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openmpi/opal/threads/mutex.h
Brian Barrett 84d1512fba Add the potential for doing some basic error checking on mutexes during
single threaded builds.  In its default configuration, all this does
is ensure that there's at least a good chance of threads building
based on non-threaded development (since the variable names will be
checked).  There is also code to make sure that a "mutex" is never
"double locked" when using the conditional macro mutex operations.
This is off by default because there are a number of places in both
ORTE and OMPI where this alarm spews mega bytes of errors on a
simple test.  So we have some work to do on our path towards
thread support.

Also removed the macro versions of the non-conditional thread locks,
as the only places they were used, the author of the code intended
to use the conditional thread locks.  So now you have upper-case
macros for conditional thread locks and lowercase functions for
non-conditional locks.  Simple, right? :).

This commit was SVN r15011.
2007-06-12 16:25:26 +00:00

383 строки
13 KiB
C

/*
* Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
* University Research and Technology
* Corporation. All rights reserved.
* Copyright (c) 2004-2006 The University of Tennessee and The University
* of Tennessee Research Foundation. All rights
* reserved.
* Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
* University of Stuttgart. All rights reserved.
* Copyright (c) 2004-2005 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 2007 Cisco, Inc. All rights reserved.
* Copyright (c) 2007 Los Alamos National Security, LLC. All rights
* reserved.
* $COPYRIGHT$
*
* Additional copyrights may follow
*
* $HEADER$
*/
#ifndef OPAL_MUTEX_H
#define OPAL_MUTEX_H 1
#include "opal_config.h"
#if OMPI_HAVE_THREAD_SUPPORT
#include "opal/sys/atomic.h"
#endif /* OMPI_HAVE_THREAD_SUPPORT */
#if OMPI_ENABLE_DEBUG
#include "opal/util/output.h"
#endif
BEGIN_C_DECLS
/**
* @file:
*
* Mutual exclusion functions.
*
* Functions for locking of critical sections.
*/
/*
* declaring this here so that CL does not complain
*/
OPAL_DECLSPEC extern bool opal_uses_threads;
#if OMPI_ENABLE_DEBUG
OPAL_DECLSPEC extern bool opal_mutex_check_locks;
#endif
/**
* Opaque mutex object
*/
typedef struct opal_mutex_t opal_mutex_t;
/**
* Try to acquire a mutex.
*
* @param mutex Address of the mutex.
* @return 0 if the mutex was acquired, 1 otherwise.
*/
static inline int opal_mutex_trylock(opal_mutex_t *mutex);
/**
* Acquire a mutex.
*
* @param mutex Address of the mutex.
*/
static inline void opal_mutex_lock(opal_mutex_t *mutex);
/**
* Release a mutex.
*
* @param mutex Address of the mutex.
*/
static inline void opal_mutex_unlock(opal_mutex_t *mutex);
/**
* Try to acquire a mutex using atomic operations.
*
* @param mutex Address of the mutex.
* @return 0 if the mutex was acquired, 1 otherwise.
*/
static inline int opal_mutex_atomic_trylock(opal_mutex_t *mutex);
/**
* Acquire a mutex using atomic operations.
*
* @param mutex Address of the mutex.
*/
static inline void opal_mutex_atomic_lock(opal_mutex_t *mutex);
/**
* Release a mutex using atomic operations.
*
* @param mutex Address of the mutex.
*/
static inline void opal_mutex_atomic_unlock(opal_mutex_t *mutex);
END_C_DECLS
#ifdef __WINDOWS__
#include "mutex_windows.h"
#else
#include "mutex_unix.h"
#endif
BEGIN_C_DECLS
/**
* Check and see if the process is using multiple threads.
*
* @retval true If the process may have more than one thread.
* @retval false If the process only has a single thread.
*
* The value that this function returns is influenced by:
*
* - how MPI_INIT or MPI_INIT_THREAD was invoked,
* - what the final MPI thread level was determined to be,
* - whether the OMPI or MPI libraries are multi-threaded (Jan 2003:
* they're not),
* - whether configure determined if we have thread support or not
*
* MPI_INIT and MPI_INIT_THREAD (specifically, back-end OMPI startup
* functions) invoke opal_set_using_threads() to influence the value of
* this function, depending on their situation. Some examples:
*
* - if configure determined that we do not have threads, then this
* value will always be false.
*
* - if MPI_INIT is invoked, and the ompi libraries are [still]
* single-threaded, this value will be false.
*
* - if MPI_INIT_THREAD is invoked with MPI_THREAD_MULTIPLE, we have
* thread support, and the final thread level is determined to be
* MPI_THREAD_MULTIPLE, this value will be true.
*
* - if the process is a single-threaded OMPI executable (e.g., mpicc),
* this value will be false.
*
* Hence, this function will return false if there is guaranteed to
* only be one thread in the process. If there is even the
* possibility that we may have multiple threads, true will be
* returned.
*/
#define opal_using_threads() opal_uses_threads
/**
* Set whether the process is using multiple threads or not.
*
* @param have Boolean indicating whether the process is using
* multiple threads or not.
*
* @retval opal_using_threads The new return value from
* opal_using_threads().
*
* This function is used to influence the return value of
* opal_using_threads(). If configure detected that we have thread
* support, the return value of future invocations of
* opal_using_threads() will be the parameter's value. If configure
* detected that we have no thread support, then the retuen from
* opal_using_threads() will always be false.
*/
static inline bool opal_set_using_threads(bool have)
{
#if OMPI_HAVE_THREAD_SUPPORT
opal_uses_threads = have;
#else
have = have; /* just shut up the compiler */
opal_uses_threads = false;
#endif
return opal_uses_threads;
}
/**
* Lock a mutex if opal_using_threads() says that multiple threads may
* be active in the process.
*
* @param mutex Pointer to a opal_mutex_t to lock.
*
* If there is a possibility that multiple threads are running in the
* process (as determined by opal_using_threads()), this function will
* block waiting to lock the mutex.
*
* If there is no possibility that multiple threads are running in the
* process, return immediately.
*/
#if OMPI_HAVE_THREAD_SUPPORT
#define OPAL_THREAD_LOCK(mutex) \
do { \
if (opal_using_threads()) { \
opal_mutex_lock(mutex); \
} \
} while (0)
#elif OMPI_ENABLE_DEBUG
#define OPAL_THREAD_LOCK(mutex) \
do { \
(mutex)->m_lock_debug++; \
if (opal_mutex_check_locks && 1 != (mutex)->m_lock_debug) { \
opal_output(0, "Warning -- mutex already locked at %s:%d," \
" now at %s:%d", \
(mutex)->m_lock_file, \
(mutex)->m_lock_line, \
__FILE__, __LINE__); \
} \
(mutex)->m_lock_file = __FILE__; \
(mutex)->m_lock_line = __LINE__; \
} while (0)
#else
#define OPAL_THREAD_LOCK(mutex)
#endif
/**
* Try to lock a mutex if opal_using_threads() says that multiple
* threads may be active in the process.
*
* @param mutex Pointer to a opal_mutex_t to trylock
*
* If there is a possibility that multiple threads are running in the
* process (as determined by opal_using_threads()), this function will
* trylock the mutex.
*
* If there is no possibility that multiple threads are running in the
* process, return immediately without modifying the mutex.
*
* Returns 0 if mutex was locked, non-zero otherwise.
*/
#if OMPI_HAVE_THREAD_SUPPORT
#define OPAL_THREAD_TRYLOCK(mutex) (opal_using_threads() ? opal_mutex_trylock(mutex) : 0)
#elif OMPI_ENABLE_DEBUG
static inline int
opal_thread_debug_trylock(opal_mutex_t *mutex, char *file, int line)
{
int ret = -1;
if (0 == (mutex)->m_lock_debug) {
(mutex)->m_lock_debug++;
(mutex)->m_lock_file = file;
(mutex)->m_lock_line = line;
ret = 0;
} else {
if (opal_mutex_check_locks) {
opal_output(0, "Warning -- during trylock, mutex already locked at %s:%d "
"now at %s:%d",
file, line,
(mutex)->m_lock_file,
(mutex)->m_lock_line);
}
}
return ret;
}
#define OPAL_THREAD_TRYLOCK(mutex) opal_thread_debug_trylock(mutex, __FILE__, __LINE__)
#else
#define OPAL_THREAD_TRYLOCK(mutex) 0
#endif
/**
* Unlock a mutex if opal_using_threads() says that multiple threads
* may be active in the process.
*
* @param mutex Pointer to a opal_mutex_t to unlock.
*
* If there is a possibility that multiple threads are running in the
* process (as determined by opal_using_threads()), this function will
* unlock the mutex.
*
* If there is no possibility that multiple threads are running in the
* process, return immediately without modifying the mutex.
*/
#if OMPI_HAVE_THREAD_SUPPORT
#define OPAL_THREAD_UNLOCK(mutex) \
do { \
if (opal_using_threads()) { \
opal_mutex_unlock(mutex); \
} \
} while (0)
#elif OMPI_ENABLE_DEBUG
#define OPAL_THREAD_UNLOCK(mutex) \
do { \
(mutex)->m_lock_debug--; \
if (opal_mutex_check_locks && 0 > (mutex)->m_lock_debug) { \
opal_output(0, "Warning -- mutex was double locked from %s:%d", \
__FILE__, __LINE__); \
} else if (opal_mutex_check_locks && 0 > (mutex)->m_lock_debug) { \
opal_output(0, "Warning -- mutex not locked from %s:%d", \
__FILE__, __LINE__); \
} else { \
(mutex)->m_lock_file = NULL; \
(mutex)->m_lock_line = 0; \
} \
} while (0)
#else
#define OPAL_THREAD_UNLOCK(mutex)
#endif
/**
* Lock a mutex if opal_using_threads() says that multiple threads may
* be active in the process for the duration of the specified action.
*
* @param mutex Pointer to a opal_mutex_t to lock.
* @param action A scope over which the lock is held.
*
* If there is a possibility that multiple threads are running in the
* process (as determined by opal_using_threads()), this function will
* acquire the lock before invoking the specified action and release
* it on return.
*
* If there is no possibility that multiple threads are running in the
* process, invoke the action without acquiring the lock.
*/
#if OMPI_HAVE_THREAD_SUPPORT
#define OPAL_THREAD_SCOPED_LOCK(mutex, action) \
do { \
if(opal_using_threads()) { \
opal_mutex_lock(mutex); \
(action); \
opal_mutex_unlock(mutex); \
} else { \
(action); \
} \
} while (0)
#elif OMPI_ENABLE_DEBUG
#define OPAL_THREAD_SCOPED_LOCK(mutex, action) \
do { \
if (0 != (mutex)->m_lock_debug) { \
opal_output(0, "scoped_lock: Warning -- mutex already " \
"locked at %s:%d, now at %s:%d", \
__FILE__, __LINE__, \
(mutex)->m_lock_file, \
(mutex)->m_lock_line); \
} \
(mutex)->m_lock_debug--; \
(action); \
(mutex)->m_lock_debug++; \
} while (0)
#else
#define OPAL_THREAD_SCOPED_LOCK(mutex, action) (action)
#endif
/**
* Use an atomic operation for increment/decrement if opal_using_threads()
* indicates that threads are in use by the application or library.
*/
#if OMPI_HAVE_THREAD_SUPPORT
#define OPAL_THREAD_ADD32(x,y) \
(opal_using_threads() ? opal_atomic_add_32(x,y) : (*x += y))
#else
#define OPAL_THREAD_ADD32(x,y) (*x += y)
#endif
#if OMPI_HAVE_THREAD_SUPPORT
#define OPAL_THREAD_ADD64(x,y) \
(opal_using_threads() ? opal_atomic_add_64(x,y) : (*x += y))
#else
#define OPAL_THREAD_ADD64(x,y) (*x += y)
#endif
#if OMPI_HAVE_THREAD_SUPPORT
#define OPAL_THREAD_ADD_SIZE_T(x,y) \
(opal_using_threads() ? opal_atomic_add_size_t(x,y) : (*x += y))
#else
#define OPAL_THREAD_ADD_SIZE_T(x,y) (*x += y)
#endif
END_C_DECLS
#endif /* OPAL_MUTEX_H */