Revamp file locking
Get rid of the semaphore implementation, no need to carry both.
Add different locking modes (exclusive and readwrite) to enable
a wider range of testing. Also combine lockfile and lockfile_batch,
the latter is now a postfix option to the former.
So to enable readers-excluding-writers locking mode with a lock batch
count of 4, you would write:
lockfile=readwrite:4
instead.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/mutex.c b/mutex.c
index bcc37ae..e6fb3f0 100644
--- a/mutex.c
+++ b/mutex.c
@@ -7,6 +7,7 @@
#include <sys/mman.h>
#include "mutex.h"
+#include "arch/arch.h"
void fio_mutex_remove(struct fio_mutex *mutex)
{
@@ -76,8 +77,13 @@
void fio_mutex_down(struct fio_mutex *mutex)
{
pthread_mutex_lock(&mutex->lock);
- while (mutex->value == 0)
+
+ while (!mutex->value) {
+ mutex->waiters++;
pthread_cond_wait(&mutex->cond, &mutex->lock);
+ mutex->waiters--;
+ }
+
mutex->value--;
pthread_mutex_unlock(&mutex->lock);
}
@@ -85,7 +91,8 @@
void fio_mutex_up(struct fio_mutex *mutex)
{
pthread_mutex_lock(&mutex->lock);
- if (!mutex->value)
+ read_barrier();
+ if (!mutex->value && mutex->waiters)
pthread_cond_signal(&mutex->cond);
mutex->value++;
pthread_mutex_unlock(&mutex->lock);
@@ -94,8 +101,13 @@
void fio_mutex_down_write(struct fio_mutex *mutex)
{
pthread_mutex_lock(&mutex->lock);
- while (mutex->value != 0)
+
+ while (mutex->value != 0) {
+ mutex->waiters++;
pthread_cond_wait(&mutex->cond, &mutex->lock);
+ mutex->waiters--;
+ }
+
mutex->value--;
pthread_mutex_unlock(&mutex->lock);
}
@@ -103,8 +115,13 @@
void fio_mutex_down_read(struct fio_mutex *mutex)
{
pthread_mutex_lock(&mutex->lock);
- while (mutex->value < 0)
+
+ while (mutex->value < 0) {
+ mutex->waiters++;
pthread_cond_wait(&mutex->cond, &mutex->lock);
+ mutex->waiters--;
+ }
+
mutex->value++;
pthread_mutex_unlock(&mutex->lock);
}
@@ -113,7 +130,8 @@
{
pthread_mutex_lock(&mutex->lock);
mutex->value--;
- if (mutex->value >= 0)
+ read_barrier();
+ if (mutex->value >= 0 && mutex->waiters)
pthread_cond_signal(&mutex->cond);
pthread_mutex_unlock(&mutex->lock);
}
@@ -122,7 +140,8 @@
{
pthread_mutex_lock(&mutex->lock);
mutex->value++;
- if (mutex->value >= 0)
+ read_barrier();
+ if (mutex->value >= 0 && mutex->waiters)
pthread_cond_signal(&mutex->cond);
pthread_mutex_unlock(&mutex->lock);
}