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Comparing libev/ev_linuxaio.c (file contents):
Revision 1.28 by root, Tue Jun 25 06:36:59 2019 UTC vs.
Revision 1.34 by root, Wed Jun 26 00:01:46 2019 UTC

… …
116 unsigned header_length; /* size of aio_ring */ 116 unsigned header_length; /* size of aio_ring */
117 117
118 struct io_event io_events[0]; 118 struct io_event io_events[0];
119}; 119};
120 120
121/*
122 * define some syscall wrappers for common architectures
123 * this is mostly for nice looks during debugging, not performance.
124 * our syscalls return < 0, not == -1, on error. which is good
125 * enough for linux aio.
126 * TODO: arm is also common nowadays, maybe even mips and x86
127 * TODO: after implementing this, it suddenly looks like overkill, but its hard to remove...
128 */
129#if __GNUC__ && __linux && ECB_AMD64 && !defined __OPTIMIZE_SIZE__
130 /* the costly errno access probably kills this for size optimisation */
131
132 #define ev_syscall(nr,narg,arg1,arg2,arg3,arg4,arg5) \
133 ({ \
134 long res; \
135 register unsigned long r5 __asm__ ("r8" ); \
136 register unsigned long r4 __asm__ ("r10"); \
137 register unsigned long r3 __asm__ ("rdx"); \
138 register unsigned long r2 __asm__ ("rsi"); \
139 register unsigned long r1 __asm__ ("rdi"); \
140 if (narg >= 5) r5 = (unsigned long)(arg5); \
141 if (narg >= 4) r4 = (unsigned long)(arg4); \
142 if (narg >= 3) r3 = (unsigned long)(arg3); \
143 if (narg >= 2) r2 = (unsigned long)(arg2); \
144 if (narg >= 1) r1 = (unsigned long)(arg1); \
145 __asm__ __volatile__ ( \
146 "syscall\n\t" \
147 : "=a" (res) \
148 : "0" (nr), "r" (r1), "r" (r2), "r" (r3), "r" (r4), "r" (r5) \
149 : "cc", "r11", "cx", "memory"); \
150 errno = -res; \
151 res; \
152 })
153
154#endif
155
156#ifdef ev_syscall
157 #define ev_syscall0(nr) ev_syscall (nr, 0, 0, 0, 0, 0, 0
158 #define ev_syscall1(nr,arg1) ev_syscall (nr, 1, arg1, 0, 0, 0, 0)
159 #define ev_syscall2(nr,arg1,arg2) ev_syscall (nr, 2, arg1, arg2, 0, 0, 0)
160 #define ev_syscall3(nr,arg1,arg2,arg3) ev_syscall (nr, 3, arg1, arg2, arg3, 0, 0)
161 #define ev_syscall4(nr,arg1,arg2,arg3,arg4) ev_syscall (nr, 3, arg1, arg2, arg3, arg4, 0)
162 #define ev_syscall5(nr,arg1,arg2,arg3,arg4,arg5) ev_syscall (nr, 5, arg1, arg2, arg3, arg4, arg5)
163#else
164 #define ev_syscall0(nr) syscall (nr)
165 #define ev_syscall1(nr,arg1) syscall (nr, arg1)
166 #define ev_syscall2(nr,arg1,arg2) syscall (nr, arg1, arg2)
167 #define ev_syscall3(nr,arg1,arg2,arg3) syscall (nr, arg1, arg2, arg3)
168 #define ev_syscall4(nr,arg1,arg2,arg3,arg4) syscall (nr, arg1, arg2, arg3, arg4)
169 #define ev_syscall5(nr,arg1,arg2,arg3,arg4,arg5) syscall (nr, arg1, arg2, arg3, arg4, arg5)
170#endif
171
121inline_size 172inline_size
122int 173int
123evsys_io_setup (unsigned nr_events, aio_context_t *ctx_idp) 174evsys_io_setup (unsigned nr_events, aio_context_t *ctx_idp)
124{ 175{
125 return syscall (SYS_io_setup, nr_events, ctx_idp); 176 return ev_syscall2 (SYS_io_setup, nr_events, ctx_idp);
126} 177}
127 178
128inline_size 179inline_size
129int 180int
130evsys_io_destroy (aio_context_t ctx_id) 181evsys_io_destroy (aio_context_t ctx_id)
131{ 182{
132 return syscall (SYS_io_destroy, ctx_id); 183 return ev_syscall1 (SYS_io_destroy, ctx_id);
133} 184}
134 185
135inline_size 186inline_size
136int 187int
137evsys_io_submit (aio_context_t ctx_id, long nr, struct iocb *cbp[]) 188evsys_io_submit (aio_context_t ctx_id, long nr, struct iocb *cbp[])
138{ 189{
139 return syscall (SYS_io_submit, ctx_id, nr, cbp); 190 return ev_syscall3 (SYS_io_submit, ctx_id, nr, cbp);
140} 191}
141 192
142inline_size 193inline_size
143int 194int
144evsys_io_cancel (aio_context_t ctx_id, struct iocb *cbp, struct io_event *result) 195evsys_io_cancel (aio_context_t ctx_id, struct iocb *cbp, struct io_event *result)
145{ 196{
146 return syscall (SYS_io_cancel, ctx_id, cbp, result); 197 return ev_syscall3 (SYS_io_cancel, ctx_id, cbp, result);
147} 198}
148 199
149inline_size 200inline_size
150int 201int
151evsys_io_getevents (aio_context_t ctx_id, long min_nr, long nr, struct io_event *events, struct timespec *timeout) 202evsys_io_getevents (aio_context_t ctx_id, long min_nr, long nr, struct io_event *events, struct timespec *timeout)
152{ 203{
153 return syscall (SYS_io_getevents, ctx_id, min_nr, nr, events, timeout); 204 return ev_syscall5 (SYS_io_getevents, ctx_id, min_nr, nr, events, timeout);
154} 205}
155 206
156/*****************************************************************************/ 207/*****************************************************************************/
157/* actual backed implementation */ 208/* actual backed implementation */
158 209
… …
238 ANIOCBP iocb = linuxaio_iocbps [fd]; 289 ANIOCBP iocb = linuxaio_iocbps [fd];
239 290
240 if (iocb->io.aio_reqprio < 0) 291 if (iocb->io.aio_reqprio < 0)
241 { 292 {
242 /* we handed this fd over to epoll, so undo this first */ 293 /* we handed this fd over to epoll, so undo this first */
243 /* we do it manually because the optimisations on epoll_modfy won't do us any good */ 294 /* we do it manually because the optimisations on epoll_modify won't do us any good */
244 epoll_ctl (backend_fd, EPOLL_CTL_DEL, fd, 0); 295 epoll_ctl (backend_fd, EPOLL_CTL_DEL, fd, 0);
296 anfds [fd].emask = 0;
245 iocb->io.aio_reqprio = 0; 297 iocb->io.aio_reqprio = 0;
246 } 298 }
247 299
248 if (iocb->io.aio_buf) 300 if (iocb->io.aio_buf)
249 /* io_cancel always returns some error on relevant kernels, but works */ 301 {
250 evsys_io_cancel (linuxaio_ctx, &iocb->io, (struct io_event *)0); 302 evsys_io_cancel (linuxaio_ctx, &iocb->io, (struct io_event *)0);
303 /* on relevant kernels, io_cancel fails with EINPROGRES if everything is fine */
304 assert (("libev: linuxaio unexpected io_cancel failed", errno != EINPROGRESS));
305 }
251 306
252 if (nev) 307 if (nev)
253 { 308 {
254 iocb->io.aio_buf = 309 iocb->io.aio_buf =
255 (nev & EV_READ ? POLLIN : 0) 310 (nev & EV_READ ? POLLIN : 0)
… …
337 } 392 }
338 393
339 ECB_MEMORY_FENCE_RELEASE; 394 ECB_MEMORY_FENCE_RELEASE;
340 /* as an extension to C, we hope that the volatile will make this atomic and once-only */ 395 /* as an extension to C, we hope that the volatile will make this atomic and once-only */
341 *(volatile unsigned *)&ring->head = tail; 396 *(volatile unsigned *)&ring->head = tail;
342 /* make sure kernel can see our new head value - probably not required */
343 397
344 return 1; 398 return 1;
345} 399}
346 400
347/* read at least one event from kernel, or timeout */ 401/* read at least one event from kernel, or timeout */
… …
374 /* ignored */; 428 /* ignored */;
375 else 429 else
376 ev_syserr ("(libev) linuxaio io_getevents"); 430 ev_syserr ("(libev) linuxaio io_getevents");
377 else if (res) 431 else if (res)
378 { 432 {
379 /* at least one event received, handle it and any remaining ones in the ring buffer */ 433 /* at least one event available, handle it and any remaining ones in the ring buffer */
380 linuxaio_parse_events (EV_A_ ioev, res); 434 linuxaio_parse_events (EV_A_ ioev, res);
381 linuxaio_get_events_from_ring (EV_A); 435 linuxaio_get_events_from_ring (EV_A);
382 } 436 }
383} 437}
384 438
385static int 439inline_size
440int
386linuxaio_io_setup (EV_P) 441linuxaio_io_setup (EV_P)
387{ 442{
388 linuxaio_ctx = 0; 443 linuxaio_ctx = 0;
389 return evsys_io_setup (linuxaio_nr_events (EV_A), &linuxaio_ctx); 444 return evsys_io_setup (linuxaio_nr_events (EV_A), &linuxaio_ctx);
390} 445}
… …
456 /* it's easiest to handle this mess in another iteration */ 511 /* it's easiest to handle this mess in another iteration */
457 return; 512 return;
458 } 513 }
459 else if (errno == EBADF) 514 else if (errno == EBADF)
460 { 515 {
516 assert (("libev: event loop rejected bad fd", errno != EBADF));
461 fd_kill (EV_A_ linuxaio_submits [submitted]->aio_fildes); 517 fd_kill (EV_A_ linuxaio_submits [submitted]->aio_fildes);
462 518
463 res = 1; /* skip this iocb */ 519 res = 1; /* skip this iocb */
464 } 520 }
465 else 521 else
… …
518void 574void
519linuxaio_destroy (EV_P) 575linuxaio_destroy (EV_P)
520{ 576{
521 epoll_destroy (EV_A); 577 epoll_destroy (EV_A);
522 linuxaio_free_iocbp (EV_A); 578 linuxaio_free_iocbp (EV_A);
523 evsys_io_destroy (linuxaio_ctx); 579 evsys_io_destroy (linuxaio_ctx); /* fails in child, aio context is destroyed */
524} 580}
525 581
526inline_size 582inline_size
527void 583void
528linuxaio_fork (EV_P) 584linuxaio_fork (EV_P)
… …
534 linuxaio_iteration = 0; /* we start over in the child */ 590 linuxaio_iteration = 0; /* we start over in the child */
535 591
536 while (linuxaio_io_setup (EV_A) < 0) 592 while (linuxaio_io_setup (EV_A) < 0)
537 ev_syserr ("(libev) linuxaio io_setup"); 593 ev_syserr ("(libev) linuxaio io_setup");
538 594
595 /* forking epoll should also effectively unregister all fds from the backend */
539 epoll_fork (EV_A); 596 epoll_fork (EV_A);
540 597
541 ev_io_stop (EV_A_ &linuxaio_epoll_w); 598 ev_io_stop (EV_A_ &linuxaio_epoll_w);
542 ev_io_set (EV_A_ &linuxaio_epoll_w, backend_fd, EV_READ); 599 ev_io_set (EV_A_ &linuxaio_epoll_w, backend_fd, EV_READ);
543 ev_io_start (EV_A_ &linuxaio_epoll_w); 600 ev_io_start (EV_A_ &linuxaio_epoll_w);

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