blob: c1aff5ba97a0843b151c65f05fff55b3575d387a [file] [log] [blame]
/*
* mmap engine
*
* IO engine that reads/writes from files by doing memcpy to/from
* a memory mapped region of the file.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/mman.h>
#include "../fio.h"
#include "../verify.h"
/*
* Limits us to 1GB of mapped files in total
*/
#define MMAP_TOTAL_SZ (1 * 1024 * 1024 * 1024UL)
static unsigned long mmap_map_size;
static unsigned long mmap_map_mask;
static int fio_mmap_file(struct thread_data *td, struct fio_file *f,
size_t length, off_t off)
{
int flags = 0;
if (td_rw(td))
flags = PROT_READ | PROT_WRITE;
else if (td_write(td)) {
flags = PROT_WRITE;
if (td->o.verify != VERIFY_NONE)
flags |= PROT_READ;
} else
flags = PROT_READ;
f->mmap_ptr = mmap(NULL, length, flags, MAP_SHARED, f->fd, off);
if (f->mmap_ptr == MAP_FAILED) {
f->mmap_ptr = NULL;
td_verror(td, errno, "mmap");
goto err;
}
if (!td_random(td)) {
if (posix_madvise(f->mmap_ptr, length, POSIX_MADV_SEQUENTIAL) < 0) {
td_verror(td, errno, "madvise");
goto err;
}
} else {
if (posix_madvise(f->mmap_ptr, length, POSIX_MADV_RANDOM) < 0) {
td_verror(td, errno, "madvise");
goto err;
}
}
err:
if (td->error && f->mmap_ptr)
munmap(f->mmap_ptr, length);
return td->error;
}
/*
* Just mmap an appropriate portion, we cannot mmap the full extent
*/
static int fio_mmapio_prep_limited(struct thread_data *td, struct io_u *io_u)
{
struct fio_file *f = io_u->file;
if (io_u->buflen > mmap_map_size) {
log_err("fio: bs too big for mmap engine\n");
return EIO;
}
f->mmap_sz = mmap_map_size;
if (f->mmap_sz > f->io_size)
f->mmap_sz = f->io_size;
f->mmap_off = io_u->offset;
return fio_mmap_file(td, f, f->mmap_sz, f->mmap_off);
}
/*
* Attempt to mmap the entire file
*/
static int fio_mmapio_prep_full(struct thread_data *td, struct io_u *io_u)
{
struct fio_file *f = io_u->file;
int ret;
if (fio_file_partial_mmap(f))
return EINVAL;
f->mmap_sz = f->io_size;
f->mmap_off = 0;
ret = fio_mmap_file(td, f, f->mmap_sz, f->mmap_off);
if (ret)
fio_file_set_partial_mmap(f);
return ret;
}
static int fio_mmapio_prep(struct thread_data *td, struct io_u *io_u)
{
struct fio_file *f = io_u->file;
int ret;
/*
* It fits within existing mapping, use it
*/
if (io_u->offset >= f->mmap_off &&
io_u->offset + io_u->buflen < f->mmap_off + f->mmap_sz)
goto done;
/*
* unmap any existing mapping
*/
if (f->mmap_ptr) {
if (munmap(f->mmap_ptr, f->mmap_sz) < 0)
return errno;
f->mmap_ptr = NULL;
}
if (fio_mmapio_prep_full(td, io_u)) {
td_clear_error(td);
ret = fio_mmapio_prep_limited(td, io_u);
if (ret)
return ret;
}
done:
io_u->mmap_data = f->mmap_ptr + io_u->offset - f->mmap_off -
f->file_offset;
return 0;
}
static int fio_mmapio_queue(struct thread_data *td, struct io_u *io_u)
{
struct fio_file *f = io_u->file;
fio_ro_check(td, io_u);
if (io_u->ddir == DDIR_READ)
memcpy(io_u->xfer_buf, io_u->mmap_data, io_u->xfer_buflen);
else if (io_u->ddir == DDIR_WRITE)
memcpy(io_u->mmap_data, io_u->xfer_buf, io_u->xfer_buflen);
else if (ddir_sync(io_u->ddir)) {
if (msync(f->mmap_ptr, f->mmap_sz, MS_SYNC)) {
io_u->error = errno;
td_verror(td, io_u->error, "msync");
}
} else if (io_u->ddir == DDIR_TRIM) {
int ret = do_io_u_trim(td, io_u);
if (!ret)
td_verror(td, io_u->error, "trim");
}
/*
* not really direct, but should drop the pages from the cache
*/
if (td->o.odirect && ddir_rw(io_u->ddir)) {
if (msync(io_u->mmap_data, io_u->xfer_buflen, MS_SYNC) < 0) {
io_u->error = errno;
td_verror(td, io_u->error, "msync");
}
if (posix_madvise(io_u->mmap_data, io_u->xfer_buflen, POSIX_MADV_DONTNEED) < 0) {
io_u->error = errno;
td_verror(td, io_u->error, "madvise");
}
}
return FIO_Q_COMPLETED;
}
static int fio_mmapio_init(struct thread_data *td)
{
struct thread_options *o = &td->o;
unsigned long shift, mask;
if ((td->o.rw_min_bs & page_mask) &&
(o->odirect || o->fsync_blocks || o->fdatasync_blocks)) {
log_err("fio: mmap options dictate a minimum block size of "
"%lu bytes\n", page_size);
return 1;
}
mmap_map_size = MMAP_TOTAL_SZ / td->o.nr_files;
mask = mmap_map_size;
shift = 0;
do {
mask >>= 1;
if (!mask)
break;
shift++;
} while (1);
mmap_map_mask = 1UL << shift;
return 0;
}
static struct ioengine_ops ioengine = {
.name = "mmap",
.version = FIO_IOOPS_VERSION,
.init = fio_mmapio_init,
.prep = fio_mmapio_prep,
.queue = fio_mmapio_queue,
.open_file = generic_open_file,
.close_file = generic_close_file,
.get_file_size = generic_get_file_size,
.flags = FIO_SYNCIO | FIO_NOEXTEND,
};
static void fio_init fio_mmapio_register(void)
{
register_ioengine(&ioengine);
}
static void fio_exit fio_mmapio_unregister(void)
{
unregister_ioengine(&ioengine);
}