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Comparing libev/ev_linuxaio.c (file contents):
Revision 1.9 by root, Sat Jun 22 22:29:38 2019 UTC vs.
Revision 1.10 by root, Sun Jun 23 02:02:24 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>
45
46#if EPOLL_FALLBACK
47# include <sys/epoll.h>
48#endif
43 49
44/* we try to fill 4kB 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 * therefore the calculation below will use "exactly" 4kB for the ring buffer 53 * therefore the calculation below will use "exactly" 4kB for the ring buffer
… …
148static void 154static void
149linuxaio_modify (EV_P_ int fd, int oev, int nev) 155linuxaio_modify (EV_P_ int fd, int oev, int nev)
150{ 156{
151 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);
152 struct aniocb *iocb = linuxaio_iocbps [fd]; 158 struct aniocb *iocb = linuxaio_iocbps [fd];
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
153 167
154 if (iocb->io.aio_buf) 168 if (iocb->io.aio_buf)
155 ev_io_cancel (linuxaio_ctx, &iocb->io, (struct io_event *)0); /* always returns an error relevant kernels */ 169 ev_io_cancel (linuxaio_ctx, &iocb->io, (struct io_event *)0); /* always returns an error relevant kernels */
156 170
157 if (nev) 171 if (nev)
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255 ts.tv_nsec = (long)((timeout - ts.tv_sec) * 1e9); 269 ts.tv_nsec = (long)((timeout - ts.tv_sec) * 1e9);
256 270
257 res = ev_io_getevents (linuxaio_ctx, 1, 1, &ioev, &ts); 271 res = ev_io_getevents (linuxaio_ctx, 1, 1, &ioev, &ts);
258 272
259 if (res < 0) 273 if (res < 0)
274 if (errno == EINTR)
275 /* ignored */;
276 else
260 ev_syserr ("(libev) linuxaio io_getevents"); 277 ev_syserr ("(libev) linuxaio io_getevents");
261 else if (res) 278 else if (res)
262 { 279 {
263 /* at least one event received, handle it and any remaining ones in the ring buffer */ 280 /* at least one event received, handle it and any remaining ones in the ring buffer */
264 linuxaio_parse_events (EV_A_ &ioev, 1); 281 linuxaio_parse_events (EV_A_ &ioev, 1);
265 linuxaio_get_events_from_ring (EV_A); 282 linuxaio_get_events_from_ring (EV_A);
266 } 283 }
267} 284}
285
286#if EPOLL_FALLBACK
287static void
288linuxaio_rearm_epoll (EV_P_ struct iocb *iocb, int op)
289{
290 struct epoll_event eev;
291
292 eev.events = EPOLLONESHOT;
293 if (iocb->aio_buf & POLLIN ) eev.events |= EPOLLIN ;
294 if (iocb->aio_buf & POLLOUT) eev.events |= EPOLLOUT;
295 eev.data.fd = iocb->aio_fildes;
296
297 if (epoll_ctl (backend_fd, op, iocb->aio_fildes, &eev) < 0)
298 ev_syserr ("(libeio) linuxaio epoll_ctl");
299}
300#endif
268 301
269static void 302static void
270linuxaio_poll (EV_P_ ev_tstamp timeout) 303linuxaio_poll (EV_P_ ev_tstamp timeout)
271{ 304{
272 int submitted; 305 int submitted;
… …
283 if (ecb_expect_false (res < 0)) 316 if (ecb_expect_false (res < 0))
284 if (errno == EAGAIN) 317 if (errno == EAGAIN)
285 { 318 {
286 /* This happens when the ring buffer is full, at least. I assume this means 319 /* This happens when the ring buffer is full, at least. I assume this means
287 * that the event was queued synchronously during io_submit, and thus 320 * that the event was queued synchronously during io_submit, and thus
288 * the buffer overflowd. 321 * the buffer overflowed.
289 * In this case, we just try next loop iteration. 322 * In this case, we just try in next loop iteration.
290 * This should not result in a few fds taking priority, as the interface 323 * This should not result in a few fds taking priority, as the interface
291 * is one-shot, and we submit iocb's in a round-robin fashion. 324 * is one-shot, and we submit iocb's in a round-robin fashion.
292 */ 325 */
293 memmove (linuxaio_submits, linuxaio_submits + submitted, (linuxaio_submitcnt - submitted) * sizeof (*linuxaio_submits)); 326 memmove (linuxaio_submits, linuxaio_submits + submitted, (linuxaio_submitcnt - submitted) * sizeof (*linuxaio_submits));
294 linuxaio_submitcnt -= submitted; 327 linuxaio_submitcnt -= submitted;
295 timeout = 0; 328 timeout = 0;
296 break; 329 break;
297 } 330 }
331#if EPOLL_FALLBACK
332 else if (errno == EINVAL)
333 {
334 /* This hapüpens for unsupported fds, officially, but in my testing,
335 * also randomly happens for supported fds. We fall back to good old
336 * poll() here, under the assumption that this is a very rare case.
337 */
338 struct iocb *iocb = linuxaio_submits [submitted];
339 res = 1; /* skip this iocb */
340
341 linuxaio_rearm_epoll (EV_A_ iocb, EPOLL_CTL_ADD);
342 iocb->aio_reqprio = -1; /* mark iocb as epoll */
343 }
344#endif
298 else 345 else
299 ev_syserr ("(libev) linuxaio io_submit"); 346 ev_syserr ("(libev) linuxaio io_submit");
300 347
301 submitted += res; 348 submitted += res;
302 } 349 }
… …
305 352
306 /* second phase: fetch and parse events */ 353 /* second phase: fetch and parse events */
307 354
308 linuxaio_get_events (EV_A_ timeout); 355 linuxaio_get_events (EV_A_ timeout);
309} 356}
357
358#if EPOLL_FALLBACK
359
360static void
361linuxaio_epoll_cb (EV_P_ struct ev_io *w, int revents)
362{
363 struct epoll_event events[16];
364
365 for (;;)
366 {
367 int idx;
368 int res = epoll_wait (backend_fd, events, sizeof (events) / sizeof (events [0]), 0);
369
370 if (ecb_expect_false (res < 0))
371 ev_syserr ("(libev) linuxaio epoll_wait");
372 else if (!res)
373 break;
374
375 for (idx = res; idx--; )
376 {
377 int fd = events [idx].data.fd;
378 uint32_t ev = events [idx].events;
379
380 assert (("libev: iocb fd must be in-bounds", fd >= 0 && fd < anfdmax));
381
382 linuxaio_rearm_epoll (EV_A_ &linuxaio_iocbps [fd]->io, EPOLL_CTL_MOD);
383
384 fd_event (EV_A_ fd,
385 (ev & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0)
386 | (ev & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0));
387 }
388
389 if (res < sizeof (events) / sizeof (events [0]))
390 break;
391 }
392}
393
394#endif
310 395
311inline_size 396inline_size
312int 397int
313linuxaio_init (EV_P_ int flags) 398linuxaio_init (EV_P_ int flags)
314{ 399{
… …
319 404
320 linuxaio_ctx = 0; 405 linuxaio_ctx = 0;
321 if (ev_io_setup (EV_LINUXAIO_DEPTH, &linuxaio_ctx) < 0) 406 if (ev_io_setup (EV_LINUXAIO_DEPTH, &linuxaio_ctx) < 0)
322 return 0; 407 return 0;
323 408
409#if EPOLL_FALLBACK
410 backend_fd = ev_epoll_create ();
411 if (backend_fd < 0)
412 {
413 ev_io_destroy (linuxaio_ctx);
414 return 0;
415 }
416
417 ev_io_init (EV_A_ &linuxaio_epoll_w, linuxaio_epoll_cb, backend_fd, EV_READ);
418 ev_io_start (EV_A_ &linuxaio_epoll_w);
419#endif
420
324 backend_modify = linuxaio_modify; 421 backend_modify = linuxaio_modify;
325 backend_poll = linuxaio_poll; 422 backend_poll = linuxaio_poll;
326 423
327 linuxaio_iocbpmax = 0; 424 linuxaio_iocbpmax = 0;
328 linuxaio_iocbps = 0; 425 linuxaio_iocbps = 0;
… …
336 433
337inline_size 434inline_size
338void 435void
339linuxaio_destroy (EV_P) 436linuxaio_destroy (EV_P)
340{ 437{
438#if EPOLL_FALLBACK
439 close (backend_fd);
440#endif
341 linuxaio_free_iocbp (EV_A); 441 linuxaio_free_iocbp (EV_A);
342 ev_io_destroy (linuxaio_ctx); 442 ev_io_destroy (linuxaio_ctx);
343} 443}
344 444
345inline_size 445inline_size
… …
352 452
353 linuxaio_ctx = 0; 453 linuxaio_ctx = 0;
354 while (ev_io_setup (EV_LINUXAIO_DEPTH, &linuxaio_ctx) < 0) 454 while (ev_io_setup (EV_LINUXAIO_DEPTH, &linuxaio_ctx) < 0)
355 ev_syserr ("(libev) linuxaio io_setup"); 455 ev_syserr ("(libev) linuxaio io_setup");
356 456
457#if EPOLL_FALLBACK
458 while ((backend_fd = ev_epoll_create ()) < 0)
459 ev_syserr ("(libev) linuxaio epoll_create");
460
461 ev_io_stop (EV_A_ &linuxaio_epoll_w);
462 ev_io_init (EV_A_ &linuxaio_epoll_w, linuxaio_epoll_cb, backend_fd, EV_READ);
463 ev_io_start (EV_A_ &linuxaio_epoll_w);
464 ev_unref (EV_A); /* watcher should not keep loop alive */
465#endif
466
357 fd_rearm_all (EV_A); 467 fd_rearm_all (EV_A);
358} 468}
359 469

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