replicant-frameworks_native/include/utils/threads.h
Dianne Hackborn 8c6cedc9bc Propagate background scheduling class across processes.
This is a very simply implementation: upon receiving an IPC, if the handling
thread is at a background priority (the driver will have taken care of
propagating this from the calling thread), then stick it in to the background
scheduling group.  Plus an API to turn this off for the process, which is
used by the system process.

This also pulls some of the code for managing scheduling classes out of
the Process JNI wrappers and in to some convenience methods in thread.h.
2009-12-07 19:11:14 -08:00

440 lines
14 KiB
C++

/*
* Copyright (C) 2007 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.
*/
#ifndef _LIBS_UTILS_THREADS_H
#define _LIBS_UTILS_THREADS_H
#include <stdint.h>
#include <sys/types.h>
#include <time.h>
#if defined(HAVE_PTHREADS)
# include <pthread.h>
#endif
// ------------------------------------------------------------------
// C API
#ifdef __cplusplus
extern "C" {
#endif
typedef void* android_thread_id_t;
typedef int (*android_thread_func_t)(void*);
enum {
/*
* ***********************************************
* ** Keep in sync with android.os.Process.java **
* ***********************************************
*
* This maps directly to the "nice" priorites we use in Android.
* A thread priority should be chosen inverse-proportinally to
* the amount of work the thread is expected to do. The more work
* a thread will do, the less favorable priority it should get so that
* it doesn't starve the system. Threads not behaving properly might
* be "punished" by the kernel.
* Use the levels below when appropriate. Intermediate values are
* acceptable, preferably use the {MORE|LESS}_FAVORABLE constants below.
*/
ANDROID_PRIORITY_LOWEST = 19,
/* use for background tasks */
ANDROID_PRIORITY_BACKGROUND = 10,
/* most threads run at normal priority */
ANDROID_PRIORITY_NORMAL = 0,
/* threads currently running a UI that the user is interacting with */
ANDROID_PRIORITY_FOREGROUND = -2,
/* the main UI thread has a slightly more favorable priority */
ANDROID_PRIORITY_DISPLAY = -4,
/* ui service treads might want to run at a urgent display (uncommon) */
ANDROID_PRIORITY_URGENT_DISPLAY = -8,
/* all normal audio threads */
ANDROID_PRIORITY_AUDIO = -16,
/* service audio threads (uncommon) */
ANDROID_PRIORITY_URGENT_AUDIO = -19,
/* should never be used in practice. regular process might not
* be allowed to use this level */
ANDROID_PRIORITY_HIGHEST = -20,
ANDROID_PRIORITY_DEFAULT = ANDROID_PRIORITY_NORMAL,
ANDROID_PRIORITY_MORE_FAVORABLE = -1,
ANDROID_PRIORITY_LESS_FAVORABLE = +1,
};
enum {
ANDROID_TGROUP_DEFAULT = 0,
ANDROID_TGROUP_BG_NONINTERACT = 1,
ANDROID_TGROUP_FG_BOOST = 2,
ANDROID_TGROUP_MAX = ANDROID_TGROUP_FG_BOOST,
};
// Create and run a new thread.
extern int androidCreateThread(android_thread_func_t, void *);
// Create thread with lots of parameters
extern int androidCreateThreadEtc(android_thread_func_t entryFunction,
void *userData,
const char* threadName,
int32_t threadPriority,
size_t threadStackSize,
android_thread_id_t *threadId);
// Get some sort of unique identifier for the current thread.
extern android_thread_id_t androidGetThreadId();
// Low-level thread creation -- never creates threads that can
// interact with the Java VM.
extern int androidCreateRawThreadEtc(android_thread_func_t entryFunction,
void *userData,
const char* threadName,
int32_t threadPriority,
size_t threadStackSize,
android_thread_id_t *threadId);
// Used by the Java Runtime to control how threads are created, so that
// they can be proper and lovely Java threads.
typedef int (*android_create_thread_fn)(android_thread_func_t entryFunction,
void *userData,
const char* threadName,
int32_t threadPriority,
size_t threadStackSize,
android_thread_id_t *threadId);
extern void androidSetCreateThreadFunc(android_create_thread_fn func);
// ------------------------------------------------------------------
// Extra functions working with raw pids.
// Get pid for the current thread.
extern pid_t androidGetTid();
// Change the scheduling group of a particular thread. The group
// should be one of the ANDROID_TGROUP constants. Returns BAD_VALUE if
// grp is out of range, else another non-zero value with errno set if
// the operation failed.
extern int androidSetThreadSchedulingGroup(pid_t tid, int grp);
// Change the priority AND scheduling group of a particular thread. The priority
// should be one of the ANDROID_PRIORITY constants. Returns INVALID_OPERATION
// if the priority set failed, else another value if just the group set failed;
// in either case errno is set.
extern int androidSetThreadPriority(pid_t tid, int prio);
#ifdef __cplusplus
}
#endif
// ------------------------------------------------------------------
// C++ API
#ifdef __cplusplus
#include <utils/Errors.h>
#include <utils/RefBase.h>
#include <utils/Timers.h>
namespace android {
typedef android_thread_id_t thread_id_t;
typedef android_thread_func_t thread_func_t;
enum {
PRIORITY_LOWEST = ANDROID_PRIORITY_LOWEST,
PRIORITY_BACKGROUND = ANDROID_PRIORITY_BACKGROUND,
PRIORITY_NORMAL = ANDROID_PRIORITY_NORMAL,
PRIORITY_FOREGROUND = ANDROID_PRIORITY_FOREGROUND,
PRIORITY_DISPLAY = ANDROID_PRIORITY_DISPLAY,
PRIORITY_URGENT_DISPLAY = ANDROID_PRIORITY_URGENT_DISPLAY,
PRIORITY_AUDIO = ANDROID_PRIORITY_AUDIO,
PRIORITY_URGENT_AUDIO = ANDROID_PRIORITY_URGENT_AUDIO,
PRIORITY_HIGHEST = ANDROID_PRIORITY_HIGHEST,
PRIORITY_DEFAULT = ANDROID_PRIORITY_DEFAULT,
PRIORITY_MORE_FAVORABLE = ANDROID_PRIORITY_MORE_FAVORABLE,
PRIORITY_LESS_FAVORABLE = ANDROID_PRIORITY_LESS_FAVORABLE,
};
// Create and run a new thread.
inline bool createThread(thread_func_t f, void *a) {
return androidCreateThread(f, a) ? true : false;
}
// Create thread with lots of parameters
inline bool createThreadEtc(thread_func_t entryFunction,
void *userData,
const char* threadName = "android:unnamed_thread",
int32_t threadPriority = PRIORITY_DEFAULT,
size_t threadStackSize = 0,
thread_id_t *threadId = 0)
{
return androidCreateThreadEtc(entryFunction, userData, threadName,
threadPriority, threadStackSize, threadId) ? true : false;
}
// Get some sort of unique identifier for the current thread.
inline thread_id_t getThreadId() {
return androidGetThreadId();
}
/*****************************************************************************/
/*
* Simple mutex class. The implementation is system-dependent.
*
* The mutex must be unlocked by the thread that locked it. They are not
* recursive, i.e. the same thread can't lock it multiple times.
*/
class Mutex {
public:
enum {
NORMAL = 0,
SHARED = 1
};
Mutex();
Mutex(const char* name);
Mutex(int type, const char* name = NULL);
~Mutex();
// lock or unlock the mutex
status_t lock();
void unlock();
// lock if possible; returns 0 on success, error otherwise
status_t tryLock();
// Manages the mutex automatically. It'll be locked when Autolock is
// constructed and released when Autolock goes out of scope.
class Autolock {
public:
inline Autolock(Mutex& mutex) : mLock(mutex) { mLock.lock(); }
inline Autolock(Mutex* mutex) : mLock(*mutex) { mLock.lock(); }
inline ~Autolock() { mLock.unlock(); }
private:
Mutex& mLock;
};
private:
friend class Condition;
// A mutex cannot be copied
Mutex(const Mutex&);
Mutex& operator = (const Mutex&);
#if defined(HAVE_PTHREADS)
pthread_mutex_t mMutex;
#else
void _init();
void* mState;
#endif
};
#if defined(HAVE_PTHREADS)
inline Mutex::Mutex() {
pthread_mutex_init(&mMutex, NULL);
}
inline Mutex::Mutex(const char* name) {
pthread_mutex_init(&mMutex, NULL);
}
inline Mutex::Mutex(int type, const char* name) {
if (type == SHARED) {
pthread_mutexattr_t attr;
pthread_mutexattr_init(&attr);
pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
pthread_mutex_init(&mMutex, &attr);
pthread_mutexattr_destroy(&attr);
} else {
pthread_mutex_init(&mMutex, NULL);
}
}
inline Mutex::~Mutex() {
pthread_mutex_destroy(&mMutex);
}
inline status_t Mutex::lock() {
return -pthread_mutex_lock(&mMutex);
}
inline void Mutex::unlock() {
pthread_mutex_unlock(&mMutex);
}
inline status_t Mutex::tryLock() {
return -pthread_mutex_trylock(&mMutex);
}
#endif // HAVE_PTHREADS
/*
* Automatic mutex. Declare one of these at the top of a function.
* When the function returns, it will go out of scope, and release the
* mutex.
*/
typedef Mutex::Autolock AutoMutex;
/*****************************************************************************/
/*
* Condition variable class. The implementation is system-dependent.
*
* Condition variables are paired up with mutexes. Lock the mutex,
* call wait(), then either re-wait() if things aren't quite what you want,
* or unlock the mutex and continue. All threads calling wait() must
* use the same mutex for a given Condition.
*/
class Condition {
public:
Condition();
~Condition();
// Wait on the condition variable. Lock the mutex before calling.
status_t wait(Mutex& mutex);
// same with relative timeout
status_t waitRelative(Mutex& mutex, nsecs_t reltime);
// Signal the condition variable, allowing one thread to continue.
void signal();
// Signal the condition variable, allowing all threads to continue.
void broadcast();
private:
#if defined(HAVE_PTHREADS)
pthread_cond_t mCond;
#else
void* mState;
#endif
};
#if defined(HAVE_PTHREADS)
inline Condition::Condition() {
pthread_cond_init(&mCond, NULL);
}
inline Condition::~Condition() {
pthread_cond_destroy(&mCond);
}
inline status_t Condition::wait(Mutex& mutex) {
return -pthread_cond_wait(&mCond, &mutex.mMutex);
}
inline status_t Condition::waitRelative(Mutex& mutex, nsecs_t reltime) {
#if defined(HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE)
struct timespec ts;
ts.tv_sec = reltime/1000000000;
ts.tv_nsec = reltime%1000000000;
return -pthread_cond_timedwait_relative_np(&mCond, &mutex.mMutex, &ts);
#else // HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE
struct timespec ts;
#if defined(HAVE_POSIX_CLOCKS)
clock_gettime(CLOCK_REALTIME, &ts);
#else // HAVE_POSIX_CLOCKS
// we don't support the clocks here.
struct timeval t;
gettimeofday(&t, NULL);
ts.tv_sec = t.tv_sec;
ts.tv_nsec= t.tv_usec*1000;
#endif // HAVE_POSIX_CLOCKS
ts.tv_sec += reltime/1000000000;
ts.tv_nsec+= reltime%1000000000;
if (ts.tv_nsec >= 1000000000) {
ts.tv_nsec -= 1000000000;
ts.tv_sec += 1;
}
return -pthread_cond_timedwait(&mCond, &mutex.mMutex, &ts);
#endif // HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE
}
inline void Condition::signal() {
pthread_cond_signal(&mCond);
}
inline void Condition::broadcast() {
pthread_cond_broadcast(&mCond);
}
#endif // HAVE_PTHREADS
/*****************************************************************************/
/*
* This is our spiffy thread object!
*/
class Thread : virtual public RefBase
{
public:
// Create a Thread object, but doesn't create or start the associated
// thread. See the run() method.
Thread(bool canCallJava = true);
virtual ~Thread();
// Start the thread in threadLoop() which needs to be implemented.
virtual status_t run( const char* name = 0,
int32_t priority = PRIORITY_DEFAULT,
size_t stack = 0);
// Ask this object's thread to exit. This function is asynchronous, when the
// function returns the thread might still be running. Of course, this
// function can be called from a different thread.
virtual void requestExit();
// Good place to do one-time initializations
virtual status_t readyToRun();
// Call requestExit() and wait until this object's thread exits.
// BE VERY CAREFUL of deadlocks. In particular, it would be silly to call
// this function from this object's thread. Will return WOULD_BLOCK in
// that case.
status_t requestExitAndWait();
protected:
// exitPending() returns true if requestExit() has been called.
bool exitPending() const;
private:
// Derived class must implement threadLoop(). The thread starts its life
// here. There are two ways of using the Thread object:
// 1) loop: if threadLoop() returns true, it will be called again if
// requestExit() wasn't called.
// 2) once: if threadLoop() returns false, the thread will exit upon return.
virtual bool threadLoop() = 0;
private:
Thread& operator=(const Thread&);
static int _threadLoop(void* user);
const bool mCanCallJava;
thread_id_t mThread;
Mutex mLock;
Condition mThreadExitedCondition;
status_t mStatus;
volatile bool mExitPending;
volatile bool mRunning;
sp<Thread> mHoldSelf;
#if HAVE_ANDROID_OS
int mTid;
#endif
};
}; // namespace android
#endif // __cplusplus
#endif // _LIBS_UTILS_THREADS_H