libaio.c revision c90e1017b9384b170d47b97d2353f7bff3b5a34d 
1/*
2 * libaio engine
3 *
4 * IO engine using the Linux native aio interface.
5 *
6 */
7#include <stdio.h>
8#include <stdlib.h>
9#include <unistd.h>
10#include <errno.h>
11#include <assert.h>
12
13#include "../fio.h"
14
15#ifdef FIO_HAVE_LIBAIO
16
17#define ev_to_iou(ev)	(struct io_u *) ((unsigned long) (ev)->obj)
18
19struct libaio_data {
20	io_context_t aio_ctx;
21	struct io_event *aio_events;
22	struct iocb **iocbs;
23	struct io_u **io_us;
24	int iocbs_nr;
25};
26
27struct libaio_options {
28	struct thread_data *td;
29	unsigned int userspace_reap;
30};
31
32static struct fio_option options[] = {
33	{
34		.name	= "userspace_reap",
35		.type	= FIO_OPT_STR_SET,
36		.off1	= offsetof(struct libaio_options, userspace_reap),
37		.help	= "Use alternative user-space reap implementation",
38	},
39	{
40		.name	= NULL,
41	},
42};
43
44static int fio_libaio_prep(struct thread_data fio_unused *td, struct io_u *io_u)
45{
46	struct fio_file *f = io_u->file;
47
48	if (io_u->ddir == DDIR_READ)
49		io_prep_pread(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
50	else if (io_u->ddir == DDIR_WRITE)
51		io_prep_pwrite(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
52	else if (ddir_sync(io_u->ddir))
53		io_prep_fsync(&io_u->iocb, f->fd);
54
55	return 0;
56}
57
58static struct io_u *fio_libaio_event(struct thread_data *td, int event)
59{
60	struct libaio_data *ld = td->io_ops->data;
61	struct io_event *ev;
62	struct io_u *io_u;
63
64	ev = ld->aio_events + event;
65	io_u = ev_to_iou(ev);
66
67	if (ev->res != io_u->xfer_buflen) {
68		if (ev->res > io_u->xfer_buflen)
69			io_u->error = -ev->res;
70		else
71			io_u->resid = io_u->xfer_buflen - ev->res;
72	} else
73		io_u->error = 0;
74
75	return io_u;
76}
77
78struct aio_ring {
79	unsigned id;		 /** kernel internal index number */
80	unsigned nr;		 /** number of io_events */
81	unsigned head;
82	unsigned tail;
83
84	unsigned magic;
85	unsigned compat_features;
86	unsigned incompat_features;
87	unsigned header_length;	/** size of aio_ring */
88
89	struct io_event events[0];
90};
91
92#define AIO_RING_MAGIC	0xa10a10a1
93
94static int user_io_getevents(io_context_t aio_ctx, unsigned int max,
95			     struct io_event *events)
96{
97	long i = 0;
98	unsigned head;
99	struct aio_ring *ring = (struct aio_ring*) aio_ctx;
100
101	while (i < max) {
102		head = ring->head;
103
104		if (head == ring->tail) {
105			/* There are no more completions */
106			break;
107		} else {
108			/* There is another completion to reap */
109			events[i] = ring->events[head];
110			read_barrier();
111			ring->head = (head + 1) % ring->nr;
112			i++;
113		}
114	}
115
116	return i;
117}
118
119static int fio_libaio_getevents(struct thread_data *td, unsigned int min,
120				unsigned int max, struct timespec *t)
121{
122	struct libaio_data *ld = td->io_ops->data;
123	struct libaio_options *o = td->eo;
124	unsigned actual_min = td->o.iodepth_batch_complete == 0 ? 0 : min;
125	int r, events = 0;
126
127	do {
128		if (o->userspace_reap == 1
129		    && actual_min == 0
130		    && ((struct aio_ring *)(ld->aio_ctx))->magic
131				== AIO_RING_MAGIC) {
132			r = user_io_getevents(ld->aio_ctx, max,
133				ld->aio_events + events);
134		} else {
135			r = io_getevents(ld->aio_ctx, actual_min,
136				max, ld->aio_events + events, t);
137		}
138		if (r >= 0)
139			events += r;
140		else if (r == -EAGAIN)
141			usleep(100);
142	} while (events < min);
143
144	return r < 0 ? r : events;
145}
146
147static int fio_libaio_queue(struct thread_data *td, struct io_u *io_u)
148{
149	struct libaio_data *ld = td->io_ops->data;
150
151	fio_ro_check(td, io_u);
152
153	if (ld->iocbs_nr == (int) td->o.iodepth)
154		return FIO_Q_BUSY;
155
156	/*
157	 * fsync is tricky, since it can fail and we need to do it
158	 * serialized with other io. the reason is that linux doesn't
159	 * support aio fsync yet. So return busy for the case where we
160	 * have pending io, to let fio complete those first.
161	 */
162	if (ddir_sync(io_u->ddir)) {
163		if (ld->iocbs_nr)
164			return FIO_Q_BUSY;
165
166		do_io_u_sync(td, io_u);
167		return FIO_Q_COMPLETED;
168	}
169
170	if (io_u->ddir == DDIR_TRIM) {
171		if (ld->iocbs_nr)
172			return FIO_Q_BUSY;
173
174		do_io_u_trim(td, io_u);
175		return FIO_Q_COMPLETED;
176	}
177
178	ld->iocbs[ld->iocbs_nr] = &io_u->iocb;
179	ld->io_us[ld->iocbs_nr] = io_u;
180	ld->iocbs_nr++;
181	return FIO_Q_QUEUED;
182}
183
184static void fio_libaio_queued(struct thread_data *td, struct io_u **io_us,
185			      unsigned int nr)
186{
187	struct timeval now;
188	unsigned int i;
189
190	if (!fio_fill_issue_time(td))
191		return;
192
193	fio_gettime(&now, NULL);
194
195	for (i = 0; i < nr; i++) {
196		struct io_u *io_u = io_us[i];
197
198		memcpy(&io_u->issue_time, &now, sizeof(now));
199		io_u_queued(td, io_u);
200	}
201}
202
203static int fio_libaio_commit(struct thread_data *td)
204{
205	struct libaio_data *ld = td->io_ops->data;
206	struct iocb **iocbs;
207	struct io_u **io_us;
208	int ret;
209
210	if (!ld->iocbs_nr)
211		return 0;
212
213	io_us = ld->io_us;
214	iocbs = ld->iocbs;
215	do {
216		ret = io_submit(ld->aio_ctx, ld->iocbs_nr, iocbs);
217		if (ret > 0) {
218			fio_libaio_queued(td, io_us, ret);
219			io_u_mark_submit(td, ret);
220			ld->iocbs_nr -= ret;
221			io_us += ret;
222			iocbs += ret;
223			ret = 0;
224		} else if (!ret || ret == -EAGAIN || ret == -EINTR) {
225			if (!ret)
226				io_u_mark_submit(td, ret);
227			continue;
228		} else
229			break;
230	} while (ld->iocbs_nr);
231
232	return ret;
233}
234
235static int fio_libaio_cancel(struct thread_data *td, struct io_u *io_u)
236{
237	struct libaio_data *ld = td->io_ops->data;
238
239	return io_cancel(ld->aio_ctx, &io_u->iocb, ld->aio_events);
240}
241
242static void fio_libaio_cleanup(struct thread_data *td)
243{
244	struct libaio_data *ld = td->io_ops->data;
245
246	if (ld) {
247		io_destroy(ld->aio_ctx);
248		free(ld->aio_events);
249		free(ld->iocbs);
250		free(ld->io_us);
251		free(ld);
252	}
253}
254
255static int fio_libaio_init(struct thread_data *td)
256{
257	struct libaio_data *ld = malloc(sizeof(*ld));
258	struct libaio_options *o = td->eo;
259	int err = 0;
260
261	memset(ld, 0, sizeof(*ld));
262
263	/*
264	 * First try passing in 0 for queue depth, since we don't
265	 * care about the user ring. If that fails, the kernel is too old
266	 * and we need the right depth.
267	 */
268	if (!o->userspace_reap)
269		err = io_queue_init(0, &ld->aio_ctx);
270	if (o->userspace_reap || err == -EINVAL)
271		err = io_queue_init(td->o.iodepth, &ld->aio_ctx);
272	if (err) {
273		td_verror(td, -err, "io_queue_init");
274		log_err("fio: check /proc/sys/fs/aio-max-nr\n");
275		free(ld);
276		return 1;
277	}
278
279	ld->aio_events = malloc(td->o.iodepth * sizeof(struct io_event));
280	memset(ld->aio_events, 0, td->o.iodepth * sizeof(struct io_event));
281	ld->iocbs = malloc(td->o.iodepth * sizeof(struct iocb *));
282	memset(ld->iocbs, 0, sizeof(struct iocb *));
283	ld->io_us = malloc(td->o.iodepth * sizeof(struct io_u *));
284	memset(ld->io_us, 0, td->o.iodepth * sizeof(struct io_u *));
285	ld->iocbs_nr = 0;
286
287	td->io_ops->data = ld;
288	return 0;
289}
290
291static struct ioengine_ops ioengine = {
292	.name			= "libaio",
293	.version		= FIO_IOOPS_VERSION,
294	.init			= fio_libaio_init,
295	.prep			= fio_libaio_prep,
296	.queue			= fio_libaio_queue,
297	.commit			= fio_libaio_commit,
298	.cancel			= fio_libaio_cancel,
299	.getevents		= fio_libaio_getevents,
300	.event			= fio_libaio_event,
301	.cleanup		= fio_libaio_cleanup,
302	.open_file		= generic_open_file,
303	.close_file		= generic_close_file,
304	.get_file_size		= generic_get_file_size,
305	.options		= options,
306	.option_struct_size	= sizeof(struct libaio_options),
307};
308
309#else /* FIO_HAVE_LIBAIO */
310
311/*
312 * When we have a proper configure system in place, we simply wont build
313 * and install this io engine. For now install a crippled version that
314 * just complains and fails to load.
315 */
316static int fio_libaio_init(struct thread_data fio_unused *td)
317{
318	log_err("fio: libaio not available\n");
319	return 1;
320}
321
322static struct ioengine_ops ioengine = {
323	.name		= "libaio",
324	.version	= FIO_IOOPS_VERSION,
325	.init		= fio_libaio_init,
326};
327
328#endif
329
330static void fio_init fio_libaio_register(void)
331{
332	register_ioengine(&ioengine);
333}
334
335static void fio_exit fio_libaio_unregister(void)
336{
337	unregister_ioengine(&ioengine);
338}
339