitMutex(&mon->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 178 | |
| 179 | /* replace the head of the list with the new monitor */ |
| 180 | do { |
| 181 | mon->next = gDvm.monitorList; |
Andy McFadden | 6e10b9a | 2010-06-14 15:24:39 -0700 | [diff] [blame] | 182 | } while (android_atomic_release_cas((int32_t)mon->next, (int32_t)mon, |
| 183 | (int32_t*)(void*)&gDvm.monitorList) != 0); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 184 | |
| 185 | return mon; |
| 186 | } |
| 187 | |
| 188 | /* |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 189 | * Free the monitor list. Only used when shutting the VM down. |
| 190 | */ |
| 191 | void dvmFreeMonitorList(void) |
| 192 | { |
| 193 | Monitor* mon; |
| 194 | Monitor* nextMon; |
| 195 | |
| 196 | mon = gDvm.monitorList; |
| 197 | while (mon != NULL) { |
| 198 | nextMon = mon->next; |
| 199 | |
| 200 | #ifdef WITH_DEADLOCK_PREDICTION |
| 201 | expandObjClear(&mon->historyChildren); |
| 202 | expandObjClear(&mon->historyParents); |
| 203 | free(mon->historyRawStackTrace); |
| 204 | #endif |
| 205 | free(mon); |
| 206 | mon = nextMon; |
| 207 | } |
| 208 | } |
| 209 | |
| 210 | /* |
| 211 | * Log some info about our monitors. |
| 212 | */ |
| 213 | void dvmDumpMonitorInfo(const char* msg) |
| 214 | { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 215 | if (gDvm.zygote) { |
| 216 | return; |
| 217 | } |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 218 | |
| 219 | int totalCount; |
| 220 | int liveCount; |
| 221 | |
| 222 | totalCount = liveCount = 0; |
| 223 | Monitor* mon = gDvm.monitorList; |
| 224 | while (mon != NULL) { |
| 225 | totalCount++; |
| 226 | if (mon->obj != NULL) |
| 227 | liveCount++; |
| 228 | mon = mon->next; |
| 229 | } |
| 230 | |
| 231 | LOGD("%s: monitor list has %d entries (%d live)\n", |
| 232 | msg, totalCount, liveCount); |
| 233 | } |
| 234 | |
| 235 | /* |
| 236 | * Get the object that a monitor is part of. |
| 237 | */ |
| 238 | Object* dvmGetMonitorObject(Monitor* mon) |
| 239 | { |
| 240 | if (mon == NULL) |
| 241 | return NULL; |
| 242 | else |
| 243 | return mon->obj; |
| 244 | } |
| 245 | |
| 246 | /* |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 247 | * Returns the thread id of the thread owning the given lock. |
| 248 | */ |
| 249 | static u4 lockOwner(Object* obj) |
| 250 | { |
| 251 | Thread *owner; |
| 252 | u4 lock; |
| 253 | |
| 254 | assert(obj != NULL); |
| 255 | /* |
| 256 | * Since we're reading the lock value multiple times, latch it so |
| 257 | * that it doesn't change out from under us if we get preempted. |
| 258 | */ |
| 259 | lock = obj->lock; |
| 260 | if (LW_SHAPE(lock) == LW_SHAPE_THIN) { |
| 261 | return LW_LOCK_OWNER(lock); |
| 262 | } else { |
| 263 | owner = LW_MONITOR(lock)->owner; |
| 264 | return owner ? owner->threadId : 0; |
| 265 | } |
| 266 | } |
| 267 | |
| 268 | /* |
Andy McFadden | fd54266 | 2010-03-12 13:39:59 -0800 | [diff] [blame] | 269 | * Get the thread that holds the lock on the specified object. The |
| 270 | * object may be unlocked, thin-locked, or fat-locked. |
| 271 | * |
| 272 | * The caller must lock the thread list before calling here. |
| 273 | */ |
| 274 | Thread* dvmGetObjectLockHolder(Object* obj) |
| 275 | { |
| 276 | u4 threadId = lockOwner(obj); |
| 277 | |
| 278 | if (threadId == 0) |
| 279 | return NULL; |
| 280 | return dvmGetThreadByThreadId(threadId); |
| 281 | } |
| 282 | |
| 283 | /* |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 284 | * Checks whether the given thread holds the given |
| 285 | * objects's lock. |
| 286 | */ |
| 287 | bool dvmHoldsLock(Thread* thread, Object* obj) |
| 288 | { |
| 289 | if (thread == NULL || obj == NULL) { |
| 290 | return false; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 291 | } else { |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 292 | return thread->threadId == lockOwner(obj); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 293 | } |
| 294 | } |
| 295 | |
| 296 | /* |
| 297 | * Free the monitor associated with an object and make the object's lock |
| 298 | * thin again. This is called during garbage collection. |
| 299 | */ |
Carl Shapiro | 5a6071b | 2010-01-07 21:35:50 -0800 | [diff] [blame] | 300 | static void freeObjectMonitor(Object* obj) |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 301 | { |
| 302 | Monitor *mon; |
| 303 | |
Carl Shapiro | 5a6071b | 2010-01-07 21:35:50 -0800 | [diff] [blame] | 304 | assert(LW_SHAPE(obj->lock) == LW_SHAPE_FAT); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 305 | |
| 306 | #ifdef WITH_DEADLOCK_PREDICTION |
| 307 | if (gDvm.deadlockPredictMode != kDPOff) |
Carl Shapiro | 5a6071b | 2010-01-07 21:35:50 -0800 | [diff] [blame] | 308 | removeCollectedObject(obj); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 309 | #endif |
| 310 | |
Carl Shapiro | 5a6071b | 2010-01-07 21:35:50 -0800 | [diff] [blame] | 311 | mon = LW_MONITOR(obj->lock); |
| 312 | obj->lock = DVM_LOCK_INITIAL_THIN_VALUE; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 313 | |
| 314 | /* This lock is associated with an object |
| 315 | * that's being swept. The only possible way |
| 316 | * anyone could be holding this lock would be |
| 317 | * if some JNI code locked but didn't unlock |
| 318 | * the object, in which case we've got some bad |
| 319 | * native code somewhere. |
| 320 | */ |
Carl Shapiro | 1ff876d | 2010-04-04 01:56:48 -0700 | [diff] [blame] | 321 | assert(pthread_mutex_trylock(&mon->lock) == 0); |
| 322 | assert(pthread_mutex_unlock(&mon->lock) == 0); |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 323 | dvmDestroyMutex(&mon->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 324 | #ifdef WITH_DEADLOCK_PREDICTION |
Carl Shapiro | 5a6071b | 2010-01-07 21:35:50 -0800 | [diff] [blame] | 325 | expandObjClear(&mon->historyChildren); |
| 326 | expandObjClear(&mon->historyParents); |
| 327 | free(mon->historyRawStackTrace); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 328 | #endif |
Carl Shapiro | 5a6071b | 2010-01-07 21:35:50 -0800 | [diff] [blame] | 329 | free(mon); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 330 | } |
| 331 | |
Carl Shapiro | 5a6071b | 2010-01-07 21:35:50 -0800 | [diff] [blame] | 332 | /* |
| 333 | * Frees monitor objects belonging to unmarked objects. |
| 334 | */ |
| 335 | void dvmSweepMonitorList(Monitor** mon, int (*isUnmarkedObject)(void*)) |
| 336 | { |
| 337 | Monitor handle; |
| 338 | Monitor *prev, *curr; |
| 339 | Object *obj; |
| 340 | |
| 341 | assert(mon != NULL); |
Carl Shapiro | 5a6071b | 2010-01-07 21:35:50 -0800 | [diff] [blame] | 342 | assert(isUnmarkedObject != NULL); |
Carl Shapiro | 8881a80 | 2010-08-10 15:55:45 -0700 | [diff] [blame] | 343 | #ifdef WITH_DEADLOCK_PREDICTION |
| 344 | dvmDumpMonitorInfo("before monitor sweep"); |
| 345 | #endif |
Carl Shapiro | 5a6071b | 2010-01-07 21:35:50 -0800 | [diff] [blame] | 346 | prev = &handle; |
| 347 | prev->next = curr = *mon; |
| 348 | while (curr != NULL) { |
| 349 | obj = curr->obj; |
| 350 | if (obj != NULL && (*isUnmarkedObject)(obj) != 0) { |
| 351 | prev->next = curr = curr->next; |
| 352 | freeObjectMonitor(obj); |
| 353 | } else { |
| 354 | prev = curr; |
| 355 | curr = curr->next; |
| 356 | } |
| 357 | } |
| 358 | *mon = handle.next; |
Carl Shapiro | 8881a80 | 2010-08-10 15:55:45 -0700 | [diff] [blame] | 359 | #ifdef WITH_DEADLOCK_PREDICTION |
| 360 | dvmDumpMonitorInfo("after monitor sweep"); |
| 361 | #endif |
Carl Shapiro | 5a6071b | 2010-01-07 21:35:50 -0800 | [diff] [blame] | 362 | } |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 363 | |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 364 | static char *logWriteInt(char *dst, int value) |
| 365 | { |
| 366 | *dst++ = EVENT_TYPE_INT; |
| 367 | set4LE((u1 *)dst, value); |
| 368 | return dst + 4; |
| 369 | } |
| 370 | |
| 371 | static char *logWriteString(char *dst, const char *value, size_t len) |
| 372 | { |
| 373 | *dst++ = EVENT_TYPE_STRING; |
Carl Shapiro | af69cf8 | 2010-04-16 17:33:15 -0700 | [diff] [blame] | 374 | len = len < 32 ? len : 32; |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 375 | set4LE((u1 *)dst, len); |
| 376 | dst += 4; |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 377 | memcpy(dst, value, len); |
| 378 | return dst + len; |
| 379 | } |
| 380 | |
Carl Shapiro | af69cf8 | 2010-04-16 17:33:15 -0700 | [diff] [blame] | 381 | #define EVENT_LOG_TAG_dvm_lock_sample 20003 |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 382 | |
Carl Shapiro | fa903b3 | 2010-08-31 15:11:46 -0700 | [diff] [blame] | 383 | static void logContentionEvent(Thread *self, u4 waitMs, u4 samplePercent, |
| 384 | const char *ownerFileName, u4 ownerLineNumber) |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 385 | { |
| 386 | const StackSaveArea *saveArea; |
| 387 | const Method *meth; |
| 388 | u4 relativePc; |
Carl Shapiro | fa903b3 | 2010-08-31 15:11:46 -0700 | [diff] [blame] | 389 | char eventBuffer[174]; |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 390 | const char *fileName; |
Carl Shapiro | e3c01da | 2010-05-20 22:54:18 -0700 | [diff] [blame] | 391 | char procName[33], *selfName; |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 392 | char *cp; |
Carl Shapiro | af69cf8 | 2010-04-16 17:33:15 -0700 | [diff] [blame] | 393 | size_t len; |
| 394 | int fd; |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 395 | |
| 396 | saveArea = SAVEAREA_FROM_FP(self->curFrame); |
| 397 | meth = saveArea->method; |
| 398 | cp = eventBuffer; |
| 399 | |
| 400 | /* Emit the event list length, 1 byte. */ |
Carl Shapiro | fa903b3 | 2010-08-31 15:11:46 -0700 | [diff] [blame] | 401 | *cp++ = 9; |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 402 | |
| 403 | /* Emit the process name, <= 37 bytes. */ |
| 404 | fd = open("/proc/self/cmdline", O_RDONLY); |
Carl Shapiro | af69cf8 | 2010-04-16 17:33:15 -0700 | [diff] [blame] | 405 | memset(procName, 0, sizeof(procName)); |
| 406 | read(fd, procName, sizeof(procName) - 1); |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 407 | close(fd); |
Carl Shapiro | af69cf8 | 2010-04-16 17:33:15 -0700 | [diff] [blame] | 408 | len = strlen(procName); |
| 409 | cp = logWriteString(cp, procName, len); |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 410 | |
| 411 | /* Emit the main thread status, 5 bytes. */ |
| 412 | bool isMainThread = (self->systemTid == getpid()); |
| 413 | cp = logWriteInt(cp, isMainThread); |
| 414 | |
| 415 | /* Emit self thread name string, <= 37 bytes. */ |
| 416 | selfName = dvmGetThreadName(self); |
| 417 | cp = logWriteString(cp, selfName, strlen(selfName)); |
| 418 | free(selfName); |
| 419 | |
| 420 | /* Emit the wait time, 5 bytes. */ |
| 421 | cp = logWriteInt(cp, waitMs); |
| 422 | |
| 423 | /* Emit the source code file name, <= 37 bytes. */ |
| 424 | fileName = dvmGetMethodSourceFile(meth); |
| 425 | if (fileName == NULL) fileName = ""; |
| 426 | cp = logWriteString(cp, fileName, strlen(fileName)); |
| 427 | |
| 428 | /* Emit the source code line number, 5 bytes. */ |
| 429 | relativePc = saveArea->xtra.currentPc - saveArea->method->insns; |
| 430 | cp = logWriteInt(cp, dvmLineNumFromPC(meth, relativePc)); |
| 431 | |
Carl Shapiro | fa903b3 | 2010-08-31 15:11:46 -0700 | [diff] [blame] | 432 | /* Emit the lock owner source code file name, <= 37 bytes. */ |
| 433 | if (ownerFileName == NULL) { |
| 434 | ownerFileName = ""; |
| 435 | } else if (strcmp(fileName, ownerFileName) == 0) { |
| 436 | /* Common case, so save on log space. */ |
| 437 | ownerFileName = "-"; |
| 438 | } |
| 439 | cp = logWriteString(cp, ownerFileName, strlen(ownerFileName)); |
| 440 | |
| 441 | /* Emit the source code line number, 5 bytes. */ |
| 442 | cp = logWriteInt(cp, ownerLineNumber); |
| 443 | |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 444 | /* Emit the sample percentage, 5 bytes. */ |
| 445 | cp = logWriteInt(cp, samplePercent); |
| 446 | |
| 447 | assert((size_t)(cp - eventBuffer) <= sizeof(eventBuffer)); |
Carl Shapiro | af69cf8 | 2010-04-16 17:33:15 -0700 | [diff] [blame] | 448 | android_btWriteLog(EVENT_LOG_TAG_dvm_lock_sample, |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 449 | EVENT_TYPE_LIST, |
| 450 | eventBuffer, |
| 451 | (size_t)(cp - eventBuffer)); |
| 452 | } |
| 453 | |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 454 | /* |
| 455 | * Lock a monitor. |
| 456 | */ |
| 457 | static void lockMonitor(Thread* self, Monitor* mon) |
| 458 | { |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 459 | ThreadStatus oldStatus; |
| 460 | u4 waitThreshold, samplePercent; |
| 461 | u8 waitStart, waitEnd, waitMs; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 462 | |
| 463 | if (mon->owner == self) { |
| 464 | mon->lockCount++; |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 465 | return; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 466 | } |
Carl Shapiro | 045fdc9 | 2010-04-13 16:48:27 -0700 | [diff] [blame] | 467 | if (dvmTryLockMutex(&mon->lock) != 0) { |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 468 | oldStatus = dvmChangeStatus(self, THREAD_MONITOR); |
| 469 | waitThreshold = gDvm.lockProfThreshold; |
| 470 | if (waitThreshold) { |
| 471 | waitStart = dvmGetRelativeTimeUsec(); |
| 472 | } |
Carl Shapiro | fa903b3 | 2010-08-31 15:11:46 -0700 | [diff] [blame] | 473 | const char* currentOwnerFileName = mon->ownerFileName; |
| 474 | u4 currentOwnerLineNumber = mon->ownerLineNumber; |
| 475 | |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 476 | dvmLockMutex(&mon->lock); |
| 477 | if (waitThreshold) { |
| 478 | waitEnd = dvmGetRelativeTimeUsec(); |
| 479 | } |
| 480 | dvmChangeStatus(self, oldStatus); |
| 481 | if (waitThreshold) { |
| 482 | waitMs = (waitEnd - waitStart) / 1000; |
| 483 | if (waitMs >= waitThreshold) { |
| 484 | samplePercent = 100; |
| 485 | } else { |
Carl Shapiro | af69cf8 | 2010-04-16 17:33:15 -0700 | [diff] [blame] | 486 | samplePercent = 100 * waitMs / waitThreshold; |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 487 | } |
Carl Shapiro | b8fcf57 | 2010-04-16 17:33:15 -0700 | [diff] [blame] | 488 | if (samplePercent != 0 && ((u4)rand() % 100 < samplePercent)) { |
Carl Shapiro | fa903b3 | 2010-08-31 15:11:46 -0700 | [diff] [blame] | 489 | logContentionEvent(self, waitMs, samplePercent, |
| 490 | currentOwnerFileName, currentOwnerLineNumber); |
Carl Shapiro | f0c514c | 2010-04-09 15:03:33 -0700 | [diff] [blame] | 491 | } |
| 492 | } |
| 493 | } |
| 494 | mon->owner = self; |
| 495 | assert(mon->lockCount == 0); |
Carl Shapiro | fa903b3 | 2010-08-31 15:11:46 -0700 | [diff] [blame] | 496 | |
| 497 | // When debugging, save the current monitor holder for future |
| 498 | // acquisition failures to use in sampled logging. |
| 499 | if (gDvm.lockProfThreshold > 0) { |
| 500 | const StackSaveArea *saveArea; |
| 501 | const Method *meth; |
| 502 | mon->ownerLineNumber = 0; |
| 503 | if (self->curFrame == NULL) { |
| 504 | mon->ownerFileName = "no_frame"; |
| 505 | } else if ((saveArea = SAVEAREA_FROM_FP(self->curFrame)) == NULL) { |
| 506 | mon->ownerFileName = "no_save_area"; |
| 507 | } else if ((meth = saveArea->method) == NULL) { |
| 508 | mon->ownerFileName = "no_method"; |
| 509 | } else { |
| 510 | u4 relativePc = saveArea->xtra.currentPc - saveArea->method->insns; |
| 511 | mon->ownerFileName = (char*) dvmGetMethodSourceFile(meth); |
| 512 | if (mon->ownerFileName == NULL) { |
| 513 | mon->ownerFileName = "no_method_file"; |
| 514 | } else { |
| 515 | mon->ownerLineNumber = dvmLineNumFromPC(meth, relativePc); |
| 516 | } |
| 517 | } |
| 518 | } |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 519 | } |
| 520 | |
| 521 | /* |
| 522 | * Try to lock a monitor. |
| 523 | * |
| 524 | * Returns "true" on success. |
| 525 | */ |
Carl Shapiro | b31b301 | 2010-05-25 18:35:37 -0700 | [diff] [blame] | 526 | #ifdef WITH_COPYING_GC |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 527 | static bool tryLockMonitor(Thread* self, Monitor* mon) |
| 528 | { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 529 | if (mon->owner == self) { |
| 530 | mon->lockCount++; |
| 531 | return true; |
| 532 | } else { |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 533 | if (dvmTryLockMutex(&mon->lock) == 0) { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 534 | mon->owner = self; |
| 535 | assert(mon->lockCount == 0); |
| 536 | return true; |
| 537 | } else { |
| 538 | return false; |
| 539 | } |
| 540 | } |
| 541 | } |
Carl Shapiro | b31b301 | 2010-05-25 18:35:37 -0700 | [diff] [blame] | 542 | #endif |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 543 | |
| 544 | /* |
| 545 | * Unlock a monitor. |
| 546 | * |
| 547 | * Returns true if the unlock succeeded. |
| 548 | * If the unlock failed, an exception will be pending. |
| 549 | */ |
| 550 | static bool unlockMonitor(Thread* self, Monitor* mon) |
| 551 | { |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 552 | assert(self != NULL); |
Carl Shapiro | 9227708 | 2010-04-06 15:35:59 -0700 | [diff] [blame] | 553 | assert(mon != NULL); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 554 | if (mon->owner == self) { |
| 555 | /* |
| 556 | * We own the monitor, so nobody else can be in here. |
| 557 | */ |
| 558 | if (mon->lockCount == 0) { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 559 | mon->owner = NULL; |
Carl Shapiro | fa903b3 | 2010-08-31 15:11:46 -0700 | [diff] [blame] | 560 | mon->ownerFileName = "unlocked"; |
| 561 | mon->ownerLineNumber = 0; |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 562 | dvmUnlockMutex(&mon->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 563 | } else { |
| 564 | mon->lockCount--; |
| 565 | } |
| 566 | } else { |
| 567 | /* |
| 568 | * We don't own this, so we're not allowed to unlock it. |
| 569 | * The JNI spec says that we should throw IllegalMonitorStateException |
| 570 | * in this case. |
| 571 | */ |
Carl Shapiro | 8782d7c | 2010-04-19 20:10:35 -0700 | [diff] [blame] | 572 | dvmThrowException("Ljava/lang/IllegalMonitorStateException;", |
| 573 | "unlock of unowned monitor"); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 574 | return false; |
| 575 | } |
| 576 | return true; |
| 577 | } |
| 578 | |
| 579 | /* |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 580 | * Checks the wait set for circular structure. Returns 0 if the list |
Carl Shapiro | b453919 | 2010-01-04 16:50:00 -0800 | [diff] [blame] | 581 | * is not circular. Otherwise, returns 1. Used only by asserts. |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 582 | */ |
Carl Shapiro | b31b301 | 2010-05-25 18:35:37 -0700 | [diff] [blame] | 583 | #ifndef NDEBUG |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 584 | static int waitSetCheck(Monitor *mon) |
| 585 | { |
| 586 | Thread *fast, *slow; |
| 587 | size_t n; |
| 588 | |
| 589 | assert(mon != NULL); |
| 590 | fast = slow = mon->waitSet; |
| 591 | n = 0; |
| 592 | for (;;) { |
| 593 | if (fast == NULL) return 0; |
| 594 | if (fast->waitNext == NULL) return 0; |
Carl Shapiro | 5f56e67 | 2010-01-05 20:38:03 -0800 | [diff] [blame] | 595 | if (fast == slow && n > 0) return 1; |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 596 | n += 2; |
| 597 | fast = fast->waitNext->waitNext; |
| 598 | slow = slow->waitNext; |
| 599 | } |
| 600 | } |
Carl Shapiro | b31b301 | 2010-05-25 18:35:37 -0700 | [diff] [blame] | 601 | #endif |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 602 | |
| 603 | /* |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 604 | * Links a thread into a monitor's wait set. The monitor lock must be |
| 605 | * held by the caller of this routine. |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 606 | */ |
| 607 | static void waitSetAppend(Monitor *mon, Thread *thread) |
| 608 | { |
| 609 | Thread *elt; |
| 610 | |
| 611 | assert(mon != NULL); |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 612 | assert(mon->owner == dvmThreadSelf()); |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 613 | assert(thread != NULL); |
| 614 | assert(thread->waitNext == NULL); |
| 615 | assert(waitSetCheck(mon) == 0); |
| 616 | if (mon->waitSet == NULL) { |
| 617 | mon->waitSet = thread; |
| 618 | return; |
| 619 | } |
| 620 | elt = mon->waitSet; |
| 621 | while (elt->waitNext != NULL) { |
| 622 | elt = elt->waitNext; |
| 623 | } |
| 624 | elt->waitNext = thread; |
| 625 | } |
| 626 | |
| 627 | /* |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 628 | * Unlinks a thread from a monitor's wait set. The monitor lock must |
| 629 | * be held by the caller of this routine. |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 630 | */ |
| 631 | static void waitSetRemove(Monitor *mon, Thread *thread) |
| 632 | { |
| 633 | Thread *elt; |
| 634 | |
| 635 | assert(mon != NULL); |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 636 | assert(mon->owner == dvmThreadSelf()); |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 637 | assert(thread != NULL); |
| 638 | assert(waitSetCheck(mon) == 0); |
| 639 | if (mon->waitSet == NULL) { |
| 640 | return; |
| 641 | } |
| 642 | if (mon->waitSet == thread) { |
| 643 | mon->waitSet = thread->waitNext; |
| 644 | thread->waitNext = NULL; |
| 645 | return; |
| 646 | } |
| 647 | elt = mon->waitSet; |
| 648 | while (elt->waitNext != NULL) { |
| 649 | if (elt->waitNext == thread) { |
| 650 | elt->waitNext = thread->waitNext; |
| 651 | thread->waitNext = NULL; |
| 652 | return; |
| 653 | } |
| 654 | elt = elt->waitNext; |
| 655 | } |
| 656 | } |
| 657 | |
Carl Shapiro | b453919 | 2010-01-04 16:50:00 -0800 | [diff] [blame] | 658 | /* |
| 659 | * Converts the given relative waiting time into an absolute time. |
| 660 | */ |
Andy McFadden | 953a0ed | 2010-09-17 15:48:38 -0700 | [diff] [blame] | 661 | static void absoluteTime(s8 msec, s4 nsec, struct timespec *ts) |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 662 | { |
| 663 | s8 endSec; |
| 664 | |
| 665 | #ifdef HAVE_TIMEDWAIT_MONOTONIC |
| 666 | clock_gettime(CLOCK_MONOTONIC, ts); |
| 667 | #else |
| 668 | { |
| 669 | struct timeval tv; |
| 670 | gettimeofday(&tv, NULL); |
| 671 | ts->tv_sec = tv.tv_sec; |
| 672 | ts->tv_nsec = tv.tv_usec * 1000; |
| 673 | } |
| 674 | #endif |
| 675 | endSec = ts->tv_sec + msec / 1000; |
| 676 | if (endSec >= 0x7fffffff) { |
| 677 | LOGV("NOTE: end time exceeds epoch\n"); |
| 678 | endSec = 0x7ffffffe; |
| 679 | } |
| 680 | ts->tv_sec = endSec; |
| 681 | ts->tv_nsec = (ts->tv_nsec + (msec % 1000) * 1000000) + nsec; |
| 682 | |
| 683 | /* catch rollover */ |
| 684 | if (ts->tv_nsec >= 1000000000L) { |
| 685 | ts->tv_sec++; |
| 686 | ts->tv_nsec -= 1000000000L; |
| 687 | } |
| 688 | } |
| 689 | |
Bill Buzbee | fccb31d | 2010-02-04 16:09:55 -0800 | [diff] [blame] | 690 | int dvmRelativeCondWait(pthread_cond_t* cond, pthread_mutex_t* mutex, |
| 691 | s8 msec, s4 nsec) |
| 692 | { |
| 693 | int ret; |
| 694 | struct timespec ts; |
| 695 | absoluteTime(msec, nsec, &ts); |
| 696 | #if defined(HAVE_TIMEDWAIT_MONOTONIC) |
| 697 | ret = pthread_cond_timedwait_monotonic(cond, mutex, &ts); |
| 698 | #else |
| 699 | ret = pthread_cond_timedwait(cond, mutex, &ts); |
| 700 | #endif |
| 701 | assert(ret == 0 || ret == ETIMEDOUT); |
| 702 | return ret; |
| 703 | } |
| 704 | |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 705 | /* |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 706 | * Wait on a monitor until timeout, interrupt, or notification. Used for |
| 707 | * Object.wait() and (somewhat indirectly) Thread.sleep() and Thread.join(). |
| 708 | * |
| 709 | * If another thread calls Thread.interrupt(), we throw InterruptedException |
| 710 | * and return immediately if one of the following are true: |
| 711 | * - blocked in wait(), wait(long), or wait(long, int) methods of Object |
| 712 | * - blocked in join(), join(long), or join(long, int) methods of Thread |
| 713 | * - blocked in sleep(long), or sleep(long, int) methods of Thread |
| 714 | * Otherwise, we set the "interrupted" flag. |
| 715 | * |
| 716 | * Checks to make sure that "nsec" is in the range 0-999999 |
| 717 | * (i.e. fractions of a millisecond) and throws the appropriate |
| 718 | * exception if it isn't. |
| 719 | * |
| 720 | * The spec allows "spurious wakeups", and recommends that all code using |
| 721 | * Object.wait() do so in a loop. This appears to derive from concerns |
| 722 | * about pthread_cond_wait() on multiprocessor systems. Some commentary |
| 723 | * on the web casts doubt on whether these can/should occur. |
| 724 | * |
| 725 | * Since we're allowed to wake up "early", we clamp extremely long durations |
| 726 | * to return at the end of the 32-bit time epoch. |
| 727 | */ |
| 728 | static void waitMonitor(Thread* self, Monitor* mon, s8 msec, s4 nsec, |
| 729 | bool interruptShouldThrow) |
| 730 | { |
| 731 | struct timespec ts; |
| 732 | bool wasInterrupted = false; |
| 733 | bool timed; |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 734 | int ret; |
Carl Shapiro | fa903b3 | 2010-08-31 15:11:46 -0700 | [diff] [blame] | 735 | char *savedFileName; |
| 736 | u4 savedLineNumber; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 737 | |
Carl Shapiro | 7193802 | 2009-12-22 13:49:53 -0800 | [diff] [blame] | 738 | assert(self != NULL); |
| 739 | assert(mon != NULL); |
| 740 | |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 741 | /* Make sure that we hold the lock. */ |
Carl Shapiro | 7193802 | 2009-12-22 13:49:53 -0800 | [diff] [blame] | 742 | if (mon->owner != self) { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 743 | dvmThrowException("Ljava/lang/IllegalMonitorStateException;", |
| 744 | "object not locked by thread before wait()"); |
| 745 | return; |
| 746 | } |
| 747 | |
| 748 | /* |
| 749 | * Enforce the timeout range. |
| 750 | */ |
| 751 | if (msec < 0 || nsec < 0 || nsec > 999999) { |
| 752 | dvmThrowException("Ljava/lang/IllegalArgumentException;", |
| 753 | "timeout arguments out of range"); |
| 754 | return; |
| 755 | } |
| 756 | |
| 757 | /* |
| 758 | * Compute absolute wakeup time, if necessary. |
| 759 | */ |
| 760 | if (msec == 0 && nsec == 0) { |
| 761 | timed = false; |
| 762 | } else { |
Bill Buzbee | fccb31d | 2010-02-04 16:09:55 -0800 | [diff] [blame] | 763 | absoluteTime(msec, nsec, &ts); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 764 | timed = true; |
| 765 | } |
| 766 | |
| 767 | /* |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 768 | * Add ourselves to the set of threads waiting on this monitor, and |
| 769 | * release our hold. We need to let it go even if we're a few levels |
| 770 | * deep in a recursive lock, and we need to restore that later. |
| 771 | * |
Carl Shapiro | 142ef27 | 2010-01-25 12:51:31 -0800 | [diff] [blame] | 772 | * We append to the wait set ahead of clearing the count and owner |
| 773 | * fields so the subroutine can check that the calling thread owns |
| 774 | * the monitor. Aside from that, the order of member updates is |
| 775 | * not order sensitive as we hold the pthread mutex. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 776 | */ |
Carl Shapiro | 142ef27 | 2010-01-25 12:51:31 -0800 | [diff] [blame] | 777 | waitSetAppend(mon, self); |
| 778 | int prevLockCount = mon->lockCount; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 779 | mon->lockCount = 0; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 780 | mon->owner = NULL; |
Carl Shapiro | fa903b3 | 2010-08-31 15:11:46 -0700 | [diff] [blame] | 781 | savedFileName = mon->ownerFileName; |
| 782 | mon->ownerFileName = NULL; |
| 783 | savedLineNumber = mon->ownerLineNumber; |
| 784 | mon->ownerLineNumber = 0; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 785 | |
| 786 | /* |
| 787 | * Update thread status. If the GC wakes up, it'll ignore us, knowing |
| 788 | * that we won't touch any references in this state, and we'll check |
| 789 | * our suspend mode before we transition out. |
| 790 | */ |
| 791 | if (timed) |
| 792 | dvmChangeStatus(self, THREAD_TIMED_WAIT); |
| 793 | else |
| 794 | dvmChangeStatus(self, THREAD_WAIT); |
| 795 | |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 796 | dvmLockMutex(&self->waitMutex); |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 797 | |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 798 | /* |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 799 | * Set waitMonitor to the monitor object we will be waiting on. |
| 800 | * When waitMonitor is non-NULL a notifying or interrupting thread |
| 801 | * must signal the thread's waitCond to wake it up. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 802 | */ |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 803 | assert(self->waitMonitor == NULL); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 804 | self->waitMonitor = mon; |
| 805 | |
| 806 | /* |
| 807 | * Handle the case where the thread was interrupted before we called |
| 808 | * wait(). |
| 809 | */ |
| 810 | if (self->interrupted) { |
| 811 | wasInterrupted = true; |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 812 | self->waitMonitor = NULL; |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 813 | dvmUnlockMutex(&self->waitMutex); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 814 | goto done; |
| 815 | } |
| 816 | |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 817 | /* |
| 818 | * Release the monitor lock and wait for a notification or |
| 819 | * a timeout to occur. |
| 820 | */ |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 821 | dvmUnlockMutex(&mon->lock); |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 822 | |
| 823 | if (!timed) { |
| 824 | ret = pthread_cond_wait(&self->waitCond, &self->waitMutex); |
| 825 | assert(ret == 0); |
| 826 | } else { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 827 | #ifdef HAVE_TIMEDWAIT_MONOTONIC |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 828 | ret = pthread_cond_timedwait_monotonic(&self->waitCond, &self->waitMutex, &ts); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 829 | #else |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 830 | ret = pthread_cond_timedwait(&self->waitCond, &self->waitMutex, &ts); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 831 | #endif |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 832 | assert(ret == 0 || ret == ETIMEDOUT); |
| 833 | } |
| 834 | if (self->interrupted) { |
| 835 | wasInterrupted = true; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 836 | } |
| 837 | |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 838 | self->interrupted = false; |
| 839 | self->waitMonitor = NULL; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 840 | |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 841 | dvmUnlockMutex(&self->waitMutex); |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 842 | |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 843 | /* Reacquire the monitor lock. */ |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 844 | lockMonitor(self, mon); |
| 845 | |
Carl Shapiro | 142ef27 | 2010-01-25 12:51:31 -0800 | [diff] [blame] | 846 | done: |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 847 | /* |
Carl Shapiro | 07b3592 | 2010-01-25 14:48:30 -0800 | [diff] [blame] | 848 | * We remove our thread from wait set after restoring the count |
| 849 | * and owner fields so the subroutine can check that the calling |
| 850 | * thread owns the monitor. Aside from that, the order of member |
| 851 | * updates is not order sensitive as we hold the pthread mutex. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 852 | */ |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 853 | mon->owner = self; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 854 | mon->lockCount = prevLockCount; |
Carl Shapiro | fa903b3 | 2010-08-31 15:11:46 -0700 | [diff] [blame] | 855 | mon->ownerFileName = savedFileName; |
| 856 | mon->ownerLineNumber = savedLineNumber; |
Carl Shapiro | 07b3592 | 2010-01-25 14:48:30 -0800 | [diff] [blame] | 857 | waitSetRemove(mon, self); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 858 | |
| 859 | /* set self->status back to THREAD_RUNNING, and self-suspend if needed */ |
| 860 | dvmChangeStatus(self, THREAD_RUNNING); |
| 861 | |
| 862 | if (wasInterrupted) { |
| 863 | /* |
| 864 | * We were interrupted while waiting, or somebody interrupted an |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 865 | * un-interruptible thread earlier and we're bailing out immediately. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 866 | * |
| 867 | * The doc sayeth: "The interrupted status of the current thread is |
| 868 | * cleared when this exception is thrown." |
| 869 | */ |
| 870 | self->interrupted = false; |
| 871 | if (interruptShouldThrow) |
| 872 | dvmThrowException("Ljava/lang/InterruptedException;", NULL); |
| 873 | } |
| 874 | } |
| 875 | |
| 876 | /* |
| 877 | * Notify one thread waiting on this monitor. |
| 878 | */ |
| 879 | static void notifyMonitor(Thread* self, Monitor* mon) |
| 880 | { |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 881 | Thread* thread; |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 882 | |
Carl Shapiro | 7193802 | 2009-12-22 13:49:53 -0800 | [diff] [blame] | 883 | assert(self != NULL); |
| 884 | assert(mon != NULL); |
| 885 | |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 886 | /* Make sure that we hold the lock. */ |
Carl Shapiro | 7193802 | 2009-12-22 13:49:53 -0800 | [diff] [blame] | 887 | if (mon->owner != self) { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 888 | dvmThrowException("Ljava/lang/IllegalMonitorStateException;", |
| 889 | "object not locked by thread before notify()"); |
| 890 | return; |
| 891 | } |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 892 | /* Signal the first waiting thread in the wait set. */ |
| 893 | while (mon->waitSet != NULL) { |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 894 | thread = mon->waitSet; |
| 895 | mon->waitSet = thread->waitNext; |
| 896 | thread->waitNext = NULL; |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 897 | dvmLockMutex(&thread->waitMutex); |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 898 | /* Check to see if the thread is still waiting. */ |
| 899 | if (thread->waitMonitor != NULL) { |
| 900 | pthread_cond_signal(&thread->waitCond); |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 901 | dvmUnlockMutex(&thread->waitMutex); |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 902 | return; |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 903 | } |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 904 | dvmUnlockMutex(&thread->waitMutex); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 905 | } |
| 906 | } |
| 907 | |
| 908 | /* |
| 909 | * Notify all threads waiting on this monitor. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 910 | */ |
| 911 | static void notifyAllMonitor(Thread* self, Monitor* mon) |
| 912 | { |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 913 | Thread* thread; |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 914 | |
Carl Shapiro | 7193802 | 2009-12-22 13:49:53 -0800 | [diff] [blame] | 915 | assert(self != NULL); |
| 916 | assert(mon != NULL); |
| 917 | |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 918 | /* Make sure that we hold the lock. */ |
Carl Shapiro | 7193802 | 2009-12-22 13:49:53 -0800 | [diff] [blame] | 919 | if (mon->owner != self) { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 920 | dvmThrowException("Ljava/lang/IllegalMonitorStateException;", |
| 921 | "object not locked by thread before notifyAll()"); |
| 922 | return; |
| 923 | } |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 924 | /* Signal all threads in the wait set. */ |
| 925 | while (mon->waitSet != NULL) { |
| 926 | thread = mon->waitSet; |
| 927 | mon->waitSet = thread->waitNext; |
| 928 | thread->waitNext = NULL; |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 929 | dvmLockMutex(&thread->waitMutex); |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 930 | /* Check to see if the thread is still waiting. */ |
| 931 | if (thread->waitMonitor != NULL) { |
| 932 | pthread_cond_signal(&thread->waitCond); |
| 933 | } |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 934 | dvmUnlockMutex(&thread->waitMutex); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 935 | } |
| 936 | } |
| 937 | |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 938 | /* |
Carl Shapiro | 66bb7df | 2010-03-12 15:25:37 -0800 | [diff] [blame] | 939 | * Changes the shape of a monitor from thin to fat, preserving the |
| 940 | * internal lock state. The calling thread must own the lock. |
| 941 | */ |
| 942 | static void inflateMonitor(Thread *self, Object *obj) |
| 943 | { |
| 944 | Monitor *mon; |
| 945 | u4 thin; |
| 946 | |
| 947 | assert(self != NULL); |
| 948 | assert(obj != NULL); |
| 949 | assert(LW_SHAPE(obj->lock) == LW_SHAPE_THIN); |
| 950 | assert(LW_LOCK_OWNER(obj->lock) == self->threadId); |
| 951 | /* Allocate and acquire a new monitor. */ |
| 952 | mon = dvmCreateMonitor(obj); |
| 953 | lockMonitor(self, mon); |
| 954 | /* Propagate the lock state. */ |
| 955 | thin = obj->lock; |
| 956 | mon->lockCount = LW_LOCK_COUNT(thin); |
| 957 | thin &= LW_HASH_STATE_MASK << LW_HASH_STATE_SHIFT; |
| 958 | thin |= (u4)mon | LW_SHAPE_FAT; |
| 959 | /* Publish the updated lock word. */ |
Carl Shapiro | 4ba5672 | 2010-06-21 11:04:33 -0700 | [diff] [blame] | 960 | android_atomic_release_store(thin, (int32_t *)&obj->lock); |
Carl Shapiro | 66bb7df | 2010-03-12 15:25:37 -0800 | [diff] [blame] | 961 | } |
| 962 | |
| 963 | /* |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 964 | * Implements monitorenter for "synchronized" stuff. |
| 965 | * |
| 966 | * This does not fail or throw an exception (unless deadlock prediction |
| 967 | * is enabled and set to "err" mode). |
| 968 | */ |
| 969 | void dvmLockObject(Thread* self, Object *obj) |
| 970 | { |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 971 | volatile u4 *thinp; |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 972 | ThreadStatus oldStatus; |
| 973 | useconds_t sleepDelay; |
| 974 | const useconds_t maxSleepDelay = 1 << 20; |
| 975 | u4 thin, newThin, threadId; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 976 | |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 977 | assert(self != NULL); |
| 978 | assert(obj != NULL); |
| 979 | threadId = self->threadId; |
| 980 | thinp = &obj->lock; |
| 981 | retry: |
| 982 | thin = *thinp; |
| 983 | if (LW_SHAPE(thin) == LW_SHAPE_THIN) { |
| 984 | /* |
| 985 | * The lock is a thin lock. The owner field is used to |
| 986 | * determine the acquire method, ordered by cost. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 987 | */ |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 988 | if (LW_LOCK_OWNER(thin) == threadId) { |
| 989 | /* |
| 990 | * The calling thread owns the lock. Increment the |
| 991 | * value of the recursion count field. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 992 | */ |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 993 | obj->lock += 1 << LW_LOCK_COUNT_SHIFT; |
Carl Shapiro | f3cfbbf | 2010-07-23 16:30:12 -0700 | [diff] [blame] | 994 | if (LW_LOCK_COUNT(obj->lock) == LW_LOCK_COUNT_MASK) { |
| 995 | /* |
| 996 | * The reacquisition limit has been reached. Inflate |
| 997 | * the lock so the next acquire will not overflow the |
| 998 | * recursion count field. |
| 999 | */ |
| 1000 | inflateMonitor(self, obj); |
| 1001 | } |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1002 | } else if (LW_LOCK_OWNER(thin) == 0) { |
| 1003 | /* |
| 1004 | * The lock is unowned. Install the thread id of the |
| 1005 | * calling thread into the owner field. This is the |
| 1006 | * common case. In performance critical code the JIT |
| 1007 | * will have tried this before calling out to the VM. |
| 1008 | */ |
| 1009 | newThin = thin | (threadId << LW_LOCK_OWNER_SHIFT); |
Carl Shapiro | 3ba10c9 | 2010-09-02 16:43:16 -0700 | [diff] [blame] | 1010 | if (android_atomic_acquire_cas(thin, newThin, |
Andy McFadden | 6e10b9a | 2010-06-14 15:24:39 -0700 | [diff] [blame] | 1011 | (int32_t*)thinp) != 0) { |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1012 | /* |
| 1013 | * The acquire failed. Try again. |
| 1014 | */ |
| 1015 | goto retry; |
| 1016 | } |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1017 | } else { |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1018 | LOG_THIN("(%d) spin on lock %p: %#x (%#x) %#x", |
| 1019 | threadId, &obj->lock, 0, *thinp, thin); |
| 1020 | /* |
| 1021 | * The lock is owned by another thread. Notify the VM |
| 1022 | * that we are about to wait. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1023 | */ |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1024 | oldStatus = dvmChangeStatus(self, THREAD_MONITOR); |
| 1025 | /* |
| 1026 | * Spin until the thin lock is released or inflated. |
| 1027 | */ |
| 1028 | sleepDelay = 0; |
| 1029 | for (;;) { |
| 1030 | thin = *thinp; |
| 1031 | /* |
| 1032 | * Check the shape of the lock word. Another thread |
| 1033 | * may have inflated the lock while we were waiting. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1034 | */ |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1035 | if (LW_SHAPE(thin) == LW_SHAPE_THIN) { |
| 1036 | if (LW_LOCK_OWNER(thin) == 0) { |
| 1037 | /* |
| 1038 | * The lock has been released. Install the |
| 1039 | * thread id of the calling thread into the |
| 1040 | * owner field. |
| 1041 | */ |
| 1042 | newThin = thin | (threadId << LW_LOCK_OWNER_SHIFT); |
Carl Shapiro | 3ba10c9 | 2010-09-02 16:43:16 -0700 | [diff] [blame] | 1043 | if (android_atomic_acquire_cas(thin, newThin, |
Andy McFadden | 6e10b9a | 2010-06-14 15:24:39 -0700 | [diff] [blame] | 1044 | (int32_t *)thinp) == 0) { |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1045 | /* |
| 1046 | * The acquire succeed. Break out of the |
| 1047 | * loop and proceed to inflate the lock. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1048 | */ |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1049 | break; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1050 | } |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1051 | } else { |
| 1052 | /* |
| 1053 | * The lock has not been released. Yield so |
| 1054 | * the owning thread can run. |
| 1055 | */ |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1056 | if (sleepDelay == 0) { |
| 1057 | sched_yield(); |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1058 | sleepDelay = 1000; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1059 | } else { |
| 1060 | usleep(sleepDelay); |
| 1061 | if (sleepDelay < maxSleepDelay / 2) { |
| 1062 | sleepDelay *= 2; |
| 1063 | } |
| 1064 | } |
| 1065 | } |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1066 | } else { |
| 1067 | /* |
| 1068 | * The thin lock was inflated by another thread. |
| 1069 | * Let the VM know we are no longer waiting and |
| 1070 | * try again. |
| 1071 | */ |
| 1072 | LOG_THIN("(%d) lock %p surprise-fattened", |
| 1073 | threadId, &obj->lock); |
| 1074 | dvmChangeStatus(self, oldStatus); |
| 1075 | goto retry; |
| 1076 | } |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1077 | } |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1078 | LOG_THIN("(%d) spin on lock done %p: %#x (%#x) %#x", |
| 1079 | threadId, &obj->lock, 0, *thinp, thin); |
| 1080 | /* |
| 1081 | * We have acquired the thin lock. Let the VM know that |
| 1082 | * we are no longer waiting. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1083 | */ |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1084 | dvmChangeStatus(self, oldStatus); |
| 1085 | /* |
| 1086 | * Fatten the lock. |
| 1087 | */ |
Carl Shapiro | 66bb7df | 2010-03-12 15:25:37 -0800 | [diff] [blame] | 1088 | inflateMonitor(self, obj); |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1089 | LOG_THIN("(%d) lock %p fattened", threadId, &obj->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1090 | } |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1091 | } else { |
| 1092 | /* |
| 1093 | * The lock is a fat lock. |
| 1094 | */ |
| 1095 | assert(LW_MONITOR(obj->lock) != NULL); |
| 1096 | lockMonitor(self, LW_MONITOR(obj->lock)); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1097 | } |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1098 | #ifdef WITH_DEADLOCK_PREDICTION |
| 1099 | /* |
| 1100 | * See if we were allowed to grab the lock at this time. We do it |
| 1101 | * *after* acquiring the lock, rather than before, so that we can |
| 1102 | * freely update the Monitor struct. This seems counter-intuitive, |
| 1103 | * but our goal is deadlock *prediction* not deadlock *prevention*. |
| 1104 | * (If we actually deadlock, the situation is easy to diagnose from |
| 1105 | * a thread dump, so there's no point making a special effort to do |
| 1106 | * the checks before the lock is held.) |
| 1107 | * |
| 1108 | * This needs to happen before we add the object to the thread's |
| 1109 | * monitor list, so we can tell the difference between first-lock and |
| 1110 | * re-lock. |
| 1111 | * |
| 1112 | * It's also important that we do this while in THREAD_RUNNING, so |
| 1113 | * that we don't interfere with cleanup operations in the GC. |
| 1114 | */ |
| 1115 | if (gDvm.deadlockPredictMode != kDPOff) { |
| 1116 | if (self->status != THREAD_RUNNING) { |
| 1117 | LOGE("Bad thread status (%d) in DP\n", self->status); |
| 1118 | dvmDumpThread(self, false); |
| 1119 | dvmAbort(); |
| 1120 | } |
| 1121 | assert(!dvmCheckException(self)); |
| 1122 | updateDeadlockPrediction(self, obj); |
| 1123 | if (dvmCheckException(self)) { |
| 1124 | /* |
| 1125 | * If we're throwing an exception here, we need to free the |
| 1126 | * lock. We add the object to the thread's monitor list so the |
| 1127 | * "unlock" code can remove it. |
| 1128 | */ |
| 1129 | dvmAddToMonitorList(self, obj, false); |
| 1130 | dvmUnlockObject(self, obj); |
| 1131 | LOGV("--- unlocked, pending is '%s'\n", |
| 1132 | dvmGetException(self)->clazz->descriptor); |
| 1133 | } |
| 1134 | } |
| 1135 | |
| 1136 | /* |
| 1137 | * Add the locked object, and the current stack trace, to the list |
| 1138 | * held by the Thread object. If deadlock prediction isn't on, |
| 1139 | * don't capture the stack trace. |
| 1140 | */ |
| 1141 | dvmAddToMonitorList(self, obj, gDvm.deadlockPredictMode != kDPOff); |
| 1142 | #elif defined(WITH_MONITOR_TRACKING) |
| 1143 | /* |
| 1144 | * Add the locked object to the list held by the Thread object. |
| 1145 | */ |
| 1146 | dvmAddToMonitorList(self, obj, false); |
| 1147 | #endif |
| 1148 | } |
| 1149 | |
| 1150 | /* |
| 1151 | * Implements monitorexit for "synchronized" stuff. |
| 1152 | * |
| 1153 | * On failure, throws an exception and returns "false". |
| 1154 | */ |
| 1155 | bool dvmUnlockObject(Thread* self, Object *obj) |
| 1156 | { |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 1157 | u4 thin; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1158 | |
Carl Shapiro | ef5b4d3 | 2010-01-26 13:22:04 -0800 | [diff] [blame] | 1159 | assert(self != NULL); |
| 1160 | assert(self->status == THREAD_RUNNING); |
| 1161 | assert(obj != NULL); |
Carl Shapiro | ef5b4d3 | 2010-01-26 13:22:04 -0800 | [diff] [blame] | 1162 | /* |
| 1163 | * Cache the lock word as its value can change while we are |
| 1164 | * examining its state. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1165 | */ |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1166 | thin = obj->lock; |
Carl Shapiro | ef5b4d3 | 2010-01-26 13:22:04 -0800 | [diff] [blame] | 1167 | if (LW_SHAPE(thin) == LW_SHAPE_THIN) { |
| 1168 | /* |
| 1169 | * The lock is thin. We must ensure that the lock is owned |
| 1170 | * by the given thread before unlocking it. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1171 | */ |
Carl Shapiro | ef5b4d3 | 2010-01-26 13:22:04 -0800 | [diff] [blame] | 1172 | if (LW_LOCK_OWNER(thin) == self->threadId) { |
| 1173 | /* |
| 1174 | * We are the lock owner. It is safe to update the lock |
| 1175 | * without CAS as lock ownership guards the lock itself. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1176 | */ |
Carl Shapiro | ef5b4d3 | 2010-01-26 13:22:04 -0800 | [diff] [blame] | 1177 | if (LW_LOCK_COUNT(thin) == 0) { |
| 1178 | /* |
| 1179 | * The lock was not recursively acquired, the common |
| 1180 | * case. Unlock by clearing all bits except for the |
| 1181 | * hash state. |
| 1182 | */ |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1183 | obj->lock &= (LW_HASH_STATE_MASK << LW_HASH_STATE_SHIFT); |
Carl Shapiro | ef5b4d3 | 2010-01-26 13:22:04 -0800 | [diff] [blame] | 1184 | } else { |
| 1185 | /* |
| 1186 | * The object was recursively acquired. Decrement the |
| 1187 | * lock recursion count field. |
| 1188 | */ |
Carl Shapiro | 147dd3f | 2010-03-08 14:38:42 -0800 | [diff] [blame] | 1189 | obj->lock -= 1 << LW_LOCK_COUNT_SHIFT; |
Carl Shapiro | ef5b4d3 | 2010-01-26 13:22:04 -0800 | [diff] [blame] | 1190 | } |
| 1191 | } else { |
| 1192 | /* |
| 1193 | * We do not own the lock. The JVM spec requires that we |
| 1194 | * throw an exception in this case. |
| 1195 | */ |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1196 | dvmThrowException("Ljava/lang/IllegalMonitorStateException;", |
Carl Shapiro | ef5b4d3 | 2010-01-26 13:22:04 -0800 | [diff] [blame] | 1197 | "unlock of unowned monitor"); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1198 | return false; |
| 1199 | } |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1200 | } else { |
Carl Shapiro | ef5b4d3 | 2010-01-26 13:22:04 -0800 | [diff] [blame] | 1201 | /* |
| 1202 | * The lock is fat. We must check to see if unlockMonitor has |
| 1203 | * raised any exceptions before continuing. |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1204 | */ |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1205 | assert(LW_MONITOR(obj->lock) != NULL); |
| 1206 | if (!unlockMonitor(self, LW_MONITOR(obj->lock))) { |
Carl Shapiro | ef5b4d3 | 2010-01-26 13:22:04 -0800 | [diff] [blame] | 1207 | /* |
| 1208 | * An exception has been raised. Do not fall through. |
| 1209 | */ |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1210 | return false; |
| 1211 | } |
| 1212 | } |
| 1213 | |
| 1214 | #ifdef WITH_MONITOR_TRACKING |
| 1215 | /* |
| 1216 | * Remove the object from the Thread's list. |
| 1217 | */ |
| 1218 | dvmRemoveFromMonitorList(self, obj); |
| 1219 | #endif |
| 1220 | |
| 1221 | return true; |
| 1222 | } |
| 1223 | |
| 1224 | /* |
| 1225 | * Object.wait(). Also called for class init. |
| 1226 | */ |
| 1227 | void dvmObjectWait(Thread* self, Object *obj, s8 msec, s4 nsec, |
| 1228 | bool interruptShouldThrow) |
| 1229 | { |
Carl Shapiro | 66bb7df | 2010-03-12 15:25:37 -0800 | [diff] [blame] | 1230 | Monitor* mon; |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1231 | u4 thin = obj->lock; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1232 | |
| 1233 | /* If the lock is still thin, we need to fatten it. |
| 1234 | */ |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 1235 | if (LW_SHAPE(thin) == LW_SHAPE_THIN) { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1236 | /* Make sure that 'self' holds the lock. |
| 1237 | */ |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 1238 | if (LW_LOCK_OWNER(thin) != self->threadId) { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1239 | dvmThrowException("Ljava/lang/IllegalMonitorStateException;", |
| 1240 | "object not locked by thread before wait()"); |
| 1241 | return; |
| 1242 | } |
| 1243 | |
| 1244 | /* This thread holds the lock. We need to fatten the lock |
| 1245 | * so 'self' can block on it. Don't update the object lock |
| 1246 | * field yet, because 'self' needs to acquire the lock before |
| 1247 | * any other thread gets a chance. |
| 1248 | */ |
Carl Shapiro | 66bb7df | 2010-03-12 15:25:37 -0800 | [diff] [blame] | 1249 | inflateMonitor(self, obj); |
Patrick Scott | 2446f44 | 2010-10-21 14:50:15 -0400 | [diff] [blame] | 1250 | LOG_THIN("(%d) lock %p fattened by wait()", self->threadId, &obj->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1251 | } |
Carl Shapiro | 66bb7df | 2010-03-12 15:25:37 -0800 | [diff] [blame] | 1252 | mon = LW_MONITOR(obj->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1253 | waitMonitor(self, mon, msec, nsec, interruptShouldThrow); |
| 1254 | } |
| 1255 | |
| 1256 | /* |
| 1257 | * Object.notify(). |
| 1258 | */ |
| 1259 | void dvmObjectNotify(Thread* self, Object *obj) |
| 1260 | { |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1261 | u4 thin = obj->lock; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1262 | |
| 1263 | /* If the lock is still thin, there aren't any waiters; |
| 1264 | * waiting on an object forces lock fattening. |
| 1265 | */ |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 1266 | if (LW_SHAPE(thin) == LW_SHAPE_THIN) { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1267 | /* Make sure that 'self' holds the lock. |
| 1268 | */ |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 1269 | if (LW_LOCK_OWNER(thin) != self->threadId) { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1270 | dvmThrowException("Ljava/lang/IllegalMonitorStateException;", |
| 1271 | "object not locked by thread before notify()"); |
| 1272 | return; |
| 1273 | } |
| 1274 | |
| 1275 | /* no-op; there are no waiters to notify. |
| 1276 | */ |
| 1277 | } else { |
| 1278 | /* It's a fat lock. |
| 1279 | */ |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 1280 | notifyMonitor(self, LW_MONITOR(thin)); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1281 | } |
| 1282 | } |
| 1283 | |
| 1284 | /* |
| 1285 | * Object.notifyAll(). |
| 1286 | */ |
| 1287 | void dvmObjectNotifyAll(Thread* self, Object *obj) |
| 1288 | { |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1289 | u4 thin = obj->lock; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1290 | |
| 1291 | /* If the lock is still thin, there aren't any waiters; |
| 1292 | * waiting on an object forces lock fattening. |
| 1293 | */ |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 1294 | if (LW_SHAPE(thin) == LW_SHAPE_THIN) { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1295 | /* Make sure that 'self' holds the lock. |
| 1296 | */ |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 1297 | if (LW_LOCK_OWNER(thin) != self->threadId) { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1298 | dvmThrowException("Ljava/lang/IllegalMonitorStateException;", |
| 1299 | "object not locked by thread before notifyAll()"); |
| 1300 | return; |
| 1301 | } |
| 1302 | |
| 1303 | /* no-op; there are no waiters to notify. |
| 1304 | */ |
| 1305 | } else { |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1306 | /* It's a fat lock. |
| 1307 | */ |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 1308 | notifyAllMonitor(self, LW_MONITOR(thin)); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1309 | } |
| 1310 | } |
| 1311 | |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1312 | /* |
| 1313 | * This implements java.lang.Thread.sleep(long msec, int nsec). |
| 1314 | * |
| 1315 | * The sleep is interruptible by other threads, which means we can't just |
| 1316 | * plop into an OS sleep call. (We probably could if we wanted to send |
| 1317 | * signals around and rely on EINTR, but that's inefficient and relies |
| 1318 | * on native code respecting our signal mask.) |
| 1319 | * |
| 1320 | * We have to do all of this stuff for Object.wait() as well, so it's |
| 1321 | * easiest to just sleep on a private Monitor. |
| 1322 | * |
| 1323 | * It appears that we want sleep(0,0) to go through the motions of sleeping |
| 1324 | * for a very short duration, rather than just returning. |
| 1325 | */ |
| 1326 | void dvmThreadSleep(u8 msec, u4 nsec) |
| 1327 | { |
| 1328 | Thread* self = dvmThreadSelf(); |
| 1329 | Monitor* mon = gDvm.threadSleepMon; |
| 1330 | |
| 1331 | /* sleep(0,0) wakes up immediately, wait(0,0) means wait forever; adjust */ |
| 1332 | if (msec == 0 && nsec == 0) |
| 1333 | nsec++; |
| 1334 | |
| 1335 | lockMonitor(self, mon); |
| 1336 | waitMonitor(self, mon, msec, nsec, true); |
| 1337 | unlockMonitor(self, mon); |
| 1338 | } |
| 1339 | |
| 1340 | /* |
| 1341 | * Implement java.lang.Thread.interrupt(). |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1342 | */ |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 1343 | void dvmThreadInterrupt(Thread* thread) |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1344 | { |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 1345 | assert(thread != NULL); |
| 1346 | |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 1347 | dvmLockMutex(&thread->waitMutex); |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 1348 | |
| 1349 | /* |
| 1350 | * If the interrupted flag is already set no additional action is |
| 1351 | * required. |
| 1352 | */ |
| 1353 | if (thread->interrupted == true) { |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 1354 | dvmUnlockMutex(&thread->waitMutex); |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 1355 | return; |
| 1356 | } |
| 1357 | |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1358 | /* |
| 1359 | * Raise the "interrupted" flag. This will cause it to bail early out |
| 1360 | * of the next wait() attempt, if it's not currently waiting on |
| 1361 | * something. |
| 1362 | */ |
| 1363 | thread->interrupted = true; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1364 | |
| 1365 | /* |
| 1366 | * Is the thread waiting? |
| 1367 | * |
| 1368 | * Note that fat vs. thin doesn't matter here; waitMonitor |
| 1369 | * is only set when a thread actually waits on a monitor, |
| 1370 | * which implies that the monitor has already been fattened. |
| 1371 | */ |
Carl Shapiro | 77f52eb | 2009-12-24 19:56:53 -0800 | [diff] [blame] | 1372 | if (thread->waitMonitor != NULL) { |
| 1373 | pthread_cond_signal(&thread->waitCond); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1374 | } |
| 1375 | |
Carl Shapiro | 980ffb0 | 2010-03-13 22:34:01 -0800 | [diff] [blame] | 1376 | dvmUnlockMutex(&thread->waitMutex); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1377 | } |
| 1378 | |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 1379 | #ifndef WITH_COPYING_GC |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 1380 | u4 dvmIdentityHashCode(Object *obj) |
| 1381 | { |
| 1382 | return (u4)obj; |
| 1383 | } |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 1384 | #else |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 1385 | /* |
| 1386 | * Returns the identity hash code of the given object. |
| 1387 | */ |
| 1388 | u4 dvmIdentityHashCode(Object *obj) |
| 1389 | { |
| 1390 | Thread *self, *thread; |
| 1391 | volatile u4 *lw; |
Carl Shapiro | bfe4dcc | 2010-04-16 17:55:27 -0700 | [diff] [blame] | 1392 | size_t size; |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 1393 | u4 lock, owner, hashState; |
| 1394 | |
| 1395 | if (obj == NULL) { |
| 1396 | /* |
| 1397 | * Null is defined to have an identity hash code of 0. |
| 1398 | */ |
| 1399 | return 0; |
| 1400 | } |
| 1401 | lw = &obj->lock; |
| 1402 | retry: |
| 1403 | hashState = LW_HASH_STATE(*lw); |
| 1404 | if (hashState == LW_HASH_STATE_HASHED) { |
| 1405 | /* |
| 1406 | * The object has been hashed but has not had its hash code |
| 1407 | * relocated by the garbage collector. Use the raw object |
| 1408 | * address. |
| 1409 | */ |
| 1410 | return (u4)obj >> 3; |
| 1411 | } else if (hashState == LW_HASH_STATE_HASHED_AND_MOVED) { |
| 1412 | /* |
| 1413 | * The object has been hashed and its hash code has been |
| 1414 | * relocated by the collector. Use the value of the naturally |
| 1415 | * aligned word following the instance data. |
| 1416 | */ |
Carl Shapiro | c48b6d0 | 2010-05-04 11:19:53 -0700 | [diff] [blame] | 1417 | assert(obj->clazz != gDvm.classJavaLangClass); |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 1418 | if (IS_CLASS_FLAG_SET(obj->clazz, CLASS_ISARRAY)) { |
Carl Shapiro | bfe4dcc | 2010-04-16 17:55:27 -0700 | [diff] [blame] | 1419 | size = dvmArrayObjectSize((ArrayObject *)obj); |
Carl Shapiro | c48b6d0 | 2010-05-04 11:19:53 -0700 | [diff] [blame] | 1420 | size = (size + 2) & ~2; |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 1421 | } else { |
Carl Shapiro | bfe4dcc | 2010-04-16 17:55:27 -0700 | [diff] [blame] | 1422 | size = obj->clazz->objectSize; |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 1423 | } |
Carl Shapiro | bfe4dcc | 2010-04-16 17:55:27 -0700 | [diff] [blame] | 1424 | return *(u4 *)(((char *)obj) + size); |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 1425 | } else if (hashState == LW_HASH_STATE_UNHASHED) { |
| 1426 | /* |
| 1427 | * The object has never been hashed. Change the hash state to |
| 1428 | * hashed and use the raw object address. |
| 1429 | */ |
| 1430 | self = dvmThreadSelf(); |
| 1431 | if (self->threadId == lockOwner(obj)) { |
| 1432 | /* |
| 1433 | * We already own the lock so we can update the hash state |
| 1434 | * directly. |
| 1435 | */ |
| 1436 | *lw |= (LW_HASH_STATE_HASHED << LW_HASH_STATE_SHIFT); |
| 1437 | return (u4)obj >> 3; |
| 1438 | } |
| 1439 | /* |
| 1440 | * We do not own the lock. Try acquiring the lock. Should |
| 1441 | * this fail, we must suspend the owning thread. |
| 1442 | */ |
| 1443 | if (LW_SHAPE(*lw) == LW_SHAPE_THIN) { |
| 1444 | /* |
| 1445 | * If the lock is thin assume it is unowned. We simulate |
| 1446 | * an acquire, update, and release with a single CAS. |
| 1447 | */ |
| 1448 | lock = DVM_LOCK_INITIAL_THIN_VALUE; |
| 1449 | lock |= (LW_HASH_STATE_HASHED << LW_HASH_STATE_SHIFT); |
Carl Shapiro | 3ba10c9 | 2010-09-02 16:43:16 -0700 | [diff] [blame] | 1450 | if (android_atomic_acquire_cas( |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 1451 | (int32_t)DVM_LOCK_INITIAL_THIN_VALUE, |
Andy McFadden | 6e10b9a | 2010-06-14 15:24:39 -0700 | [diff] [blame] | 1452 | (int32_t)lock, |
| 1453 | (int32_t *)lw) == 0) { |
Carl Shapiro | 30aa997 | 2010-01-13 22:07:50 -0800 | [diff] [blame] | 1454 | /* |
| 1455 | * A new lockword has been installed with a hash state |
| 1456 | * of hashed. Use the raw object address. |
| 1457 | */ |
| 1458 | return (u4)obj >> 3; |
| 1459 | } |
| 1460 | } else { |
| 1461 | if (tryLockMonitor(self, LW_MONITOR(*lw))) { |
| 1462 | /* |
| 1463 | * The monitor lock has been acquired. Change the |
| 1464 | * hash state to hashed and use the raw object |
| 1465 | * address. |
| 1466 | */ |
| 1467 | *lw |= (LW_HASH_STATE_HASHED << LW_HASH_STATE_SHIFT); |
| 1468 | unlockMonitor(self, LW_MONITOR(*lw)); |
| 1469 | return (u4)obj >> 3; |
| 1470 | } |
| 1471 | } |
| 1472 | /* |
| 1473 | * At this point we have failed to acquire the lock. We must |
| 1474 | * identify the owning thread and suspend it. |
| 1475 | */ |
| 1476 | dvmLockThreadList(self); |
| 1477 | /* |
| 1478 | * Cache the lock word as its value can change between |
| 1479 | * determining its shape and retrieving its owner. |
| 1480 | */ |
| 1481 | lock = *lw; |
| 1482 | if (LW_SHAPE(lock) == LW_SHAPE_THIN) { |
| 1483 | /* |
| 1484 | * Find the thread with the corresponding thread id. |
| 1485 | */ |
| 1486 | owner = LW_LOCK_OWNER(lock); |
| 1487 | assert(owner != self->threadId); |
| 1488 | /* |
| 1489 | * If the lock has no owner do not bother scanning the |
| 1490 | * thread list and fall through to the failure handler. |
| 1491 | */ |
| 1492 | thread = owner ? gDvm.threadList : NULL; |
| 1493 | while (thread != NULL) { |
| 1494 | if (thread->threadId == owner) { |
| 1495 | break; |
| 1496 | } |
| 1497 | thread = thread->next; |
| 1498 | } |
| 1499 | } else { |
| 1500 | thread = LW_MONITOR(lock)->owner; |
| 1501 | } |
| 1502 | /* |
| 1503 | * If thread is NULL the object has been released since the |
| 1504 | * thread list lock was acquired. Try again. |
| 1505 | */ |
| 1506 | if (thread == NULL) { |
| 1507 | dvmUnlockThreadList(); |
| 1508 | goto retry; |
| 1509 | } |
| 1510 | /* |
| 1511 | * Wait for the owning thread to suspend. |
| 1512 | */ |
| 1513 | dvmSuspendThread(thread); |
| 1514 | if (dvmHoldsLock(thread, obj)) { |
| 1515 | /* |
| 1516 | * The owning thread has been suspended. We can safely |
| 1517 | * change the hash state to hashed. |
| 1518 | */ |
| 1519 | *lw |= (LW_HASH_STATE_HASHED << LW_HASH_STATE_SHIFT); |
| 1520 | dvmResumeThread(thread); |
| 1521 | dvmUnlockThreadList(); |
| 1522 | return (u4)obj >> 3; |
| 1523 | } |
| 1524 | /* |
| 1525 | * The wrong thread has been suspended. Try again. |
| 1526 | */ |
| 1527 | dvmResumeThread(thread); |
| 1528 | dvmUnlockThreadList(); |
| 1529 | goto retry; |
| 1530 | } |
| 1531 | LOGE("object %p has an unknown hash state %#x", obj, hashState); |
| 1532 | dvmDumpThread(dvmThreadSelf(), false); |
| 1533 | dvmAbort(); |
| 1534 | return 0; /* Quiet the compiler. */ |
| 1535 | } |
| 1536 | #endif /* WITH_COPYING_GC */ |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1537 | |
| 1538 | #ifdef WITH_DEADLOCK_PREDICTION |
| 1539 | /* |
| 1540 | * =========================================================================== |
| 1541 | * Deadlock prediction |
| 1542 | * =========================================================================== |
| 1543 | */ |
| 1544 | /* |
| 1545 | The idea is to predict the possibility of deadlock by recording the order |
| 1546 | in which monitors are acquired. If we see an attempt to acquire a lock |
| 1547 | out of order, we can identify the locks and offending code. |
| 1548 | |
| 1549 | To make this work, we need to keep track of the locks held by each thread, |
| 1550 | and create history trees for each lock. When a thread tries to acquire |
| 1551 | a new lock, we walk through the "history children" of the lock, looking |
| 1552 | for a match with locks the thread already holds. If we find a match, |
| 1553 | it means the thread has made a request that could result in a deadlock. |
| 1554 | |
| 1555 | To support recursive locks, we always allow re-locking a currently-held |
| 1556 | lock, and maintain a recursion depth count. |
| 1557 | |
| 1558 | An ASCII-art example, where letters represent Objects: |
| 1559 | |
| 1560 | A |
| 1561 | /|\ |
| 1562 | / | \ |
| 1563 | B | D |
| 1564 | \ | |
| 1565 | \| |
| 1566 | C |
| 1567 | |
| 1568 | The above is the tree we'd have after handling Object synchronization |
| 1569 | sequences "ABC", "AC", "AD". A has three children, {B, C, D}. C is also |
| 1570 | a child of B. (The lines represent pointers between parent and child. |
| 1571 | Every node can have multiple parents and multiple children.) |
| 1572 | |
| 1573 | If we hold AC, and want to lock B, we recursively search through B's |
| 1574 | children to see if A or C appears. It does, so we reject the attempt. |
| 1575 | (A straightforward way to implement it: add a link from C to B, then |
| 1576 | determine whether the graph starting at B contains a cycle.) |
| 1577 | |
| 1578 | If we hold AC and want to lock D, we would succeed, creating a new link |
| 1579 | from C to D. |
| 1580 | |
| 1581 | The lock history and a stack trace is attached to the Object's Monitor |
| 1582 | struct, which means we need to fatten every Object we lock (thin locking |
| 1583 | is effectively disabled). If we don't need the stack trace we can |
| 1584 | avoid fattening the leaf nodes, only fattening objects that need to hold |
| 1585 | history trees. |
| 1586 | |
| 1587 | Updates to Monitor structs are only allowed for the thread that holds |
| 1588 | the Monitor, so we actually do most of our deadlock prediction work after |
| 1589 | the lock has been acquired. |
| 1590 | |
| 1591 | When an object with a monitor is GCed, we need to remove it from the |
| 1592 | history trees. There are two basic approaches: |
| 1593 | (1) For through the entire set of known monitors, search all child |
| 1594 | lists for the object in question. This is rather slow, resulting |
| 1595 | in GC passes that take upwards of 10 seconds to complete. |
| 1596 | (2) Maintain "parent" pointers in each node. Remove the entries as |
| 1597 | required. This requires additional storage and maintenance for |
| 1598 | every operation, but is significantly faster at GC time. |
| 1599 | For each GCed object, we merge all of the object's children into each of |
| 1600 | the object's parents. |
| 1601 | */ |
| 1602 | |
| 1603 | #if !defined(WITH_MONITOR_TRACKING) |
| 1604 | # error "WITH_DEADLOCK_PREDICTION requires WITH_MONITOR_TRACKING" |
| 1605 | #endif |
| 1606 | |
| 1607 | /* |
| 1608 | * Clear out the contents of an ExpandingObjectList, freeing any |
| 1609 | * dynamic allocations. |
| 1610 | */ |
| 1611 | static void expandObjClear(ExpandingObjectList* pList) |
| 1612 | { |
| 1613 | if (pList->list != NULL) { |
| 1614 | free(pList->list); |
| 1615 | pList->list = NULL; |
| 1616 | } |
| 1617 | pList->alloc = pList->count = 0; |
| 1618 | } |
| 1619 | |
| 1620 | /* |
| 1621 | * Get the number of objects currently stored in the list. |
| 1622 | */ |
| 1623 | static inline int expandBufGetCount(const ExpandingObjectList* pList) |
| 1624 | { |
| 1625 | return pList->count; |
| 1626 | } |
| 1627 | |
| 1628 | /* |
| 1629 | * Get the Nth entry from the list. |
| 1630 | */ |
| 1631 | static inline Object* expandBufGetEntry(const ExpandingObjectList* pList, |
| 1632 | int i) |
| 1633 | { |
| 1634 | return pList->list[i]; |
| 1635 | } |
| 1636 | |
| 1637 | /* |
| 1638 | * Add a new entry to the list. |
| 1639 | * |
| 1640 | * We don't check for or try to enforce uniqueness. It's expected that |
| 1641 | * the higher-level code does this for us. |
| 1642 | */ |
| 1643 | static void expandObjAddEntry(ExpandingObjectList* pList, Object* obj) |
| 1644 | { |
| 1645 | if (pList->count == pList->alloc) { |
| 1646 | /* time to expand */ |
| 1647 | Object** newList; |
| 1648 | |
| 1649 | if (pList->alloc == 0) |
| 1650 | pList->alloc = 4; |
| 1651 | else |
| 1652 | pList->alloc *= 2; |
| 1653 | LOGVV("expanding %p to %d\n", pList, pList->alloc); |
| 1654 | newList = realloc(pList->list, pList->alloc * sizeof(Object*)); |
| 1655 | if (newList == NULL) { |
| 1656 | LOGE("Failed expanding DP object list (alloc=%d)\n", pList->alloc); |
| 1657 | dvmAbort(); |
| 1658 | } |
| 1659 | pList->list = newList; |
| 1660 | } |
| 1661 | |
| 1662 | pList->list[pList->count++] = obj; |
| 1663 | } |
| 1664 | |
| 1665 | /* |
| 1666 | * Returns "true" if the element was successfully removed. |
| 1667 | */ |
| 1668 | static bool expandObjRemoveEntry(ExpandingObjectList* pList, Object* obj) |
| 1669 | { |
| 1670 | int i; |
| 1671 | |
| 1672 | for (i = pList->count-1; i >= 0; i--) { |
| 1673 | if (pList->list[i] == obj) |
| 1674 | break; |
| 1675 | } |
| 1676 | if (i < 0) |
| 1677 | return false; |
| 1678 | |
| 1679 | if (i != pList->count-1) { |
| 1680 | /* |
| 1681 | * The order of elements is not important, so we just copy the |
| 1682 | * last entry into the new slot. |
| 1683 | */ |
| 1684 | //memmove(&pList->list[i], &pList->list[i+1], |
| 1685 | // (pList->count-1 - i) * sizeof(pList->list[0])); |
| 1686 | pList->list[i] = pList->list[pList->count-1]; |
| 1687 | } |
| 1688 | |
| 1689 | pList->count--; |
| 1690 | pList->list[pList->count] = (Object*) 0xdecadead; |
| 1691 | return true; |
| 1692 | } |
| 1693 | |
| 1694 | /* |
| 1695 | * Returns "true" if "obj" appears in the list. |
| 1696 | */ |
| 1697 | static bool expandObjHas(const ExpandingObjectList* pList, Object* obj) |
| 1698 | { |
| 1699 | int i; |
| 1700 | |
| 1701 | for (i = 0; i < pList->count; i++) { |
| 1702 | if (pList->list[i] == obj) |
| 1703 | return true; |
| 1704 | } |
| 1705 | return false; |
| 1706 | } |
| 1707 | |
| 1708 | /* |
| 1709 | * Print the list contents to stdout. For debugging. |
| 1710 | */ |
| 1711 | static void expandObjDump(const ExpandingObjectList* pList) |
| 1712 | { |
| 1713 | int i; |
| 1714 | for (i = 0; i < pList->count; i++) |
| 1715 | printf(" %p", pList->list[i]); |
| 1716 | } |
| 1717 | |
| 1718 | /* |
| 1719 | * Check for duplicate entries. Returns the index of the first instance |
| 1720 | * of the duplicated value, or -1 if no duplicates were found. |
| 1721 | */ |
| 1722 | static int expandObjCheckForDuplicates(const ExpandingObjectList* pList) |
| 1723 | { |
| 1724 | int i, j; |
| 1725 | for (i = 0; i < pList->count-1; i++) { |
| 1726 | for (j = i + 1; j < pList->count; j++) { |
| 1727 | if (pList->list[i] == pList->list[j]) { |
| 1728 | return i; |
| 1729 | } |
| 1730 | } |
| 1731 | } |
| 1732 | |
| 1733 | return -1; |
| 1734 | } |
| 1735 | |
| 1736 | |
| 1737 | /* |
| 1738 | * Determine whether "child" appears in the list of objects associated |
| 1739 | * with the Monitor in "parent". If "parent" is a thin lock, we return |
| 1740 | * false immediately. |
| 1741 | */ |
| 1742 | static bool objectInChildList(const Object* parent, Object* child) |
| 1743 | { |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1744 | u4 lock = parent->lock; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1745 | if (!IS_LOCK_FAT(&lock)) { |
| 1746 | //LOGI("on thin\n"); |
| 1747 | return false; |
| 1748 | } |
| 1749 | |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1750 | return expandObjHas(&LW_MONITOR(lock)->historyChildren, child); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1751 | } |
| 1752 | |
| 1753 | /* |
| 1754 | * Print the child list. |
| 1755 | */ |
| 1756 | static void dumpKids(Object* parent) |
| 1757 | { |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1758 | Monitor* mon = LW_MONITOR(parent->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1759 | |
| 1760 | printf("Children of %p:", parent); |
| 1761 | expandObjDump(&mon->historyChildren); |
| 1762 | printf("\n"); |
| 1763 | } |
| 1764 | |
| 1765 | /* |
| 1766 | * Add "child" to the list of children in "parent", and add "parent" to |
| 1767 | * the list of parents in "child". |
| 1768 | */ |
| 1769 | static void linkParentToChild(Object* parent, Object* child) |
| 1770 | { |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1771 | //assert(LW_MONITOR(parent->lock)->owner == dvmThreadSelf()); // !owned for merge |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1772 | assert(IS_LOCK_FAT(&parent->lock)); |
| 1773 | assert(IS_LOCK_FAT(&child->lock)); |
| 1774 | assert(parent != child); |
| 1775 | Monitor* mon; |
| 1776 | |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1777 | mon = LW_MONITOR(parent->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1778 | assert(!expandObjHas(&mon->historyChildren, child)); |
| 1779 | expandObjAddEntry(&mon->historyChildren, child); |
| 1780 | |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1781 | mon = LW_MONITOR(child->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1782 | assert(!expandObjHas(&mon->historyParents, parent)); |
| 1783 | expandObjAddEntry(&mon->historyParents, parent); |
| 1784 | } |
| 1785 | |
| 1786 | |
| 1787 | /* |
| 1788 | * Remove "child" from the list of children in "parent". |
| 1789 | */ |
| 1790 | static void unlinkParentFromChild(Object* parent, Object* child) |
| 1791 | { |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1792 | //assert(LW_MONITOR(parent->lock)->owner == dvmThreadSelf()); // !owned for GC |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1793 | assert(IS_LOCK_FAT(&parent->lock)); |
| 1794 | assert(IS_LOCK_FAT(&child->lock)); |
| 1795 | assert(parent != child); |
| 1796 | Monitor* mon; |
| 1797 | |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1798 | mon = LW_MONITOR(parent->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1799 | if (!expandObjRemoveEntry(&mon->historyChildren, child)) { |
| 1800 | LOGW("WARNING: child %p not found in parent %p\n", child, parent); |
| 1801 | } |
| 1802 | assert(!expandObjHas(&mon->historyChildren, child)); |
| 1803 | assert(expandObjCheckForDuplicates(&mon->historyChildren) < 0); |
| 1804 | |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1805 | mon = LW_MONITOR(child->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1806 | if (!expandObjRemoveEntry(&mon->historyParents, parent)) { |
| 1807 | LOGW("WARNING: parent %p not found in child %p\n", parent, child); |
| 1808 | } |
| 1809 | assert(!expandObjHas(&mon->historyParents, parent)); |
| 1810 | assert(expandObjCheckForDuplicates(&mon->historyParents) < 0); |
| 1811 | } |
| 1812 | |
| 1813 | |
| 1814 | /* |
| 1815 | * Log the monitors held by the current thread. This is done as part of |
| 1816 | * flagging an error. |
| 1817 | */ |
| 1818 | static void logHeldMonitors(Thread* self) |
| 1819 | { |
| 1820 | char* name = NULL; |
| 1821 | |
| 1822 | name = dvmGetThreadName(self); |
| 1823 | LOGW("Monitors currently held by thread (threadid=%d '%s')\n", |
| 1824 | self->threadId, name); |
| 1825 | LOGW("(most-recently-acquired on top):\n"); |
| 1826 | free(name); |
| 1827 | |
| 1828 | LockedObjectData* lod = self->pLockedObjects; |
| 1829 | while (lod != NULL) { |
| 1830 | LOGW("--- object %p[%d] (%s)\n", |
| 1831 | lod->obj, lod->recursionCount, lod->obj->clazz->descriptor); |
| 1832 | dvmLogRawStackTrace(lod->rawStackTrace, lod->stackDepth); |
| 1833 | |
| 1834 | lod = lod->next; |
| 1835 | } |
| 1836 | } |
| 1837 | |
| 1838 | /* |
| 1839 | * Recursively traverse the object hierarchy starting at "obj". We mark |
| 1840 | * ourselves on entry and clear the mark on exit. If we ever encounter |
| 1841 | * a marked object, we have a cycle. |
| 1842 | * |
| 1843 | * Returns "true" if all is well, "false" if we found a cycle. |
| 1844 | */ |
| 1845 | static bool traverseTree(Thread* self, const Object* obj) |
| 1846 | { |
| 1847 | assert(IS_LOCK_FAT(&obj->lock)); |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1848 | Monitor* mon = LW_MONITOR(obj->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1849 | |
| 1850 | /* |
| 1851 | * Have we been here before? |
| 1852 | */ |
| 1853 | if (mon->historyMark) { |
| 1854 | int* rawStackTrace; |
| 1855 | int stackDepth; |
| 1856 | |
| 1857 | LOGW("%s\n", kStartBanner); |
| 1858 | LOGW("Illegal lock attempt:\n"); |
| 1859 | LOGW("--- object %p (%s)\n", obj, obj->clazz->descriptor); |
| 1860 | |
| 1861 | rawStackTrace = dvmFillInStackTraceRaw(self, &stackDepth); |
| 1862 | dvmLogRawStackTrace(rawStackTrace, stackDepth); |
| 1863 | free(rawStackTrace); |
| 1864 | |
| 1865 | LOGW(" "); |
| 1866 | logHeldMonitors(self); |
| 1867 | |
| 1868 | LOGW(" "); |
| 1869 | LOGW("Earlier, the following lock order (from last to first) was\n"); |
| 1870 | LOGW("established -- stack trace is from first successful lock):\n"); |
| 1871 | return false; |
| 1872 | } |
| 1873 | mon->historyMark = true; |
| 1874 | |
| 1875 | /* |
| 1876 | * Examine the children. We do NOT hold these locks, so they might |
| 1877 | * very well transition from thin to fat or change ownership while |
| 1878 | * we work. |
| 1879 | * |
| 1880 | * NOTE: we rely on the fact that they cannot revert from fat to thin |
| 1881 | * while we work. This is currently a safe assumption. |
| 1882 | * |
| 1883 | * We can safely ignore thin-locked children, because by definition |
| 1884 | * they have no history and are leaf nodes. In the current |
| 1885 | * implementation we always fatten the locks to provide a place to |
| 1886 | * hang the stack trace. |
| 1887 | */ |
| 1888 | ExpandingObjectList* pList = &mon->historyChildren; |
| 1889 | int i; |
| 1890 | for (i = expandBufGetCount(pList)-1; i >= 0; i--) { |
| 1891 | const Object* child = expandBufGetEntry(pList, i); |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1892 | u4 lock = child->lock; |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1893 | if (!IS_LOCK_FAT(&lock)) |
| 1894 | continue; |
| 1895 | if (!traverseTree(self, child)) { |
| 1896 | LOGW("--- object %p (%s)\n", obj, obj->clazz->descriptor); |
| 1897 | dvmLogRawStackTrace(mon->historyRawStackTrace, |
| 1898 | mon->historyStackDepth); |
| 1899 | mon->historyMark = false; |
| 1900 | return false; |
| 1901 | } |
| 1902 | } |
| 1903 | |
| 1904 | mon->historyMark = false; |
| 1905 | |
| 1906 | return true; |
| 1907 | } |
| 1908 | |
| 1909 | /* |
| 1910 | * Update the deadlock prediction tree, based on the current thread |
| 1911 | * acquiring "acqObj". This must be called before the object is added to |
| 1912 | * the thread's list of held monitors. |
| 1913 | * |
| 1914 | * If the thread already holds the lock (recursion), or this is a known |
| 1915 | * lock configuration, we return without doing anything. Otherwise, we add |
| 1916 | * a link from the most-recently-acquired lock in this thread to "acqObj" |
| 1917 | * after ensuring that the parent lock is "fat". |
| 1918 | * |
| 1919 | * This MUST NOT be called while a GC is in progress in another thread, |
| 1920 | * because we assume exclusive access to history trees in owned monitors. |
| 1921 | */ |
| 1922 | static void updateDeadlockPrediction(Thread* self, Object* acqObj) |
| 1923 | { |
| 1924 | LockedObjectData* lod; |
| 1925 | LockedObjectData* mrl; |
| 1926 | |
| 1927 | /* |
| 1928 | * Quick check for recursive access. |
| 1929 | */ |
| 1930 | lod = dvmFindInMonitorList(self, acqObj); |
| 1931 | if (lod != NULL) { |
| 1932 | LOGV("+++ DP: recursive %p\n", acqObj); |
| 1933 | return; |
| 1934 | } |
| 1935 | |
| 1936 | /* |
| 1937 | * Make the newly-acquired object's monitor "fat". In some ways this |
| 1938 | * isn't strictly necessary, but we need the GC to tell us when |
| 1939 | * "interesting" objects go away, and right now the only way to make |
| 1940 | * an object look interesting is to give it a monitor. |
| 1941 | * |
| 1942 | * This also gives us a place to hang a stack trace. |
| 1943 | * |
| 1944 | * Our thread holds the lock, so we're allowed to rewrite the lock |
| 1945 | * without worrying that something will change out from under us. |
| 1946 | */ |
| 1947 | if (!IS_LOCK_FAT(&acqObj->lock)) { |
| 1948 | LOGVV("fattening lockee %p (recur=%d)\n", |
Carl Shapiro | 94338aa | 2009-12-21 11:42:59 -0800 | [diff] [blame] | 1949 | acqObj, LW_LOCK_COUNT(acqObj->lock.thin)); |
Carl Shapiro | 66bb7df | 2010-03-12 15:25:37 -0800 | [diff] [blame] | 1950 | inflateMonitor(self, acqObj); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1951 | } |
| 1952 | |
| 1953 | /* if we don't have a stack trace for this monitor, establish one */ |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1954 | if (LW_MONITOR(acqObj->lock)->historyRawStackTrace == NULL) { |
| 1955 | Monitor* mon = LW_MONITOR(acqObj->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1956 | mon->historyRawStackTrace = dvmFillInStackTraceRaw(self, |
| 1957 | &mon->historyStackDepth); |
| 1958 | } |
| 1959 | |
| 1960 | /* |
| 1961 | * We need to examine and perhaps modify the most-recently-locked |
| 1962 | * monitor. We own that, so there's no risk of another thread |
| 1963 | * stepping on us. |
| 1964 | * |
| 1965 | * Retrieve the most-recently-locked entry from our thread. |
| 1966 | */ |
| 1967 | mrl = self->pLockedObjects; |
| 1968 | if (mrl == NULL) |
| 1969 | return; /* no other locks held */ |
| 1970 | |
| 1971 | /* |
| 1972 | * Do a quick check to see if "acqObj" is a direct descendant. We can do |
| 1973 | * this without holding the global lock because of our assertion that |
| 1974 | * a GC is not running in parallel -- nobody except the GC can |
| 1975 | * modify a history list in a Monitor they don't own, and we own "mrl". |
| 1976 | * (There might be concurrent *reads*, but no concurrent *writes.) |
| 1977 | * |
| 1978 | * If we find it, this is a known good configuration, and we're done. |
| 1979 | */ |
| 1980 | if (objectInChildList(mrl->obj, acqObj)) |
| 1981 | return; |
| 1982 | |
| 1983 | /* |
| 1984 | * "mrl" is going to need to have a history tree. If it's currently |
| 1985 | * a thin lock, we make it fat now. The thin lock might have a |
| 1986 | * nonzero recursive lock count, which we need to carry over. |
| 1987 | * |
| 1988 | * Our thread holds the lock, so we're allowed to rewrite the lock |
| 1989 | * without worrying that something will change out from under us. |
| 1990 | */ |
| 1991 | if (!IS_LOCK_FAT(&mrl->obj->lock)) { |
| 1992 | LOGVV("fattening parent %p f/b/o child %p (recur=%d)\n", |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 1993 | mrl->obj, acqObj, LW_LOCK_COUNT(mrl->obj->lock)); |
Carl Shapiro | 66bb7df | 2010-03-12 15:25:37 -0800 | [diff] [blame] | 1994 | inflateMonitor(self, mrl->obj); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 1995 | } |
| 1996 | |
| 1997 | /* |
| 1998 | * We haven't seen this configuration before. We need to scan down |
| 1999 | * acqObj's tree to see if any of the monitors in self->pLockedObjects |
| 2000 | * appear. We grab a global lock before traversing or updating the |
| 2001 | * history list. |
| 2002 | * |
| 2003 | * If we find a match for any of our held locks, we know that the lock |
| 2004 | * has previously been acquired *after* acqObj, and we throw an error. |
| 2005 | * |
| 2006 | * The easiest way to do this is to create a link from "mrl" to "acqObj" |
| 2007 | * and do a recursive traversal, marking nodes as we cross them. If |
| 2008 | * we cross one a second time, we have a cycle and can throw an error. |
| 2009 | * (We do the flag-clearing traversal before adding the new link, so |
| 2010 | * that we're guaranteed to terminate.) |
| 2011 | * |
| 2012 | * If "acqObj" is a thin lock, it has no history, and we can create a |
| 2013 | * link to it without additional checks. [ We now guarantee that it's |
| 2014 | * always fat. ] |
| 2015 | */ |
| 2016 | bool failed = false; |
| 2017 | dvmLockMutex(&gDvm.deadlockHistoryLock); |
| 2018 | linkParentToChild(mrl->obj, acqObj); |
| 2019 | if (!traverseTree(self, acqObj)) { |
| 2020 | LOGW("%s\n", kEndBanner); |
| 2021 | failed = true; |
| 2022 | |
| 2023 | /* remove the entry so we're still okay when in "warning" mode */ |
| 2024 | unlinkParentFromChild(mrl->obj, acqObj); |
| 2025 | } |
| 2026 | dvmUnlockMutex(&gDvm.deadlockHistoryLock); |
| 2027 | |
| 2028 | if (failed) { |
| 2029 | switch (gDvm.deadlockPredictMode) { |
| 2030 | case kDPErr: |
| 2031 | dvmThrowException("Ldalvik/system/PotentialDeadlockError;", NULL); |
| 2032 | break; |
| 2033 | case kDPAbort: |
| 2034 | LOGE("Aborting due to potential deadlock\n"); |
| 2035 | dvmAbort(); |
| 2036 | break; |
| 2037 | default: |
| 2038 | /* warn only */ |
| 2039 | break; |
| 2040 | } |
| 2041 | } |
| 2042 | } |
| 2043 | |
| 2044 | /* |
| 2045 | * We're removing "child" from existence. We want to pull all of |
| 2046 | * child's children into "parent", filtering out duplicates. This is |
| 2047 | * called during the GC. |
| 2048 | * |
| 2049 | * This does not modify "child", which might have multiple parents. |
| 2050 | */ |
| 2051 | static void mergeChildren(Object* parent, const Object* child) |
| 2052 | { |
| 2053 | Monitor* mon; |
| 2054 | int i; |
| 2055 | |
| 2056 | assert(IS_LOCK_FAT(&child->lock)); |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 2057 | mon = LW_MONITOR(child->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 2058 | ExpandingObjectList* pList = &mon->historyChildren; |
| 2059 | |
| 2060 | for (i = expandBufGetCount(pList)-1; i >= 0; i--) { |
| 2061 | Object* grandChild = expandBufGetEntry(pList, i); |
| 2062 | |
| 2063 | if (!objectInChildList(parent, grandChild)) { |
| 2064 | LOGVV("+++ migrating %p link to %p\n", grandChild, parent); |
| 2065 | linkParentToChild(parent, grandChild); |
| 2066 | } else { |
| 2067 | LOGVV("+++ parent %p already links to %p\n", parent, grandChild); |
| 2068 | } |
| 2069 | } |
| 2070 | } |
| 2071 | |
| 2072 | /* |
| 2073 | * An object with a fat lock is being collected during a GC pass. We |
| 2074 | * want to remove it from any lock history trees that it is a part of. |
| 2075 | * |
| 2076 | * This may require updating the history trees in several monitors. The |
| 2077 | * monitor semantics guarantee that no other thread will be accessing |
| 2078 | * the history trees at the same time. |
| 2079 | */ |
| 2080 | static void removeCollectedObject(Object* obj) |
| 2081 | { |
| 2082 | Monitor* mon; |
| 2083 | |
| 2084 | LOGVV("+++ collecting %p\n", obj); |
| 2085 | |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 2086 | /* |
| 2087 | * For every parent of this object: |
| 2088 | * - merge all of our children into the parent's child list (creates |
| 2089 | * a two-way link between parent and child) |
| 2090 | * - remove ourselves from the parent's child list |
| 2091 | */ |
| 2092 | ExpandingObjectList* pList; |
| 2093 | int i; |
| 2094 | |
| 2095 | assert(IS_LOCK_FAT(&obj->lock)); |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 2096 | mon = LW_MONITOR(obj->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 2097 | pList = &mon->historyParents; |
| 2098 | for (i = expandBufGetCount(pList)-1; i >= 0; i--) { |
| 2099 | Object* parent = expandBufGetEntry(pList, i); |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 2100 | Monitor* parentMon = LW_MONITOR(parent->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 2101 | |
| 2102 | if (!expandObjRemoveEntry(&parentMon->historyChildren, obj)) { |
| 2103 | LOGW("WARNING: child %p not found in parent %p\n", obj, parent); |
| 2104 | } |
| 2105 | assert(!expandObjHas(&parentMon->historyChildren, obj)); |
| 2106 | |
| 2107 | mergeChildren(parent, obj); |
| 2108 | } |
| 2109 | |
| 2110 | /* |
| 2111 | * For every child of this object: |
| 2112 | * - remove ourselves from the child's parent list |
| 2113 | */ |
| 2114 | pList = &mon->historyChildren; |
| 2115 | for (i = expandBufGetCount(pList)-1; i >= 0; i--) { |
| 2116 | Object* child = expandBufGetEntry(pList, i); |
Carl Shapiro | 8d7f9b2 | 2009-12-21 20:23:45 -0800 | [diff] [blame] | 2117 | Monitor* childMon = LW_MONITOR(child->lock); |
The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame] | 2118 | |
| 2119 | if (!expandObjRemoveEntry(&childMon->historyParents, obj)) { |
| 2120 | LOGW("WARNING: parent %p not found in child %p\n", obj, child); |
| 2121 | } |
| 2122 | assert(!expandObjHas(&childMon->historyParents, obj)); |
| 2123 | } |
| 2124 | } |
| 2125 | |
| 2126 | #endif /*WITH_DEADLOCK_PREDICTION*/ |