diff options
Diffstat (limited to 'Source/WTF/wtf/TCSpinLock.h')
-rw-r--r-- | Source/WTF/wtf/TCSpinLock.h | 133 |
1 files changed, 0 insertions, 133 deletions
diff --git a/Source/WTF/wtf/TCSpinLock.h b/Source/WTF/wtf/TCSpinLock.h deleted file mode 100644 index d8eddcfb2..000000000 --- a/Source/WTF/wtf/TCSpinLock.h +++ /dev/null @@ -1,133 +0,0 @@ -// Copyright (c) 2005, 2006, Google Inc. -// Copyright (c) 2010, Patrick Gansterer <paroga@paroga.com> -// All rights reserved. -// -// Redistribution and use in source and binary forms, with or without -// modification, are permitted provided that the following conditions are -// met: -// -// * Redistributions of source code must retain the above copyright -// notice, this list of conditions and the following disclaimer. -// * Redistributions in binary form must reproduce the above -// copyright notice, this list of conditions and the following disclaimer -// in the documentation and/or other materials provided with the -// distribution. -// * Neither the name of Google Inc. nor the names of its -// contributors may be used to endorse or promote products derived from -// this software without specific prior written permission. -// -// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR -// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT -// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, -// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT -// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, -// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY -// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT -// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE -// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - -// --- -// Author: Sanjay Ghemawat <opensource@google.com> - -#ifndef TCMALLOC_INTERNAL_SPINLOCK_H__ -#define TCMALLOC_INTERNAL_SPINLOCK_H__ - -#include <wtf/Atomics.h> -#if OS(UNIX) -#include <sched.h> -#endif - -#if ENABLE(COMPARE_AND_SWAP) - -static void TCMalloc_SlowLock(unsigned* lockword); - -// The following is a struct so that it can be initialized at compile time -struct TCMalloc_SpinLock { - void Lock() { - if (!WTF::weakCompareAndSwap(&lockword_, 0, 1)) - TCMalloc_SlowLock(&lockword_); - WTF::memoryBarrierAfterLock(); - } - - void Unlock() { - WTF::memoryBarrierBeforeUnlock(); - lockword_ = 0; - } - - // Report if we think the lock can be held by this thread. - // When the lock is truly held by the invoking thread - // we will always return true. - // Indended to be used as CHECK(lock.IsHeld()); - bool IsHeld() const { - return lockword_ != 0; - } - - void Init() { lockword_ = 0; } - void Finalize() { } - - unsigned lockword_; -}; - -#define SPINLOCK_INITIALIZER { 0 } - -static void TCMalloc_SlowLock(unsigned* lockword) { - do { -#if OS(WINDOWS) - Sleep(0); -#else - sched_yield(); -#endif - } while (!WTF::weakCompareAndSwap(lockword, 0, 1)); -} - -#else - -#include <pthread.h> - -// Portable version -struct TCMalloc_SpinLock { - pthread_mutex_t private_lock_; - - inline void Init() { - if (pthread_mutex_init(&private_lock_, NULL) != 0) CRASH(); - } - inline void Finalize() { - if (pthread_mutex_destroy(&private_lock_) != 0) CRASH(); - } - inline void Lock() { - if (pthread_mutex_lock(&private_lock_) != 0) CRASH(); - } - inline void Unlock() { - if (pthread_mutex_unlock(&private_lock_) != 0) CRASH(); - } - bool IsHeld() { - if (pthread_mutex_trylock(&private_lock_)) - return true; - - Unlock(); - return false; - } -}; - -#define SPINLOCK_INITIALIZER { PTHREAD_MUTEX_INITIALIZER } - -#endif - -// Corresponding locker object that arranges to acquire a spinlock for -// the duration of a C++ scope. -class TCMalloc_SpinLockHolder { - private: - TCMalloc_SpinLock* lock_; - public: - inline explicit TCMalloc_SpinLockHolder(TCMalloc_SpinLock* l) - : lock_(l) { l->Lock(); } - inline ~TCMalloc_SpinLockHolder() { lock_->Unlock(); } -}; - -// Short-hands for convenient use by tcmalloc.cc -typedef TCMalloc_SpinLock SpinLock; -typedef TCMalloc_SpinLockHolder SpinLockHolder; - -#endif // TCMALLOC_INTERNAL_SPINLOCK_H__ |