Date: Sun, 16 Jan 2005 00:59:55 GMT From: David Xu <davidxu@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 69096 for review Message-ID: <200501160059.j0G0xtrs014699@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=69096 Change 69096 by davidxu@davidxu_tiger on 2005/01/16 00:59:51 Revert some code, some tests show using a static lock is better. Affected files ... .. //depot/projects/davidxu_thread/src/lib/libthread/thread/thr_cond.c#11 edit .. //depot/projects/davidxu_thread/src/lib/libthread/thread/thr_mutex.c#15 edit .. //depot/projects/davidxu_thread/src/lib/libthread/thread/thr_rwlock.c#4 edit Differences ... ==== //depot/projects/davidxu_thread/src/lib/libthread/thread/thr_cond.c#11 (text+ko) ==== @@ -73,13 +73,29 @@ pcond->c_waiters = 0; pcond->c_wakeups = 0; pcond->c_flags = 0; - if (!atomic_cmpset_acq_ptr(cond, NULL, pcond)) - free(pcond); + *cond = pcond; } /* Return the completion status: */ return (rval); } +static int +init_static(struct pthread *thread, pthread_cond_t *cond) +{ + int ret; + + THR_LOCK_ACQUIRE(thread, &_cond_static_lock); + + if (*cond == NULL) + ret = cond_init(cond, NULL); + else + ret = 0; + + THR_LOCK_RELEASE(thread, &_cond_static_lock); + + return (ret); +} + int _pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *cond_attr) { @@ -98,9 +114,9 @@ rval = EINVAL; else { /* Lock the condition variable structure: */ - THR_UMTX_LOCK(curthread, &(*cond)->c_lock); + THR_LOCK_ACQUIRE(curthread, &(*cond)->c_lock); if ((*cond)->c_waiters + (*cond)->c_wakeups != 0) { - THR_UMTX_UNLOCK(curthread, &(*cond)->c_lock); + THR_LOCK_RELEASE(curthread, &(*cond)->c_lock); return (EBUSY); } @@ -112,7 +128,7 @@ *cond = NULL; /* Unlock the condition variable structure: */ - THR_UMTX_UNLOCK(curthread, &cv->c_lock); + THR_LOCK_RELEASE(curthread, &cv->c_lock); /* Free the cond lock structure: */ @@ -142,7 +158,7 @@ pthread_cond_t cv; cv = *(cci->cond); - THR_UMTX_LOCK(curthread, &cv->c_lock); + THR_LOCK_ACQUIRE(curthread, &cv->c_lock); if (cv->c_seqno != cci->seqno && cv->c_wakeups != 0) { if (cv->c_waiters > 0) { cv->c_seqno++; @@ -152,7 +168,7 @@ } else { cv->c_waiters--; } - THR_UMTX_UNLOCK(curthread, &cv->c_lock); + THR_LOCK_RELEASE(curthread, &cv->c_lock); _mutex_cv_lock(cci->mutex); } @@ -173,14 +189,14 @@ * perform the dynamic initialization: */ if (__predict_false(*cond == NULL && - (ret = cond_init(cond, NULL)) != 0)) + (ret = init_static(curthread, cond)) != 0)) return (ret); cv = *cond; - THR_UMTX_LOCK(curthread, &cv->c_lock); + THR_LOCK_ACQUIRE(curthread, &cv->c_lock); ret = _mutex_cv_unlock(mutex); if (ret) { - THR_UMTX_UNLOCK(curthread, &cv->c_lock); + THR_LOCK_RELEASE(curthread, &cv->c_lock); return (ret); } oldseq = seq = cv->c_seqno; @@ -192,18 +208,18 @@ do { if (cancel) { THR_CLEANUP_PUSH(curthread, cond_cancel_handler, &cci); - THR_UMTX_UNLOCK(curthread, &cv->c_lock); + THR_LOCK_RELEASE(curthread, &cv->c_lock); oldcancel = _thr_cancel_enter(curthread); ret = umtx_timedwait((struct umtx *)&cv->c_seqno, seq, abstime); _thr_cancel_leave(curthread, oldcancel); THR_CLEANUP_POP(curthread, 0); } else { - THR_UMTX_UNLOCK(curthread, &cv->c_lock); + THR_LOCK_RELEASE(curthread, &cv->c_lock); ret = umtx_timedwait((struct umtx *)&cv->c_seqno, seq, abstime); } - THR_UMTX_LOCK(curthread, &cv->c_lock); + THR_LOCK_ACQUIRE(curthread, &cv->c_lock); seq = cv->c_seqno; if (abstime != NULL && ret != 0) { if (ret == EINTR) @@ -222,7 +238,7 @@ } else { cv->c_waiters--; } - THR_UMTX_UNLOCK(curthread, &cv->c_lock); + THR_LOCK_RELEASE(curthread, &cv->c_lock); _mutex_cv_lock(mutex); return (ret); } @@ -280,12 +296,12 @@ * initialization. */ if (__predict_false(*cond == NULL && - (ret = cond_init(cond, NULL)) != 0)) + (ret = init_static(curthread, cond)) != 0)) return (ret); cv = *cond; /* Lock the condition variable structure. */ - THR_UMTX_LOCK(curthread, &cv->c_lock); + THR_LOCK_ACQUIRE(curthread, &cv->c_lock); if (cv->c_waiters) { if (!broadcast) { cv->c_wakeups++; @@ -299,7 +315,7 @@ umtx_wake((struct umtx *)&cv->c_seqno, INT_MAX); } } - THR_UMTX_UNLOCK(curthread, &cv->c_lock); + THR_LOCK_RELEASE(curthread, &cv->c_lock); return (ret); } ==== //depot/projects/davidxu_thread/src/lib/libthread/thread/thr_mutex.c#15 (text+ko) ==== @@ -84,7 +84,6 @@ static inline pthread_t mutex_queue_deq(pthread_mutex_t); static inline void mutex_queue_remove(pthread_mutex_t, pthread_t); static inline void mutex_queue_enq(pthread_mutex_t, pthread_t); -static void mutex_lock_backout(void *arg); __weak_reference(__pthread_mutex_init, pthread_mutex_init); __weak_reference(__pthread_mutex_lock, pthread_mutex_lock); @@ -182,8 +181,7 @@ pmutex->m_prio = -1; pmutex->m_saved_prio = 0; MUTEX_INIT_LINK(pmutex); - if (!atomic_cmpset_acq_ptr(mutex, NULL, pmutex)) - MUTEX_DESTROY(pmutex); + *mutex = pmutex; } else { /* Free the mutex lock structure: */ MUTEX_DESTROY(pmutex); @@ -195,11 +193,44 @@ return (ret); } +static int +init_static(struct pthread *thread, pthread_mutex_t *mutex) +{ + int ret; + + THR_LOCK_ACQUIRE(thread, &_mutex_static_lock); + + if (*mutex == NULL) + ret = mutex_init(mutex, NULL, 0); + else + ret = 0; + + THR_LOCK_RELEASE(thread, &_mutex_static_lock); + + return (ret); +} + +static int +init_static_private(struct pthread *thread, pthread_mutex_t *mutex) +{ + int ret; + + THR_LOCK_ACQUIRE(thread, &_mutex_static_lock); + + if (*mutex == NULL) + ret = mutex_init(mutex, NULL, 1); + else + ret = 0; + + THR_LOCK_RELEASE(thread, &_mutex_static_lock); + + return (ret); +} + int _pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *mutex_attr) { - *mutex = NULL; return mutex_init(mutex, mutex_attr, 1); } @@ -207,11 +238,9 @@ __pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *mutex_attr) { - *mutex = NULL; return mutex_init(mutex, mutex_attr, 0); } -/* used to reinitialize mutex after fork() */ int _mutex_reinit(pthread_mutex_t *mutex) { @@ -302,7 +331,7 @@ int ret = 0; THR_ASSERT((mutex != NULL) && (*mutex != NULL), - "Uninitialized mutex in pthread_mutex_trylock"); + "Uninitialized mutex in mutex_trylock_common"); /* Short cut for simple mutex. */ if ((*mutex)->m_protocol == PTHREAD_PRIO_NONE) { @@ -426,15 +455,12 @@ struct pthread *curthread = _get_curthread(); int ret = 0; - if (mutex == NULL) - ret = EINVAL; - /* * If the mutex is statically initialized, perform the dynamic * initialization: */ - else if ((*mutex != NULL) || - ((ret = mutex_init(mutex, NULL, 0)) == 0)) + if ((*mutex != NULL) || + ((ret = init_static(curthread, mutex)) == 0)) ret = mutex_trylock_common(curthread, mutex); return (ret); @@ -446,15 +472,12 @@ struct pthread *curthread = _get_curthread(); int ret = 0; - if (mutex == NULL) - ret = EINVAL; - /* * If the mutex is statically initialized, perform the dynamic * initialization marking the mutex private (delete safe): */ - else if ((*mutex != NULL) || - ((ret = mutex_init(mutex, NULL, 1)) == 0)) + if ((*mutex != NULL) || + ((ret = init_static_private(curthread, mutex)) == 0)) ret = mutex_trylock_common(curthread, mutex); return (ret); @@ -470,6 +493,10 @@ THR_ASSERT((m != NULL) && (*m != NULL), "Uninitialized mutex in mutex_lock_common"); + if (abstime != NULL && (abstime->tv_sec < 0 || abstime->tv_nsec < 0 || + abstime->tv_nsec >= 1000000000)) + return (EINVAL); + /* Short cut for simple mutex. */ if ((*m)->m_protocol == PTHREAD_PRIO_NONE) { @@ -510,10 +537,6 @@ /* Code for priority mutex */ - if (abstime != NULL && (abstime->tv_sec < 0 || abstime->tv_nsec < 0 || - abstime->tv_nsec >= 1000000000)) - return (EINVAL); - /* * Enter a loop waiting to become the mutex owner. We need a * loop in case the waiting thread is interrupted by a signal @@ -580,7 +603,6 @@ */ mutex_queue_enq(*m, curthread); curthread->data.mutex = *m; - curthread->sigbackout = mutex_lock_backout; if (curthread->active_priority > (*m)->m_prio) /* Adjust priorities: */ @@ -612,7 +634,6 @@ * thread is dequeued. */ curthread->data.mutex = NULL; - curthread->sigbackout = NULL; } break; @@ -668,7 +689,6 @@ */ mutex_queue_enq(*m, curthread); curthread->data.mutex = *m; - curthread->sigbackout = mutex_lock_backout; /* Clear any previous error: */ curthread->error = 0; @@ -700,7 +720,6 @@ * thread is dequeued. */ curthread->data.mutex = NULL; - curthread->sigbackout = NULL; /* * The threads priority may have changed while @@ -737,14 +756,12 @@ _thr_check_init(); curthread = _get_curthread(); - if (m == NULL) - ret = EINVAL; /* * If the mutex is statically initialized, perform the dynamic * initialization: */ - else if ((*m != NULL) || ((ret = mutex_init(m, NULL, 0)) == 0)) + if ((*m != NULL) || ((ret = init_static(curthread, m)) == 0)) ret = mutex_lock_common(curthread, m, NULL); return (ret); @@ -762,15 +779,12 @@ curthread = _get_curthread(); - if (m == NULL) - ret = EINVAL; - /* * If the mutex is statically initialized, perform the dynamic * initialization marking it private (delete safe): */ - else if ((*m != NULL) || - ((ret = mutex_init(m, NULL, 1)) == 0)) + if ((*m != NULL) || + ((ret = init_static_private(curthread, m)) == 0)) ret = mutex_lock_common(curthread, m, NULL); return (ret); @@ -786,14 +800,12 @@ _thr_check_init(); curthread = _get_curthread(); - if (m == NULL) - ret = EINVAL; /* * If the mutex is statically initialized, perform the dynamic * initialization: */ - else if ((*m != NULL) || ((ret = mutex_init(m, NULL, 0)) == 0)) + if ((*m != NULL) || ((ret = init_static(curthread, m)) == 0)) ret = mutex_lock_common(curthread, m, abs_timeout); return (ret); @@ -810,15 +822,12 @@ curthread = _get_curthread(); - if (m == NULL) - ret = EINVAL; - /* * If the mutex is statically initialized, perform the dynamic * initialization marking it private (delete safe): */ - else if ((*m != NULL) || - ((ret = mutex_init(m, NULL, 1)) == 0)) + if ((*m != NULL) || + ((ret = init_static_private(curthread, m)) == 0)) ret = mutex_lock_common(curthread, m, abs_timeout); return (ret); @@ -889,11 +898,18 @@ switch (m->m_type) { /* case PTHREAD_MUTEX_DEFAULT: */ case PTHREAD_MUTEX_ERRORCHECK: - /* - * POSIX specifies that mutexes should return EDEADLK if a - * recursive lock is detected. - */ - ret = EDEADLK; + if (abstime) { + clock_gettime(CLOCK_REALTIME, &ts1); + TIMESPEC_SUB(&ts2, abstime, &ts1); + __sys_nanosleep(&ts2, NULL); + ret = ETIMEDOUT; + } else { + /* + * POSIX specifies that mutexes should return EDEADLK if a + * recursive lock is detected. + */ + ret = EDEADLK; + } break; case PTHREAD_MUTEX_NORMAL: @@ -970,6 +986,11 @@ */ (*m)->m_count = 0; (*m)->m_owner = NULL; + /* + * XXX there should be a separated list + * for owned mutex, separated it from + * priority mutex list + */ /* Remove the mutex from the threads queue. */ MUTEX_ASSERT_IS_OWNED(*m); TAILQ_REMOVE(&curthread->mutexq, (*m), m_qe); @@ -1476,58 +1497,6 @@ } /* - * This is called by the current thread when it wants to back out of a - * mutex_lock in order to run a signal handler. - */ -static void -mutex_lock_backout(void *arg) -{ - struct pthread *curthread = (struct pthread *)arg; - struct pthread_mutex *m; - - if ((curthread->sflags & THR_FLAGS_IN_SYNCQ) != 0) { - /* - * Any other thread may clear the "in sync queue flag", - * but only the current thread can clear the pointer - * to the mutex. So if the flag is set, we can - * guarantee that the pointer to the mutex is valid. - * The only problem may be if the mutex is destroyed - * out from under us, but that should be considered - * an application bug. - */ - m = curthread->data.mutex; - - /* Lock the mutex structure: */ - THR_LOCK_ACQUIRE(curthread, &m->m_lock); - curthread->data.mutex = NULL; - - /* - * Check to make sure this thread doesn't already own - * the mutex. Since mutexes are unlocked with direct - * handoffs, it is possible the previous owner gave it - * to us after we checked the sync queue flag and before - * we locked the mutex structure. - */ - if (m->m_owner == curthread) { - THR_LOCK_RELEASE(curthread, &m->m_lock); - mutex_unlock_common(&m, /* add_reference */ 0); - } else { - /* - * Remove ourselves from the mutex queue and - * clear the pointer to the mutex. We may no - * longer be in the mutex queue, but the removal - * function will DTRT. - */ - mutex_queue_remove(m, curthread); - curthread->data.mutex = NULL; - THR_LOCK_RELEASE(curthread, &m->m_lock); - } - } - /* No need to call this again. */ - curthread->sigbackout = NULL; -} - -/* * Dequeue a waiting thread from the head of a mutex queue in descending * priority order. * ==== //depot/projects/davidxu_thread/src/lib/libthread/thread/thr_rwlock.c#4 (text+ko) ==== @@ -86,12 +86,7 @@ /* success */ prwlock->state = 0; prwlock->blocked_writers = 0; - if (!atomic_cmpset_acq_ptr(rwlock, NULL, prwlock)) { - /* we lost a race, it was already initialized */ - _pthread_cond_destroy(&prwlock->read_signal); - _pthread_mutex_destroy(&prwlock->lock); - free(prwlock); - } + *rwlock = prwlock; } } } @@ -123,6 +118,23 @@ return (ret); } +static int +init_static(struct pthread *thread, pthread_rwlock_t *rwlock) +{ + int ret; + + THR_LOCK_ACQUIRE(thread, &_rwlock_static_lock); + + if (*rwlock == NULL) + ret = rwlock_init(rwlock, NULL); + else + ret = 0; + + THR_LOCK_RELEASE(thread, &_rwlock_static_lock); + + return (ret); +} + int _pthread_rwlock_init (pthread_rwlock_t *rwlock, const pthread_rwlockattr_t *attr) { @@ -133,8 +145,8 @@ static int rwlock_rdlock_common (pthread_rwlock_t *rwlock, const struct timespec *abstime) { + struct pthread *curthread = _get_curthread(); pthread_rwlock_t prwlock; - struct pthread *curthread; int ret; if (rwlock == NULL) @@ -144,7 +156,7 @@ /* check for static initialization */ if (prwlock == NULL) { - if ((ret = rwlock_init(rwlock, NULL)) != 0) + if ((ret = init_static(curthread, rwlock)) != 0) return (ret); prwlock = *rwlock; @@ -225,7 +237,7 @@ int _pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock) { - struct pthread *curthread; + struct pthread *curthread = _get_curthread(); pthread_rwlock_t prwlock; int ret; @@ -236,7 +248,7 @@ /* check for static initialization */ if (prwlock == NULL) { - if ((ret = rwlock_init(rwlock, NULL)) != 0) + if ((ret = init_static(curthread, rwlock)) != 0) return (ret); prwlock = *rwlock; @@ -271,6 +283,7 @@ int _pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock) { + struct pthread *curthread = _get_curthread(); pthread_rwlock_t prwlock; int ret; @@ -281,7 +294,7 @@ /* check for static initialization */ if (prwlock == NULL) { - if ((ret = rwlock_init(rwlock, NULL)) != 0) + if ((ret = init_static(curthread, rwlock)) != 0) return (ret); prwlock = *rwlock; @@ -349,6 +362,7 @@ static int rwlock_wrlock_common (pthread_rwlock_t *rwlock, const struct timespec *abstime) { + struct pthread *curthread = _get_curthread(); pthread_rwlock_t prwlock; int ret; @@ -359,7 +373,7 @@ /* check for static initialization */ if (prwlock == NULL) { - if ((ret = rwlock_init(rwlock, NULL)) != 0) + if ((ret = init_static(curthread, rwlock)) != 0) return (ret); prwlock = *rwlock;
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