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/cvs/libev/ev_iouring.c
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Comparing libev/ev_iouring.c (file contents):
Revision 1.12 by root, Fri Dec 27 22:16:10 2019 UTC vs.
Revision 1.14 by root, Sat Dec 28 05:20:17 2019 UTC

… …
228 228
229/* the submit/completion queue entries */ 229/* the submit/completion queue entries */
230#define EV_SQES ((struct io_uring_sqe *) iouring_sqes) 230#define EV_SQES ((struct io_uring_sqe *) iouring_sqes)
231#define EV_CQES ((struct io_uring_cqe *)((char *)iouring_cq_ring + iouring_cq_cqes)) 231#define EV_CQES ((struct io_uring_cqe *)((char *)iouring_cq_ring + iouring_cq_cqes))
232 232
233/* TODO: this is not enough, we might have to reap events */
234/* TODO: but we can't, as that will re-arm events, causing */
235/* TODO: an endless loop in fd_reify */
236static int
237iouring_enter (EV_P_ ev_tstamp timeout)
238{
239 int res;
240
241 EV_RELEASE_CB;
242
243 res = evsys_io_uring_enter (iouring_fd, iouring_to_submit, 1,
244 timeout > EV_TS_CONST (0.) ? IORING_ENTER_GETEVENTS : 0, 0, 0);
245
246 assert (("libev: io_uring_enter did not consume all sqes", (res < 0 || res == iouring_to_submit)));
247
248 iouring_to_submit = 0;
249
250 EV_ACQUIRE_CB;
251
252 return res;
253}
254
233static 255static
234struct io_uring_sqe * 256struct io_uring_sqe *
235iouring_sqe_get (EV_P) 257iouring_sqe_get (EV_P)
236{ 258{
237 unsigned tail = EV_SQ_VAR (tail); 259 unsigned tail = EV_SQ_VAR (tail);
238 260
239 if (tail + 1 - EV_SQ_VAR (head) > EV_SQ_VAR (ring_entries)) 261 while (ecb_expect_false (tail + 1 - EV_SQ_VAR (head) > EV_SQ_VAR (ring_entries)))
240 { 262 {
241 /* queue full, flush */ 263 /* queue full, need to flush */
242 evsys_io_uring_enter (iouring_fd, iouring_to_submit, 0, 0, 0, 0);
243 iouring_to_submit = 0;
244 }
245 264
265 int res = iouring_enter (EV_A_ EV_TS_CONST (0.));
266
267 /* io_uring_enter might fail with EBUSY and won't submit anything */
268 /* unfortunately, we can't handle this at the moment */
269
270 if (res < 0 && errno == EBUSY)
271 //TODO
272 ev_syserr ("(libev) io_uring_enter could not clear sq");
273 else
274 break;
275
276 /* iouring_poll should have done ECB_MEMORY_FENCE_ACQUIRE */
277 }
278
246 assert (("libev: io_uring queue full after flush", tail + 1 - EV_SQ_VAR (head) <= EV_SQ_VAR (ring_entries))); 279 /*assert (("libev: io_uring queue full after flush", tail + 1 - EV_SQ_VAR (head) <= EV_SQ_VAR (ring_entries)));*/
247 280
248 return EV_SQES + (tail & EV_SQ_VAR (ring_mask)); 281 return EV_SQES + (tail & EV_SQ_VAR (ring_mask));
249} 282}
250 283
251inline_size 284inline_size
… …
400 { 433 {
401 /* we assume the sqe's are all "properly" initialised */ 434 /* we assume the sqe's are all "properly" initialised */
402 struct io_uring_sqe *sqe = iouring_sqe_get (EV_A); 435 struct io_uring_sqe *sqe = iouring_sqe_get (EV_A);
403 sqe->opcode = IORING_OP_POLL_REMOVE; 436 sqe->opcode = IORING_OP_POLL_REMOVE;
404 sqe->fd = fd; 437 sqe->fd = fd;
405 sqe->user_data = -1; 438 /* Jens Axboe notified me that user_data is not what is documented, but is
439 * some kind of unique ID that has to match, otherwise the request cannot
440 * be removed. Since we don't *really* have that, we pass in the old
441 * generation counter - if that fails, too bad, it will hopefully be removed
442 * at close time and then be ignored. */
443 sqe->user_data = (uint32_t)fd | ((__u64)(uint32_t)anfds [fd].egen << 32);
406 iouring_sqe_submit (EV_A_ sqe); 444 iouring_sqe_submit (EV_A_ sqe);
407 445
408 /* increment generation counter to avoid handling old events */ 446 /* increment generation counter to avoid handling old events */
409 ++anfds [fd].egen; 447 ++anfds [fd].egen;
410 } 448 }
… …
451{ 489{
452 int fd = cqe->user_data & 0xffffffffU; 490 int fd = cqe->user_data & 0xffffffffU;
453 uint32_t gen = cqe->user_data >> 32; 491 uint32_t gen = cqe->user_data >> 32;
454 int res = cqe->res; 492 int res = cqe->res;
455 493
456 /* ignore fd removal events, if there are any. TODO: verify */
457 /* TODO: yes, this triggers */
458 if (cqe->user_data == (__u64)-1)
459 return;
460
461 assert (("libev: io_uring fd must be in-bounds", fd >= 0 && fd < anfdmax)); 494 assert (("libev: io_uring fd must be in-bounds", fd >= 0 && fd < anfdmax));
462 495
463 /* documentation lies, of course. the result value is NOT like 496 /* documentation lies, of course. the result value is NOT like
464 * normal syscalls, but like linux raw syscalls, i.e. negative 497 * normal syscalls, but like linux raw syscalls, i.e. negative
465 * error numbers. fortunate, as otherwise there would be no way 498 * error numbers. fortunate, as otherwise there would be no way
466 * to get error codes at all. still, why not document this? 499 * to get error codes at all. still, why not document this?
467 */ 500 */
468 501
469 /* ignore event if generation doesn't match */ 502 /* ignore event if generation doesn't match */
503 /* other than skipping removal events, */
470 /* this should actually be very rare */ 504 /* this should actually be very rare */
471 if (ecb_expect_false (gen != (uint32_t)anfds [fd].egen)) 505 if (ecb_expect_false (gen != (uint32_t)anfds [fd].egen))
472 return; 506 return;
473 507
474 if (ecb_expect_false (res < 0)) 508 if (ecb_expect_false (res < 0))
… …
597 iouring_tfd_update (EV_A_ timeout); 631 iouring_tfd_update (EV_A_ timeout);
598 632
599 /* only enter the kernel if we have something to submit, or we need to wait */ 633 /* only enter the kernel if we have something to submit, or we need to wait */
600 if (timeout || iouring_to_submit) 634 if (timeout || iouring_to_submit)
601 { 635 {
602 int res; 636 int res = iouring_enter (EV_A_ timeout);
603
604 EV_RELEASE_CB;
605
606 res = evsys_io_uring_enter (iouring_fd, iouring_to_submit, 1,
607 timeout > EV_TS_CONST (0.) ? IORING_ENTER_GETEVENTS : 0, 0, 0);
608 iouring_to_submit = 0;
609
610 EV_ACQUIRE_CB;
611 637
612 if (ecb_expect_false (res < 0)) 638 if (ecb_expect_false (res < 0))
613 if (errno == EINTR) 639 if (errno == EINTR)
614 /* ignore */; 640 /* ignore */;
641 else if (errno == EBUSY)
642 /* cq full, cannot submit - should be rare because we flush the cq first, so simply ignore */;
615 else 643 else
616 ev_syserr ("(libev) iouring setup"); 644 ev_syserr ("(libev) iouring setup");
617 else 645 else
618 iouring_handle_cq (EV_A); 646 iouring_handle_cq (EV_A);
619 } 647 }

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