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 #include <libaio.h>
13
14 #include "../fio.h"
15
16 static int fio_libaio_commit(struct thread_data *td);
17
18 struct libaio_data {
19 io_context_t aio_ctx;
20 struct io_event *aio_events;
21 struct iocb **iocbs;
22 struct io_u **io_us;
23
24 /*
25 * Basic ring buffer. 'head' is incremented in _queue(), and
26 * 'tail' is incremented in _commit(). We keep 'queued' so
27 * that we know if the ring is full or empty, when
28 * 'head' == 'tail'. 'entries' is the ring size, and
29 * 'is_pow2' is just an optimization to use AND instead of
30 * modulus to get the remainder on ring increment.
31 */
32 int is_pow2;
33 unsigned int entries;
34 unsigned int queued;
35 unsigned int head;
36 unsigned int tail;
37 };
38
39 struct libaio_options {
40 void *pad;
41 unsigned int userspace_reap;
42 };
43
44 static struct fio_option options[] = {
45 {
46 .name = "userspace_reap",
47 .lname = "Libaio userspace reaping",
48 .type = FIO_OPT_STR_SET,
49 .off1 = offsetof(struct libaio_options, userspace_reap),
50 .help = "Use alternative user-space reap implementation",
51 .category = FIO_OPT_C_ENGINE,
52 .group = FIO_OPT_G_LIBAIO,
53 },
54 {
55 .name = NULL,
56 },
57 };
58
ring_inc(struct libaio_data * ld,unsigned int * val,unsigned int add)59 static inline void ring_inc(struct libaio_data *ld, unsigned int *val,
60 unsigned int add)
61 {
62 if (ld->is_pow2)
63 *val = (*val + add) & (ld->entries - 1);
64 else
65 *val = (*val + add) % ld->entries;
66 }
67
fio_libaio_prep(struct thread_data fio_unused * td,struct io_u * io_u)68 static int fio_libaio_prep(struct thread_data fio_unused *td, struct io_u *io_u)
69 {
70 struct fio_file *f = io_u->file;
71
72 if (io_u->ddir == DDIR_READ)
73 io_prep_pread(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
74 else if (io_u->ddir == DDIR_WRITE)
75 io_prep_pwrite(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
76 else if (ddir_sync(io_u->ddir))
77 io_prep_fsync(&io_u->iocb, f->fd);
78
79 return 0;
80 }
81
fio_libaio_event(struct thread_data * td,int event)82 static struct io_u *fio_libaio_event(struct thread_data *td, int event)
83 {
84 struct libaio_data *ld = td->io_ops->data;
85 struct io_event *ev;
86 struct io_u *io_u;
87
88 ev = ld->aio_events + event;
89 io_u = container_of(ev->obj, struct io_u, iocb);
90
91 if (ev->res != io_u->xfer_buflen) {
92 if (ev->res > io_u->xfer_buflen)
93 io_u->error = -ev->res;
94 else
95 io_u->resid = io_u->xfer_buflen - ev->res;
96 } else
97 io_u->error = 0;
98
99 return io_u;
100 }
101
102 struct aio_ring {
103 unsigned id; /** kernel internal index number */
104 unsigned nr; /** number of io_events */
105 unsigned head;
106 unsigned tail;
107
108 unsigned magic;
109 unsigned compat_features;
110 unsigned incompat_features;
111 unsigned header_length; /** size of aio_ring */
112
113 struct io_event events[0];
114 };
115
116 #define AIO_RING_MAGIC 0xa10a10a1
117
user_io_getevents(io_context_t aio_ctx,unsigned int max,struct io_event * events)118 static int user_io_getevents(io_context_t aio_ctx, unsigned int max,
119 struct io_event *events)
120 {
121 long i = 0;
122 unsigned head;
123 struct aio_ring *ring = (struct aio_ring*) aio_ctx;
124
125 while (i < max) {
126 head = ring->head;
127
128 if (head == ring->tail) {
129 /* There are no more completions */
130 break;
131 } else {
132 /* There is another completion to reap */
133 events[i] = ring->events[head];
134 read_barrier();
135 ring->head = (head + 1) % ring->nr;
136 i++;
137 }
138 }
139
140 return i;
141 }
142
fio_libaio_getevents(struct thread_data * td,unsigned int min,unsigned int max,const struct timespec * t)143 static int fio_libaio_getevents(struct thread_data *td, unsigned int min,
144 unsigned int max, const struct timespec *t)
145 {
146 struct libaio_data *ld = td->io_ops->data;
147 struct libaio_options *o = td->eo;
148 unsigned actual_min = td->o.iodepth_batch_complete == 0 ? 0 : min;
149 struct timespec __lt, *lt = NULL;
150 int r, events = 0;
151
152 if (t) {
153 __lt = *t;
154 lt = &__lt;
155 }
156
157 do {
158 if (o->userspace_reap == 1
159 && actual_min == 0
160 && ((struct aio_ring *)(ld->aio_ctx))->magic
161 == AIO_RING_MAGIC) {
162 r = user_io_getevents(ld->aio_ctx, max,
163 ld->aio_events + events);
164 } else {
165 r = io_getevents(ld->aio_ctx, actual_min,
166 max, ld->aio_events + events, lt);
167 }
168 if (r > 0)
169 events += r;
170 else if ((min && r == 0) || r == -EAGAIN) {
171 fio_libaio_commit(td);
172 usleep(100);
173 } else if (r != -EINTR)
174 break;
175 } while (events < min);
176
177 return r < 0 ? r : events;
178 }
179
fio_libaio_queue(struct thread_data * td,struct io_u * io_u)180 static int fio_libaio_queue(struct thread_data *td, struct io_u *io_u)
181 {
182 struct libaio_data *ld = td->io_ops->data;
183
184 fio_ro_check(td, io_u);
185
186 if (ld->queued == td->o.iodepth)
187 return FIO_Q_BUSY;
188
189 /*
190 * fsync is tricky, since it can fail and we need to do it
191 * serialized with other io. the reason is that linux doesn't
192 * support aio fsync yet. So return busy for the case where we
193 * have pending io, to let fio complete those first.
194 */
195 if (ddir_sync(io_u->ddir)) {
196 if (ld->queued)
197 return FIO_Q_BUSY;
198
199 do_io_u_sync(td, io_u);
200 return FIO_Q_COMPLETED;
201 }
202
203 if (io_u->ddir == DDIR_TRIM) {
204 if (ld->queued)
205 return FIO_Q_BUSY;
206
207 do_io_u_trim(td, io_u);
208 return FIO_Q_COMPLETED;
209 }
210
211 ld->iocbs[ld->head] = &io_u->iocb;
212 ld->io_us[ld->head] = io_u;
213 ring_inc(ld, &ld->head, 1);
214 ld->queued++;
215 return FIO_Q_QUEUED;
216 }
217
fio_libaio_queued(struct thread_data * td,struct io_u ** io_us,unsigned int nr)218 static void fio_libaio_queued(struct thread_data *td, struct io_u **io_us,
219 unsigned int nr)
220 {
221 struct timeval now;
222 unsigned int i;
223
224 if (!fio_fill_issue_time(td))
225 return;
226
227 fio_gettime(&now, NULL);
228
229 for (i = 0; i < nr; i++) {
230 struct io_u *io_u = io_us[i];
231
232 memcpy(&io_u->issue_time, &now, sizeof(now));
233 io_u_queued(td, io_u);
234 }
235 }
236
fio_libaio_commit(struct thread_data * td)237 static int fio_libaio_commit(struct thread_data *td)
238 {
239 struct libaio_data *ld = td->io_ops->data;
240 struct iocb **iocbs;
241 struct io_u **io_us;
242 struct timeval tv;
243 int ret, wait_start = 0;
244
245 if (!ld->queued)
246 return 0;
247
248 do {
249 long nr = ld->queued;
250
251 nr = min((unsigned int) nr, ld->entries - ld->tail);
252 io_us = ld->io_us + ld->tail;
253 iocbs = ld->iocbs + ld->tail;
254
255 ret = io_submit(ld->aio_ctx, nr, iocbs);
256 if (ret > 0) {
257 fio_libaio_queued(td, io_us, ret);
258 io_u_mark_submit(td, ret);
259
260 ld->queued -= ret;
261 ring_inc(ld, &ld->tail, ret);
262 ret = 0;
263 wait_start = 0;
264 } else if (ret == -EINTR || !ret) {
265 if (!ret)
266 io_u_mark_submit(td, ret);
267 wait_start = 0;
268 continue;
269 } else if (ret == -EAGAIN) {
270 /*
271 * If we get EAGAIN, we should break out without
272 * error and let the upper layer reap some
273 * events for us. If we have no queued IO, we
274 * must loop here. If we loop for more than 30s,
275 * just error out, something must be buggy in the
276 * IO path.
277 */
278 if (ld->queued) {
279 ret = 0;
280 break;
281 }
282 if (!wait_start) {
283 fio_gettime(&tv, NULL);
284 wait_start = 1;
285 } else if (mtime_since_now(&tv) > 30000) {
286 log_err("fio: aio appears to be stalled, giving up\n");
287 break;
288 }
289 usleep(1);
290 continue;
291 } else if (ret == -ENOMEM) {
292 /*
293 * If we get -ENOMEM, reap events if we can. If
294 * we cannot, treat it as a fatal event since there's
295 * nothing we can do about it.
296 */
297 if (ld->queued)
298 ret = 0;
299 break;
300 } else
301 break;
302 } while (ld->queued);
303
304 return ret;
305 }
306
fio_libaio_cancel(struct thread_data * td,struct io_u * io_u)307 static int fio_libaio_cancel(struct thread_data *td, struct io_u *io_u)
308 {
309 struct libaio_data *ld = td->io_ops->data;
310
311 return io_cancel(ld->aio_ctx, &io_u->iocb, ld->aio_events);
312 }
313
fio_libaio_cleanup(struct thread_data * td)314 static void fio_libaio_cleanup(struct thread_data *td)
315 {
316 struct libaio_data *ld = td->io_ops->data;
317
318 if (ld) {
319 io_destroy(ld->aio_ctx);
320 free(ld->aio_events);
321 free(ld->iocbs);
322 free(ld->io_us);
323 free(ld);
324 }
325 }
326
fio_libaio_init(struct thread_data * td)327 static int fio_libaio_init(struct thread_data *td)
328 {
329 struct libaio_options *o = td->eo;
330 struct libaio_data *ld;
331 int err = 0;
332
333 ld = calloc(1, sizeof(*ld));
334
335 /*
336 * First try passing in 0 for queue depth, since we don't
337 * care about the user ring. If that fails, the kernel is too old
338 * and we need the right depth.
339 */
340 if (!o->userspace_reap)
341 err = io_queue_init(INT_MAX, &ld->aio_ctx);
342 if (o->userspace_reap || err == -EINVAL)
343 err = io_queue_init(td->o.iodepth, &ld->aio_ctx);
344 if (err) {
345 td_verror(td, -err, "io_queue_init");
346 log_err("fio: check /proc/sys/fs/aio-max-nr\n");
347 free(ld);
348 return 1;
349 }
350
351 ld->entries = td->o.iodepth;
352 ld->is_pow2 = is_power_of_2(ld->entries);
353 ld->aio_events = calloc(ld->entries, sizeof(struct io_event));
354 ld->iocbs = calloc(ld->entries, sizeof(struct iocb *));
355 ld->io_us = calloc(ld->entries, sizeof(struct io_u *));
356
357 td->io_ops->data = ld;
358 return 0;
359 }
360
361 static struct ioengine_ops ioengine = {
362 .name = "libaio",
363 .version = FIO_IOOPS_VERSION,
364 .init = fio_libaio_init,
365 .prep = fio_libaio_prep,
366 .queue = fio_libaio_queue,
367 .commit = fio_libaio_commit,
368 .cancel = fio_libaio_cancel,
369 .getevents = fio_libaio_getevents,
370 .event = fio_libaio_event,
371 .cleanup = fio_libaio_cleanup,
372 .open_file = generic_open_file,
373 .close_file = generic_close_file,
374 .get_file_size = generic_get_file_size,
375 .options = options,
376 .option_struct_size = sizeof(struct libaio_options),
377 };
378
fio_libaio_register(void)379 static void fio_init fio_libaio_register(void)
380 {
381 register_ioengine(&ioengine);
382 }
383
fio_libaio_unregister(void)384 static void fio_exit fio_libaio_unregister(void)
385 {
386 unregister_ioengine(&ioengine);
387 }
388