engines/libaio.c - platform/external/fio - Git at Google

 /*
  * libaio engine
  *
  * IO engine using the Linux native aio interface.
  *
  */
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <errno.h>
 #include <assert.h>
 #include <libaio.h>

 #include "../fio.h"

 static int fio_libaio_commit(struct thread_data *td);

 struct libaio_data {
 	io_context_t aio_ctx;
 	struct io_event *aio_events;
 	struct iocb **iocbs;
 	struct io_u **io_us;

 	/*
 	 * Basic ring buffer. 'head' is incremented in _queue(), and
 	 * 'tail' is incremented in _commit(). We keep 'queued' so
 	 * that we know if the ring is full or empty, when
 	 * 'head' == 'tail'. 'entries' is the ring size, and
 	 * 'is_pow2' is just an optimization to use AND instead of
 	 * modulus to get the remainder on ring increment.
 	 */
 	int is_pow2;
 	unsigned int entries;
 	unsigned int queued;
 	unsigned int head;
 	unsigned int tail;
 };

 struct libaio_options {
 	struct thread_data *td;
 	unsigned int userspace_reap;
 };

 static struct fio_option options[] = {
 	{
 		.name	= "userspace_reap",
 		.lname	= "Libaio userspace reaping",
 		.type	= FIO_OPT_STR_SET,
 		.off1	= offsetof(struct libaio_options, userspace_reap),
 		.help	= "Use alternative user-space reap implementation",
 		.category = FIO_OPT_C_ENGINE,
 		.group	= FIO_OPT_G_LIBAIO,
 	},
 	{
 		.name	= NULL,
 	},
 };

 static inline void ring_inc(struct libaio_data *ld, unsigned int *val,
 			    unsigned int add)
 {
 	if (ld->is_pow2)
 		*val = (*val + add) & (ld->entries - 1);
 	else
 		*val = (*val + add) % ld->entries;
 }

 static int fio_libaio_prep(struct thread_data fio_unused *td, struct io_u *io_u)
 {
 	struct fio_file *f = io_u->file;

 	if (io_u->ddir == DDIR_READ)
 		io_prep_pread(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
 	else if (io_u->ddir == DDIR_WRITE)
 		io_prep_pwrite(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
 	else if (ddir_sync(io_u->ddir))
 		io_prep_fsync(&io_u->iocb, f->fd);

 	return 0;
 }

 static struct io_u *fio_libaio_event(struct thread_data *td, int event)
 {
 	struct libaio_data *ld = td->io_ops->data;
 	struct io_event *ev;
 	struct io_u *io_u;

 	ev = ld->aio_events + event;
 	io_u = container_of(ev->obj, struct io_u, iocb);

 	if (ev->res != io_u->xfer_buflen) {
 		if (ev->res > io_u->xfer_buflen)
 			io_u->error = -ev->res;
 		else
 			io_u->resid = io_u->xfer_buflen - ev->res;
 	} else
 		io_u->error = 0;

 	return io_u;
 }

 struct aio_ring {
 	unsigned id;		 /** kernel internal index number */
 	unsigned nr;		 /** number of io_events */
 	unsigned head;
 	unsigned tail;

 	unsigned magic;
 	unsigned compat_features;
 	unsigned incompat_features;
 	unsigned header_length;	/** size of aio_ring */

 	struct io_event events[0];
 };

 #define AIO_RING_MAGIC	0xa10a10a1

 static int user_io_getevents(io_context_t aio_ctx, unsigned int max,
 			     struct io_event *events)
 {
 	long i = 0;
 	unsigned head;
 	struct aio_ring *ring = (struct aio_ring*) aio_ctx;

 	while (i < max) {
 		head = ring->head;

 		if (head == ring->tail) {
 			/* There are no more completions */
 			break;
 		} else {
 			/* There is another completion to reap */
 			events[i] = ring->events[head];
 			read_barrier();
 			ring->head = (head + 1) % ring->nr;
 			i++;
 		}
 	}

 	return i;
 }

 static int fio_libaio_getevents(struct thread_data *td, unsigned int min,
 				unsigned int max, const struct timespec *t)
 {
 	struct libaio_data *ld = td->io_ops->data;
 	struct libaio_options *o = td->eo;
 	unsigned actual_min = td->o.iodepth_batch_complete == 0 ? 0 : min;
 	struct timespec __lt, *lt = NULL;
 	int r, events = 0;

 	if (t) {
 		__lt = *t;
 		lt = &__lt;
 	}

 	do {
 		if (o->userspace_reap == 1
 		    && actual_min == 0
 		    && ((struct aio_ring *)(ld->aio_ctx))->magic
 				== AIO_RING_MAGIC) {
 			r = user_io_getevents(ld->aio_ctx, max,
 				ld->aio_events + events);
 		} else {
 			r = io_getevents(ld->aio_ctx, actual_min,
 				max, ld->aio_events + events, lt);
 		}
 		if (r > 0)
 			events += r;
 		else if ((min && r == 0) || r == -EAGAIN) {
 			fio_libaio_commit(td);
 			usleep(100);
 		} else if (r != -EINTR)
 			break;
 	} while (events < min);

 	return r < 0 ? r : events;
 }

 static int fio_libaio_queue(struct thread_data *td, struct io_u *io_u)
 {
 	struct libaio_data *ld = td->io_ops->data;

 	fio_ro_check(td, io_u);

 	if (ld->queued == td->o.iodepth)
 		return FIO_Q_BUSY;

 	/*
 	 * fsync is tricky, since it can fail and we need to do it
 	 * serialized with other io. the reason is that linux doesn't
 	 * support aio fsync yet. So return busy for the case where we
 	 * have pending io, to let fio complete those first.
 	 */
 	if (ddir_sync(io_u->ddir)) {
 		if (ld->queued)
 			return FIO_Q_BUSY;

 		do_io_u_sync(td, io_u);
 		return FIO_Q_COMPLETED;
 	}

 	if (io_u->ddir == DDIR_TRIM) {
 		if (ld->queued)
 			return FIO_Q_BUSY;

 		do_io_u_trim(td, io_u);
 		return FIO_Q_COMPLETED;
 	}

 	ld->iocbs[ld->head] = &io_u->iocb;
 	ld->io_us[ld->head] = io_u;
 	ring_inc(ld, &ld->head, 1);
 	ld->queued++;
 	return FIO_Q_QUEUED;
 }

 static void fio_libaio_queued(struct thread_data *td, struct io_u **io_us,
 			      unsigned int nr)
 {
 	struct timeval now;
 	unsigned int i;

 	if (!fio_fill_issue_time(td))
 		return;

 	fio_gettime(&now, NULL);

 	for (i = 0; i < nr; i++) {
 		struct io_u *io_u = io_us[i];

 		memcpy(&io_u->issue_time, &now, sizeof(now));
 		io_u_queued(td, io_u);
 	}
 }

 static int fio_libaio_commit(struct thread_data *td)
 {
 	struct libaio_data *ld = td->io_ops->data;
 	struct iocb **iocbs;
 	struct io_u **io_us;
 	struct timeval tv;
 	int ret, wait_start = 0;

 	if (!ld->queued)
 		return 0;

 	do {
 		long nr = ld->queued;

 		nr = min((unsigned int) nr, ld->entries - ld->tail);
 		io_us = ld->io_us + ld->tail;
 		iocbs = ld->iocbs + ld->tail;

 		ret = io_submit(ld->aio_ctx, nr, iocbs);
 		if (ret > 0) {
 			fio_libaio_queued(td, io_us, ret);
 			io_u_mark_submit(td, ret);

 			ld->queued -= ret;
 			ring_inc(ld, &ld->tail, ret);
 			ret = 0;
 			wait_start = 0;
 		} else if (ret == -EINTR || !ret) {
 			if (!ret)
 				io_u_mark_submit(td, ret);
 			wait_start = 0;
 			continue;
 		} else if (ret == -EAGAIN) {
 			/*
 			 * If we get EAGAIN, we should break out without
 			 * error and let the upper layer reap some
 			 * events for us. If we have no queued IO, we
 			 * must loop here. If we loop for more than 30s,
 			 * just error out, something must be buggy in the
 			 * IO path.
 			 */
 			if (ld->queued) {
 				ret = 0;
 				break;
 			}
 			if (!wait_start) {
 				fio_gettime(&tv, NULL);
 				wait_start = 0;
 			} else if (mtime_since_now(&tv) > 30000) {
 				log_err("fio: aio appears to be stalled, giving up\n");
 				break;
 			}
 			usleep(1);
 			continue;
 		} else if (ret == -ENOMEM) {
 			/*
 			 * If we get -ENOMEM, reap events if we can. If
 			 * we cannot, treat it as a fatal event since there's
 			 * nothing we can do about it.
 			 */
 			if (ld->queued)
 				ret = 0;
 			break;
 		} else
 			break;
 	} while (ld->queued);

 	return ret;
 }

 static int fio_libaio_cancel(struct thread_data *td, struct io_u *io_u)
 {
 	struct libaio_data *ld = td->io_ops->data;

 	return io_cancel(ld->aio_ctx, &io_u->iocb, ld->aio_events);
 }

 static void fio_libaio_cleanup(struct thread_data *td)
 {
 	struct libaio_data *ld = td->io_ops->data;

 	if (ld) {
 		io_destroy(ld->aio_ctx);
 		free(ld->aio_events);
 		free(ld->iocbs);
 		free(ld->io_us);
 		free(ld);
 	}
 }

 static int fio_libaio_init(struct thread_data *td)
 {
 	struct libaio_options *o = td->eo;
 	struct libaio_data *ld;
 	int err = 0;

 	ld = calloc(1, sizeof(*ld));

 	/*
 	 * First try passing in 0 for queue depth, since we don't
 	 * care about the user ring. If that fails, the kernel is too old
 	 * and we need the right depth.
 	 */
 	if (!o->userspace_reap)
 		err = io_queue_init(INT_MAX, &ld->aio_ctx);
 	if (o->userspace_reap || err == -EINVAL)
 		err = io_queue_init(td->o.iodepth, &ld->aio_ctx);
 	if (err) {
 		td_verror(td, -err, "io_queue_init");
 		log_err("fio: check /proc/sys/fs/aio-max-nr\n");
 		free(ld);
 		return 1;
 	}

 	ld->entries = td->o.iodepth;
 	ld->is_pow2 = is_power_of_2(ld->entries);
 	ld->aio_events = calloc(ld->entries, sizeof(struct io_event));
 	ld->iocbs = calloc(ld->entries, sizeof(struct iocb *));
 	ld->io_us = calloc(ld->entries, sizeof(struct io_u *));

 	td->io_ops->data = ld;
 	return 0;
 }

 static struct ioengine_ops ioengine = {
 	.name			= "libaio",
 	.version		= FIO_IOOPS_VERSION,
 	.init			= fio_libaio_init,
 	.prep			= fio_libaio_prep,
 	.queue			= fio_libaio_queue,
 	.commit			= fio_libaio_commit,
 	.cancel			= fio_libaio_cancel,
 	.getevents		= fio_libaio_getevents,
 	.event			= fio_libaio_event,
 	.cleanup		= fio_libaio_cleanup,
 	.open_file		= generic_open_file,
 	.close_file		= generic_close_file,
 	.get_file_size		= generic_get_file_size,
 	.options		= options,
 	.option_struct_size	= sizeof(struct libaio_options),
 };

 static void fio_init fio_libaio_register(void)
 {
 	register_ioengine(&ioengine);
 }

 static void fio_exit fio_libaio_unregister(void)
 {
 	unregister_ioengine(&ioengine);
 }
	/*
	* libaio engine
	*
	* IO engine using the Linux native aio interface.
	*
	*/
	#include <stdio.h>
	#include <stdlib.h>
	#include <unistd.h>
	#include <errno.h>
	#include <assert.h>
	#include <libaio.h>

	#include "../fio.h"

	static int fio_libaio_commit(struct thread_data *td);

	struct libaio_data {
	io_context_t aio_ctx;
	struct io_event *aio_events;
	struct iocb **iocbs;
	struct io_u **io_us;

	/*
	* Basic ring buffer. 'head' is incremented in _queue(), and
	* 'tail' is incremented in _commit(). We keep 'queued' so
	* that we know if the ring is full or empty, when
	* 'head' == 'tail'. 'entries' is the ring size, and
	* 'is_pow2' is just an optimization to use AND instead of
	* modulus to get the remainder on ring increment.
	*/
	int is_pow2;
	unsigned int entries;
	unsigned int queued;
	unsigned int head;
	unsigned int tail;
	};

	struct libaio_options {
	struct thread_data *td;
	unsigned int userspace_reap;
	};

	static struct fio_option options[] = {
	{
	.name = "userspace_reap",
	.lname = "Libaio userspace reaping",
	.type = FIO_OPT_STR_SET,
	.off1 = offsetof(struct libaio_options, userspace_reap),
	.help = "Use alternative user-space reap implementation",
	.category = FIO_OPT_C_ENGINE,
	.group = FIO_OPT_G_LIBAIO,
	},
	{
	.name = NULL,
	},
	};

	static inline void ring_inc(struct libaio_data ld, unsigned int val,
	unsigned int add)
	{
	if (ld->is_pow2)
	val = (val + add) & (ld->entries - 1);
	else
	val = (val + add) % ld->entries;
	}

	static int fio_libaio_prep(struct thread_data fio_unused td, struct io_u io_u)
	{
	struct fio_file *f = io_u->file;

	if (io_u->ddir == DDIR_READ)
	io_prep_pread(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
	else if (io_u->ddir == DDIR_WRITE)
	io_prep_pwrite(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
	else if (ddir_sync(io_u->ddir))
	io_prep_fsync(&io_u->iocb, f->fd);

	return 0;
	}

	static struct io_u fio_libaio_event(struct thread_data td, int event)
	{
	struct libaio_data *ld = td->io_ops->data;
	struct io_event *ev;
	struct io_u *io_u;

	ev = ld->aio_events + event;
	io_u = container_of(ev->obj, struct io_u, iocb);

	if (ev->res != io_u->xfer_buflen) {
	if (ev->res > io_u->xfer_buflen)
	io_u->error = -ev->res;
	else
	io_u->resid = io_u->xfer_buflen - ev->res;
	} else
	io_u->error = 0;

	return io_u;
	}

	struct aio_ring {
	unsigned id; /** kernel internal index number */
	unsigned nr; /** number of io_events */
	unsigned head;
	unsigned tail;

	unsigned magic;
	unsigned compat_features;
	unsigned incompat_features;
	unsigned header_length; /** size of aio_ring */

	struct io_event events[0];
	};

	#define AIO_RING_MAGIC 0xa10a10a1

	static int user_io_getevents(io_context_t aio_ctx, unsigned int max,
	struct io_event *events)
	{
	long i = 0;
	unsigned head;
	struct aio_ring ring = (struct aio_ring) aio_ctx;

	while (i < max) {
	head = ring->head;

	if (head == ring->tail) {
	/* There are no more completions */
	break;
	} else {
	/* There is another completion to reap */
	events[i] = ring->events[head];
	read_barrier();
	ring->head = (head + 1) % ring->nr;
	i++;
	}
	}

	return i;
	}

	static int fio_libaio_getevents(struct thread_data *td, unsigned int min,
	unsigned int max, const struct timespec *t)
	{
	struct libaio_data *ld = td->io_ops->data;
	struct libaio_options *o = td->eo;
	unsigned actual_min = td->o.iodepth_batch_complete == 0 ? 0 : min;
	struct timespec __lt, *lt = NULL;
	int r, events = 0;

	if (t) {
	__lt = *t;
	lt = &__lt;
	}

	do {
	if (o->userspace_reap == 1
	&& actual_min == 0
	&& ((struct aio_ring *)(ld->aio_ctx))->magic
	== AIO_RING_MAGIC) {
	r = user_io_getevents(ld->aio_ctx, max,
	ld->aio_events + events);
	} else {
	r = io_getevents(ld->aio_ctx, actual_min,
	max, ld->aio_events + events, lt);
	}
	if (r > 0)
	events += r;
	else if ((min && r == 0) \|\| r == -EAGAIN) {
	fio_libaio_commit(td);
	usleep(100);
	} else if (r != -EINTR)
	break;
	} while (events < min);

	return r < 0 ? r : events;
	}

	static int fio_libaio_queue(struct thread_data td, struct io_u io_u)
	{
	struct libaio_data *ld = td->io_ops->data;

	fio_ro_check(td, io_u);

	if (ld->queued == td->o.iodepth)
	return FIO_Q_BUSY;

	/*
	* fsync is tricky, since it can fail and we need to do it
	* serialized with other io. the reason is that linux doesn't
	* support aio fsync yet. So return busy for the case where we
	* have pending io, to let fio complete those first.
	*/
	if (ddir_sync(io_u->ddir)) {
	if (ld->queued)
	return FIO_Q_BUSY;

	do_io_u_sync(td, io_u);
	return FIO_Q_COMPLETED;
	}

	if (io_u->ddir == DDIR_TRIM) {
	if (ld->queued)
	return FIO_Q_BUSY;

	do_io_u_trim(td, io_u);
	return FIO_Q_COMPLETED;
	}

	ld->iocbs[ld->head] = &io_u->iocb;
	ld->io_us[ld->head] = io_u;
	ring_inc(ld, &ld->head, 1);
	ld->queued++;
	return FIO_Q_QUEUED;
	}

	static void fio_libaio_queued(struct thread_data td, struct io_u *io_us,
	unsigned int nr)
	{
	struct timeval now;
	unsigned int i;

	if (!fio_fill_issue_time(td))
	return;

	fio_gettime(&now, NULL);

	for (i = 0; i < nr; i++) {
	struct io_u *io_u = io_us[i];

	memcpy(&io_u->issue_time, &now, sizeof(now));
	io_u_queued(td, io_u);
	}
	}

	static int fio_libaio_commit(struct thread_data *td)
	{
	struct libaio_data *ld = td->io_ops->data;
	struct iocb **iocbs;
	struct io_u **io_us;
	struct timeval tv;
	int ret, wait_start = 0;

	if (!ld->queued)
	return 0;

	do {
	long nr = ld->queued;

	nr = min((unsigned int) nr, ld->entries - ld->tail);
	io_us = ld->io_us + ld->tail;
	iocbs = ld->iocbs + ld->tail;

	ret = io_submit(ld->aio_ctx, nr, iocbs);
	if (ret > 0) {
	fio_libaio_queued(td, io_us, ret);
	io_u_mark_submit(td, ret);

	ld->queued -= ret;
	ring_inc(ld, &ld->tail, ret);
	ret = 0;
	wait_start = 0;
	} else if (ret == -EINTR \|\| !ret) {
	if (!ret)
	io_u_mark_submit(td, ret);
	wait_start = 0;
	continue;
	} else if (ret == -EAGAIN) {
	/*
	* If we get EAGAIN, we should break out without
	* error and let the upper layer reap some
	* events for us. If we have no queued IO, we
	* must loop here. If we loop for more than 30s,
	* just error out, something must be buggy in the
	* IO path.
	*/
	if (ld->queued) {
	ret = 0;
	break;
	}
	if (!wait_start) {
	fio_gettime(&tv, NULL);
	wait_start = 0;
	} else if (mtime_since_now(&tv) > 30000) {
	log_err("fio: aio appears to be stalled, giving up\n");
	break;
	}
	usleep(1);
	continue;
	} else if (ret == -ENOMEM) {
	/*
	* If we get -ENOMEM, reap events if we can. If
	* we cannot, treat it as a fatal event since there's
	* nothing we can do about it.
	*/
	if (ld->queued)
	ret = 0;
	break;
	} else
	break;
	} while (ld->queued);

	return ret;
	}

	static int fio_libaio_cancel(struct thread_data td, struct io_u io_u)
	{
	struct libaio_data *ld = td->io_ops->data;

	return io_cancel(ld->aio_ctx, &io_u->iocb, ld->aio_events);
	}

	static void fio_libaio_cleanup(struct thread_data *td)
	{
	struct libaio_data *ld = td->io_ops->data;

	if (ld) {
	io_destroy(ld->aio_ctx);
	free(ld->aio_events);
	free(ld->iocbs);
	free(ld->io_us);
	free(ld);
	}
	}

	static int fio_libaio_init(struct thread_data *td)
	{
	struct libaio_options *o = td->eo;
	struct libaio_data *ld;
	int err = 0;

	ld = calloc(1, sizeof(*ld));

	/*
	* First try passing in 0 for queue depth, since we don't
	* care about the user ring. If that fails, the kernel is too old
	* and we need the right depth.
	*/
	if (!o->userspace_reap)
	err = io_queue_init(INT_MAX, &ld->aio_ctx);
	if (o->userspace_reap \|\| err == -EINVAL)
	err = io_queue_init(td->o.iodepth, &ld->aio_ctx);
	if (err) {
	td_verror(td, -err, "io_queue_init");
	log_err("fio: check /proc/sys/fs/aio-max-nr\n");
	free(ld);
	return 1;
	}

	ld->entries = td->o.iodepth;
	ld->is_pow2 = is_power_of_2(ld->entries);
	ld->aio_events = calloc(ld->entries, sizeof(struct io_event));
	ld->iocbs = calloc(ld->entries, sizeof(struct iocb *));
	ld->io_us = calloc(ld->entries, sizeof(struct io_u *));

	td->io_ops->data = ld;
	return 0;
	}

	static struct ioengine_ops ioengine = {
	.name = "libaio",
	.version = FIO_IOOPS_VERSION,
	.init = fio_libaio_init,
	.prep = fio_libaio_prep,
	.queue = fio_libaio_queue,
	.commit = fio_libaio_commit,
	.cancel = fio_libaio_cancel,
	.getevents = fio_libaio_getevents,
	.event = fio_libaio_event,
	.cleanup = fio_libaio_cleanup,
	.open_file = generic_open_file,
	.close_file = generic_close_file,
	.get_file_size = generic_get_file_size,
	.options = options,
	.option_struct_size = sizeof(struct libaio_options),
	};

	static void fio_init fio_libaio_register(void)
	{
	register_ioengine(&ioengine);
	}

	static void fio_exit fio_libaio_unregister(void)
	{
	unregister_ioengine(&ioengine);
	}