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Comparing libev/ev_iouring.c (file contents):
Revision 1.7 by root, Sun Dec 22 15:05:32 2019 UTC vs.
Revision 1.11 by root, Fri Dec 27 21:56:29 2019 UTC

… …
80 * k) overall, the *API* itself is, I dare to say, not a total trainwreck. 80 * k) overall, the *API* itself is, I dare to say, not a total trainwreck.
81 * the big isuess with it are the bugs requiring epoll, which might 81 * the big isuess with it are the bugs requiring epoll, which might
82 * or might not get fixed (do I hold my breath?). 82 * or might not get fixed (do I hold my breath?).
83 */ 83 */
84 84
85/* TODO: use internal TIMEOUT */
86/* TODO: take advantage of single mmap, NODROP etc. */
87/* TODO: resize cq/sq size independently */
88
85#include <sys/timerfd.h> 89#include <sys/timerfd.h>
86#include <sys/mman.h> 90#include <sys/mman.h>
87#include <poll.h> 91#include <poll.h>
88 92
89#define IOURING_INIT_ENTRIES 32 93#define IOURING_INIT_ENTRIES 32
… …
100{ 104{
101 __u8 opcode; 105 __u8 opcode;
102 __u8 flags; 106 __u8 flags;
103 __u16 ioprio; 107 __u16 ioprio;
104 __s32 fd; 108 __s32 fd;
109 union {
105 __u64 off; 110 __u64 off;
111 __u64 addr2;
112 };
106 __u64 addr; 113 __u64 addr;
107 __u32 len; 114 __u32 len;
108 union { 115 union {
109 __kernel_rwf_t rw_flags; 116 __kernel_rwf_t rw_flags;
110 __u32 fsync_flags; 117 __u32 fsync_flags;
111 __u16 poll_events; 118 __u16 poll_events;
112 __u32 sync_range_flags; 119 __u32 sync_range_flags;
113 __u32 msg_flags; 120 __u32 msg_flags;
121 __u32 timeout_flags;
122 __u32 accept_flags;
123 __u32 cancel_flags;
124 __u32 open_flags;
125 __u32 statx_flags;
114 }; 126 };
115 __u64 user_data; 127 __u64 user_data;
116 union { 128 union {
117 __u16 buf_index; 129 __u16 buf_index;
118 __u64 __pad2[3]; 130 __u64 __pad2[3];
… …
155 __u32 sq_entries; 167 __u32 sq_entries;
156 __u32 cq_entries; 168 __u32 cq_entries;
157 __u32 flags; 169 __u32 flags;
158 __u32 sq_thread_cpu; 170 __u32 sq_thread_cpu;
159 __u32 sq_thread_idle; 171 __u32 sq_thread_idle;
172 __u32 features;
160 __u32 resv[5]; 173 __u32 resv[4];
161 struct io_sqring_offsets sq_off; 174 struct io_sqring_offsets sq_off;
162 struct io_cqring_offsets cq_off; 175 struct io_cqring_offsets cq_off;
163}; 176};
164 177
165#define IORING_OP_POLL_ADD 6 178#define IORING_OP_POLL_ADD 6
… …
168#define IORING_ENTER_GETEVENTS 0x01 181#define IORING_ENTER_GETEVENTS 0x01
169 182
170#define IORING_OFF_SQ_RING 0x00000000ULL 183#define IORING_OFF_SQ_RING 0x00000000ULL
171#define IORING_OFF_CQ_RING 0x08000000ULL 184#define IORING_OFF_CQ_RING 0x08000000ULL
172#define IORING_OFF_SQES 0x10000000ULL 185#define IORING_OFF_SQES 0x10000000ULL
186
187#define IORING_FEAT_SINGLE_MMAP 0x1
188#define IORING_FEAT_NODROP 0x2
189#define IORING_FEAT_SUBMIT_STABLE 0x4
173 190
174inline_size 191inline_size
175int 192int
176evsys_io_uring_setup (unsigned entries, struct io_uring_params *params) 193evsys_io_uring_setup (unsigned entries, struct io_uring_params *params)
177{ 194{
… …
240iouring_tfd_cb (EV_P_ struct ev_io *w, int revents) 257iouring_tfd_cb (EV_P_ struct ev_io *w, int revents)
241{ 258{
242 iouring_tfd_to = EV_TSTAMP_HUGE; 259 iouring_tfd_to = EV_TSTAMP_HUGE;
243} 260}
244 261
245static void
246iouring_epoll_cb (EV_P_ struct ev_io *w, int revents)
247{
248 epoll_poll (EV_A_ 0);
249}
250
251/* called for full and partial cleanup */ 262/* called for full and partial cleanup */
252ecb_cold 263ecb_cold
253static int 264static int
254iouring_internal_destroy (EV_P) 265iouring_internal_destroy (EV_P)
255{ 266{
… …
258 269
259 if (iouring_sq_ring != MAP_FAILED) munmap (iouring_sq_ring, iouring_sq_ring_size); 270 if (iouring_sq_ring != MAP_FAILED) munmap (iouring_sq_ring, iouring_sq_ring_size);
260 if (iouring_cq_ring != MAP_FAILED) munmap (iouring_cq_ring, iouring_cq_ring_size); 271 if (iouring_cq_ring != MAP_FAILED) munmap (iouring_cq_ring, iouring_cq_ring_size);
261 if (iouring_sqes != MAP_FAILED) munmap (iouring_sqes , iouring_sqes_size ); 272 if (iouring_sqes != MAP_FAILED) munmap (iouring_sqes , iouring_sqes_size );
262 273
263 if (ev_is_active (&iouring_epoll_w)) ev_ref (EV_A); ev_io_stop (EV_A_ &iouring_epoll_w); 274 if (ev_is_active (&iouring_tfd_w))
264 if (ev_is_active (&iouring_tfd_w )) ev_ref (EV_A); ev_io_stop (EV_A_ &iouring_tfd_w ); 275 {
276 ev_ref (EV_A);
277 ev_io_stop (EV_A_ &iouring_tfd_w);
278 }
265} 279}
266 280
267ecb_cold 281ecb_cold
268static int 282static int
269iouring_internal_init (EV_P) 283iouring_internal_init (EV_P)
… …
284 if (iouring_fd >= 0) 298 if (iouring_fd >= 0)
285 break; /* yippie */ 299 break; /* yippie */
286 300
287 if (errno != EINVAL) 301 if (errno != EINVAL)
288 return -1; /* we failed */ 302 return -1; /* we failed */
303
304#if TODO
305 if ((~params.features) & (IORING_FEAT_NODROP | IORING_FEATURE_SINGLE_MMAP))
306 return -1; /* we require the above features */
307#endif
289 308
290 /* EINVAL: lots of possible reasons, but maybe 309 /* EINVAL: lots of possible reasons, but maybe
291 * it is because we hit the unqueryable hardcoded size limit 310 * it is because we hit the unqueryable hardcoded size limit
292 */ 311 */
293 312
… …
346 iouring_internal_destroy (EV_A); 365 iouring_internal_destroy (EV_A);
347 366
348 while (iouring_internal_init (EV_A) < 0) 367 while (iouring_internal_init (EV_A) < 0)
349 ev_syserr ("(libev) io_uring_setup"); 368 ev_syserr ("(libev) io_uring_setup");
350 369
351 /* forking epoll should also effectively unregister all fds from the backend */
352 epoll_fork (EV_A);
353 /* epoll_fork already did this. hopefully */
354 /*fd_rearm_all (EV_A);*/ 370 fd_rearm_all (EV_A);
355
356 ev_io_stop (EV_A_ &iouring_epoll_w);
357 ev_io_set (EV_A_ &iouring_epoll_w, backend_fd, EV_READ);
358 ev_io_start (EV_A_ &iouring_epoll_w);
359 371
360 ev_io_stop (EV_A_ &iouring_tfd_w); 372 ev_io_stop (EV_A_ &iouring_tfd_w);
361 ev_io_set (EV_A_ &iouring_tfd_w, iouring_tfd, EV_READ); 373 ev_io_set (EV_A_ &iouring_tfd_w, iouring_tfd, EV_READ);
362 ev_io_start (EV_A_ &iouring_tfd_w); 374 ev_io_start (EV_A_ &iouring_tfd_w);
363} 375}
… …
365/*****************************************************************************/ 377/*****************************************************************************/
366 378
367static void 379static void
368iouring_modify (EV_P_ int fd, int oev, int nev) 380iouring_modify (EV_P_ int fd, int oev, int nev)
369{ 381{
370 if (ecb_expect_false (anfds [fd].eflags))
371 {
372 /* we handed this fd over to epoll, so undo this first */
373 /* we do it manually because the optimisations on epoll_modify won't do us any good */
374 epoll_ctl (iouring_fd, EPOLL_CTL_DEL, fd, 0);
375 anfds [fd].eflags = 0;
376 oev = 0;
377 }
378
379 if (oev) 382 if (oev)
380 { 383 {
381 /* we assume the sqe's are all "properly" initialised */ 384 /* we assume the sqe's are all "properly" initialised */
382 struct io_uring_sqe *sqe = iouring_sqe_get (EV_A); 385 struct io_uring_sqe *sqe = iouring_sqe_get (EV_A);
383 sqe->opcode = IORING_OP_POLL_REMOVE; 386 sqe->opcode = IORING_OP_POLL_REMOVE;
… …
432 int fd = cqe->user_data & 0xffffffffU; 435 int fd = cqe->user_data & 0xffffffffU;
433 uint32_t gen = cqe->user_data >> 32; 436 uint32_t gen = cqe->user_data >> 32;
434 int res = cqe->res; 437 int res = cqe->res;
435 438
436 /* ignore fd removal events, if there are any. TODO: verify */ 439 /* ignore fd removal events, if there are any. TODO: verify */
440 /* TODO: yes, this triggers */
437 if (cqe->user_data == (__u64)-1) 441 if (cqe->user_data == (__u64)-1)
438 abort ();//D 442 return;
439 443
440 assert (("libev: io_uring fd must be in-bounds", fd >= 0 && fd < anfdmax)); 444 assert (("libev: io_uring fd must be in-bounds", fd >= 0 && fd < anfdmax));
441 445
442 /* documentation lies, of course. the result value is NOT like 446 /* documentation lies, of course. the result value is NOT like
443 * normal syscalls, but like linux raw syscalls, i.e. negative 447 * normal syscalls, but like linux raw syscalls, i.e. negative
… …
450 if (ecb_expect_false (gen != (uint32_t)anfds [fd].egen)) 454 if (ecb_expect_false (gen != (uint32_t)anfds [fd].egen))
451 return; 455 return;
452 456
453 if (ecb_expect_false (res < 0)) 457 if (ecb_expect_false (res < 0))
454 { 458 {
455 if (res == -EINVAL) 459 /*TODO: EINVAL handling (was something failed with this fd)*/
456 { 460 /*TODO: EBUSY happens when?*/
457 /* we assume this error code means the fd/poll combination is buggy
458 * and fall back to epoll.
459 * this error code might also indicate a bug, but the kernel doesn't
460 * distinguish between those two conditions, so... sigh...
461 */
462 461
463 epoll_modify (EV_A_ fd, 0, anfds [fd].events);
464 }
465 else if (res == -EBADF) 462 if (res == -EBADF)
466 { 463 {
467 assert (("libev: event loop rejected bad fd", res != -EBADF)); 464 assert (("libev: event loop rejected bad fd", res != -EBADF));
468 fd_kill (EV_A_ fd); 465 fd_kill (EV_A_ fd);
469 } 466 }
470 else 467 else
… …
496iouring_overflow (EV_P) 493iouring_overflow (EV_P)
497{ 494{
498 /* we have two options, resize the queue (by tearing down 495 /* we have two options, resize the queue (by tearing down
499 * everything and recreating it, or living with it 496 * everything and recreating it, or living with it
500 * and polling. 497 * and polling.
501 * we implement this by resizing tghe queue, and, if that fails, 498 * we implement this by resizing the queue, and, if that fails,
502 * we just recreate the state on every failure, which 499 * we just recreate the state on every failure, which
503 * kind of is a very inefficient poll. 500 * kind of is a very inefficient poll.
504 * one danger is, due to the bios toward lower fds, 501 * one danger is, due to the bios toward lower fds,
505 * we will only really get events for those, so 502 * we will only really get events for those, so
506 * maybe we need a poll() fallback, after all. 503 * maybe we need a poll() fallback, after all.
… …
518 else 515 else
519 { 516 {
520 /* we hit the kernel limit, we should fall back to something else. 517 /* we hit the kernel limit, we should fall back to something else.
521 * we can either poll() a few times and hope for the best, 518 * we can either poll() a few times and hope for the best,
522 * poll always, or switch to epoll. 519 * poll always, or switch to epoll.
523 * since we use epoll anyways, go epoll. 520 * TODO: is this necessary with newer kernels?
524 */ 521 */
525 522
526 iouring_internal_destroy (EV_A); 523 iouring_internal_destroy (EV_A);
527 524
528 /* this should make it so that on return, we don'T call any uring functions */ 525 /* this should make it so that on return, we don't call any uring functions */
529 iouring_to_submit = 0; 526 iouring_to_submit = 0;
530 527
531 for (;;) 528 for (;;)
532 { 529 {
533 backend = epoll_init (EV_A_ 0); 530 backend = epoll_init (EV_A_ 0);
… …
607 604
608inline_size 605inline_size
609int 606int
610iouring_init (EV_P_ int flags) 607iouring_init (EV_P_ int flags)
611{ 608{
612 if (!epoll_init (EV_A_ 0))
613 return 0;
614
615 iouring_entries = IOURING_INIT_ENTRIES; 609 iouring_entries = IOURING_INIT_ENTRIES;
616 iouring_max_entries = 0; 610 iouring_max_entries = 0;
617 611
618 if (iouring_internal_init (EV_A) < 0) 612 if (iouring_internal_init (EV_A) < 0)
619 { 613 {
620 iouring_internal_destroy (EV_A); 614 iouring_internal_destroy (EV_A);
621 return 0; 615 return 0;
622 } 616 }
623 617
624 ev_io_init (&iouring_epoll_w, iouring_epoll_cb, backend_fd, EV_READ);
625 ev_set_priority (&iouring_epoll_w, EV_MAXPRI);
626
627 ev_io_init (&iouring_tfd_w, iouring_tfd_cb, iouring_tfd, EV_READ); 618 ev_io_init (&iouring_tfd_w, iouring_tfd_cb, iouring_tfd, EV_READ);
628 ev_set_priority (&iouring_tfd_w, EV_MAXPRI); 619 ev_set_priority (&iouring_tfd_w, EV_MINPRI);
629
630 ev_io_start (EV_A_ &iouring_epoll_w);
631 ev_unref (EV_A); /* watcher should not keep loop alive */
632
633 ev_io_start (EV_A_ &iouring_tfd_w); 620 ev_io_start (EV_A_ &iouring_tfd_w);
634 ev_unref (EV_A); /* watcher should not keep loop alive */ 621 ev_unref (EV_A); /* watcher should not keep loop alive */
635 622
636 backend_modify = iouring_modify; 623 backend_modify = iouring_modify;
637 backend_poll = iouring_poll; 624 backend_poll = iouring_poll;
… …
642inline_size 629inline_size
643void 630void
644iouring_destroy (EV_P) 631iouring_destroy (EV_P)
645{ 632{
646 iouring_internal_destroy (EV_A); 633 iouring_internal_destroy (EV_A);
647 epoll_destroy (EV_A);
648} 634}
649 635

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