mutex: move pthread_cond_signal() outside of lock
[fio.git] / mutex.c
diff --git a/mutex.c b/mutex.c
index e33e7cc8f2611a42256e72a3bceddf9e7560b1ef..9ee3bd838cb1ae801b71f2604f94441264130343 100644 (file)
--- a/mutex.c
+++ b/mutex.c
 #include <stdlib.h>
 #include <fcntl.h>
 #include <time.h>
+#include <errno.h>
 #include <pthread.h>
 #include <sys/mman.h>
+#include <assert.h>
 
+#include "fio.h"
 #include "log.h"
 #include "mutex.h"
 #include "arch/arch.h"
 #include "os/os.h"
 #include "helpers.h"
+#include "fio_time.h"
+#include "gettime.h"
 
 void fio_mutex_remove(struct fio_mutex *mutex)
 {
-       close(mutex->mutex_fd);
+       assert(mutex->magic == FIO_MUTEX_MAGIC);
+       pthread_cond_destroy(&mutex->cond);
        munmap((void *) mutex, sizeof(*mutex));
 }
 
-struct fio_mutex *fio_mutex_init(int value)
+int __fio_mutex_init(struct fio_mutex *mutex, int value)
 {
-       char mutex_name[] = "/tmp/.fio_mutex.XXXXXX";
-       struct fio_mutex *mutex = NULL;
        pthread_mutexattr_t attr;
        pthread_condattr_t cond;
-       int fd, ret, mflag;
-
-       fd = mkstemp(mutex_name);
-       if (fd < 0) {
-               perror("open mutex");
-               return NULL;
-       }
-
-#ifdef FIO_HAVE_FALLOCATE
-       posix_fallocate(fd, 0, sizeof(struct fio_mutex));
-#endif
+       int ret;
 
-       if (ftruncate(fd, sizeof(struct fio_mutex)) < 0) {
-               perror("ftruncate mutex");
-               goto err;
-       }
-
-       mutex = (void *) mmap(NULL, sizeof(struct fio_mutex),
-                               PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
-       if (mutex == MAP_FAILED) {
-               perror("mmap mutex");
-               close(fd);
-               mutex = NULL;
-               goto err;
-       }
-
-       unlink(mutex_name);
-       mutex->mutex_fd = fd;
        mutex->value = value;
-
-       /*
-        * Not all platforms support process shared mutexes (FreeBSD)
-        */
-#ifdef FIO_HAVE_PSHARED_MUTEX
-       mflag = PTHREAD_PROCESS_SHARED;
-#else
-       mflag = PTHREAD_PROCESS_PRIVATE;
-#endif
+       mutex->magic = FIO_MUTEX_MAGIC;
 
        ret = pthread_mutexattr_init(&attr);
        if (ret) {
                log_err("pthread_mutexattr_init: %s\n", strerror(ret));
-               goto err;
+               return ret;
        }
+
+       /*
+        * Not all platforms support process shared mutexes (FreeBSD)
+        */
 #ifdef FIO_HAVE_PSHARED_MUTEX
-       ret = pthread_mutexattr_setpshared(&attr, mflag);
+       ret = pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
        if (ret) {
                log_err("pthread_mutexattr_setpshared: %s\n", strerror(ret));
-               goto err;
+               return ret;
        }
 #endif
 
        pthread_condattr_init(&cond);
 #ifdef FIO_HAVE_PSHARED_MUTEX
-       pthread_condattr_setpshared(&cond, mflag);
+       pthread_condattr_setpshared(&cond, PTHREAD_PROCESS_SHARED);
 #endif
        pthread_cond_init(&mutex->cond, &cond);
 
        ret = pthread_mutex_init(&mutex->lock, &attr);
        if (ret) {
                log_err("pthread_mutex_init: %s\n", strerror(ret));
-               goto err;
+               return ret;
        }
 
        pthread_condattr_destroy(&cond);
        pthread_mutexattr_destroy(&attr);
+       return 0;
+}
 
-       return mutex;
-err:
-       if (mutex)
-               fio_mutex_remove(mutex);
+struct fio_mutex *fio_mutex_init(int value)
+{
+       struct fio_mutex *mutex = NULL;
+
+       mutex = (void *) mmap(NULL, sizeof(struct fio_mutex),
+                               PROT_READ | PROT_WRITE,
+                               OS_MAP_ANON | MAP_SHARED, -1, 0);
+       if (mutex == MAP_FAILED) {
+               perror("mmap mutex");
+               return NULL;
+       }
+
+       if (!__fio_mutex_init(mutex, value))
+               return mutex;
 
-       unlink(mutex_name);
+       fio_mutex_remove(mutex);
        return NULL;
 }
 
+static int mutex_timed_out(struct timeval *t, unsigned int seconds)
+{
+       return mtime_since_now(t) >= seconds * 1000;
+}
+
 int fio_mutex_down_timeout(struct fio_mutex *mutex, unsigned int seconds)
 {
+       struct timeval tv_s;
        struct timespec t;
        int ret = 0;
 
-       clock_gettime(CLOCK_REALTIME, &t);
-       t.tv_sec += seconds;
+       assert(mutex->magic == FIO_MUTEX_MAGIC);
+
+       gettimeofday(&tv_s, NULL);
+       t.tv_sec = tv_s.tv_sec + seconds;
+       t.tv_nsec = tv_s.tv_usec * 1000;
 
        pthread_mutex_lock(&mutex->lock);
 
        while (!mutex->value && !ret) {
                mutex->waiters++;
+
+               /*
+                * Some platforms (FreeBSD 9?) seems to return timed out
+                * way too early, double check.
+                */
                ret = pthread_cond_timedwait(&mutex->cond, &mutex->lock, &t);
+               if (ret == ETIMEDOUT && !mutex_timed_out(&tv_s, seconds))
+                       ret = 0;
+
                mutex->waiters--;
        }
 
@@ -125,8 +128,26 @@ int fio_mutex_down_timeout(struct fio_mutex *mutex, unsigned int seconds)
        return ret;
 }
 
+int fio_mutex_down_trylock(struct fio_mutex *mutex)
+{
+       int ret = 1;
+
+       assert(mutex->magic == FIO_MUTEX_MAGIC);
+
+       pthread_mutex_lock(&mutex->lock);
+       if (mutex->value) {
+               mutex->value--;
+               ret = 0;
+       }
+       pthread_mutex_unlock(&mutex->lock);
+
+       return ret;
+}
+
 void fio_mutex_down(struct fio_mutex *mutex)
 {
+       assert(mutex->magic == FIO_MUTEX_MAGIC);
+
        pthread_mutex_lock(&mutex->lock);
 
        while (!mutex->value) {
@@ -141,58 +162,91 @@ void fio_mutex_down(struct fio_mutex *mutex)
 
 void fio_mutex_up(struct fio_mutex *mutex)
 {
+       int do_wake = 0;
+
+       assert(mutex->magic == FIO_MUTEX_MAGIC);
+
        pthread_mutex_lock(&mutex->lock);
        read_barrier();
        if (!mutex->value && mutex->waiters)
-               pthread_cond_signal(&mutex->cond);
+               do_wake = 1;
        mutex->value++;
        pthread_mutex_unlock(&mutex->lock);
+
+       if (do_wake)
+               pthread_cond_signal(&mutex->cond);
 }
 
-void fio_mutex_down_write(struct fio_mutex *mutex)
+void fio_rwlock_write(struct fio_rwlock *lock)
 {
-       pthread_mutex_lock(&mutex->lock);
-
-       while (mutex->value != 0) {
-               mutex->waiters++;
-               pthread_cond_wait(&mutex->cond, &mutex->lock);
-               mutex->waiters--;
-       }
-
-       mutex->value--;
-       pthread_mutex_unlock(&mutex->lock);
+       assert(lock->magic == FIO_RWLOCK_MAGIC);
+       pthread_rwlock_wrlock(&lock->lock);
 }
 
-void fio_mutex_down_read(struct fio_mutex *mutex)
+void fio_rwlock_read(struct fio_rwlock *lock)
 {
-       pthread_mutex_lock(&mutex->lock);
-
-       while (mutex->value < 0) {
-               mutex->waiters++;
-               pthread_cond_wait(&mutex->cond, &mutex->lock);
-               mutex->waiters--;
-       }
+       assert(lock->magic == FIO_RWLOCK_MAGIC);
+       pthread_rwlock_rdlock(&lock->lock);
+}
 
-       mutex->value++;
-       pthread_mutex_unlock(&mutex->lock);
+void fio_rwlock_unlock(struct fio_rwlock *lock)
+{
+       assert(lock->magic == FIO_RWLOCK_MAGIC);
+       pthread_rwlock_unlock(&lock->lock);
 }
 
-void fio_mutex_up_read(struct fio_mutex *mutex)
+void fio_rwlock_remove(struct fio_rwlock *lock)
 {
-       pthread_mutex_lock(&mutex->lock);
-       mutex->value--;
-       read_barrier();
-       if (mutex->value >= 0 && mutex->waiters)
-               pthread_cond_signal(&mutex->cond);
-       pthread_mutex_unlock(&mutex->lock);
+       assert(lock->magic == FIO_RWLOCK_MAGIC);
+       munmap((void *) lock, sizeof(*lock));
 }
 
-void fio_mutex_up_write(struct fio_mutex *mutex)
+struct fio_rwlock *fio_rwlock_init(void)
 {
-       pthread_mutex_lock(&mutex->lock);
-       mutex->value++;
-       read_barrier();
-       if (mutex->value >= 0 && mutex->waiters)
-               pthread_cond_signal(&mutex->cond);
-       pthread_mutex_unlock(&mutex->lock);
+       struct fio_rwlock *lock;
+       pthread_rwlockattr_t attr;
+       int ret;
+
+       lock = (void *) mmap(NULL, sizeof(struct fio_rwlock),
+                               PROT_READ | PROT_WRITE,
+                               OS_MAP_ANON | MAP_SHARED, -1, 0);
+       if (lock == MAP_FAILED) {
+               perror("mmap rwlock");
+               lock = NULL;
+               goto err;
+       }
+
+       lock->magic = FIO_RWLOCK_MAGIC;
+
+       ret = pthread_rwlockattr_init(&attr);
+       if (ret) {
+               log_err("pthread_rwlockattr_init: %s\n", strerror(ret));
+               goto err;
+       }
+#ifdef FIO_HAVE_PSHARED_MUTEX
+       ret = pthread_rwlockattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
+       if (ret) {
+               log_err("pthread_rwlockattr_setpshared: %s\n", strerror(ret));
+               goto destroy_attr;
+       }
+
+       ret = pthread_rwlock_init(&lock->lock, &attr);
+#else
+       ret = pthread_rwlock_init(&lock->lock, NULL);
+#endif
+
+       if (ret) {
+               log_err("pthread_rwlock_init: %s\n", strerror(ret));
+               goto destroy_attr;
+       }
+
+       pthread_rwlockattr_destroy(&attr);
+
+       return lock;
+destroy_attr:
+       pthread_rwlockattr_destroy(&attr);
+err:
+       if (lock)
+               fio_rwlock_remove(lock);
+       return NULL;
 }