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Comparing libev/ev_linuxaio.c (file contents):
Revision 1.5 by root, Fri Jun 21 03:41:40 2019 UTC vs.
Revision 1.21 by root, Mon Jun 24 20:44:15 2019 UTC

… …
35 * and other provisions required by the GPL. If you do not delete the 35 * and other provisions required by the GPL. If you do not delete the
36 * provisions above, a recipient may use your version of this file under 36 * provisions above, a recipient may use your version of this file under
37 * either the BSD or the GPL. 37 * either the BSD or the GPL.
38 */ 38 */
39 39
40#define EPOLL_FALLBACK 1
41
40#include <sys/time.h> /* actually linux/time.h, but we must assume they are compatible */ 42#include <sys/time.h> /* actually linux/time.h, but we must assume they are compatible */
41#include <poll.h> 43#include <poll.h>
42#include <linux/aio_abi.h> 44#include <linux/aio_abi.h>
43 45
46#if EPOLL_FALLBACK
47# include <sys/epoll.h>
48#endif
49
44/* we try to fill 4kn pages exactly. 50/* we try to fill 4kB pages exactly.
45 * the ring buffer header is 32 bytes, every io event is 32 bytes. 51 * the ring buffer header is 32 bytes, every io event is 32 bytes.
46 * the kernel takes the io event number, doubles it, adds 2, adds the ring buffer 52 * the kernel takes the io event number, doubles it, adds 2, adds the ring buffer.
47 * so the calculation below will use "exactly" 8kB for the ring buffer 53 * therefore the calculation below will use "exactly" 4kB for the ring buffer
48 */ 54 */
49#define EV_LINUXAIO_DEPTH (256 / 2 - 2 - 1) /* max. number of io events per batch */ 55#define EV_LINUXAIO_DEPTH (128 / 2 - 2 - 1) /* max. number of io events per batch */
50 56
51/*****************************************************************************/ 57/*****************************************************************************/
52/* syscall wrapdadoop */ 58/* syscall wrapdadoop - this section has the raw syscall definitions */
53 59
54#include <sys/syscall.h> /* no glibc wrappers */ 60#include <sys/syscall.h> /* no glibc wrappers */
55 61
56/* aio_abi.h is not versioned in any way, so we cannot test for its existance */ 62/* aio_abi.h is not versioned in any way, so we cannot test for its existance */
57#define IOCB_CMD_POLL 5 63#define IOCB_CMD_POLL 5
… …
72 unsigned header_length; /* size of aio_ring */ 78 unsigned header_length; /* size of aio_ring */
73 79
74 struct io_event io_events[0]; 80 struct io_event io_events[0];
75}; 81};
76 82
77static int 83inline_size
84int
78ev_io_setup (unsigned nr_events, aio_context_t *ctx_idp) 85evsys_io_setup (unsigned nr_events, aio_context_t *ctx_idp)
79{ 86{
80 return syscall (SYS_io_setup, nr_events, ctx_idp); 87 return syscall (SYS_io_setup, nr_events, ctx_idp);
81} 88}
82 89
83static int 90inline_size
91int
84ev_io_destroy (aio_context_t ctx_id) 92evsys_io_destroy (aio_context_t ctx_id)
85{ 93{
86 return syscall (SYS_io_destroy, ctx_id); 94 return syscall (SYS_io_destroy, ctx_id);
87} 95}
88 96
89static int 97inline_size
98int
90ev_io_submit (aio_context_t ctx_id, long nr, struct iocb *cbp[]) 99evsys_io_submit (aio_context_t ctx_id, long nr, struct iocb *cbp[])
91{ 100{
92 return syscall (SYS_io_submit, ctx_id, nr, cbp); 101 return syscall (SYS_io_submit, ctx_id, nr, cbp);
93} 102}
94 103
95static int 104inline_size
105int
96ev_io_cancel (aio_context_t ctx_id, struct iocb *cbp, struct io_event *result) 106evsys_io_cancel (aio_context_t ctx_id, struct iocb *cbp, struct io_event *result)
97{ 107{
98 return syscall (SYS_io_cancel, ctx_id, cbp, result); 108 return syscall (SYS_io_cancel, ctx_id, cbp, result);
99} 109}
100 110
101static int 111inline_size
112int
102ev_io_getevents (aio_context_t ctx_id, long min_nr, long nr, struct io_event *events, struct timespec *timeout) 113evsys_io_getevents (aio_context_t ctx_id, long min_nr, long nr, struct io_event *events, struct timespec *timeout)
103{ 114{
104 return syscall (SYS_io_getevents, ctx_id, min_nr, nr, events, timeout); 115 return syscall (SYS_io_getevents, ctx_id, min_nr, nr, events, timeout);
105} 116}
106
107typedef void (*ev_io_cb) (long nr, struct io_event *events);
108 117
109/*****************************************************************************/ 118/*****************************************************************************/
110/* actual backed implementation */ 119/* actual backed implementation */
111 120
112/* two iocbs for every fd, one for read, one for write */ 121/* we use out own wrapper structure in acse we ever want to do something "clever" */
113typedef struct aniocb 122typedef struct aniocb
114{ 123{
115 struct iocb io; 124 struct iocb io;
116 /*int inuse;*/ 125 /*int inuse;*/
117} *ANIOCBP; 126} *ANIOCBP;
118 127
119inline_size 128inline_size
120void 129void
121linuxaio_array_needsize_iocbp (ANIOCBP *base, int count) 130linuxaio_array_needsize_iocbp (ANIOCBP *base, int count)
122{ 131{
123 /* TODO: quite the overhead to allocate every iocb separately */ 132 /* TODO: quite the overhead to allocate every iocb separately, maybe use our own alocator? */
124 while (count--) 133 while (count--)
125 { 134 {
126 *base = (ANIOCBP)ev_malloc (sizeof (**base)); 135 *base = (ANIOCBP)ev_malloc (sizeof (**base));
127 /* TODO: full zero initialize required? */ 136 /* TODO: full zero initialize required? */
128 memset (*base, 0, sizeof (**base)); 137 memset (*base, 0, sizeof (**base));
129 /* would be nice to initialize fd/data as well */ 138 /* would be nice to initialize fd/data as well, but array_needsize API doesn't support that */
130 (*base)->io.aio_lio_opcode = IOCB_CMD_POLL; 139 (*base)->io.aio_lio_opcode = IOCB_CMD_POLL;
131 ++base; 140 ++base;
132 } 141 }
133} 142}
134 143
144ecb_cold
135static void 145static void
136linuxaio_free_iocbp (EV_P) 146linuxaio_free_iocbp (EV_P)
137{ 147{
138 while (linuxaio_iocbpmax--) 148 while (linuxaio_iocbpmax--)
139 ev_free (linuxaio_iocbps [linuxaio_iocbpmax]); 149 ev_free (linuxaio_iocbps [linuxaio_iocbpmax]);
140 150
141 /* next resize will completely reallocate the array */ 151 linuxaio_iocbpmax = 0; /* next resize will completely reallocate the array, at some overhead */
142 linuxaio_iocbpmax = 0;
143 linuxaio_submitcnt = 0; /* all pointers invalidated */
144} 152}
145 153
146static void 154static void
147linuxaio_modify (EV_P_ int fd, int oev, int nev) 155linuxaio_modify (EV_P_ int fd, int oev, int nev)
148{ 156{
149 array_needsize (ANIOCBP, linuxaio_iocbps, linuxaio_iocbpmax, fd + 1, linuxaio_array_needsize_iocbp); 157 array_needsize (ANIOCBP, linuxaio_iocbps, linuxaio_iocbpmax, fd + 1, linuxaio_array_needsize_iocbp);
150 struct aniocb *iocb = linuxaio_iocbps [fd]; 158 struct aniocb *iocb = linuxaio_iocbps [fd];
151 159
160#if EPOLL_FALLBACK
161 if (iocb->io.aio_reqprio < 0)
162 {
163 epoll_ctl (backend_fd, EPOLL_CTL_DEL, fd, 0);
164 iocb->io.aio_reqprio = 0;
165 }
166#endif
167
152 if (iocb->io.aio_buf) 168 if (iocb->io.aio_buf)
153 ev_io_cancel (linuxaio_ctx, &iocb->io, (struct io_event *)0); /* always returns an error relevant kernels */ 169 evsys_io_cancel (linuxaio_ctx, &iocb->io, (struct io_event *)0); /* always returns an error relevant kernels */
154 170
155 if (nev) 171 if (nev)
156 { 172 {
157 iocb->io.aio_data = fd; 173 iocb->io.aio_data = fd;
158 iocb->io.aio_fildes = fd; 174 iocb->io.aio_fildes = fd;
… …
166 array_needsize (struct iocb *, linuxaio_submits, linuxaio_submitmax, linuxaio_submitcnt, array_needsize_noinit); 182 array_needsize (struct iocb *, linuxaio_submits, linuxaio_submitmax, linuxaio_submitcnt, array_needsize_noinit);
167 linuxaio_submits [linuxaio_submitcnt - 1] = &iocb->io; 183 linuxaio_submits [linuxaio_submitcnt - 1] = &iocb->io;
168 } 184 }
169} 185}
170 186
187#if EPOLL_FALLBACK
188
189static void
190linuxaio_rearm_epoll (EV_P_ struct iocb *iocb, int op)
191{
192 struct epoll_event eev;
193
194 eev.events = EPOLLONESHOT;
195 if (iocb->aio_buf & POLLIN ) eev.events |= EPOLLIN ;
196 if (iocb->aio_buf & POLLOUT) eev.events |= EPOLLOUT;
197 eev.data.fd = iocb->aio_fildes;
198
199 if (epoll_ctl (backend_fd, op, iocb->aio_fildes, &eev) < 0)
200 ev_syserr ("(libeio) linuxaio epoll_ctl");
201}
202
203static void
204linuxaio_epoll_cb (EV_P_ struct ev_io *w, int revents)
205{
206 struct epoll_event events[16];
207
208 for (;;)
209 {
210 int idx;
211 int res = epoll_wait (backend_fd, events, sizeof (events) / sizeof (events [0]), 0);
212
213 if (expect_false (res < 0))
214 ev_syserr ("(libev) linuxaio epoll_wait");
215 else if (!res)
216 break;
217
218 for (idx = res; idx--; )
219 {
220 int fd = events [idx].data.fd;
221 uint32_t ev = events [idx].events;
222
223 assert (("libev: iocb fd must be in-bounds", fd >= 0 && fd < anfdmax));
224
225 linuxaio_rearm_epoll (EV_A_ &linuxaio_iocbps [fd]->io, EPOLL_CTL_MOD);
226
227 fd_event (EV_A_ fd,
228 (ev & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0)
229 | (ev & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0));
230 }
231
232 if (res < sizeof (events) / sizeof (events [0]))
233 break;
234 }
235}
236
237#endif
238
171static void 239static void
172linuxaio_parse_events (EV_P_ struct io_event *ev, int nr) 240linuxaio_parse_events (EV_P_ struct io_event *ev, int nr)
173{ 241{
174 while (nr) 242 while (nr)
175 { 243 {
176 int fd = ev->data; 244 int fd = ev->data;
177 int res = ev->res; 245 int res = ev->res;
178 246
179 assert (("libev: iocb fd must be in-bounds", fd >= 0 && fd < anfdmax)); 247 assert (("libev: iocb fd must be in-bounds", fd >= 0 && fd < anfdmax));
180 248
181 /* linux aio is oneshot: rearm fd */ 249 /* linux aio is oneshot: rearm fd. TODO: this does more work than needed */
182 linuxaio_iocbps [fd]->io.aio_buf = 0; 250 linuxaio_iocbps [fd]->io.aio_buf = 0;
183 anfds [fd].events = 0; 251 anfds [fd].events = 0;
184 fd_change (EV_A_ fd, 0); 252 fd_change (EV_A_ fd, 0);
185 253
186 /* feed events, we do not expect or handle POLLNVAL */ 254 /* feed events, we do not expect or handle POLLNVAL */
187 if (ecb_expect_false (res & POLLNVAL))
188 fd_kill (EV_A_ fd);
189 else
190 fd_event ( 255 fd_event (
191 EV_A_ 256 EV_A_
192 fd, 257 fd,
193 (res & (POLLOUT | POLLERR | POLLHUP) ? EV_WRITE : 0) 258 (res & (POLLOUT | POLLERR | POLLHUP) ? EV_WRITE : 0)
194 | (res & (POLLIN | POLLERR | POLLHUP) ? EV_READ : 0) 259 | (res & (POLLIN | POLLERR | POLLHUP) ? EV_READ : 0)
195 ); 260 );
196 261
197 --nr; 262 --nr;
198 ++ev; 263 ++ev;
199 } 264 }
200} 265}
… …
203static int 268static int
204linuxaio_get_events_from_ring (EV_P) 269linuxaio_get_events_from_ring (EV_P)
205{ 270{
206 struct aio_ring *ring = (struct aio_ring *)linuxaio_ctx; 271 struct aio_ring *ring = (struct aio_ring *)linuxaio_ctx;
207 272
273 /* the kernel reads and writes both of these variables, */
274 /* as a C extension, we assume that volatile use here */
275 /* both makes reads atomic and once-only */
276 unsigned head = *(volatile unsigned *)&ring->head;
277 unsigned tail = *(volatile unsigned *)&ring->tail;
278
279 if (head == tail)
280 return 0;
281
282 /* bail out if the ring buffer doesn't match the expected layout */
283 if (expect_false (ring->magic != AIO_RING_MAGIC)
284 || ring->incompat_features != AIO_RING_INCOMPAT_FEATURES
285 || ring->header_length != sizeof (struct aio_ring)) /* TODO: or use it to find io_event[0]? */
286 return 0;
287
288 /* make sure the events up to tail are visible */
208 ECB_MEMORY_FENCE_ACQUIRE; 289 ECB_MEMORY_FENCE_ACQUIRE;
209
210 unsigned head = ring->head;
211 unsigned tail = *(volatile unsigned *)&ring->tail;
212
213 if (ring->magic != AIO_RING_MAGIC
214 || ring->incompat_features != AIO_RING_INCOMPAT_FEATURES
215 || ring->header_length != sizeof (struct aio_ring) /* TODO: or use it to find io_event[0]? */
216 || head == tail)
217 return 0;
218 290
219 /* parse all available events, but only once, to avoid starvation */ 291 /* parse all available events, but only once, to avoid starvation */
220 if (tail > head) /* normal case around */ 292 if (tail > head) /* normal case around */
221 linuxaio_parse_events (EV_A_ ring->io_events + head, tail - head); 293 linuxaio_parse_events (EV_A_ ring->io_events + head, tail - head);
222 else
223 {
224 /* wrapped around */ 294 else /* wrapped around */
295 {
225 linuxaio_parse_events (EV_A_ ring->io_events + head, ring->nr - head); 296 linuxaio_parse_events (EV_A_ ring->io_events + head, ring->nr - head);
226 linuxaio_parse_events (EV_A_ ring->io_events, tail); 297 linuxaio_parse_events (EV_A_ ring->io_events, tail);
227 } 298 }
228 299
229 ring->head = tail; 300 /* TODO: we only need a compiler barrier here, not a read fence */
301 ECB_MEMORY_FENCE_RELEASE;
302 /* as an extension to C, we hope that the volatile will make this atomic and once-only */
303 *(volatile unsigned *)&ring->head = tail;
304 /* make sure kernel can see our new head value - probably not required */
305 ECB_MEMORY_FENCE_RELEASE;
230 306
231 return 1; 307 return 1;
232} 308}
233 309
234/* read at least one event from kernel, or timeout */ 310/* read at least one event from kernel, or timeout */
235inline_size 311inline_size
236void 312void
237linuxaio_get_events (EV_P_ ev_tstamp timeout) 313linuxaio_get_events (EV_P_ ev_tstamp timeout)
238{ 314{
239 struct timespec ts; 315 struct timespec ts;
240 struct io_event ioev; 316 struct io_event ioev[1];
241 int res; 317 int res;
242 318
243 if (linuxaio_get_events_from_ring (EV_A)) 319 if (linuxaio_get_events_from_ring (EV_A))
244 return; 320 return;
245 321
246 /* no events, so wait for at least one, then poll ring buffer again */ 322 /* no events, so wait for at least one, then poll ring buffer again */
247 /* this degraded to one event per loop iteration */ 323 /* this degrades to one event per loop iteration */
248 /* if the ring buffer changes layout, but so be it */ 324 /* if the ring buffer changes layout, but so be it */
325
326 EV_RELEASE_CB;
249 327
250 ts.tv_sec = (long)timeout; 328 ts.tv_sec = (long)timeout;
251 ts.tv_nsec = (long)((timeout - ts.tv_sec) * 1e9); 329 ts.tv_nsec = (long)((timeout - ts.tv_sec) * 1e9);
252 330
253 res = ev_io_getevents (linuxaio_ctx, 1, 1, &ioev, &ts); 331 res = evsys_io_getevents (linuxaio_ctx, 1, sizeof (ioev) / sizeof (ioev [0]), ioev, &ts);
332
333 EV_ACQUIRE_CB;
254 334
255 if (res < 0) 335 if (res < 0)
336 if (errno == EINTR)
337 /* ignored */;
338 else
256 ev_syserr ("(libev) io_getevents"); 339 ev_syserr ("(libev) linuxaio io_getevents");
257 else if (res) 340 else if (res)
258 { 341 {
259 /* at least one event received, handle it and any remaining ones in the ring buffer */ 342 /* at least one event received, handle it and any remaining ones in the ring buffer */
260 linuxaio_parse_events (EV_A_ &ioev, 1); 343 linuxaio_parse_events (EV_A_ ioev, res);
261 linuxaio_get_events_from_ring (EV_A); 344 linuxaio_get_events_from_ring (EV_A);
262 } 345 }
263} 346}
264 347
265static void 348static void
… …
272 /* io_submit might return less than the requested number of iocbs */ 355 /* io_submit might return less than the requested number of iocbs */
273 /* this is, afaics, only because of errors, but we go by the book and use a loop, */ 356 /* this is, afaics, only because of errors, but we go by the book and use a loop, */
274 /* which allows us to pinpoint the errornous iocb */ 357 /* which allows us to pinpoint the errornous iocb */
275 for (submitted = 0; submitted < linuxaio_submitcnt; ) 358 for (submitted = 0; submitted < linuxaio_submitcnt; )
276 { 359 {
360#if 0
361 int res;
362 if (linuxaio_submits[submitted]->aio_fildes == backend_fd)
363 res = evsys_io_submit (linuxaio_ctx, 1, linuxaio_submits + submitted);
364 else
365 { res = -1; errno = EINVAL; };
366#else
277 int res = ev_io_submit (linuxaio_ctx, linuxaio_submitcnt - submitted, linuxaio_submits + submitted); 367 int res = evsys_io_submit (linuxaio_ctx, linuxaio_submitcnt - submitted, linuxaio_submits + submitted);
368#endif
278 369
279 if (res < 0) 370 if (expect_false (res < 0))
280 if (errno == EAGAIN) 371 if (errno == EAGAIN)
281 { 372 {
282 /* This happens when the ring buffer is full, at least. I assume this means 373 /* This happens when the ring buffer is full, at least. I assume this means
283 * that the event was queued synchronously during io_submit, and thus 374 * that the event was queued synchronously during io_submit, and thus
284 * the buffer overflowd. 375 * the buffer overflowed.
285 * In this case, we just try next loop iteration. 376 * In this case, we just try in next loop iteration.
377 * This should not result in a few fds taking priority, as the interface
378 * is one-shot, and we submit iocb's in a round-robin fashion.
379 * TODO: maybe make "submitted" persistent, so we don't have to memmove?
286 */ 380 */
381 if (ecb_expect_false (submitted))
382 {
287 memmove (linuxaio_submits, linuxaio_submits + submitted, (linuxaio_submitcnt - submitted) * sizeof (*linuxaio_submits)); 383 memmove (linuxaio_submits, linuxaio_submits + submitted, (linuxaio_submitcnt - submitted) * sizeof (*linuxaio_submits));
288 linuxaio_submitcnt -= submitted; 384 linuxaio_submitcnt -= submitted;
385 }
386
289 timeout = 0; 387 timeout = 0;
290 break; 388 break;
291 } 389 }
390#if EPOLL_FALLBACK
391 else if (errno == EINVAL)
392 {
393 /* This happens for unsupported fds, officially, but in my testing,
394 * also randomly happens for supported fds. We fall back to good old
395 * poll() here, under the assumption that this is a very rare case.
396 * See https://lore.kernel.org/patchwork/patch/1047453/ to see
397 * discussion about such a case (ttys) where polling for POLLIN
398 * fails but POLLIN|POLLOUT works.
399 */
400 struct iocb *iocb = linuxaio_submits [submitted];
401
402 linuxaio_rearm_epoll (EV_A_ linuxaio_submits [submitted], EPOLL_CTL_ADD);
403 iocb->aio_reqprio = -1; /* mark iocb as epoll */
404
405 res = 1; /* skip this iocb */
406 }
407#endif
408 else if (errno == EBADF)
409 {
410 fd_kill (EV_A_ linuxaio_submits [submitted]->aio_fildes);
411
412 res = 1; /* skip this iocb */
413 }
292 else 414 else
293 /* TODO: we get EAGAIN when the ring buffer is full for some reason */
294 /* TODO: should we always just try next time? */
295 ev_syserr ("(libev) io_submit"); 415 ev_syserr ("(libev) linuxaio io_submit");
296 416
297 submitted += res; 417 submitted += res;
298 } 418 }
299 419
300 linuxaio_submitcnt = 0; 420 linuxaio_submitcnt = 0;
… …
308int 428int
309linuxaio_init (EV_P_ int flags) 429linuxaio_init (EV_P_ int flags)
310{ 430{
311 /* would be great to have a nice test for IOCB_CMD_POLL instead */ 431 /* would be great to have a nice test for IOCB_CMD_POLL instead */
312 /* also: test some semi-common fd types, such as files and ttys in recommended_backends */ 432 /* also: test some semi-common fd types, such as files and ttys in recommended_backends */
313 if (ev_linux_version () < 0x041200) /* 4.18 introduced IOCB_CMD_POLL */ 433#if EPOLL_FALLBACK
434 /* 4.19 made epoll work */
435 if (ev_linux_version () < 0x041300)
314 return 0; 436 return 0;
437#else
438 /* 4.18 introduced IOCB_CMD_POLL */
439 if (ev_linux_version () < 0x041200)
440 return 0;
441#endif
315 442
316 linuxaio_ctx = 0; 443 linuxaio_ctx = 0;
317 if (ev_io_setup (EV_LINUXAIO_DEPTH, &linuxaio_ctx) < 0) 444 if (evsys_io_setup (EV_LINUXAIO_DEPTH, &linuxaio_ctx) < 0)
318 return 0; 445 return 0;
446
447#if EPOLL_FALLBACK
448 backend_fd = ev_epoll_create ();
449 if (backend_fd < 0)
450 {
451 evsys_io_destroy (linuxaio_ctx);
452 return 0;
453 }
454
455 ev_io_init (EV_A_ &linuxaio_epoll_w, linuxaio_epoll_cb, backend_fd, EV_READ);
456 ev_set_priority (&linuxaio_epoll_w, EV_MAXPRI);
457 ev_io_start (EV_A_ &linuxaio_epoll_w);
458 ev_unref (EV_A); /* watcher should not keep loop alive */
459#endif
319 460
320 backend_modify = linuxaio_modify; 461 backend_modify = linuxaio_modify;
321 backend_poll = linuxaio_poll; 462 backend_poll = linuxaio_poll;
322 463
323 linuxaio_iocbpmax = 0; 464 linuxaio_iocbpmax = 0;
… …
332 473
333inline_size 474inline_size
334void 475void
335linuxaio_destroy (EV_P) 476linuxaio_destroy (EV_P)
336{ 477{
478#if EPOLL_FALLBACK
479 close (backend_fd);
480#endif
337 linuxaio_free_iocbp (EV_A); 481 linuxaio_free_iocbp (EV_A);
338 ev_io_destroy (linuxaio_ctx); 482 evsys_io_destroy (linuxaio_ctx);
339} 483}
340 484
341inline_size 485inline_size
342void 486void
343linuxaio_fork (EV_P) 487linuxaio_fork (EV_P)
344{ 488{
345 /* TODO: verify and test */ 489 /* this frees all iocbs, which is very heavy-handed */
346 linuxaio_destroy (EV_A); 490 linuxaio_destroy (EV_A);
491 linuxaio_submitcnt = 0; /* all pointers were invalidated */
347 492
348 linuxaio_ctx = 0; 493 linuxaio_ctx = 0;
349 while (ev_io_setup (EV_LINUXAIO_DEPTH, &linuxaio_ctx) < 0) 494 while (evsys_io_setup (EV_LINUXAIO_DEPTH, &linuxaio_ctx) < 0)
350 ev_syserr ("(libev) io_setup"); 495 ev_syserr ("(libev) linuxaio io_setup");
496
497#if EPOLL_FALLBACK
498 while ((backend_fd = ev_epoll_create ()) < 0)
499 ev_syserr ("(libev) linuxaio epoll_create");
500
501 ev_io_stop (EV_A_ &linuxaio_epoll_w);
502 ev_io_init (EV_A_ &linuxaio_epoll_w, linuxaio_epoll_cb, backend_fd, EV_READ);
503 ev_io_start (EV_A_ &linuxaio_epoll_w);
504#endif
351 505
352 fd_rearm_all (EV_A); 506 fd_rearm_all (EV_A);
353} 507}
354 508

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