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 */
16
17 /*
18 * VM thread support.
19 */
20 #ifndef DALVIK_THREAD_H_
21 #define DALVIK_THREAD_H_
22
23 #include "jni.h"
24 #include "interp/InterpState.h"
25
26 #include <errno.h>
27 #include <cutils/sched_policy.h>
28
29 #if defined(CHECK_MUTEX) && !defined(__USE_UNIX98)
30 /* glibc lacks this unless you #define __USE_UNIX98 */
31 int pthread_mutexattr_settype(pthread_mutexattr_t *attr, int type);
32 enum { PTHREAD_MUTEX_ERRORCHECK = PTHREAD_MUTEX_ERRORCHECK_NP };
33 #endif
34
35 /*
36 * Current status; these map to JDWP constants, so don't rearrange them.
37 * (If you do alter this, update the strings in dvmDumpThread and the
38 * conversion table in VMThread.java.)
39 *
40 * Note that "suspended" is orthogonal to these values (so says JDWP).
41 */
42 enum ThreadStatus {
43 THREAD_UNDEFINED = -1, /* makes enum compatible with int32_t */
44
45 /* these match up with JDWP values */
46 THREAD_ZOMBIE = 0, /* TERMINATED */
47 THREAD_RUNNING = 1, /* RUNNABLE or running now */
48 THREAD_TIMED_WAIT = 2, /* TIMED_WAITING in Object.wait() */
49 THREAD_MONITOR = 3, /* BLOCKED on a monitor */
50 THREAD_WAIT = 4, /* WAITING in Object.wait() */
51 /* non-JDWP states */
52 THREAD_INITIALIZING = 5, /* allocated, not yet running */
53 THREAD_STARTING = 6, /* started, not yet on thread list */
54 THREAD_NATIVE = 7, /* off in a JNI native method */
55 THREAD_VMWAIT = 8, /* waiting on a VM resource */
56 THREAD_SUSPENDED = 9, /* suspended, usually by GC or debugger */
57 };
58
59 /* thread priorities, from java.lang.Thread */
60 enum {
61 THREAD_MIN_PRIORITY = 1,
62 THREAD_NORM_PRIORITY = 5,
63 THREAD_MAX_PRIORITY = 10,
64 };
65
66
67 /* initialization */
68 bool dvmThreadStartup(void);
69 void dvmThreadShutdown(void);
70 void dvmSlayDaemons(void);
71
72
73 #define kJniLocalRefMin 64
74 #define kJniLocalRefMax 512 /* arbitrary; should be plenty */
75 #define kInternalRefDefault 32 /* equally arbitrary */
76 #define kInternalRefMax 4096 /* mainly a sanity check */
77
78 #define kMinStackSize (512 + STACK_OVERFLOW_RESERVE)
79 #define kDefaultStackSize (16*1024) /* four 4K pages */
80 #define kMaxStackSize (256*1024 + STACK_OVERFLOW_RESERVE)
81
82 /*
83 * Interpreter control struction. Packed into a long long to enable
84 * atomic updates.
85 */
86 union InterpBreak {
87 volatile int64_t all;
88 struct {
89 uint16_t subMode;
90 uint8_t breakFlags;
91 int8_t unused; /* for future expansion */
92 #ifndef DVM_NO_ASM_INTERP
93 void* curHandlerTable;
94 #else
95 int32_t unused1;
96 #endif
97 } ctl;
98 };
99
100 /*
101 * Our per-thread data.
102 *
103 * These are allocated on the system heap.
104 */
105 struct Thread {
106 /*
107 * Interpreter state which must be preserved across nested
108 * interpreter invocations (via JNI callbacks). Must be the first
109 * element in Thread.
110 */
111 InterpSaveState interpSave;
112
113 /* small unique integer; useful for "thin" locks and debug messages */
114 u4 threadId;
115
116 /*
117 * Begin interpreter state which does not need to be preserved, but should
118 * be located towards the beginning of the Thread structure for
119 * efficiency.
120 */
121
122 /*
123 * interpBreak contains info about the interpreter mode, as well as
124 * a count of the number of times the thread has been suspended. When
125 * the count drops to zero, the thread resumes.
126 */
127 InterpBreak interpBreak;
128
129 /*
130 * "dbgSuspendCount" is the portion of the suspend count that the
131 * debugger is responsible for. This has to be tracked separately so
132 * that we can recover correctly if the debugger abruptly disconnects
133 * (suspendCount -= dbgSuspendCount). The debugger should not be able
134 * to resume GC-suspended threads, because we ignore the debugger while
135 * a GC is in progress.
136 *
137 * Both of these are guarded by gDvm.threadSuspendCountLock.
138 *
139 * Note the non-debug component will rarely be other than 1 or 0 -- (not
140 * sure it's even possible with the way mutexes are currently used.)
141 */
142
143 int suspendCount;
144 int dbgSuspendCount;
145
146 u1* cardTable;
147
148 /* current limit of stack; flexes for StackOverflowError */
149 const u1* interpStackEnd;
150
151 /* FP of bottom-most (currently executing) stack frame on interp stack */
152 void* XcurFrame;
153 /* current exception, or NULL if nothing pending */
154 Object* exception;
155
156 bool debugIsMethodEntry;
157 /* interpreter stack size; our stacks are fixed-length */
158 int interpStackSize;
159 bool stackOverflowed;
160
161 /* thread handle, as reported by pthread_self() */
162 pthread_t handle;
163
164 /* Assembly interpreter handler tables */
165 #ifndef DVM_NO_ASM_INTERP
166 void* mainHandlerTable; // Table of actual instruction handler
167 void* altHandlerTable; // Table of breakout handlers
168 #else
169 void* unused0; // Consume space to keep offsets
170 void* unused1; // the same between builds with
171 #endif
172
173 /*
174 * singleStepCount is a countdown timer used with the breakFlag
175 * kInterpSingleStep. If kInterpSingleStep is set in breakFlags,
176 * singleStepCount will decremented each instruction execution.
177 * Once it reaches zero, the kInterpSingleStep flag in breakFlags
178 * will be cleared. This can be used to temporarily prevent
179 * execution from re-entering JIT'd code or force inter-instruction
180 * checks by delaying the reset of curHandlerTable to mainHandlerTable.
181 */
182 int singleStepCount;
183
184 #ifdef WITH_JIT
185 struct JitToInterpEntries jitToInterpEntries;
186 /*
187 * Whether the current top VM frame is in the interpreter or JIT cache:
188 * NULL : in the interpreter
189 * non-NULL: entry address of the JIT'ed code (the actual value doesn't
190 * matter)
191 */
192 void* inJitCodeCache;
193 unsigned char* pJitProfTable;
194 int jitThreshold;
195 const void* jitResumeNPC; // Translation return point
196 const u4* jitResumeNSP; // Native SP at return point
197 const u2* jitResumeDPC; // Dalvik inst following single-step
198 JitState jitState;
199 int icRechainCount;
200 const void* pProfileCountdown;
201 const ClassObject* callsiteClass;
202 const Method* methodToCall;
203 #endif
204
205 /* JNI local reference tracking */
206 IndirectRefTable jniLocalRefTable;
207
208 #if defined(WITH_JIT)
209 #if defined(WITH_SELF_VERIFICATION)
210 /* Buffer for register state during self verification */
211 struct ShadowSpace* shadowSpace;
212 #endif
213 int currTraceRun;
214 int totalTraceLen; // Number of Dalvik insts in trace
215 const u2* currTraceHead; // Start of the trace we're building
216 const u2* currRunHead; // Start of run we're building
217 int currRunLen; // Length of run in 16-bit words
218 const u2* lastPC; // Stage the PC for the threaded interpreter
219 const Method* traceMethod; // Starting method of current trace
220 intptr_t threshFilter[JIT_TRACE_THRESH_FILTER_SIZE];
221 JitTraceRun trace[MAX_JIT_RUN_LEN];
222 #endif
223
224 /*
225 * Thread's current status. Can only be changed by the thread itself
226 * (i.e. don't mess with this from other threads).
227 */
228 volatile ThreadStatus status;
229
230 /* thread ID, only useful under Linux */
231 pid_t systemTid;
232
233 /* start (high addr) of interp stack (subtract size to get malloc addr) */
234 u1* interpStackStart;
235
236 /* the java/lang/Thread that we are associated with */
237 Object* threadObj;
238
239 /* the JNIEnv pointer associated with this thread */
240 JNIEnv* jniEnv;
241
242 /* internal reference tracking */
243 ReferenceTable internalLocalRefTable;
244
245
246 /* JNI native monitor reference tracking (initialized on first use) */
247 ReferenceTable jniMonitorRefTable;
248
249 /* hack to make JNI_OnLoad work right */
250 Object* classLoaderOverride;
251
252 /* mutex to guard the interrupted and the waitMonitor members */
253 pthread_mutex_t waitMutex;
254
255 /* pointer to the monitor lock we're currently waiting on */
256 /* guarded by waitMutex */
257 /* TODO: consider changing this to Object* for better JDWP interaction */
258 Monitor* waitMonitor;
259
260 /* thread "interrupted" status; stays raised until queried or thrown */
261 /* guarded by waitMutex */
262 bool interrupted;
263
264 /* links to the next thread in the wait set this thread is part of */
265 struct Thread* waitNext;
266
267 /* object to sleep on while we are waiting for a monitor */
268 pthread_cond_t waitCond;
269
270 /*
271 * Set to true when the thread is in the process of throwing an
272 * OutOfMemoryError.
273 */
274 bool throwingOOME;
275
276 /* links to rest of thread list; grab global lock before traversing */
277 struct Thread* prev;
278 struct Thread* next;
279
280 /* used by threadExitCheck when a thread exits without detaching */
281 int threadExitCheckCount;
282
283 /* JDWP invoke-during-breakpoint support */
284 DebugInvokeReq invokeReq;
285
286 /* base time for per-thread CPU timing (used by method profiling) */
287 bool cpuClockBaseSet;
288 u8 cpuClockBase;
289
290 /* memory allocation profiling state */
291 AllocProfState allocProf;
292
293 #ifdef WITH_JNI_STACK_CHECK
294 u4 stackCrc;
295 #endif
296
297 #if WITH_EXTRA_GC_CHECKS > 1
298 /* PC, saved on every instruction; redundant with StackSaveArea */
299 const u2* currentPc2;
300 #endif
301
302 /* Safepoint callback state */
303 pthread_mutex_t callbackMutex;
304 SafePointCallback callback;
305 void* callbackArg;
306
307 #if defined(ARCH_IA32) && defined(WITH_JIT)
308 u4 spillRegion[MAX_SPILL_JIT_IA];
309 #endif
310 };
311
312 /* start point for an internal thread; mimics pthread args */
313 typedef void* (*InternalThreadStart)(void* arg);
314
315 /* args for internal thread creation */
316 struct InternalStartArgs {
317 /* inputs */
318 InternalThreadStart func;
319 void* funcArg;
320 char* name;
321 Object* group;
322 bool isDaemon;
323 /* result */
324 volatile Thread** pThread;
325 volatile int* pCreateStatus;
326 };
327
328 /* finish init */
329 bool dvmPrepMainForJni(JNIEnv* pEnv);
330 bool dvmPrepMainThread(void);
331
332 /* utility function to get the tid */
333 pid_t dvmGetSysThreadId(void);
334
335 /*
336 * Get our Thread* from TLS.
337 *
338 * Returns NULL if this isn't a thread that the VM is aware of.
339 */
340 Thread* dvmThreadSelf(void);
341
342 /* grab the thread list global lock */
343 void dvmLockThreadList(Thread* self);
344 /* try to grab the thread list global lock */
345 bool dvmTryLockThreadList(void);
346 /* release the thread list global lock */
347 void dvmUnlockThreadList(void);
348
349 /*
350 * Thread suspend/resume, used by the GC and debugger.
351 */
352 enum SuspendCause {
353 SUSPEND_NOT = 0,
354 SUSPEND_FOR_GC,
355 SUSPEND_FOR_DEBUG,
356 SUSPEND_FOR_DEBUG_EVENT,
357 SUSPEND_FOR_STACK_DUMP,
358 SUSPEND_FOR_DEX_OPT,
359 SUSPEND_FOR_VERIFY,
360 SUSPEND_FOR_HPROF,
361 #if defined(WITH_JIT)
362 SUSPEND_FOR_TBL_RESIZE, // jit-table resize
363 SUSPEND_FOR_IC_PATCH, // polymorphic callsite inline-cache patch
364 SUSPEND_FOR_CC_RESET, // code-cache reset
365 SUSPEND_FOR_REFRESH, // Reload data cached in interpState
366 #endif
367 };
368 void dvmSuspendThread(Thread* thread);
369 void dvmSuspendSelf(bool jdwpActivity);
370 void dvmResumeThread(Thread* thread);
371 void dvmSuspendAllThreads(SuspendCause why);
372 void dvmResumeAllThreads(SuspendCause why);
373 void dvmUndoDebuggerSuspensions(void);
374
375 /*
376 * Check suspend state. Grab threadListLock before calling.
377 */
378 bool dvmIsSuspended(const Thread* thread);
379
380 /*
381 * Wait until a thread has suspended. (Used by debugger support.)
382 */
383 void dvmWaitForSuspend(Thread* thread);
384
385 /*
386 * Check to see if we should be suspended now. If so, suspend ourselves
387 * by sleeping on a condition variable.
388 */
389 extern "C" bool dvmCheckSuspendPending(Thread* self);
390
391 /*
392 * Fast test for use in the interpreter. Returns "true" if our suspend
393 * count is nonzero.
394 */
dvmCheckSuspendQuick(Thread * self)395 INLINE bool dvmCheckSuspendQuick(Thread* self) {
396 return (self->interpBreak.ctl.subMode & kSubModeSuspendPending);
397 }
398
399 /*
400 * Used when changing thread state. Threads may only change their own.
401 * The "self" argument, which may be NULL, is accepted as an optimization.
402 *
403 * If you're calling this before waiting on a resource (e.g. THREAD_WAIT
404 * or THREAD_MONITOR), do so in the same function as the wait -- this records
405 * the current stack depth for the GC.
406 *
407 * If you're changing to THREAD_RUNNING, this will check for suspension.
408 *
409 * Returns the old status.
410 */
411 ThreadStatus dvmChangeStatus(Thread* self, ThreadStatus newStatus);
412
413 /*
414 * Initialize a mutex.
415 */
dvmInitMutex(pthread_mutex_t * pMutex)416 INLINE void dvmInitMutex(pthread_mutex_t* pMutex)
417 {
418 #ifdef CHECK_MUTEX
419 pthread_mutexattr_t attr;
420 int cc;
421
422 pthread_mutexattr_init(&attr);
423 cc = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK_NP);
424 assert(cc == 0);
425 pthread_mutex_init(pMutex, &attr);
426 pthread_mutexattr_destroy(&attr);
427 #else
428 pthread_mutex_init(pMutex, NULL); // default=PTHREAD_MUTEX_FAST_NP
429 #endif
430 }
431
432 /*
433 * Grab a plain mutex.
434 */
dvmLockMutex(pthread_mutex_t * pMutex)435 INLINE void dvmLockMutex(pthread_mutex_t* pMutex)
436 {
437 int cc __attribute__ ((__unused__)) = pthread_mutex_lock(pMutex);
438 assert(cc == 0);
439 }
440
441 /*
442 * Try grabbing a plain mutex. Returns 0 if successful.
443 */
dvmTryLockMutex(pthread_mutex_t * pMutex)444 INLINE int dvmTryLockMutex(pthread_mutex_t* pMutex)
445 {
446 int cc = pthread_mutex_trylock(pMutex);
447 assert(cc == 0 || cc == EBUSY);
448 return cc;
449 }
450
451 /*
452 * Unlock pthread mutex.
453 */
dvmUnlockMutex(pthread_mutex_t * pMutex)454 INLINE void dvmUnlockMutex(pthread_mutex_t* pMutex)
455 {
456 int cc __attribute__ ((__unused__)) = pthread_mutex_unlock(pMutex);
457 assert(cc == 0);
458 }
459
460 /*
461 * Destroy a mutex.
462 */
dvmDestroyMutex(pthread_mutex_t * pMutex)463 INLINE void dvmDestroyMutex(pthread_mutex_t* pMutex)
464 {
465 int cc __attribute__ ((__unused__)) = pthread_mutex_destroy(pMutex);
466 assert(cc == 0);
467 }
468
dvmBroadcastCond(pthread_cond_t * pCond)469 INLINE void dvmBroadcastCond(pthread_cond_t* pCond)
470 {
471 int cc __attribute__ ((__unused__)) = pthread_cond_broadcast(pCond);
472 assert(cc == 0);
473 }
474
dvmSignalCond(pthread_cond_t * pCond)475 INLINE void dvmSignalCond(pthread_cond_t* pCond)
476 {
477 int cc __attribute__ ((__unused__)) = pthread_cond_signal(pCond);
478 assert(cc == 0);
479 }
480
dvmWaitCond(pthread_cond_t * pCond,pthread_mutex_t * pMutex)481 INLINE void dvmWaitCond(pthread_cond_t* pCond, pthread_mutex_t* pMutex)
482 {
483 int cc __attribute__ ((__unused__)) = pthread_cond_wait(pCond, pMutex);
484 assert(cc == 0);
485 }
486
487 /*
488 * Create a thread as a result of java.lang.Thread.start().
489 */
490 bool dvmCreateInterpThread(Object* threadObj, int reqStackSize);
491
492 /*
493 * Create a thread internal to the VM. It's visible to interpreted code,
494 * but found in the "system" thread group rather than "main".
495 */
496 bool dvmCreateInternalThread(pthread_t* pHandle, const char* name,
497 InternalThreadStart func, void* funcArg);
498
499 /*
500 * Attach or detach the current thread from the VM.
501 */
502 bool dvmAttachCurrentThread(const JavaVMAttachArgs* pArgs, bool isDaemon);
503 void dvmDetachCurrentThread(void);
504
505 /*
506 * Get the "main" or "system" thread group.
507 */
508 Object* dvmGetMainThreadGroup(void);
509 Object* dvmGetSystemThreadGroup(void);
510
511 /*
512 * Given a java/lang/VMThread object, return our Thread.
513 */
514 Thread* dvmGetThreadFromThreadObject(Object* vmThreadObj);
515
516 /*
517 * Given a pthread handle, return the associated Thread*.
518 * Caller must hold the thread list lock.
519 *
520 * Returns NULL if the thread was not found.
521 */
522 Thread* dvmGetThreadByHandle(pthread_t handle);
523
524 /*
525 * Given a thread ID, return the associated Thread*.
526 * Caller must hold the thread list lock.
527 *
528 * Returns NULL if the thread was not found.
529 */
530 Thread* dvmGetThreadByThreadId(u4 threadId);
531
532 /*
533 * Sleep in a thread. Returns when the sleep timer returns or the thread
534 * is interrupted.
535 */
536 void dvmThreadSleep(u8 msec, u4 nsec);
537
538 /*
539 * Get the name of a thread.
540 *
541 * For correctness, the caller should hold the thread list lock to ensure
542 * that the thread doesn't go away mid-call.
543 */
544 std::string dvmGetThreadName(Thread* thread);
545
546 /*
547 * Convert ThreadStatus to a string.
548 */
549 const char* dvmGetThreadStatusStr(ThreadStatus status);
550
551 /*
552 * Return true if a thread is on the internal list. If it is, the
553 * thread is part of the GC's root set.
554 */
555 bool dvmIsOnThreadList(const Thread* thread);
556
557 /*
558 * Get/set the JNIEnv field.
559 */
dvmGetThreadJNIEnv(Thread * self)560 INLINE JNIEnv* dvmGetThreadJNIEnv(Thread* self) { return self->jniEnv; }
dvmSetThreadJNIEnv(Thread * self,JNIEnv * env)561 INLINE void dvmSetThreadJNIEnv(Thread* self, JNIEnv* env) { self->jniEnv = env;}
562
563 /*
564 * Update the priority value of the underlying pthread.
565 */
566 void dvmChangeThreadPriority(Thread* thread, int newPriority);
567
568 /* "change flags" values for raise/reset thread priority calls */
569 #define kChangedPriority 0x01
570 #define kChangedPolicy 0x02
571
572 /*
573 * If necessary, raise the thread's priority to nice=0 cgroup=fg.
574 *
575 * Returns bit flags indicating changes made (zero if nothing was done).
576 */
577 int dvmRaiseThreadPriorityIfNeeded(Thread* thread, int* pSavedThreadPrio,
578 SchedPolicy* pSavedThreadPolicy);
579
580 /*
581 * Drop the thread priority to what it was before an earlier call to
582 * dvmRaiseThreadPriorityIfNeeded().
583 */
584 void dvmResetThreadPriority(Thread* thread, int changeFlags,
585 int savedThreadPrio, SchedPolicy savedThreadPolicy);
586
587 /*
588 * Debug: dump information about a single thread.
589 */
590 void dvmDumpThread(Thread* thread, bool isRunning);
591 void dvmDumpThreadEx(const DebugOutputTarget* target, Thread* thread,
592 bool isRunning);
593
594 /*
595 * Debug: dump information about all threads.
596 */
597 void dvmDumpAllThreads(bool grabLock);
598 void dvmDumpAllThreadsEx(const DebugOutputTarget* target, bool grabLock);
599
600 /*
601 * Debug: kill a thread to get a debuggerd stack trace. Leaves the VM
602 * in an uncertain state.
603 */
604 void dvmNukeThread(Thread* thread);
605
606 #endif // DALVIK_THREAD_H_
607