Add the file sharing bits
When you use the same filename for several jobs now, they will share
the same file structure. Enable locking through two new options:
- lockfile. If set, a semaphore is associated with the file and it is
held from ->prep() to ->queue() has done its work.
- lockfile_batch. This controls how many IOs the job gets to do per
semaphore acqusition.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/HOWTO b/HOWTO
index d8c6b94..3e0a31b 100644
--- a/HOWTO
+++ b/HOWTO
@@ -219,6 +219,14 @@
opendir=str Tell fio to recursively add any file it can find in this
directory and down the file system tree.
+lockfile=bool If set, fio will lock a file internally before doing IO to it.
+ This makes it safe to share file descriptors across fio
+ jobs that run at the same time.
+
+lockfile_batch=int Acquiring a semaphore can be quite expensive, so
+ allow a process to complete this number of IOs before releasing
+ the semaphore again. Defaults to 1.
+
readwrite=str
rw=str Type of io pattern. Accepted values are:
diff --git a/filesetup.c b/filesetup.c
index e2c71cd..4e2a36c 100644
--- a/filesetup.c
+++ b/filesetup.c
@@ -228,8 +228,10 @@
int generic_open_file(struct thread_data *td, struct fio_file *f)
{
+ struct fio_file *__f;
int is_std = 0;
int flags = 0;
+ int from_hash = 0;
dprint(FD_FILE, "fd open %s\n", f->file_name);
@@ -265,8 +267,16 @@
if (is_std)
f->fd = dup(STDOUT_FILENO);
- else
- f->fd = open(f->file_name, flags, 0600);
+ else {
+ __f = lookup_file_hash(f->file_name);
+ if (__f) {
+ f->sem = __f->sem;
+ f->fd = dup(__f->fd);
+ f->references++;
+ from_hash = 1;
+ } else
+ f->fd = open(f->file_name, flags, 0600);
+ }
} else {
if (f->filetype == FIO_TYPE_CHAR && !read_only)
flags |= O_RDWR;
@@ -275,8 +285,16 @@
if (is_std)
f->fd = dup(STDIN_FILENO);
- else
- f->fd = open(f->file_name, flags);
+ else {
+ __f = lookup_file_hash(f->file_name);
+ if (__f) {
+ f->sem = __f->sem;
+ f->fd = dup(__f->fd);
+ f->references++;
+ from_hash = 1;
+ } else
+ f->fd = open(f->file_name, flags);
+ }
}
if (f->fd == -1) {
@@ -296,7 +314,17 @@
if (get_file_size(td, f))
goto err;
- add_file_hash(f);
+ if (!from_hash && f->fd != -1) {
+ if (add_file_hash(f)) {
+ int ret;
+
+ /*
+ * OK to ignore, we haven't done anything with it
+ */
+ ret = generic_close_file(td, f);
+ goto open_again;
+ }
+ }
return 0;
err:
@@ -613,6 +641,9 @@
get_file_type(f);
+ if (td->o.lockfile)
+ f->sem = fio_sem_init(1);
+
td->files_index++;
if (f->filetype == FIO_TYPE_FILE)
td->nr_normal_files++;
@@ -653,10 +684,29 @@
void lock_file(struct thread_data *td, struct fio_file *f)
{
+ if (f && f->sem) {
+ if (f->sem_owner == td && f->sem_batch--)
+ return;
+
+ fio_sem_down(f->sem);
+ f->sem_owner = td;
+ f->sem_batch = td->o.lockfile_batch;
+ }
}
void unlock_file(struct fio_file *f)
{
+ if (f && f->sem) {
+ int sem_val;
+
+ if (f->sem_batch)
+ return;
+
+ sem_getvalue(&f->sem->sem, &sem_val);
+ if (!sem_val)
+ f->sem_owner = NULL;
+ fio_sem_up(f->sem);
+ }
}
static int recurse_dir(struct thread_data *td, const char *dirname)
diff --git a/fio.h b/fio.h
index fe1a227..ffd3d7d 100644
--- a/fio.h
+++ b/fio.h
@@ -22,6 +22,7 @@
#include "arch/arch.h"
#include "os/os.h"
#include "mutex.h"
+#include "sem.h"
#include "log.h"
#include "debug.h"
@@ -310,6 +311,13 @@
unsigned long long last_pos;
/*
+ * if io is protected by a semaphore, this is set
+ */
+ struct fio_sem *sem;
+ void *sem_owner;
+ unsigned int sem_batch;
+
+ /*
* block map for random io
*/
unsigned long *file_map;
@@ -407,6 +415,8 @@
unsigned int nr_files;
unsigned int open_files;
+ unsigned int lockfile;
+ unsigned int lockfile_batch;
unsigned int odirect;
unsigned int invalidate_cache;
diff --git a/ioengines.c b/ioengines.c
index 5a2d6b9..bd2eb4a 100644
--- a/ioengines.c
+++ b/ioengines.c
@@ -359,5 +359,10 @@
*/
f->flags |= FIO_FILE_CLOSING;
+ if (f->sem_owner == td && f->sem_batch) {
+ f->sem_batch = 0;
+ unlock_file(f);
+ }
+
return put_file(td, f);
}
diff --git a/options.c b/options.c
index 1119a98..27b4fb6 100644
--- a/options.c
+++ b/options.c
@@ -385,6 +385,22 @@
.help = "File(s) to use for the workload",
},
{
+ .name = "lockfile",
+ .type = FIO_OPT_BOOL,
+ .off1 = td_var_offset(lockfile),
+ .help = "Lock file when doing IO to it",
+ .parent = "filename",
+ .def = "0",
+ },
+ {
+ .name = "lockfile_batch",
+ .type = FIO_OPT_INT,
+ .off1 = td_var_offset(lockfile_batch),
+ .help = "Number of IOs to allow per file lock",
+ .parent = "lockfile",
+ .def = "1",
+ },
+ {
.name = "opendir",
.type = FIO_OPT_STR_STORE,
.off1 = td_var_offset(opendir),