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Comparing libev/ev_iouring.c (file contents):
Revision 1.10 by root, Fri Dec 27 21:17:11 2019 UTC vs.
Revision 1.17 by root, Sat Dec 28 07:39:18 2019 UTC

… …
87/* TODO: resize cq/sq size independently */ 87/* TODO: resize cq/sq size independently */
88 88
89#include <sys/timerfd.h> 89#include <sys/timerfd.h>
90#include <sys/mman.h> 90#include <sys/mman.h>
91#include <poll.h> 91#include <poll.h>
92#include <stdint.h>
92 93
93#define IOURING_INIT_ENTRIES 32 94#define IOURING_INIT_ENTRIES 32
94 95
95/*****************************************************************************/ 96/*****************************************************************************/
96/* syscall wrapdadoop - this section has the raw api/abi definitions */ 97/* syscall wrapdadoop - this section has the raw api/abi definitions */
… …
173 __u32 resv[4]; 174 __u32 resv[4];
174 struct io_sqring_offsets sq_off; 175 struct io_sqring_offsets sq_off;
175 struct io_cqring_offsets cq_off; 176 struct io_cqring_offsets cq_off;
176}; 177};
177 178
179#define IORING_SETUP_CQSIZE 0x00000008
180
178#define IORING_OP_POLL_ADD 6 181#define IORING_OP_POLL_ADD 6
179#define IORING_OP_POLL_REMOVE 7 182#define IORING_OP_POLL_REMOVE 7
183#define IORING_OP_TIMEOUT 11
184#define IORING_OP_TIMEOUT_REMOVE 12
185
186/* relative or absolute, reference clock is CLOCK_MONOTONIC */
187struct iouring_kernel_timespec
188{
189 int64_t tv_sec;
190 long long tv_nsec;
191};
192
193#define IORING_TIMEOUT_ABS 0x00000001
180 194
181#define IORING_ENTER_GETEVENTS 0x01 195#define IORING_ENTER_GETEVENTS 0x01
182 196
183#define IORING_OFF_SQ_RING 0x00000000ULL 197#define IORING_OFF_SQ_RING 0x00000000ULL
184#define IORING_OFF_CQ_RING 0x08000000ULL 198#define IORING_OFF_CQ_RING 0x08000000ULL
185#define IORING_OFF_SQES 0x10000000ULL 199#define IORING_OFF_SQES 0x10000000ULL
186 200
187#define IORING_FEAT_SINGLE_MMAP 0x1 201#define IORING_FEAT_SINGLE_MMAP 0x00000001
188#define IORING_FEAT_NODROP 0x2 202#define IORING_FEAT_NODROP 0x00000002
189#define IORING_FEAT_SUBMIT_STABLE 0x4 203#define IORING_FEAT_SUBMIT_STABLE 0x00000004
190 204
191inline_size 205inline_size
192int 206int
193evsys_io_uring_setup (unsigned entries, struct io_uring_params *params) 207evsys_io_uring_setup (unsigned entries, struct io_uring_params *params)
194{ 208{
… …
214 228
215/* the submit/completion queue entries */ 229/* the submit/completion queue entries */
216#define EV_SQES ((struct io_uring_sqe *) iouring_sqes) 230#define EV_SQES ((struct io_uring_sqe *) iouring_sqes)
217#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))
218 232
233inline_speed
234int
235iouring_enter (EV_P_ ev_tstamp timeout)
236{
237 int res;
238
239 EV_RELEASE_CB;
240
241 res = evsys_io_uring_enter (iouring_fd, iouring_to_submit, 1,
242 timeout > EV_TS_CONST (0.) ? IORING_ENTER_GETEVENTS : 0, 0, 0);
243
244 assert (("libev: io_uring_enter did not consume all sqes", (res < 0 || res == iouring_to_submit)));
245
246 iouring_to_submit = 0;
247
248 EV_ACQUIRE_CB;
249
250 return res;
251}
252
253/* TODO: can we move things around so we don't need this forward-reference? */
254static void
255iouring_poll (EV_P_ ev_tstamp timeout);
256
219static 257static
220struct io_uring_sqe * 258struct io_uring_sqe *
221iouring_sqe_get (EV_P) 259iouring_sqe_get (EV_P)
222{ 260{
261 unsigned tail;
262
263 for (;;)
264 {
223 unsigned tail = EV_SQ_VAR (tail); 265 tail = EV_SQ_VAR (tail);
224 266
225 if (tail + 1 - EV_SQ_VAR (head) > EV_SQ_VAR (ring_entries)) 267 if (ecb_expect_true (tail + 1 - EV_SQ_VAR (head) <= EV_SQ_VAR (ring_entries)))
268 break; /* whats the problem, we have free sqes */
269
270 /* queue full, need to flush and possibly handle some events */
271
272#if EV_FEATURE_CODE
273 /* first we ask the kernel nicely, most often this frees up some sqes */
274 int res = iouring_enter (EV_A_ EV_TS_CONST (0.));
275
276 ECB_MEMORY_FENCE_ACQUIRE; /* better safe than sorry */
277
278 if (res >= 0)
279 continue; /* yes, it worked, try again */
280#endif
281
282 /* some problem, possibly EBUSY - do the full poll and let it handle any issues */
283
284 iouring_poll (EV_A_ EV_TS_CONST (0.));
285 /* iouring_poll should have done ECB_MEMORY_FENCE_ACQUIRE for us */
226 { 286 }
227 /* queue full, flush */
228 evsys_io_uring_enter (iouring_fd, iouring_to_submit, 0, 0, 0, 0);
229 iouring_to_submit = 0;
230 }
231 287
232 assert (("libev: io_uring queue full after flush", tail + 1 - EV_SQ_VAR (head) <= EV_SQ_VAR (ring_entries))); 288 /*assert (("libev: io_uring queue full after flush", tail + 1 - EV_SQ_VAR (head) <= EV_SQ_VAR (ring_entries)));*/
233 289
234 return EV_SQES + (tail & EV_SQ_VAR (ring_mask)); 290 return EV_SQES + (tail & EV_SQ_VAR (ring_mask));
235} 291}
236 292
237inline_size 293inline_size
… …
289 iouring_tfd = -1; 345 iouring_tfd = -1;
290 iouring_sq_ring = MAP_FAILED; 346 iouring_sq_ring = MAP_FAILED;
291 iouring_cq_ring = MAP_FAILED; 347 iouring_cq_ring = MAP_FAILED;
292 iouring_sqes = MAP_FAILED; 348 iouring_sqes = MAP_FAILED;
293 349
350 if (!have_monotonic) /* cannot really happen, but what if11 */
351 return -1;
352
294 for (;;) 353 for (;;)
295 { 354 {
296 iouring_fd = evsys_io_uring_setup (iouring_entries, &params); 355 iouring_fd = evsys_io_uring_setup (iouring_entries, &params);
297 356
298 if (iouring_fd >= 0) 357 if (iouring_fd >= 0)
299 break; /* yippie */ 358 break; /* yippie */
300 359
301 if (errno != EINVAL) 360 if (errno != EINVAL)
302 return -1; /* we failed */ 361 return -1; /* we failed */
362
363#if TODO
364 if ((~params.features) & (IORING_FEAT_NODROP | IORING_FEATURE_SINGLE_MMAP | IORING_FEAT_SUBMIT_STABLE))
365 return -1; /* we require the above features */
366#endif
303 367
304 /* EINVAL: lots of possible reasons, but maybe 368 /* EINVAL: lots of possible reasons, but maybe
305 * it is because we hit the unqueryable hardcoded size limit 369 * it is because we hit the unqueryable hardcoded size limit
306 */ 370 */
307 371
… …
378 { 442 {
379 /* we assume the sqe's are all "properly" initialised */ 443 /* we assume the sqe's are all "properly" initialised */
380 struct io_uring_sqe *sqe = iouring_sqe_get (EV_A); 444 struct io_uring_sqe *sqe = iouring_sqe_get (EV_A);
381 sqe->opcode = IORING_OP_POLL_REMOVE; 445 sqe->opcode = IORING_OP_POLL_REMOVE;
382 sqe->fd = fd; 446 sqe->fd = fd;
447 /* Jens Axboe notified me that user_data is not what is documented, but is
448 * some kind of unique ID that has to match, otherwise the request cannot
449 * be removed. Since we don't *really* have that, we pass in the old
450 * generation counter - if that fails, too bad, it will hopefully be removed
451 * at close time and then be ignored. */
452 sqe->addr = (uint32_t)fd | ((__u64)(uint32_t)anfds [fd].egen << 32);
383 sqe->user_data = -1; 453 sqe->user_data = (uint64_t)-1;
384 iouring_sqe_submit (EV_A_ sqe); 454 iouring_sqe_submit (EV_A_ sqe);
385 455
386 /* increment generation counter to avoid handling old events */ 456 /* increment generation counter to avoid handling old events */
387 ++anfds [fd].egen; 457 ++anfds [fd].egen;
388 } 458 }
… …
429{ 499{
430 int fd = cqe->user_data & 0xffffffffU; 500 int fd = cqe->user_data & 0xffffffffU;
431 uint32_t gen = cqe->user_data >> 32; 501 uint32_t gen = cqe->user_data >> 32;
432 int res = cqe->res; 502 int res = cqe->res;
433 503
434 /* ignore fd removal events, if there are any. TODO: verify */ 504 /* user_data -1 is a remove that we are not atm. interested in */
435 /* TODO: yes, this triggers */
436 if (cqe->user_data == (__u64)-1) 505 if (cqe->user_data == (uint64_t)-1)
437 return; 506 return;
438 507
439 assert (("libev: io_uring fd must be in-bounds", fd >= 0 && fd < anfdmax)); 508 assert (("libev: io_uring fd must be in-bounds", fd >= 0 && fd < anfdmax));
440 509
441 /* documentation lies, of course. the result value is NOT like 510 /* documentation lies, of course. the result value is NOT like
… …
443 * error numbers. fortunate, as otherwise there would be no way 512 * error numbers. fortunate, as otherwise there would be no way
444 * to get error codes at all. still, why not document this? 513 * to get error codes at all. still, why not document this?
445 */ 514 */
446 515
447 /* ignore event if generation doesn't match */ 516 /* ignore event if generation doesn't match */
517 /* other than skipping removal events, */
448 /* this should actually be very rare */ 518 /* this should actually be very rare */
449 if (ecb_expect_false (gen != (uint32_t)anfds [fd].egen)) 519 if (ecb_expect_false (gen != (uint32_t)anfds [fd].egen))
450 return; 520 return;
451 521
452 if (ecb_expect_false (res < 0)) 522 if (ecb_expect_false (res < 0))
453 { 523 {
454 //TODO: EINVAL handling (was something failed with this fd) 524 /*TODO: EINVAL handling (was something failed with this fd)*/
455 //TODO: EBUSY happens when? 525 /*TODO: EBUSY happens when?*/
456 526
457 if (res == -EBADF) 527 if (res == -EBADF)
458 { 528 {
459 assert (("libev: event loop rejected bad fd", res != -EBADF)); 529 assert (("libev: event loop rejected bad fd", res != -EBADF));
460 fd_kill (EV_A_ fd); 530 fd_kill (EV_A_ fd);
… …
566 636
567static void 637static void
568iouring_poll (EV_P_ ev_tstamp timeout) 638iouring_poll (EV_P_ ev_tstamp timeout)
569{ 639{
570 /* if we have events, no need for extra syscalls, but we might have to queue events */ 640 /* if we have events, no need for extra syscalls, but we might have to queue events */
641 /* we also clar the timeout if there are outstanding fdchanges */
642 /* the latter should only happen if both the sq and cq are full, most likely */
643 /* because we have a lot of event sources that immediately complete */
644 /* TODO: fdchacngecnt is always 0 because fd_reify does not have two buffers yet */
571 if (iouring_handle_cq (EV_A)) 645 if (iouring_handle_cq (EV_A) || fdchangecnt)
572 timeout = EV_TS_CONST (0.); 646 timeout = EV_TS_CONST (0.);
573 else 647 else
574 /* no events, so maybe wait for some */ 648 /* no events, so maybe wait for some */
575 iouring_tfd_update (EV_A_ timeout); 649 iouring_tfd_update (EV_A_ timeout);
576 650
577 /* only enter the kernel if we have something to submit, or we need to wait */ 651 /* only enter the kernel if we have something to submit, or we need to wait */
578 if (timeout || iouring_to_submit) 652 if (timeout || iouring_to_submit)
579 { 653 {
580 int res; 654 int res = iouring_enter (EV_A_ timeout);
581
582 EV_RELEASE_CB;
583
584 res = evsys_io_uring_enter (iouring_fd, iouring_to_submit, 1,
585 timeout > EV_TS_CONST (0.) ? IORING_ENTER_GETEVENTS : 0, 0, 0);
586 iouring_to_submit = 0;
587
588 EV_ACQUIRE_CB;
589 655
590 if (ecb_expect_false (res < 0)) 656 if (ecb_expect_false (res < 0))
591 if (errno == EINTR) 657 if (errno == EINTR)
592 /* ignore */; 658 /* ignore */;
659 else if (errno == EBUSY)
660 /* cq full, cannot submit - should be rare because we flush the cq first, so simply ignore */;
593 else 661 else
594 ev_syserr ("(libev) iouring setup"); 662 ev_syserr ("(libev) iouring setup");
595 else 663 else
596 iouring_handle_cq (EV_A); 664 iouring_handle_cq (EV_A);
597 } 665 }

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