/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* VM thread support.
*/
#ifndef _DALVIK_THREAD
#define _DALVIK_THREAD
#include "jni.h"
#if defined(CHECK_MUTEX) && !defined(__USE_UNIX98)
/* glibc lacks this unless you #define __USE_UNIX98 */
int pthread_mutexattr_settype(pthread_mutexattr_t *attr, int type);
enum { PTHREAD_MUTEX_ERRORCHECK = PTHREAD_MUTEX_ERRORCHECK_NP };
#endif
#ifdef WITH_MONITOR_TRACKING
struct LockedObjectData;
#endif
/*
* Current status; these map to JDWP constants, so don't rearrange them.
* (If you do alter this, update the strings in dvmDumpThread and the
* conversion table in VMThread.java.)
*
* Note that "suspended" is orthogonal to these values (so says JDWP).
*/
typedef enum ThreadStatus {
/* these match up with JDWP values */
THREAD_ZOMBIE = 0, /* TERMINATED */
THREAD_RUNNING = 1, /* RUNNABLE or running now */
THREAD_TIMED_WAIT = 2, /* TIMED_WAITING in Object.wait() */
THREAD_MONITOR = 3, /* BLOCKED on a monitor */
THREAD_WAIT = 4, /* WAITING in Object.wait() */
/* non-JDWP states */
THREAD_INITIALIZING = 5, /* allocated, not yet running */
THREAD_STARTING = 6, /* started, not yet on thread list */
THREAD_NATIVE = 7, /* off in a JNI native method */
THREAD_VMWAIT = 8, /* waiting on a VM resource */
} ThreadStatus;
/* thread priorities, from java.lang.Thread */
enum {
THREAD_MIN_PRIORITY = 1,
THREAD_NORM_PRIORITY = 5,
THREAD_MAX_PRIORITY = 10,
};
/* initialization */
bool dvmThreadStartup(void);
bool dvmThreadObjStartup(void);
void dvmThreadShutdown(void);
void dvmSlayDaemons(void);
#define kJniLocalRefMin 32
#define kJniLocalRefMax 512 /* arbitrary; should be plenty */
#define kInternalRefDefault 32 /* equally arbitrary */
#define kInternalRefMax 4096 /* mainly a sanity check */
#define kMinStackSize (512 + STACK_OVERFLOW_RESERVE)
#define kDefaultStackSize (12*1024) /* three 4K pages */
#define kMaxStackSize (256*1024 + STACK_OVERFLOW_RESERVE)
/*
* System thread state. See native/SystemThread.h.
*/
typedef struct SystemThread SystemThread;
/*
* Our per-thread data.
*
* These are allocated on the system heap.
*/
typedef struct Thread {
/* small unique integer; useful for "thin" locks and debug messages */
u4 threadId;
/*
* Thread's current status. Can only be changed by the thread itself
* (i.e. don't mess with this from other threads).
*/
volatile ThreadStatus status;
/*
* This is the number of times the thread has been suspended. When the
* count drops to zero, the thread resumes.
*
* "dbgSuspendCount" is the portion of the suspend count that the
* debugger is responsible for. This has to be tracked separately so
* that we can recover correctly if the debugger abruptly disconnects
* (suspendCount -= dbgSuspendCount). The debugger should not be able
* to resume GC-suspended threads, because we ignore the debugger while
* a GC is in progress.
*
* Both of these are guarded by gDvm.threadSuspendCountLock.
*
* (We could store both of these in the same 32-bit, using 16-bit
* halves, to make atomic ops possible. In practice, you only need
* to read suspendCount, and we need to hold a mutex when making
* changes, so there's no need to merge them. Note the non-debug
* component will rarely be other than 1 or 0 -- not sure it's even
* possible with the way mutexes are currently used.)
*/
int suspendCount;
int dbgSuspendCount;
/*
* Set to true when the thread suspends itself, false when it wakes up.
* This is only expected to be set when status==THREAD_RUNNING.
*/
bool isSuspended;
/* thread handle, as reported by pthread_self() */
pthread_t handle;
/* thread ID, only useful under Linux */
pid_t systemTid;
/* start (high addr) of interp stack (subtract size to get malloc addr) */
u1* interpStackStart;
/* current limit of stack; flexes for StackOverflowError */
const u1* interpStackEnd;
/* interpreter stack size; our stacks are fixed-length */
int interpStackSize;
bool stackOverflowed;
/* FP of bottom-most (currently executing) stack frame on interp stack */
void* curFrame;
/* current exception, or NULL if nothing pending */
Object* exception;
/* the java/lang/Thread that we are associated with */
Object* threadObj;
/* the JNIEnv pointer associated with this thread */
JNIEnv* jniEnv;
/* internal reference tracking */
ReferenceTable internalLocalRefTable;
/* JNI local reference tracking */
#ifdef USE_INDIRECT_REF
IndirectRefTable jniLocalRefTable;
#else
ReferenceTable jniLocalRefTable;
#endif
/* JNI native monitor reference tracking (initialized on first use) */
ReferenceTable jniMonitorRefTable;
/* hack to make JNI_OnLoad work right */
Object* classLoaderOverride;
/* pointer to the monitor lock we're currently waiting on */
/* (do not set or clear unless the Monitor itself is held) */
/* TODO: consider changing this to Object* for better JDWP interaction */
Monitor* waitMonitor;
/* set when we confirm that the thread must be interrupted from a wait */
bool interruptingWait;
/* thread "interrupted" status; stays raised until queried or thrown */
bool interrupted;
/*
* Set to true when the thread is in the process of throwing an
* OutOfMemoryError.
*/
bool throwingOOME;
/* links to rest of thread list; grab global lock before traversing */
struct Thread* prev;
struct Thread* next;
/* JDWP invoke-during-breakpoint support */
DebugInvokeReq invokeReq;
#ifdef WITH_MONITOR_TRACKING
/* objects locked by this thread; most recent is at head of list */
struct LockedObjectData* pLockedObjects;
#endif
#ifdef WITH_ALLOC_LIMITS
/* allocation limit, for Debug.setAllocationLimit() regression testing */
int allocLimit;
#endif
#ifdef WITH_PROFILER
/* base time for per-thread CPU timing */
bool cpuClockBaseSet;
u8 cpuClockBase;
/* memory allocation profiling state */
AllocProfState allocProf;
#endif
#ifdef WITH_JNI_STACK_CHECK
u4 stackCrc;
#endif
#if WITH_EXTRA_GC_CHECKS > 1
/* PC, saved on every instruction; redundant with StackSaveArea */
const u2* currentPc2;
#endif
/* system thread state */
SystemThread* systemThread;
} Thread;
/* start point for an internal thread; mimics pthread args */
typedef void* (*InternalThreadStart)(void* arg);
/* args for internal thread creation */
typedef struct InternalStartArgs {
/* inputs */
InternalThreadStart func;
void* funcArg;
char* name;
Object* group;
bool isDaemon;
/* result */
volatile Thread** pThread;
volatile int* pCreateStatus;
} InternalStartArgs;
/* finish init */
bool dvmPrepMainForJni(JNIEnv* pEnv);
bool dvmPrepMainThread(void);
/* utility function to get the tid */
pid_t dvmGetSysThreadId(void);
/*
* Get our Thread* from TLS.
*
* Returns NULL if this isn't a thread that the VM is aware of.
*/
Thread* dvmThreadSelf(void);
/* grab the thread list global lock */
void dvmLockThreadList(Thread* self);
/* release the thread list global lock */
void dvmUnlockThreadList(void);
/*
* Thread suspend/resume, used by the GC and debugger.
*/
typedef enum SuspendCause {
SUSPEND_NOT = 0,
SUSPEND_FOR_GC,
SUSPEND_FOR_DEBUG,
SUSPEND_FOR_DEBUG_EVENT,
SUSPEND_FOR_STACK_DUMP,
SUSPEND_FOR_DEX_OPT,
#if defined(WITH_JIT)
SUSPEND_FOR_JIT,
#endif
} SuspendCause;
void dvmSuspendThread(Thread* thread);
void dvmSuspendSelf(bool jdwpActivity);
void dvmResumeThread(Thread* thread);
void dvmSuspendAllThreads(SuspendCause why);
void dvmResumeAllThreads(SuspendCause why);
void dvmUndoDebuggerSuspensions(void);
/*
* Check suspend state. Grab threadListLock before calling.
*/
bool dvmIsSuspended(Thread* thread);
/*
* Wait until a thread has suspended. (Used by debugger support.)
*/
void dvmWaitForSuspend(Thread* thread);
/*
* Check to see if we should be suspended now. If so, suspend ourselves
* by sleeping on a condition variable.
*
* If "self" is NULL, this will use dvmThreadSelf().
*/
bool dvmCheckSuspendPending(Thread* self);
/*
* Fast test for use in the interpreter. Returns "true" if our suspend
* count is nonzero.
*/
INLINE bool dvmCheckSuspendQuick(Thread* self) {
return (self->suspendCount != 0);
}
/*
* Used when changing thread state. Threads may only change their own.
* The "self" argument, which may be NULL, is accepted as an optimization.
*
* If you're calling this before waiting on a resource (e.g. THREAD_WAIT
* or THREAD_MONITOR), do so in the same function as the wait -- this records
* the current stack depth for the GC.
*
* If you're changing to THREAD_RUNNING, this will check for suspension.
*
* Returns the old status.
*/
ThreadStatus dvmChangeStatus(Thread* self, ThreadStatus newStatus);
/*
* Initialize a mutex.
*/
INLINE void dvmInitMutex(pthread_mutex_t* pMutex)
{
#ifdef CHECK_MUTEX
pthread_mutexattr_t attr;
int cc;
pthread_mutexattr_init(&attr);
cc = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK_NP);
assert(cc == 0);
pthread_mutex_init(pMutex, &attr);
pthread_mutexattr_destroy(&attr);
#else
pthread_mutex_init(pMutex, NULL); // default=PTHREAD_MUTEX_FAST_NP
#endif
}
/*
* Grab a plain mutex.
*/
INLINE void dvmLockMutex(pthread_mutex_t* pMutex)
{
int cc = pthread_mutex_lock(pMutex);
assert(cc == 0);
}
/*
* Unlock pthread mutex.
*/
INLINE void dvmUnlockMutex(pthread_mutex_t* pMutex)
{
int cc = pthread_mutex_unlock(pMutex);
assert(cc == 0);
}
/*
* Destroy a mutex.
*/
INLINE void dvmDestroyMutex(pthread_mutex_t* pMutex)
{
int cc = pthread_mutex_destroy(pMutex);
assert(cc == 0);
}
/*
* Create a thread as a result of java.lang.Thread.start().
*/
bool dvmCreateInterpThread(Object* threadObj, int reqStackSize);
/*
* Create a thread internal to the VM. It's visible to interpreted code,
* but found in the "system" thread group rather than "main".
*/
bool dvmCreateInternalThread(pthread_t* pHandle, const char* name,
InternalThreadStart func, void* funcArg);
/*
* Attach or detach the current thread from the VM.
*/
bool dvmAttachCurrentThread(const JavaVMAttachArgs* pArgs, bool isDaemon);
void dvmDetachCurrentThread(void);
/*
* Get the "main" or "system" thread group.
*/
Object* dvmGetMainThreadGroup(void);
Object* dvmGetSystemThreadGroup(void);
/*
* Given a java/lang/VMThread object, return our Thread.
*/
Thread* dvmGetThreadFromThreadObject(Object* vmThreadObj);
/*
* Sleep in a thread. Returns when the sleep timer returns or the thread
* is interrupted.
*/
void dvmThreadSleep(u8 msec, u4 nsec);
/*
* Get the name of a thread. (For safety, hold the thread list lock.)
*/
char* dvmGetThreadName(Thread* thread);
/*
* Return true if a thread is on the internal list. If it is, the
* thread is part of the GC's root set.
*/
bool dvmIsOnThreadList(const Thread* thread);
/*
* Get/set the JNIEnv field.
*/
INLINE JNIEnv* dvmGetThreadJNIEnv(Thread* self) { return self->jniEnv; }
INLINE void dvmSetThreadJNIEnv(Thread* self, JNIEnv* env) { self->jniEnv = env;}
/*
* Update the priority value of the underlying pthread.
*/
void dvmChangeThreadPriority(Thread* thread, int newPriority);
/*
* Debug: dump information about a single thread.
*/
void dvmDumpThread(Thread* thread, bool isRunning);
void dvmDumpThreadEx(const DebugOutputTarget* target, Thread* thread,
bool isRunning);
/*
* Debug: dump information about all threads.
*/
void dvmDumpAllThreads(bool grabLock);
void dvmDumpAllThreadsEx(const DebugOutputTarget* target, bool grabLock);
#ifdef WITH_MONITOR_TRACKING
/*
* Track locks held by the current thread, along with the stack trace at
* the point the lock was acquired.
*
* At any given time the number of locks held across the VM should be
* fairly small, so there's no reason not to generate and store the entire
* stack trace.
*/
typedef struct LockedObjectData {
/* the locked object */
struct Object* obj;
/* number of times it has been locked recursively (zero-based ref count) */
int recursionCount;
/* stack trace at point of initial acquire */
u4 stackDepth;
int* rawStackTrace;
struct LockedObjectData* next;
} LockedObjectData;
/*
* Add/remove/find objects from the thread's monitor list.
*/
void dvmAddToMonitorList(Thread* self, Object* obj, bool withTrace);
void dvmRemoveFromMonitorList(Thread* self, Object* obj);
LockedObjectData* dvmFindInMonitorList(const Thread* self, const Object* obj);
#endif
#endif /*_DALVIK_THREAD*/