runtime/thread-inl.h - platform/art - Git at Google

 /*
  * 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.
  */

 #ifndef ART_RUNTIME_THREAD_INL_H_
 #define ART_RUNTIME_THREAD_INL_H_

 #include "thread.h"

 #include <pthread.h>

 #include "cutils/atomic-inline.h"

 #include "base/casts.h"
 #include "base/mutex-inl.h"
 #include "gc/heap.h"
 #include "jni_internal.h"

 namespace art {

 // Quickly access the current thread from a JNIEnv.
 static inline Thread* ThreadForEnv(JNIEnv* env) {
   JNIEnvExt* full_env(down_cast<JNIEnvExt*>(env));
   return full_env->self;
 }

 inline Thread* Thread::Current() {
   // We rely on Thread::Current returning NULL for a detached thread, so it's not obvious
   // that we can replace this with a direct %fs access on x86.
   if (!is_started_) {
     return NULL;
   } else {
     void* thread = pthread_getspecific(Thread::pthread_key_self_);
     return reinterpret_cast<Thread*>(thread);
   }
 }

 inline ThreadState Thread::SetState(ThreadState new_state) {
   // Cannot use this code to change into Runnable as changing to Runnable should fail if
   // old_state_and_flags.suspend_request is true.
   DCHECK_NE(new_state, kRunnable);
   DCHECK_EQ(this, Thread::Current());
   union StateAndFlags old_state_and_flags;
   old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
   tls32_.state_and_flags.as_struct.state = new_state;
   return static_cast<ThreadState>(old_state_and_flags.as_struct.state);
 }

 inline void Thread::AssertThreadSuspensionIsAllowable(bool check_locks) const {
 #ifdef NDEBUG
   UNUSED(check_locks);  // Keep GCC happy about unused parameters.
 #else
   CHECK_EQ(0u, tls32_.no_thread_suspension) << tlsPtr_.last_no_thread_suspension_cause;
   if (check_locks) {
     bool bad_mutexes_held = false;
     for (int i = kLockLevelCount - 1; i >= 0; --i) {
       // We expect no locks except the mutator_lock_.
       if (i != kMutatorLock) {
         BaseMutex* held_mutex = GetHeldMutex(static_cast<LockLevel>(i));
         if (held_mutex != NULL) {
           LOG(ERROR) << "holding \"" << held_mutex->GetName()
                   << "\" at point where thread suspension is expected";
           bad_mutexes_held = true;
         }
       }
     }
     CHECK(!bad_mutexes_held);
   }
 #endif
 }

 inline void Thread::TransitionFromRunnableToSuspended(ThreadState new_state) {
   AssertThreadSuspensionIsAllowable();
   DCHECK_NE(new_state, kRunnable);
   DCHECK_EQ(this, Thread::Current());
   // Change to non-runnable state, thereby appearing suspended to the system.
   DCHECK_EQ(GetState(), kRunnable);
   union StateAndFlags old_state_and_flags;
   union StateAndFlags new_state_and_flags;
   while (true) {
     old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
     if (UNLIKELY((old_state_and_flags.as_struct.flags & kCheckpointRequest) != 0)) {
       RunCheckpointFunction();
       continue;
     }
     // Change the state but keep the current flags (kCheckpointRequest is clear).
     DCHECK_EQ((old_state_and_flags.as_struct.flags & kCheckpointRequest), 0);
     new_state_and_flags.as_struct.flags = old_state_and_flags.as_struct.flags;
     new_state_and_flags.as_struct.state = new_state;
     int status = android_atomic_cas(old_state_and_flags.as_int, new_state_and_flags.as_int,
                                        &tls32_.state_and_flags.as_int);
     if (LIKELY(status == 0)) {
       break;
     }
   }
   // Release share on mutator_lock_.
   Locks::mutator_lock_->SharedUnlock(this);
 }

 inline ThreadState Thread::TransitionFromSuspendedToRunnable() {
   bool done = false;
   union StateAndFlags old_state_and_flags;
   old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
   int16_t old_state = old_state_and_flags.as_struct.state;
   DCHECK_NE(static_cast<ThreadState>(old_state), kRunnable);
   do {
     Locks::mutator_lock_->AssertNotHeld(this);  // Otherwise we starve GC..
     old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
     DCHECK_EQ(old_state_and_flags.as_struct.state, old_state);
     if (UNLIKELY((old_state_and_flags.as_struct.flags & kSuspendRequest) != 0)) {
       // Wait while our suspend count is non-zero.
       MutexLock mu(this, *Locks::thread_suspend_count_lock_);
       old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
       DCHECK_EQ(old_state_and_flags.as_struct.state, old_state);
       while ((old_state_and_flags.as_struct.flags & kSuspendRequest) != 0) {
         // Re-check when Thread::resume_cond_ is notified.
         Thread::resume_cond_->Wait(this);
         old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
         DCHECK_EQ(old_state_and_flags.as_struct.state, old_state);
       }
       DCHECK_EQ(GetSuspendCount(), 0);
     }
     // Re-acquire shared mutator_lock_ access.
     Locks::mutator_lock_->SharedLock(this);
     // Atomically change from suspended to runnable if no suspend request pending.
     old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
     DCHECK_EQ(old_state_and_flags.as_struct.state, old_state);
     if (LIKELY((old_state_and_flags.as_struct.flags & kSuspendRequest) == 0)) {
       union StateAndFlags new_state_and_flags;
       new_state_and_flags.as_int = old_state_and_flags.as_int;
       new_state_and_flags.as_struct.state = kRunnable;
       // CAS the value without a memory barrier, that occurred in the lock above.
       done = android_atomic_cas(old_state_and_flags.as_int, new_state_and_flags.as_int,
                                 &tls32_.state_and_flags.as_int) == 0;
     }
     if (UNLIKELY(!done)) {
       // Failed to transition to Runnable. Release shared mutator_lock_ access and try again.
       Locks::mutator_lock_->SharedUnlock(this);
     } else {
       return static_cast<ThreadState>(old_state);
     }
   } while (true);
 }

 inline void Thread::VerifyStack() {
   if (kVerifyStack) {
     if (Runtime::Current()->GetHeap()->IsObjectValidationEnabled()) {
       VerifyStackImpl();
     }
   }
 }

 inline size_t Thread::TlabSize() const {
   return tlsPtr_.thread_local_end - tlsPtr_.thread_local_pos;
 }

 inline mirror::Object* Thread::AllocTlab(size_t bytes) {
   DCHECK_GE(TlabSize(), bytes);
   ++tlsPtr_.thread_local_objects;
   mirror::Object* ret = reinterpret_cast<mirror::Object*>(tlsPtr_.thread_local_pos);
   tlsPtr_.thread_local_pos += bytes;
   return ret;
 }

 inline bool Thread::PushOnThreadLocalAllocationStack(mirror::Object* obj) {
   DCHECK_LE(tlsPtr_.thread_local_alloc_stack_top, tlsPtr_.thread_local_alloc_stack_end);
   if (tlsPtr_.thread_local_alloc_stack_top < tlsPtr_.thread_local_alloc_stack_end) {
     // There's room.
     DCHECK_LE(reinterpret_cast<byte*>(tlsPtr_.thread_local_alloc_stack_top) +
                   sizeof(mirror::Object*),
               reinterpret_cast<byte*>(tlsPtr_.thread_local_alloc_stack_end));
     DCHECK(*tlsPtr_.thread_local_alloc_stack_top == nullptr);
     *tlsPtr_.thread_local_alloc_stack_top = obj;
     ++tlsPtr_.thread_local_alloc_stack_top;
     return true;
   }
   return false;
 }

 inline void Thread::SetThreadLocalAllocationStack(mirror::Object** start, mirror::Object** end) {
   DCHECK(Thread::Current() == this) << "Should be called by self";
   DCHECK(start != nullptr);
   DCHECK(end != nullptr);
   DCHECK_ALIGNED(start, sizeof(mirror::Object*));
   DCHECK_ALIGNED(end, sizeof(mirror::Object*));
   DCHECK_LT(start, end);
   tlsPtr_.thread_local_alloc_stack_end = end;
   tlsPtr_.thread_local_alloc_stack_top = start;
 }

 inline void Thread::RevokeThreadLocalAllocationStack() {
   if (kIsDebugBuild) {
     // Note: self is not necessarily equal to this thread since thread may be suspended.
     Thread* self = Thread::Current();
     DCHECK(this == self || IsSuspended() || GetState() == kWaitingPerformingGc)
         << GetState() << " thread " << this << " self " << self;
   }
   tlsPtr_.thread_local_alloc_stack_end = nullptr;
   tlsPtr_.thread_local_alloc_stack_top = nullptr;
 }

 }  // namespace art

 #endif  // ART_RUNTIME_THREAD_INL_H_
	/*
	* 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.
	*/

	#ifndef ART_RUNTIME_THREAD_INL_H_
	#define ART_RUNTIME_THREAD_INL_H_

	#include "thread.h"

	#include <pthread.h>

	#include "cutils/atomic-inline.h"

	#include "base/casts.h"
	#include "base/mutex-inl.h"
	#include "gc/heap.h"
	#include "jni_internal.h"

	namespace art {

	// Quickly access the current thread from a JNIEnv.
	static inline Thread* ThreadForEnv(JNIEnv* env) {
	JNIEnvExt* full_env(down_cast<JNIEnvExt*>(env));
	return full_env->self;
	}

	inline Thread* Thread::Current() {
	// We rely on Thread::Current returning NULL for a detached thread, so it's not obvious
	// that we can replace this with a direct %fs access on x86.
	if (!is_started_) {
	return NULL;
	} else {
	void* thread = pthread_getspecific(Thread::pthread_key_self_);
	return reinterpret_cast<Thread*>(thread);
	}
	}

	inline ThreadState Thread::SetState(ThreadState new_state) {
	// Cannot use this code to change into Runnable as changing to Runnable should fail if
	// old_state_and_flags.suspend_request is true.
	DCHECK_NE(new_state, kRunnable);
	DCHECK_EQ(this, Thread::Current());
	union StateAndFlags old_state_and_flags;
	old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
	tls32_.state_and_flags.as_struct.state = new_state;
	return static_cast<ThreadState>(old_state_and_flags.as_struct.state);
	}

	inline void Thread::AssertThreadSuspensionIsAllowable(bool check_locks) const {
	#ifdef NDEBUG
	UNUSED(check_locks); // Keep GCC happy about unused parameters.
	#else
	CHECK_EQ(0u, tls32_.no_thread_suspension) << tlsPtr_.last_no_thread_suspension_cause;
	if (check_locks) {
	bool bad_mutexes_held = false;
	for (int i = kLockLevelCount - 1; i >= 0; --i) {
	// We expect no locks except the mutator_lock_.
	if (i != kMutatorLock) {
	BaseMutex* held_mutex = GetHeldMutex(static_cast<LockLevel>(i));
	if (held_mutex != NULL) {
	LOG(ERROR) << "holding \"" << held_mutex->GetName()
	<< "\" at point where thread suspension is expected";
	bad_mutexes_held = true;
	}
	}
	}
	CHECK(!bad_mutexes_held);
	}
	#endif
	}

	inline void Thread::TransitionFromRunnableToSuspended(ThreadState new_state) {
	AssertThreadSuspensionIsAllowable();
	DCHECK_NE(new_state, kRunnable);
	DCHECK_EQ(this, Thread::Current());
	// Change to non-runnable state, thereby appearing suspended to the system.
	DCHECK_EQ(GetState(), kRunnable);
	union StateAndFlags old_state_and_flags;
	union StateAndFlags new_state_and_flags;
	while (true) {
	old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
	if (UNLIKELY((old_state_and_flags.as_struct.flags & kCheckpointRequest) != 0)) {
	RunCheckpointFunction();
	continue;
	}
	// Change the state but keep the current flags (kCheckpointRequest is clear).
	DCHECK_EQ((old_state_and_flags.as_struct.flags & kCheckpointRequest), 0);
	new_state_and_flags.as_struct.flags = old_state_and_flags.as_struct.flags;
	new_state_and_flags.as_struct.state = new_state;
	int status = android_atomic_cas(old_state_and_flags.as_int, new_state_and_flags.as_int,
	&tls32_.state_and_flags.as_int);
	if (LIKELY(status == 0)) {
	break;
	}
	}
	// Release share on mutator_lock_.
	Locks::mutator_lock_->SharedUnlock(this);
	}

	inline ThreadState Thread::TransitionFromSuspendedToRunnable() {
	bool done = false;
	union StateAndFlags old_state_and_flags;
	old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
	int16_t old_state = old_state_and_flags.as_struct.state;
	DCHECK_NE(static_cast<ThreadState>(old_state), kRunnable);
	do {
	Locks::mutator_lock_->AssertNotHeld(this); // Otherwise we starve GC..
	old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
	DCHECK_EQ(old_state_and_flags.as_struct.state, old_state);
	if (UNLIKELY((old_state_and_flags.as_struct.flags & kSuspendRequest) != 0)) {
	// Wait while our suspend count is non-zero.
	MutexLock mu(this, *Locks::thread_suspend_count_lock_);
	old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
	DCHECK_EQ(old_state_and_flags.as_struct.state, old_state);
	while ((old_state_and_flags.as_struct.flags & kSuspendRequest) != 0) {
	// Re-check when Thread::resume_cond_ is notified.
	Thread::resume_cond_->Wait(this);
	old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
	DCHECK_EQ(old_state_and_flags.as_struct.state, old_state);
	}
	DCHECK_EQ(GetSuspendCount(), 0);
	}
	// Re-acquire shared mutator_lock_ access.
	Locks::mutator_lock_->SharedLock(this);
	// Atomically change from suspended to runnable if no suspend request pending.
	old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
	DCHECK_EQ(old_state_and_flags.as_struct.state, old_state);
	if (LIKELY((old_state_and_flags.as_struct.flags & kSuspendRequest) == 0)) {
	union StateAndFlags new_state_and_flags;
	new_state_and_flags.as_int = old_state_and_flags.as_int;
	new_state_and_flags.as_struct.state = kRunnable;
	// CAS the value without a memory barrier, that occurred in the lock above.
	done = android_atomic_cas(old_state_and_flags.as_int, new_state_and_flags.as_int,
	&tls32_.state_and_flags.as_int) == 0;
	}
	if (UNLIKELY(!done)) {
	// Failed to transition to Runnable. Release shared mutator_lock_ access and try again.
	Locks::mutator_lock_->SharedUnlock(this);
	} else {
	return static_cast<ThreadState>(old_state);
	}
	} while (true);
	}

	inline void Thread::VerifyStack() {
	if (kVerifyStack) {
	if (Runtime::Current()->GetHeap()->IsObjectValidationEnabled()) {
	VerifyStackImpl();
	}
	}
	}

	inline size_t Thread::TlabSize() const {
	return tlsPtr_.thread_local_end - tlsPtr_.thread_local_pos;
	}

	inline mirror::Object* Thread::AllocTlab(size_t bytes) {
	DCHECK_GE(TlabSize(), bytes);
	++tlsPtr_.thread_local_objects;
	mirror::Object* ret = reinterpret_cast<mirror::Object*>(tlsPtr_.thread_local_pos);
	tlsPtr_.thread_local_pos += bytes;
	return ret;
	}

	inline bool Thread::PushOnThreadLocalAllocationStack(mirror::Object* obj) {
	DCHECK_LE(tlsPtr_.thread_local_alloc_stack_top, tlsPtr_.thread_local_alloc_stack_end);
	if (tlsPtr_.thread_local_alloc_stack_top < tlsPtr_.thread_local_alloc_stack_end) {
	// There's room.
	DCHECK_LE(reinterpret_cast<byte*>(tlsPtr_.thread_local_alloc_stack_top) +
	sizeof(mirror::Object*),
	reinterpret_cast<byte*>(tlsPtr_.thread_local_alloc_stack_end));
	DCHECK(*tlsPtr_.thread_local_alloc_stack_top == nullptr);
	*tlsPtr_.thread_local_alloc_stack_top = obj;
	++tlsPtr_.thread_local_alloc_stack_top;
	return true;
	}
	return false;
	}

	inline void Thread::SetThreadLocalAllocationStack(mirror::Object start, mirror::Object end) {
	DCHECK(Thread::Current() == this) << "Should be called by self";
	DCHECK(start != nullptr);
	DCHECK(end != nullptr);
	DCHECK_ALIGNED(start, sizeof(mirror::Object*));
	DCHECK_ALIGNED(end, sizeof(mirror::Object*));
	DCHECK_LT(start, end);
	tlsPtr_.thread_local_alloc_stack_end = end;
	tlsPtr_.thread_local_alloc_stack_top = start;
	}

	inline void Thread::RevokeThreadLocalAllocationStack() {
	if (kIsDebugBuild) {
	// Note: self is not necessarily equal to this thread since thread may be suspended.
	Thread* self = Thread::Current();
	DCHECK(this == self \|\| IsSuspended() \|\| GetState() == kWaitingPerformingGc)
	<< GetState() << " thread " << this << " self " << self;
	}
	tlsPtr_.thread_local_alloc_stack_end = nullptr;
	tlsPtr_.thread_local_alloc_stack_top = nullptr;
	}

	} // namespace art

	#endif // ART_RUNTIME_THREAD_INL_H_