source: libcfa/src/concurrency/io.cfa@ 3251b66

ADT arm-eh ast-experimental enum forall-pointer-decay jacob/cs343-translation new-ast new-ast-unique-expr pthread-emulation qualifiedEnum
Last change on this file since 3251b66 was 87e0b015, checked in by Thierry Delisle <tdelisle@…>, 5 years ago

Merge branch 'master' of plg.uwaterloo.ca:software/cfa/cfa-cc

  • Property mode set to 100644
File size: 33.6 KB
Line 
1//
2// Cforall Version 1.0.0 Copyright (C) 2020 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// io.cfa --
8//
9// Author : Thierry Delisle
10// Created On : Thu Apr 23 17:31:00 2020
11// Last Modified By :
12// Last Modified On :
13// Update Count :
14//
15
16// #define __CFA_DEBUG_PRINT_IO__
17// #define __CFA_DEBUG_PRINT_IO_CORE__
18
19#include "kernel.hfa"
20
21#if !defined(HAVE_LINUX_IO_URING_H)
22 void __kernel_io_startup( cluster &, int, bool ) {
23 // Nothing to do without io_uring
24 }
25
26 void __kernel_io_finish_start( cluster & ) {
27 // Nothing to do without io_uring
28 }
29
30 void __kernel_io_prepare_stop( cluster & ) {
31 // Nothing to do without io_uring
32 }
33
34 void __kernel_io_shutdown( cluster &, bool ) {
35 // Nothing to do without io_uring
36 }
37
38#else
39 extern "C" {
40 #define _GNU_SOURCE /* See feature_test_macros(7) */
41 #include <errno.h>
42 #include <stdint.h>
43 #include <string.h>
44 #include <unistd.h>
45 #include <sys/mman.h>
46 #include <sys/syscall.h>
47
48 #include <linux/io_uring.h>
49 }
50
51 #include "bits/signal.hfa"
52 #include "kernel_private.hfa"
53 #include "thread.hfa"
54
55 uint32_t entries_per_cluster() {
56 return 256;
57 }
58
59 static void * __io_poller_slow( void * arg );
60
61 // Weirdly, some systems that do support io_uring don't actually define these
62 #ifdef __alpha__
63 /*
64 * alpha is the only exception, all other architectures
65 * have common numbers for new system calls.
66 */
67 #ifndef __NR_io_uring_setup
68 #define __NR_io_uring_setup 535
69 #endif
70 #ifndef __NR_io_uring_enter
71 #define __NR_io_uring_enter 536
72 #endif
73 #ifndef __NR_io_uring_register
74 #define __NR_io_uring_register 537
75 #endif
76 #else /* !__alpha__ */
77 #ifndef __NR_io_uring_setup
78 #define __NR_io_uring_setup 425
79 #endif
80 #ifndef __NR_io_uring_enter
81 #define __NR_io_uring_enter 426
82 #endif
83 #ifndef __NR_io_uring_register
84 #define __NR_io_uring_register 427
85 #endif
86 #endif
87
88 // Fast poller user-thread
89 // Not using the "thread" keyword because we want to control
90 // more carefully when to start/stop it
91 struct __io_poller_fast {
92 struct __io_data * ring;
93 bool waiting;
94 $thread thrd;
95 };
96
97 void ?{}( __io_poller_fast & this, struct cluster & cltr ) {
98 this.ring = cltr.io;
99 this.waiting = true;
100 (this.thrd){ "Fast I/O Poller", cltr };
101 }
102 void ^?{}( __io_poller_fast & mutex this );
103 void main( __io_poller_fast & this );
104 static inline $thread * get_thread( __io_poller_fast & this ) { return &this.thrd; }
105 void ^?{}( __io_poller_fast & mutex this ) {}
106
107 struct __submition_data {
108 // Head and tail of the ring (associated with array)
109 volatile uint32_t * head;
110 volatile uint32_t * tail;
111
112 // The actual kernel ring which uses head/tail
113 // indexes into the sqes arrays
114 uint32_t * array;
115
116 // number of entries and mask to go with it
117 const uint32_t * num;
118 const uint32_t * mask;
119
120 // Submission flags (Not sure what for)
121 uint32_t * flags;
122
123 // number of sqes not submitted (whatever that means)
124 uint32_t * dropped;
125
126 // Like head/tail but not seen by the kernel
127 volatile uint32_t alloc;
128 volatile uint32_t ready;
129
130 __spinlock_t lock;
131
132 // A buffer of sqes (not the actual ring)
133 struct io_uring_sqe * sqes;
134
135 // The location and size of the mmaped area
136 void * ring_ptr;
137 size_t ring_sz;
138
139 // Statistics
140 #if !defined(__CFA_NO_STATISTICS__)
141 struct {
142 struct {
143 volatile unsigned long long int val;
144 volatile unsigned long long int cnt;
145 volatile unsigned long long int block;
146 } submit_avg;
147 } stats;
148 #endif
149 };
150
151 struct __completion_data {
152 // Head and tail of the ring
153 volatile uint32_t * head;
154 volatile uint32_t * tail;
155
156 // number of entries and mask to go with it
157 const uint32_t * mask;
158 const uint32_t * num;
159
160 // number of cqes not submitted (whatever that means)
161 uint32_t * overflow;
162
163 // the kernel ring
164 struct io_uring_cqe * cqes;
165
166 // The location and size of the mmaped area
167 void * ring_ptr;
168 size_t ring_sz;
169
170 // Statistics
171 #if !defined(__CFA_NO_STATISTICS__)
172 struct {
173 struct {
174 unsigned long long int val;
175 unsigned long long int slow_cnt;
176 unsigned long long int fast_cnt;
177 } completed_avg;
178 } stats;
179 #endif
180 };
181
182 struct __io_data {
183 struct __submition_data submit_q;
184 struct __completion_data completion_q;
185 uint32_t ring_flags;
186 int cltr_flags;
187 int fd;
188 semaphore submit;
189 volatile bool done;
190 struct {
191 struct {
192 void * stack;
193 pthread_t kthrd;
194 } slow;
195 __io_poller_fast fast;
196 __bin_sem_t sem;
197 } poller;
198 };
199
200//=============================================================================================
201// I/O Startup / Shutdown logic
202//=============================================================================================
203 void __kernel_io_startup( cluster & this, int io_flags, bool main_cluster ) {
204 this.io = malloc();
205
206 // Step 1 : call to setup
207 struct io_uring_params params;
208 memset(&params, 0, sizeof(params));
209
210 uint32_t nentries = entries_per_cluster();
211
212 int fd = syscall(__NR_io_uring_setup, nentries, &params );
213 if(fd < 0) {
214 abort("KERNEL ERROR: IO_URING SETUP - %s\n", strerror(errno));
215 }
216
217 // Step 2 : mmap result
218 memset( this.io, 0, sizeof(struct __io_data) );
219 struct __submition_data & sq = this.io->submit_q;
220 struct __completion_data & cq = this.io->completion_q;
221
222 // calculate the right ring size
223 sq.ring_sz = params.sq_off.array + (params.sq_entries * sizeof(unsigned) );
224 cq.ring_sz = params.cq_off.cqes + (params.cq_entries * sizeof(struct io_uring_cqe));
225
226 // Requires features
227 #if defined(IORING_FEAT_SINGLE_MMAP)
228 // adjust the size according to the parameters
229 if ((params.features & IORING_FEAT_SINGLE_MMAP) != 0) {
230 cq->ring_sz = sq->ring_sz = max(cq->ring_sz, sq->ring_sz);
231 }
232 #endif
233
234 // mmap the Submit Queue into existence
235 sq.ring_ptr = mmap(0, sq.ring_sz, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_SQ_RING);
236 if (sq.ring_ptr == (void*)MAP_FAILED) {
237 abort("KERNEL ERROR: IO_URING MMAP1 - %s\n", strerror(errno));
238 }
239
240 // Requires features
241 #if defined(IORING_FEAT_SINGLE_MMAP)
242 // mmap the Completion Queue into existence (may or may not be needed)
243 if ((params.features & IORING_FEAT_SINGLE_MMAP) != 0) {
244 cq->ring_ptr = sq->ring_ptr;
245 }
246 else
247 #endif
248 {
249 // We need multiple call to MMAP
250 cq.ring_ptr = mmap(0, cq.ring_sz, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_CQ_RING);
251 if (cq.ring_ptr == (void*)MAP_FAILED) {
252 munmap(sq.ring_ptr, sq.ring_sz);
253 abort("KERNEL ERROR: IO_URING MMAP2 - %s\n", strerror(errno));
254 }
255 }
256
257 // mmap the submit queue entries
258 size_t size = params.sq_entries * sizeof(struct io_uring_sqe);
259 sq.sqes = (struct io_uring_sqe *)mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_SQES);
260 if (sq.sqes == (struct io_uring_sqe *)MAP_FAILED) {
261 munmap(sq.ring_ptr, sq.ring_sz);
262 if (cq.ring_ptr != sq.ring_ptr) munmap(cq.ring_ptr, cq.ring_sz);
263 abort("KERNEL ERROR: IO_URING MMAP3 - %s\n", strerror(errno));
264 }
265
266 // Get the pointers from the kernel to fill the structure
267 // submit queue
268 sq.head = (volatile uint32_t *)(((intptr_t)sq.ring_ptr) + params.sq_off.head);
269 sq.tail = (volatile uint32_t *)(((intptr_t)sq.ring_ptr) + params.sq_off.tail);
270 sq.mask = ( const uint32_t *)(((intptr_t)sq.ring_ptr) + params.sq_off.ring_mask);
271 sq.num = ( const uint32_t *)(((intptr_t)sq.ring_ptr) + params.sq_off.ring_entries);
272 sq.flags = ( uint32_t *)(((intptr_t)sq.ring_ptr) + params.sq_off.flags);
273 sq.dropped = ( uint32_t *)(((intptr_t)sq.ring_ptr) + params.sq_off.dropped);
274 sq.array = ( uint32_t *)(((intptr_t)sq.ring_ptr) + params.sq_off.array);
275 sq.alloc = *sq.tail;
276 sq.ready = *sq.tail;
277
278 // completion queue
279 cq.head = (volatile uint32_t *)(((intptr_t)cq.ring_ptr) + params.cq_off.head);
280 cq.tail = (volatile uint32_t *)(((intptr_t)cq.ring_ptr) + params.cq_off.tail);
281 cq.mask = ( const uint32_t *)(((intptr_t)cq.ring_ptr) + params.cq_off.ring_mask);
282 cq.num = ( const uint32_t *)(((intptr_t)cq.ring_ptr) + params.cq_off.ring_entries);
283 cq.overflow = ( uint32_t *)(((intptr_t)cq.ring_ptr) + params.cq_off.overflow);
284 cq.cqes = (struct io_uring_cqe *)(((intptr_t)cq.ring_ptr) + params.cq_off.cqes);
285
286 // some paranoid checks
287 /* paranoid */ verifyf( (*cq.mask) == ((*cq.num) - 1ul32), "IO_URING Expected mask to be %u (%u entries), was %u", (*cq.num) - 1ul32, *cq.num, *cq.mask );
288 /* paranoid */ verifyf( (*cq.num) >= nentries, "IO_URING Expected %u entries, got %u", nentries, *cq.num );
289 /* paranoid */ verifyf( (*cq.head) == 0, "IO_URING Expected head to be 0, got %u", *cq.head );
290 /* paranoid */ verifyf( (*cq.tail) == 0, "IO_URING Expected tail to be 0, got %u", *cq.tail );
291
292 /* paranoid */ verifyf( (*sq.mask) == ((*sq.num) - 1ul32), "IO_URING Expected mask to be %u (%u entries), was %u", (*sq.num) - 1ul32, *sq.num, *sq.mask );
293 /* paranoid */ verifyf( (*sq.num) >= nentries, "IO_URING Expected %u entries, got %u", nentries, *sq.num );
294 /* paranoid */ verifyf( (*sq.head) == 0, "IO_URING Expected head to be 0, got %u", *sq.head );
295 /* paranoid */ verifyf( (*sq.tail) == 0, "IO_URING Expected tail to be 0, got %u", *sq.tail );
296
297 // Update the global ring info
298 this.io->ring_flags = params.flags;
299 this.io->cltr_flags = io_flags;
300 this.io->fd = fd;
301 this.io->done = false;
302 (this.io->submit){ min(*sq.num, *cq.num) };
303
304 // Initialize statistics
305 #if !defined(__CFA_NO_STATISTICS__)
306 this.io->submit_q.stats.submit_avg.val = 0;
307 this.io->submit_q.stats.submit_avg.cnt = 0;
308 this.io->submit_q.stats.submit_avg.block = 0;
309 this.io->completion_q.stats.completed_avg.val = 0;
310 this.io->completion_q.stats.completed_avg.slow_cnt = 0;
311 this.io->completion_q.stats.completed_avg.fast_cnt = 0;
312 #endif
313
314 if(!main_cluster) {
315 __kernel_io_finish_start( this );
316 }
317 }
318
319 void __kernel_io_finish_start( cluster & this ) {
320 if( this.io->cltr_flags & CFA_CLUSTER_IO_POLLER_USER_THREAD ) {
321 __cfadbg_print_safe(io_core, "Kernel I/O : Creating fast poller for cluter %p\n", &this);
322 (this.io->poller.fast){ this };
323 __thrd_start( this.io->poller.fast, main );
324 }
325
326 // Create the poller thread
327 __cfadbg_print_safe(io_core, "Kernel I/O : Creating slow poller for cluter %p\n", &this);
328 this.io->poller.slow.stack = __create_pthread( &this.io->poller.slow.kthrd, __io_poller_slow, &this );
329 }
330
331 void __kernel_io_prepare_stop( cluster & this ) {
332 __cfadbg_print_safe(io_core, "Kernel I/O : Stopping pollers for cluster\n", &this);
333 // Notify the poller thread of the shutdown
334 __atomic_store_n(&this.io->done, true, __ATOMIC_SEQ_CST);
335
336 // Stop the IO Poller
337 sigval val = { 1 };
338 pthread_sigqueue( this.io->poller.slow.kthrd, SIGUSR1, val );
339 post( this.io->poller.sem );
340
341 // Wait for the poller thread to finish
342 pthread_join( this.io->poller.slow.kthrd, 0p );
343 free( this.io->poller.slow.stack );
344
345 __cfadbg_print_safe(io_core, "Kernel I/O : Slow poller stopped for cluster\n", &this);
346
347 if( this.io->cltr_flags & CFA_CLUSTER_IO_POLLER_USER_THREAD ) {
348 with( this.io->poller.fast ) {
349 /* paranoid */ verify( waiting ); // The thread shouldn't be in a system call
350 /* paranoid */ verify( this.procs.head == 0p || &this == mainCluster );
351 /* paranoid */ verify( this.idles.head == 0p || &this == mainCluster );
352
353 // We need to adjust the clean-up based on where the thread is
354 if( thrd.preempted != __NO_PREEMPTION ) {
355
356 // This is the tricky case
357 // The thread was preempted and now it is on the ready queue
358 /* paranoid */ verify( thrd.state == Active ); // The thread better be in this state
359 /* paranoid */ verify( thrd.next == 1p ); // The thread should be the last on the list
360 /* paranoid */ verify( this.ready_queue.head == &thrd ); // The thread should be the only thing on the list
361
362 // Remove the thread from the ready queue of this cluster
363 this.ready_queue.head = 1p;
364 thrd.next = 0p;
365
366 // Fixup the thread state
367 thrd.state = Blocked;
368 thrd.preempted = __NO_PREEMPTION;
369
370 // Pretend like the thread was blocked all along
371 }
372 // !!! This is not an else if !!!
373 if( thrd.state == Blocked ) {
374
375 // This is the "easy case"
376 // The thread is parked and can easily be moved to active cluster
377 verify( thrd.curr_cluster != active_cluster() || thrd.curr_cluster == mainCluster );
378 thrd.curr_cluster = active_cluster();
379
380 // unpark the fast io_poller
381 unpark( &thrd __cfaabi_dbg_ctx2 );
382 }
383 else {
384
385 // The thread is in a weird state
386 // I don't know what to do here
387 abort("Fast poller thread is in unexpected state, cannot clean-up correctly\n");
388 }
389
390 }
391
392 ^(this.io->poller.fast){};
393
394 __cfadbg_print_safe(io_core, "Kernel I/O : Fast poller stopped for cluster\n", &this);
395 }
396 }
397
398 void __kernel_io_shutdown( cluster & this, bool main_cluster ) {
399 if(!main_cluster) {
400 __kernel_io_prepare_stop( this );
401 }
402
403 // print statistics
404 #if !defined(__CFA_NO_STATISTICS__)
405 if(this.print_stats) {
406 with(this.io->submit_q.stats, this.io->completion_q.stats) {
407 __cfaabi_bits_print_safe( STDERR_FILENO,
408 "----- I/O uRing Stats -----\n"
409 "- total submit calls : %'15llu\n"
410 "- avg submit : %'18.2lf\n"
411 "- pre-submit block %% : %'18.2lf\n"
412 "- total wait calls : %'15llu (%'llu slow, %'llu fast)\n"
413 "- avg completion/wait : %'18.2lf\n",
414 submit_avg.cnt,
415 ((double)submit_avg.val) / submit_avg.cnt,
416 (100.0 * submit_avg.block) / submit_avg.cnt,
417 completed_avg.slow_cnt + completed_avg.fast_cnt,
418 completed_avg.slow_cnt, completed_avg.fast_cnt,
419 ((double)completed_avg.val) / (completed_avg.slow_cnt + completed_avg.fast_cnt)
420 );
421 }
422 }
423 #endif
424
425 // Shutdown the io rings
426 struct __submition_data & sq = this.io->submit_q;
427 struct __completion_data & cq = this.io->completion_q;
428
429 // unmap the submit queue entries
430 munmap(sq.sqes, (*sq.num) * sizeof(struct io_uring_sqe));
431
432 // unmap the Submit Queue ring
433 munmap(sq.ring_ptr, sq.ring_sz);
434
435 // unmap the Completion Queue ring, if it is different
436 if (cq.ring_ptr != sq.ring_ptr) {
437 munmap(cq.ring_ptr, cq.ring_sz);
438 }
439
440 // close the file descriptor
441 close(this.io->fd);
442
443 free( this.io );
444 }
445
446//=============================================================================================
447// I/O Polling
448//=============================================================================================
449 struct io_user_data {
450 int32_t result;
451 $thread * thrd;
452 };
453
454 // Process a single completion message from the io_uring
455 // This is NOT thread-safe
456 static int __drain_io( struct __io_data & ring, sigset_t * mask, int waitcnt, bool in_kernel ) {
457 int ret = syscall( __NR_io_uring_enter, ring.fd, 0, waitcnt, IORING_ENTER_GETEVENTS, mask, _NSIG / 8);
458 if( ret < 0 ) {
459 switch((int)errno) {
460 case EAGAIN:
461 case EINTR:
462 return -EAGAIN;
463 default:
464 abort( "KERNEL ERROR: IO_URING WAIT - %s\n", strerror(errno) );
465 }
466 }
467
468 // Drain the queue
469 unsigned head = *ring.completion_q.head;
470 unsigned tail = __atomic_load_n(ring.completion_q.tail, __ATOMIC_ACQUIRE);
471
472 // Nothing was new return 0
473 if (head == tail) {
474 return 0;
475 }
476
477 uint32_t count = tail - head;
478 for(i; count) {
479 unsigned idx = (head + i) & (*ring.completion_q.mask);
480 struct io_uring_cqe & cqe = ring.completion_q.cqes[idx];
481
482 /* paranoid */ verify(&cqe);
483
484 struct io_user_data * data = (struct io_user_data *)cqe.user_data;
485 __cfadbg_print_safe( io, "Kernel I/O : Performed reading io cqe %p, result %d for %p\n", data, cqe.res, data->thrd );
486
487 data->result = cqe.res;
488 if(!in_kernel) { unpark( data->thrd __cfaabi_dbg_ctx2 ); }
489 else { __unpark( data->thrd __cfaabi_dbg_ctx2 ); }
490 }
491
492 // Allow new submissions to happen
493 V(ring.submit, count);
494
495 // Mark to the kernel that the cqe has been seen
496 // Ensure that the kernel only sees the new value of the head index after the CQEs have been read.
497 __atomic_fetch_add( ring.completion_q.head, count, __ATOMIC_RELAXED );
498
499 return count;
500 }
501
502 static void * __io_poller_slow( void * arg ) {
503 cluster * cltr = (cluster *)arg;
504 struct __io_data & ring = *cltr->io;
505
506 sigset_t mask;
507 sigfillset(&mask);
508 if ( pthread_sigmask( SIG_BLOCK, &mask, 0p ) == -1 ) {
509 abort( "KERNEL ERROR: IO_URING - pthread_sigmask" );
510 }
511
512 sigdelset( &mask, SIGUSR1 );
513
514 verify( (*ring.submit_q.head) == (*ring.submit_q.tail) );
515 verify( (*ring.completion_q.head) == (*ring.completion_q.tail) );
516
517 __cfadbg_print_safe(io_core, "Kernel I/O : Slow poller for ring %p ready\n", &ring);
518
519 if( ring.cltr_flags & CFA_CLUSTER_IO_POLLER_USER_THREAD ) {
520 while(!__atomic_load_n(&ring.done, __ATOMIC_SEQ_CST)) {
521 // In the user-thread approach drain and if anything was drained,
522 // batton pass to the user-thread
523 int count = __drain_io( ring, &mask, 1, true );
524
525 // Update statistics
526 #if !defined(__CFA_NO_STATISTICS__)
527 ring.completion_q.stats.completed_avg.val += count;
528 ring.completion_q.stats.completed_avg.slow_cnt += 1;
529 #endif
530
531 if(count > 0) {
532 __cfadbg_print_safe(io_core, "Kernel I/O : Moving to ring %p to fast poller\n", &ring);
533 __unpark( &ring.poller.fast.thrd __cfaabi_dbg_ctx2 );
534 wait( ring.poller.sem );
535 }
536 }
537 }
538 else {
539 while(!__atomic_load_n(&ring.done, __ATOMIC_SEQ_CST)) {
540 //In the naive approach, just poll the io completion queue directly
541 int count = __drain_io( ring, &mask, 1, true );
542
543 // Update statistics
544 #if !defined(__CFA_NO_STATISTICS__)
545 ring.completion_q.stats.completed_avg.val += count;
546 ring.completion_q.stats.completed_avg.slow_cnt += 1;
547 #endif
548 }
549 }
550
551 __cfadbg_print_safe(io_core, "Kernel I/O : Slow poller for ring %p stopping\n", &ring);
552
553 return 0p;
554 }
555
556 void main( __io_poller_fast & this ) {
557 verify( this.ring->cltr_flags & CFA_CLUSTER_IO_POLLER_USER_THREAD );
558
559 // Start parked
560 park( __cfaabi_dbg_ctx );
561
562 __cfadbg_print_safe(io_core, "Kernel I/O : Fast poller for ring %p ready\n", &this.ring);
563
564 int reset = 0;
565
566 // Then loop until we need to start
567 while(!__atomic_load_n(&this.ring->done, __ATOMIC_SEQ_CST)) {
568 // Drain the io
569 this.waiting = false;
570 int count = __drain_io( *this.ring, 0p, 0, false );
571 reset += count > 0 ? 1 : 0;
572
573 // Update statistics
574 #if !defined(__CFA_NO_STATISTICS__)
575 this.ring->completion_q.stats.completed_avg.val += count;
576 this.ring->completion_q.stats.completed_avg.fast_cnt += 1;
577 #endif
578
579 this.waiting = true;
580 if(reset < 5) {
581 // If we got something, just yield and check again
582 yield();
583 }
584 else {
585 // We didn't get anything baton pass to the slow poller
586 __cfadbg_print_safe(io_core, "Kernel I/O : Moving to ring %p to slow poller\n", &this.ring);
587 post( this.ring->poller.sem );
588 park( __cfaabi_dbg_ctx );
589 reset = 0;
590 }
591 }
592
593 __cfadbg_print_safe(io_core, "Kernel I/O : Fast poller for ring %p stopping\n", &this.ring);
594 }
595
596//=============================================================================================
597// I/O Submissions
598//=============================================================================================
599
600// Submition steps :
601// 1 - We need to make sure we don't overflow any of the buffer, P(ring.submit) to make sure
602// entries are available. The semaphore make sure that there is no more operations in
603// progress then the number of entries in the buffer. This probably limits concurrency
604// more than necessary since submitted but not completed operations don't need any
605// entries in user space. However, I don't know what happens if we overflow the buffers
606// because too many requests completed at once. This is a safe approach in all cases.
607// Furthermore, with hundreds of entries, this may be okay.
608//
609// 2 - Allocate a queue entry. The ring already has memory for all entries but only the ones
610// listed in sq.array are visible by the kernel. For those not listed, the kernel does not
611// offer any assurance that an entry is not being filled by multiple flags. Therefore, we
612// need to write an allocator that allows allocating concurrently.
613//
614// 3 - Actually fill the submit entry, this is the only simple and straightforward step.
615//
616// 4 - Append the entry index to the array and adjust the tail accordingly. This operation
617// needs to arrive to two concensus at the same time:
618// A - The order in which entries are listed in the array: no two threads must pick the
619// same index for their entries
620// B - When can the tail be update for the kernel. EVERY entries in the array between
621// head and tail must be fully filled and shouldn't ever be touched again.
622//
623
624 static inline [* struct io_uring_sqe, uint32_t] __submit_alloc( struct __io_data & ring ) {
625 // Wait for a spot to be available
626 __attribute__((unused)) bool blocked = P(ring.submit);
627 #if !defined(__CFA_NO_STATISTICS__)
628 __atomic_fetch_add( &ring.submit_q.stats.submit_avg.block, blocked ? 1ul64 : 0ul64, __ATOMIC_RELAXED );
629 #endif
630
631 // Allocate the sqe
632 uint32_t idx = __atomic_fetch_add(&ring.submit_q.alloc, 1ul32, __ATOMIC_SEQ_CST);
633
634 // Validate that we didn't overflow anything
635 // Check that nothing overflowed
636 /* paranoid */ verify( true );
637
638 // Check that it goes head -> tail -> alloc and never head -> alloc -> tail
639 /* paranoid */ verify( true );
640
641 // Return the sqe
642 return [&ring.submit_q.sqes[ idx & (*ring.submit_q.mask)], idx];
643 }
644
645 static inline void __submit( struct __io_data & ring, uint32_t idx ) {
646 // get mutual exclusion
647 lock(ring.submit_q.lock __cfaabi_dbg_ctx2);
648
649 // Append to the list of ready entries
650 uint32_t * tail = ring.submit_q.tail;
651 const uint32_t mask = *ring.submit_q.mask;
652
653 ring.submit_q.array[ (*tail) & mask ] = idx & mask;
654 __atomic_fetch_add(tail, 1ul32, __ATOMIC_SEQ_CST);
655
656 // Submit however, many entries need to be submitted
657 int ret = syscall( __NR_io_uring_enter, ring.fd, 1, 0, 0, 0p, 0);
658 if( ret < 0 ) {
659 switch((int)errno) {
660 default:
661 abort( "KERNEL ERROR: IO_URING SUBMIT - %s\n", strerror(errno) );
662 }
663 }
664
665 // update statistics
666 #if !defined(__CFA_NO_STATISTICS__)
667 ring.submit_q.stats.submit_avg.val += 1;
668 ring.submit_q.stats.submit_avg.cnt += 1;
669 #endif
670
671 unlock(ring.submit_q.lock);
672 // Make sure that idx was submitted
673 // Be careful to not get false positive if we cycled the entire list or that someone else submitted for us
674 __cfadbg_print_safe( io, "Kernel I/O : Performed io_submit for %p, returned %d\n", active_thread(), ret );
675 }
676
677 static inline void ?{}(struct io_uring_sqe & this, uint8_t opcode, int fd) {
678 this.opcode = opcode;
679 #if !defined(IOSQE_ASYNC)
680 this.flags = 0;
681 #else
682 this.flags = IOSQE_ASYNC;
683 #endif
684 this.ioprio = 0;
685 this.fd = fd;
686 this.off = 0;
687 this.addr = 0;
688 this.len = 0;
689 this.rw_flags = 0;
690 this.__pad2[0] = this.__pad2[1] = this.__pad2[2] = 0;
691 }
692
693 static inline void ?{}(struct io_uring_sqe & this, uint8_t opcode, int fd, void * addr, uint32_t len, uint64_t off ) {
694 (this){ opcode, fd };
695 this.off = off;
696 this.addr = (uint64_t)addr;
697 this.len = len;
698 }
699
700
701//=============================================================================================
702// I/O Interface
703//=============================================================================================
704
705 #define __submit_prelude \
706 struct __io_data & ring = *active_cluster()->io; \
707 struct io_uring_sqe * sqe; \
708 uint32_t idx; \
709 [sqe, idx] = __submit_alloc( ring );
710
711 #define __submit_wait \
712 io_user_data data = { 0, active_thread() }; \
713 /*__cfaabi_bits_print_safe( STDERR_FILENO, "Preparing user data %p for %p\n", &data, data.thrd );*/ \
714 sqe->user_data = (uint64_t)&data; \
715 __submit( ring, idx ); \
716 park( __cfaabi_dbg_ctx ); \
717 return data.result;
718#endif
719
720// Some forward declarations
721extern "C" {
722 #include <unistd.h>
723 #include <sys/types.h>
724 #include <sys/socket.h>
725 #include <sys/syscall.h>
726
727#if defined(HAVE_PREADV2)
728 struct iovec;
729 extern ssize_t preadv2 (int fd, const struct iovec *iov, int iovcnt, off_t offset, int flags);
730#endif
731#if defined(HAVE_PWRITEV2)
732 struct iovec;
733 extern ssize_t pwritev2(int fd, const struct iovec *iov, int iovcnt, off_t offset, int flags);
734#endif
735
736 extern int fsync(int fd);
737 extern int sync_file_range(int fd, int64_t offset, int64_t nbytes, unsigned int flags);
738
739 struct msghdr;
740 struct sockaddr;
741 extern ssize_t sendmsg(int sockfd, const struct msghdr *msg, int flags);
742 extern ssize_t recvmsg(int sockfd, struct msghdr *msg, int flags);
743 extern ssize_t send(int sockfd, const void *buf, size_t len, int flags);
744 extern ssize_t recv(int sockfd, void *buf, size_t len, int flags);
745 extern int accept4(int sockfd, struct sockaddr *addr, socklen_t *addrlen, int flags);
746 extern int connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen);
747
748 extern int fallocate(int fd, int mode, uint64_t offset, uint64_t len);
749 extern int posix_fadvise(int fd, uint64_t offset, uint64_t len, int advice);
750 extern int madvise(void *addr, size_t length, int advice);
751
752 extern int openat(int dirfd, const char *pathname, int flags, mode_t mode);
753 extern int close(int fd);
754
755 extern ssize_t read (int fd, void *buf, size_t count);
756}
757
758//-----------------------------------------------------------------------------
759// Asynchronous operations
760#if defined(HAVE_PREADV2)
761 ssize_t cfa_preadv2(int fd, const struct iovec *iov, int iovcnt, off_t offset, int flags) {
762 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_READV)
763 return preadv2(fd, iov, iovcnt, offset, flags);
764 #else
765 __submit_prelude
766
767 (*sqe){ IORING_OP_READV, fd, iov, iovcnt, offset };
768
769 __submit_wait
770 #endif
771 }
772#endif
773
774#if defined(HAVE_PWRITEV2)
775 ssize_t cfa_pwritev2(int fd, const struct iovec *iov, int iovcnt, off_t offset, int flags) {
776 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_WRITEV)
777 return pwritev2(fd, iov, iovcnt, offset, flags);
778 #else
779 __submit_prelude
780
781 (*sqe){ IORING_OP_WRITEV, fd, iov, iovcnt, offset };
782
783 __submit_wait
784 #endif
785 }
786#endif
787
788int cfa_fsync(int fd) {
789 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_FSYNC)
790 return fsync(fd);
791 #else
792 __submit_prelude
793
794 (*sqe){ IORING_OP_FSYNC, fd };
795
796 __submit_wait
797 #endif
798}
799
800int cfa_sync_file_range(int fd, int64_t offset, int64_t nbytes, unsigned int flags) {
801 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_SYNC_FILE_RANGE)
802 return sync_file_range(fd, offset, nbytes, flags);
803 #else
804 __submit_prelude
805
806 (*sqe){ IORING_OP_SYNC_FILE_RANGE, fd };
807 sqe->off = offset;
808 sqe->len = nbytes;
809 sqe->sync_range_flags = flags;
810
811 __submit_wait
812 #endif
813}
814
815
816ssize_t cfa_sendmsg(int sockfd, const struct msghdr *msg, int flags) {
817 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_SENDMSG)
818 return sendmsg(sockfd, msg, flags);
819 #else
820 __submit_prelude
821
822 (*sqe){ IORING_OP_SENDMSG, sockfd, msg, 1, 0 };
823 sqe->msg_flags = flags;
824
825 __submit_wait
826 #endif
827}
828
829ssize_t cfa_recvmsg(int sockfd, struct msghdr *msg, int flags) {
830 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_RECVMSG)
831 return recvmsg(sockfd, msg, flags);
832 #else
833 __submit_prelude
834
835 (*sqe){ IORING_OP_RECVMSG, sockfd, msg, 1, 0 };
836 sqe->msg_flags = flags;
837
838 __submit_wait
839 #endif
840}
841
842ssize_t cfa_send(int sockfd, const void *buf, size_t len, int flags) {
843 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_SEND)
844 return send( sockfd, buf, len, flags );
845 #else
846 __submit_prelude
847
848 (*sqe){ IORING_OP_SEND, sockfd };
849 sqe->addr = (uint64_t)buf;
850 sqe->len = len;
851 sqe->msg_flags = flags;
852
853 __submit_wait
854 #endif
855}
856
857ssize_t cfa_recv(int sockfd, void *buf, size_t len, int flags) {
858 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_RECV)
859 return recv( sockfd, buf, len, flags );
860 #else
861 __submit_prelude
862
863 (*sqe){ IORING_OP_RECV, sockfd };
864 sqe->addr = (uint64_t)buf;
865 sqe->len = len;
866 sqe->msg_flags = flags;
867
868 __submit_wait
869 #endif
870}
871
872int cfa_accept4(int sockfd, struct sockaddr *addr, socklen_t *addrlen, int flags) {
873 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_ACCEPT)
874 return accept4( sockfd, addr, addrlen, flags );
875 #else
876 __submit_prelude
877
878 (*sqe){ IORING_OP_ACCEPT, sockfd };
879 sqe->addr = addr;
880 sqe->addr2 = addrlen;
881 sqe->accept_flags = flags;
882
883 __submit_wait
884 #endif
885}
886
887int cfa_connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen) {
888 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_CONNECT)
889 return connect( sockfd, addr, addrlen );
890 #else
891 __submit_prelude
892
893 (*sqe){ IORING_OP_CONNECT, sockfd };
894 sqe->addr = (uint64_t)addr;
895 sqe->off = addrlen;
896
897 __submit_wait
898 #endif
899}
900
901int cfa_fallocate(int fd, int mode, uint64_t offset, uint64_t len) {
902 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_FALLOCATE)
903 return fallocate( fd, mode, offset, len );
904 #else
905 __submit_prelude
906
907 (*sqe){ IORING_OP_FALLOCATE, fd };
908 sqe->off = offset;
909 sqe->len = length;
910 sqe->mode = mode;
911
912 __submit_wait
913 #endif
914}
915
916int cfa_fadvise(int fd, uint64_t offset, uint64_t len, int advice) {
917 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_FADVISE)
918 return posix_fadvise( fd, offset, len, advice );
919 #else
920 __submit_prelude
921
922 (*sqe){ IORING_OP_FADVISE, fd };
923 sqe->off = (uint64_t)offset;
924 sqe->len = length;
925 sqe->fadvise_advice = advice;
926
927 __submit_wait
928 #endif
929}
930
931int cfa_madvise(void *addr, size_t length, int advice) {
932 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_MADVISE)
933 return madvise( addr, length, advice );
934 #else
935 __submit_prelude
936
937 (*sqe){ IORING_OP_MADVISE, 0 };
938 sqe->addr = (uint64_t)addr;
939 sqe->len = length;
940 sqe->fadvise_advice = advice;
941
942 __submit_wait
943 #endif
944}
945
946int cfa_openat(int dirfd, const char *pathname, int flags, mode_t mode) {
947 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_OPENAT)
948 return openat( dirfd, pathname, flags, mode );
949 #else
950 __submit_prelude
951
952 (*sqe){ IORING_OP_OPENAT, dirfd };
953 sqe->addr = (uint64_t)pathname;
954 sqe->open_flags = flags;
955 sqe->mode = mode;
956
957 __submit_wait
958 #endif
959}
960
961int cfa_close(int fd) {
962 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_CLOSE)
963 return close( fd );
964 #else
965 __submit_prelude
966
967 (*sqe){ IORING_OP_CLOSE, fd };
968
969 __submit_wait
970 #endif
971}
972
973
974ssize_t cfa_read(int fd, void *buf, size_t count) {
975 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_READ)
976 return read( fd, buf, count );
977 #else
978 __submit_prelude
979
980 (*sqe){ IORING_OP_READ, fd, buf, count, 0 };
981
982 __submit_wait
983 #endif
984}
985
986ssize_t cfa_write(int fd, void *buf, size_t count) {
987 #if !defined(HAVE_LINUX_IO_URING_H) || !defined(IORING_OP_WRITE)
988 return read( fd, buf, count );
989 #else
990 __submit_prelude
991
992 (*sqe){ IORING_OP_WRITE, fd, buf, count, 0 };
993
994 __submit_wait
995 #endif
996}
997
998//-----------------------------------------------------------------------------
999// Check if a function is asynchronous
1000
1001// Macro magic to reduce the size of the following switch case
1002#define IS_DEFINED_APPLY(f, ...) f(__VA_ARGS__)
1003#define IS_DEFINED_SECOND(first, second, ...) second
1004#define IS_DEFINED_TEST(expansion) _CFA_IO_FEATURE_##expansion
1005#define IS_DEFINED(macro) IS_DEFINED_APPLY( IS_DEFINED_SECOND,IS_DEFINED_TEST(macro) false, true)
1006
1007bool has_user_level_blocking( fptr_t func ) {
1008 #if defined(HAVE_LINUX_IO_URING_H)
1009 #if defined(HAVE_PREADV2)
1010 if( /*func == (fptr_t)preadv2 || */
1011 func == (fptr_t)cfa_preadv2 )
1012 #define _CFA_IO_FEATURE_IORING_OP_READV ,
1013 return IS_DEFINED(IORING_OP_READV);
1014 #endif
1015
1016 #if defined(HAVE_PWRITEV2)
1017 if( /*func == (fptr_t)pwritev2 || */
1018 func == (fptr_t)cfa_pwritev2 )
1019 #define _CFA_IO_FEATURE_IORING_OP_WRITEV ,
1020 return IS_DEFINED(IORING_OP_WRITEV);
1021 #endif
1022
1023 if( /*func == (fptr_t)fsync || */
1024 func == (fptr_t)cfa_fsync )
1025 #define _CFA_IO_FEATURE_IORING_OP_FSYNC ,
1026 return IS_DEFINED(IORING_OP_FSYNC);
1027
1028 if( /*func == (fptr_t)ync_file_range || */
1029 func == (fptr_t)cfa_sync_file_range )
1030 #define _CFA_IO_FEATURE_IORING_OP_SYNC_FILE_RANGE ,
1031 return IS_DEFINED(IORING_OP_SYNC_FILE_RANGE);
1032
1033 if( /*func == (fptr_t)sendmsg || */
1034 func == (fptr_t)cfa_sendmsg )
1035 #define _CFA_IO_FEATURE_IORING_OP_SENDMSG ,
1036 return IS_DEFINED(IORING_OP_SENDMSG);
1037
1038 if( /*func == (fptr_t)recvmsg || */
1039 func == (fptr_t)cfa_recvmsg )
1040 #define _CFA_IO_FEATURE_IORING_OP_RECVMSG ,
1041 return IS_DEFINED(IORING_OP_RECVMSG);
1042
1043 if( /*func == (fptr_t)send || */
1044 func == (fptr_t)cfa_send )
1045 #define _CFA_IO_FEATURE_IORING_OP_SEND ,
1046 return IS_DEFINED(IORING_OP_SEND);
1047
1048 if( /*func == (fptr_t)recv || */
1049 func == (fptr_t)cfa_recv )
1050 #define _CFA_IO_FEATURE_IORING_OP_RECV ,
1051 return IS_DEFINED(IORING_OP_RECV);
1052
1053 if( /*func == (fptr_t)accept4 || */
1054 func == (fptr_t)cfa_accept4 )
1055 #define _CFA_IO_FEATURE_IORING_OP_ACCEPT ,
1056 return IS_DEFINED(IORING_OP_ACCEPT);
1057
1058 if( /*func == (fptr_t)connect || */
1059 func == (fptr_t)cfa_connect )
1060 #define _CFA_IO_FEATURE_IORING_OP_CONNECT ,
1061 return IS_DEFINED(IORING_OP_CONNECT);
1062
1063 if( /*func == (fptr_t)fallocate || */
1064 func == (fptr_t)cfa_fallocate )
1065 #define _CFA_IO_FEATURE_IORING_OP_FALLOCATE ,
1066 return IS_DEFINED(IORING_OP_FALLOCATE);
1067
1068 if( /*func == (fptr_t)posix_fadvise || */
1069 func == (fptr_t)cfa_fadvise )
1070 #define _CFA_IO_FEATURE_IORING_OP_FADVISE ,
1071 return IS_DEFINED(IORING_OP_FADVISE);
1072
1073 if( /*func == (fptr_t)madvise || */
1074 func == (fptr_t)cfa_madvise )
1075 #define _CFA_IO_FEATURE_IORING_OP_MADVISE ,
1076 return IS_DEFINED(IORING_OP_MADVISE);
1077
1078 if( /*func == (fptr_t)openat || */
1079 func == (fptr_t)cfa_openat )
1080 #define _CFA_IO_FEATURE_IORING_OP_OPENAT ,
1081 return IS_DEFINED(IORING_OP_OPENAT);
1082
1083 if( /*func == (fptr_t)close || */
1084 func == (fptr_t)cfa_close )
1085 #define _CFA_IO_FEATURE_IORING_OP_CLOSE ,
1086 return IS_DEFINED(IORING_OP_CLOSE);
1087
1088 if( /*func == (fptr_t)read || */
1089 func == (fptr_t)cfa_read )
1090 #define _CFA_IO_FEATURE_IORING_OP_READ ,
1091 return IS_DEFINED(IORING_OP_READ);
1092
1093 if( /*func == (fptr_t)write || */
1094 func == (fptr_t)cfa_write )
1095 #define _CFA_IO_FEATURE_IORING_OP_WRITE ,
1096 return IS_DEFINED(IORING_OP_WRITE);
1097 #endif
1098
1099 return false;
1100}
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