blob: c066bec2dcd4cdff7234c7626e72ec6914f00825 [file] [log] [blame]
/*
* Copyright (C) 2011 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.
*/
#include "mutex.h"
#include <errno.h>
#include "logging.h"
#include "runtime.h"
#include "thread.h"
#include "utils.h"
#if defined(__APPLE__)
#include "AvailabilityMacros.h" // For MAC_OS_X_VERSION_MAX_ALLOWED
#endif
#define CHECK_MUTEX_CALL(call, args) CHECK_PTHREAD_CALL(call, args, name_)
extern int pthread_mutex_lock(pthread_mutex_t* mutex) EXCLUSIVE_LOCK_FUNCTION(mutex);
extern int pthread_mutex_unlock(pthread_mutex_t* mutex) UNLOCK_FUNCTION(1);
extern int pthread_mutex_trylock(pthread_mutex_t* mutex) EXCLUSIVE_TRYLOCK_FUNCTION(0, mutex);
namespace art {
// This works on Mac OS 10.6 but hasn't been tested on older releases.
struct __attribute__((__may_alias__)) darwin_pthread_mutex_t {
long padding0;
int padding1;
uint32_t padding2;
int16_t padding3;
int16_t padding4;
uint32_t padding5;
pthread_t darwin_pthread_mutex_owner;
// ...other stuff we don't care about.
};
struct __attribute__((__may_alias__)) darwin_pthread_rwlock_t {
long padding0;
pthread_mutex_t padding1;
int padding2;
pthread_cond_t padding3;
pthread_cond_t padding4;
int padding5;
int padding6;
pthread_t darwin_pthread_rwlock_owner;
// ...other stuff we don't care about.
};
struct __attribute__((__may_alias__)) glibc_pthread_mutex_t {
int32_t padding0[2];
int owner;
// ...other stuff we don't care about.
};
struct __attribute__((__may_alias__)) glibc_pthread_rwlock_t {
#ifdef __LP64__
int32_t padding0[6];
#else
int32_t padding0[7];
#endif
int writer;
// ...other stuff we don't care about.
};
ReaderWriterMutex* Locks::mutator_lock_ = NULL;
Mutex* Locks::thread_list_lock_ = NULL;
Mutex* Locks::classlinker_classes_lock_ = NULL;
ReaderWriterMutex* Locks::heap_bitmap_lock_ = NULL;
Mutex* Locks::abort_lock_ = NULL;
Mutex* Locks::logging_lock_ = NULL;
Mutex* Locks::unexpected_signal_lock_ = NULL;
Mutex* Locks::thread_suspend_count_lock_ = NULL;
void Locks::Init() {
if (logging_lock_ != NULL) {
// Already initialized.
DCHECK(mutator_lock_ != NULL);
DCHECK(thread_list_lock_ != NULL);
DCHECK(classlinker_classes_lock_ != NULL);
DCHECK(heap_bitmap_lock_ != NULL);
DCHECK(abort_lock_ != NULL);
DCHECK(logging_lock_ != NULL);
DCHECK(unexpected_signal_lock_ != NULL);
DCHECK(thread_suspend_count_lock_ != NULL);
} else {
logging_lock_ = new Mutex("logging lock", kLoggingLock, true);
abort_lock_ = new Mutex("abort lock", kAbortLock, true);
DCHECK(mutator_lock_ == NULL);
mutator_lock_ = new ReaderWriterMutex("mutator lock", kMutatorLock);
DCHECK(thread_list_lock_ == NULL);
thread_list_lock_ = new Mutex("thread list lock", kThreadListLock);
DCHECK(classlinker_classes_lock_ == NULL);
classlinker_classes_lock_ = new Mutex("ClassLinker classes lock", kClassLinkerClassesLock);
DCHECK(heap_bitmap_lock_ == NULL);
heap_bitmap_lock_ = new ReaderWriterMutex("heap bitmap lock", kHeapBitmapLock);
DCHECK(unexpected_signal_lock_ == NULL);
unexpected_signal_lock_ = new Mutex("unexpected signal lock", kUnexpectedSignalLock, true);
DCHECK(thread_suspend_count_lock_ == NULL);
thread_suspend_count_lock_ = new Mutex("thread suspend count lock", kThreadSuspendCountLock);
}
}
BaseMutex::BaseMutex(const char* name, MutexLevel level) : level_(level), name_(name) {}
static void CheckUnattachedThread(MutexLevel level) {
// The check below enumerates the cases where we expect not to be able to sanity check locks
// on a thread. TODO: tighten this check.
if (kDebugLocking) {
Runtime* runtime = Runtime::Current();
CHECK(runtime == NULL || !runtime->IsStarted() || runtime->IsShuttingDown() ||
level == kDefaultMutexLevel || level == kThreadListLock ||
level == kLoggingLock || level == kAbortLock);
}
}
void BaseMutex::RegisterAsLockedWithCurrentThread() {
Thread* self = Thread::Current();
if (self == NULL) {
CheckUnattachedThread(level_);
return;
}
if (kDebugLocking) {
// Check if a bad Mutex of this level or lower is held.
bool bad_mutexes_held = false;
for (int i = level_; i >= 0; --i) {
BaseMutex* held_mutex = self->GetHeldMutex(static_cast<MutexLevel>(i));
if (UNLIKELY(held_mutex != NULL)) {
LOG(ERROR) << "Lock level violation: holding \"" << held_mutex->name_ << "\" (level " << i
<< ") while locking \"" << name_ << "\" (level " << static_cast<int>(level_) << ")";
if (i > kAbortLock) {
// Only abort in the check below if this is more than abort level lock.
bad_mutexes_held = true;
}
}
}
CHECK(!bad_mutexes_held);
}
// Don't record monitors as they are outside the scope of analysis. They may be inspected off of
// the monitor list.
if (level_ != kMonitorLock) {
self->SetHeldMutex(level_, this);
}
}
void BaseMutex::RegisterAsUnlockedWithCurrentThread() {
Thread* self = Thread::Current();
if (self == NULL) {
CheckUnattachedThread(level_);
return;
}
if (level_ != kMonitorLock) {
if (kDebugLocking) {
CHECK(self->GetHeldMutex(level_) == this) << "Unlocking on unacquired mutex: " << name_;
}
self->SetHeldMutex(level_, NULL);
}
}
void BaseMutex::CheckSafeToWait() {
Thread* self = Thread::Current();
if (self == NULL) {
CheckUnattachedThread(level_);
return;
}
if (kDebugLocking) {
CHECK(self->GetHeldMutex(level_) == this) << "Waiting on unacquired mutex: " << name_;
bool bad_mutexes_held = false;
for (int i = kMaxMutexLevel; i >= 0; --i) {
if (i != level_) {
BaseMutex* held_mutex = self->GetHeldMutex(static_cast<MutexLevel>(i));
if (held_mutex != NULL) {
LOG(ERROR) << "Holding " << held_mutex->name_ << " (level " << i
<< ") while performing wait on: "
<< name_ << " (level " << static_cast<int>(level_) << ")";
bad_mutexes_held = true;
}
}
}
CHECK(!bad_mutexes_held);
}
}
Mutex::Mutex(const char* name, MutexLevel level, bool recursive)
: BaseMutex(name, level), recursive_(recursive), recursion_count_(0) {
#if defined(__BIONIC__) || defined(__APPLE__)
// Use recursive mutexes for bionic and Apple otherwise the
// non-recursive mutexes don't have TIDs to check lock ownership of.
pthread_mutexattr_t attributes;
CHECK_MUTEX_CALL(pthread_mutexattr_init, (&attributes));
CHECK_MUTEX_CALL(pthread_mutexattr_settype, (&attributes, PTHREAD_MUTEX_RECURSIVE));
CHECK_MUTEX_CALL(pthread_mutex_init, (&mutex_, &attributes));
CHECK_MUTEX_CALL(pthread_mutexattr_destroy, (&attributes));
#else
CHECK_MUTEX_CALL(pthread_mutex_init, (&mutex_, NULL));
#endif
}
Mutex::~Mutex() {
// We can't use CHECK_MUTEX_CALL here because on shutdown a suspended daemon thread
// may still be using locks.
int rc = pthread_mutex_destroy(&mutex_);
if (rc != 0) {
errno = rc;
// TODO: should we just not log at all if shutting down? this could be the logging mutex!
bool shutting_down = Runtime::Current()->IsShuttingDown();
PLOG(shutting_down ? WARNING : FATAL) << "pthread_mutex_destroy failed for " << name_;
}
}
void Mutex::ExclusiveLock() {
if (kDebugLocking && !recursive_) {
AssertNotHeld();
}
if (!recursive_ || !IsExclusiveHeld()) {
CHECK_MUTEX_CALL(pthread_mutex_lock, (&mutex_));
RegisterAsLockedWithCurrentThread();
}
recursion_count_++;
if (kDebugLocking) {
CHECK(recursion_count_ == 1 || recursive_) << "Unexpected recursion count on mutex: "
<< name_ << " " << recursion_count_;
AssertHeld();
}
}
bool Mutex::ExclusiveTryLock() {
if (kDebugLocking && !recursive_) {
AssertNotHeld();
}
if (!recursive_ || !IsExclusiveHeld()) {
int result = pthread_mutex_trylock(&mutex_);
if (result == EBUSY) {
return false;
}
if (result != 0) {
errno = result;
PLOG(FATAL) << "pthread_mutex_trylock failed for " << name_;
}
RegisterAsLockedWithCurrentThread();
}
recursion_count_++;
if (kDebugLocking) {
CHECK(recursion_count_ == 1 || recursive_) << "Unexpected recursion count on mutex: "
<< name_ << " " << recursion_count_;
AssertHeld();
}
return true;
}
void Mutex::ExclusiveUnlock() {
AssertHeld();
recursion_count_--;
if (!recursive_ || recursion_count_ == 0) {
if (kDebugLocking) {
CHECK(recursion_count_ == 0 || recursive_) << "Unexpected recursion count on mutex: "
<< name_ << " " << recursion_count_;
}
RegisterAsUnlockedWithCurrentThread();
CHECK_MUTEX_CALL(pthread_mutex_unlock, (&mutex_));
}
}
bool Mutex::IsExclusiveHeld() const {
Thread* self = Thread::Current();
bool result;
if (self == NULL || level_ == kMonitorLock) { // Handle unattached threads and monitors.
result = (GetExclusiveOwnerTid() == static_cast<uint64_t>(GetTid()));
} else {
result = (self->GetHeldMutex(level_) == this);
// Sanity debug check that if we think it is locked, so does the pthread.
if (kDebugLocking) {
CHECK(result == (GetExclusiveOwnerTid() == static_cast<uint64_t>(GetTid())));
}
}
return result;
}
uint64_t Mutex::GetExclusiveOwnerTid() const {
#if defined(__BIONIC__)
return static_cast<uint64_t>((mutex_.value >> 16) & 0xffff);
#elif defined(__GLIBC__)
return reinterpret_cast<const glibc_pthread_mutex_t*>(&mutex_)->owner;
#elif defined(__APPLE__)
const darwin_pthread_mutex_t* dpmutex = reinterpret_cast<const darwin_pthread_mutex_t*>(&mutex_);
pthread_t owner = dpmutex->darwin_pthread_mutex_owner;
// 0 for unowned, -1 for PTHREAD_MTX_TID_SWITCHING
// TODO: should we make darwin_pthread_mutex_owner volatile and recheck until not -1?
if ((owner == (pthread_t)0) || (owner == (pthread_t)-1)) {
return 0;
}
uint64_t tid;
CHECK_PTHREAD_CALL(pthread_threadid_np, (owner, &tid), __FUNCTION__); // Requires Mac OS 10.6
return tid;
#else
#error unsupported C library
#endif
}
ReaderWriterMutex::ReaderWriterMutex(const char* name, MutexLevel level) : BaseMutex(name, level) {
CHECK_MUTEX_CALL(pthread_rwlock_init, (&rwlock_, NULL));
}
ReaderWriterMutex::~ReaderWriterMutex() {
// We can't use CHECK_MUTEX_CALL here because on shutdown a suspended daemon thread
// may still be using locks.
int rc = pthread_rwlock_destroy(&rwlock_);
if (rc != 0) {
errno = rc;
// TODO: should we just not log at all if shutting down? this could be the logging mutex!
bool shutting_down = Runtime::Current()->IsShuttingDown();
PLOG(shutting_down ? WARNING : FATAL) << "pthread_mutex_destroy failed for " << name_;
}
}
void ReaderWriterMutex::ExclusiveLock() {
AssertNotExclusiveHeld();
CHECK_MUTEX_CALL(pthread_rwlock_wrlock, (&rwlock_));
RegisterAsLockedWithCurrentThread();
AssertExclusiveHeld();
}
void ReaderWriterMutex::ExclusiveUnlock() {
AssertExclusiveHeld();
RegisterAsUnlockedWithCurrentThread();
CHECK_MUTEX_CALL(pthread_rwlock_unlock, (&rwlock_));
}
#if HAVE_TIMED_RWLOCK
bool ReaderWriterMutex::ExclusiveLockWithTimeout(const timespec& abs_timeout) {
int result = pthread_rwlock_timedwrlock(&rwlock_, &abs_timeout);
if (result == ETIMEDOUT) {
return false;
}
if (result != 0) {
errno = result;
PLOG(FATAL) << "pthread_rwlock_timedwrlock failed for " << name_;
}
RegisterAsLockedWithCurrentThread();
AssertSharedHeld();
return true;
}
#endif
void ReaderWriterMutex::SharedLock() {
CHECK_MUTEX_CALL(pthread_rwlock_rdlock, (&rwlock_));
RegisterAsLockedWithCurrentThread();
AssertSharedHeld();
}
bool ReaderWriterMutex::SharedTryLock() {
int result = pthread_rwlock_tryrdlock(&rwlock_);
if (result == EBUSY) {
return false;
}
if (result != 0) {
errno = result;
PLOG(FATAL) << "pthread_mutex_trylock failed for " << name_;
}
RegisterAsLockedWithCurrentThread();
AssertSharedHeld();
return true;
}
void ReaderWriterMutex::SharedUnlock() {
AssertSharedHeld();
RegisterAsUnlockedWithCurrentThread();
CHECK_MUTEX_CALL(pthread_rwlock_unlock, (&rwlock_));
}
bool ReaderWriterMutex::IsExclusiveHeld() const {
bool result = (GetExclusiveOwnerTid() == static_cast<uint64_t>(GetTid()));
if (kDebugLocking) {
// Sanity that if the pthread thinks we own the lock the Thread agrees.
Thread* self = Thread::Current();
CHECK((self == NULL) || !result || (self->GetHeldMutex(level_) == this));
}
return result;
}
bool ReaderWriterMutex::IsSharedHeld() const {
Thread* self = Thread::Current();
bool result;
if (UNLIKELY(self == NULL)) { // Handle unattached threads.
result = IsExclusiveHeld(); // TODO: a better best effort here.
} else {
result = (self->GetHeldMutex(level_) == this);
}
return result;
}
uint64_t ReaderWriterMutex::GetExclusiveOwnerTid() const {
#if defined(__BIONIC__)
return rwlock_.writerThreadId;
#elif defined(__GLIBC__)
return reinterpret_cast<const glibc_pthread_rwlock_t*>(&rwlock_)->writer;
#elif defined(__APPLE__)
const darwin_pthread_rwlock_t* dprwlock = reinterpret_cast<const darwin_pthread_rwlock_t*>(&rwlock_);
pthread_t owner = dprwlock->darwin_pthread_rwlock_owner;
if (owner == (pthread_t)0) {
return 0;
}
uint64_t tid;
CHECK_PTHREAD_CALL(pthread_threadid_np, (owner, &tid), __FUNCTION__); // Requires Mac OS 10.6
return tid;
#else
#error unsupported C library
#endif
}
ConditionVariable::ConditionVariable(const std::string& name) : name_(name) {
CHECK_MUTEX_CALL(pthread_cond_init, (&cond_, NULL));
}
ConditionVariable::~ConditionVariable() {
// We can't use CHECK_MUTEX_CALL here because on shutdown a suspended daemon thread
// may still be using condition variables.
int rc = pthread_cond_destroy(&cond_);
if (rc != 0) {
errno = rc;
bool shutting_down = Runtime::Current()->IsShuttingDown();
PLOG(shutting_down ? WARNING : FATAL) << "pthread_cond_destroy failed for " << name_;
}
}
void ConditionVariable::Broadcast() {
CHECK_MUTEX_CALL(pthread_cond_broadcast, (&cond_));
}
void ConditionVariable::Signal() {
CHECK_MUTEX_CALL(pthread_cond_signal, (&cond_));
}
void ConditionVariable::Wait(Mutex& mutex) {
mutex.CheckSafeToWait();
unsigned int old_recursion_count = mutex.recursion_count_;
mutex.recursion_count_ = 0;
CHECK_MUTEX_CALL(pthread_cond_wait, (&cond_, &mutex.mutex_));
mutex.recursion_count_ = old_recursion_count;
}
void ConditionVariable::TimedWait(Mutex& mutex, const timespec& ts) {
#ifdef HAVE_TIMEDWAIT_MONOTONIC
#define TIMEDWAIT pthread_cond_timedwait_monotonic
#else
#define TIMEDWAIT pthread_cond_timedwait
#endif
mutex.CheckSafeToWait();
unsigned int old_recursion_count = mutex.recursion_count_;
mutex.recursion_count_ = 0;
int rc = TIMEDWAIT(&cond_, &mutex.mutex_, &ts);
mutex.recursion_count_ = old_recursion_count;
if (rc != 0 && rc != ETIMEDOUT) {
errno = rc;
PLOG(FATAL) << "TimedWait failed for " << name_;
}
}
} // namespace art