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1 /*
2 * Copyright (c) 2000-2012 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
29 /*
30 * Copyright (c) 1989, 1993, 1995
31 * The Regents of the University of California. All rights reserved.
32 *
33 * Redistribution and use in source and binary forms, with or without
34 * modification, are permitted provided that the following conditions
35 * are met:
36 * 1. Redistributions of source code must retain the above copyright
37 * notice, this list of conditions and the following disclaimer.
38 * 2. Redistributions in binary form must reproduce the above copyright
39 * notice, this list of conditions and the following disclaimer in the
40 * documentation and/or other materials provided with the distribution.
41 * 3. All advertising materials mentioning features or use of this software
42 * must display the following acknowledgement:
43 * This product includes software developed by the University of
44 * California, Berkeley and its contributors.
45 * 4. Neither the name of the University nor the names of its contributors
46 * may be used to endorse or promote products derived from this software
47 * without specific prior written permission.
48 *
49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59 * SUCH DAMAGE.
60 *
61 * @(#)spec_vnops.c 8.14 (Berkeley) 5/21/95
62 */
63
64 #include <sys/param.h>
65 #include <sys/proc_internal.h>
66 #include <sys/kauth.h>
67 #include <sys/systm.h>
68 #include <sys/kernel.h>
69 #include <sys/conf.h>
70 #include <sys/buf_internal.h>
71 #include <sys/mount_internal.h>
72 #include <sys/vnode_internal.h>
73 #include <sys/file_internal.h>
74 #include <sys/namei.h>
75 #include <sys/stat.h>
76 #include <sys/errno.h>
77 #include <sys/ioctl.h>
78 #include <sys/file.h>
79 #include <sys/user.h>
80 #include <sys/malloc.h>
81 #include <sys/disk.h>
82 #include <sys/uio_internal.h>
83 #include <sys/resource.h>
84 #include <miscfs/specfs/specdev.h>
85 #include <vfs/vfs_support.h>
86 #include <kern/assert.h>
87 #include <kern/task.h>
88 #include <pexpert/pexpert.h>
89
90 #include <sys/kdebug.h>
91
92 /* XXX following three prototypes should be in a header file somewhere */
93 extern dev_t chrtoblk(dev_t dev);
94 extern int iskmemdev(dev_t dev);
95 extern int bpfkqfilter(dev_t dev, struct knote *kn);
96 extern int ptsd_kqfilter(dev_t dev, struct knote *kn);
97
98 extern int ignore_is_ssd;
99
100 struct vnode *speclisth[SPECHSZ];
101
102 /* symbolic sleep message strings for devices */
103 char devopn[] = "devopn";
104 char devio[] = "devio";
105 char devwait[] = "devwait";
106 char devin[] = "devin";
107 char devout[] = "devout";
108 char devioc[] = "devioc";
109 char devcls[] = "devcls";
110
111 #define VOPFUNC int (*)(void *)
112
113 int (**spec_vnodeop_p)(void *);
114 struct vnodeopv_entry_desc spec_vnodeop_entries[] = {
115 { &vnop_default_desc, (VOPFUNC)vn_default_error },
116 { &vnop_lookup_desc, (VOPFUNC)spec_lookup }, /* lookup */
117 { &vnop_create_desc, (VOPFUNC)err_create }, /* create */
118 { &vnop_mknod_desc, (VOPFUNC)err_mknod }, /* mknod */
119 { &vnop_open_desc, (VOPFUNC)spec_open }, /* open */
120 { &vnop_close_desc, (VOPFUNC)spec_close }, /* close */
121 { &vnop_access_desc, (VOPFUNC)spec_access }, /* access */
122 { &vnop_getattr_desc, (VOPFUNC)spec_getattr }, /* getattr */
123 { &vnop_setattr_desc, (VOPFUNC)spec_setattr }, /* setattr */
124 { &vnop_read_desc, (VOPFUNC)spec_read }, /* read */
125 { &vnop_write_desc, (VOPFUNC)spec_write }, /* write */
126 { &vnop_ioctl_desc, (VOPFUNC)spec_ioctl }, /* ioctl */
127 { &vnop_select_desc, (VOPFUNC)spec_select }, /* select */
128 { &vnop_revoke_desc, (VOPFUNC)nop_revoke }, /* revoke */
129 { &vnop_mmap_desc, (VOPFUNC)err_mmap }, /* mmap */
130 { &vnop_fsync_desc, (VOPFUNC)spec_fsync }, /* fsync */
131 { &vnop_remove_desc, (VOPFUNC)err_remove }, /* remove */
132 { &vnop_link_desc, (VOPFUNC)err_link }, /* link */
133 { &vnop_rename_desc, (VOPFUNC)err_rename }, /* rename */
134 { &vnop_mkdir_desc, (VOPFUNC)err_mkdir }, /* mkdir */
135 { &vnop_rmdir_desc, (VOPFUNC)err_rmdir }, /* rmdir */
136 { &vnop_symlink_desc, (VOPFUNC)err_symlink }, /* symlink */
137 { &vnop_readdir_desc, (VOPFUNC)err_readdir }, /* readdir */
138 { &vnop_readlink_desc, (VOPFUNC)err_readlink }, /* readlink */
139 { &vnop_inactive_desc, (VOPFUNC)nop_inactive }, /* inactive */
140 { &vnop_reclaim_desc, (VOPFUNC)nop_reclaim }, /* reclaim */
141 { &vnop_strategy_desc, (VOPFUNC)spec_strategy }, /* strategy */
142 { &vnop_pathconf_desc, (VOPFUNC)spec_pathconf }, /* pathconf */
143 { &vnop_advlock_desc, (VOPFUNC)err_advlock }, /* advlock */
144 { &vnop_bwrite_desc, (VOPFUNC)spec_bwrite }, /* bwrite */
145 { &vnop_pagein_desc, (VOPFUNC)err_pagein }, /* Pagein */
146 { &vnop_pageout_desc, (VOPFUNC)err_pageout }, /* Pageout */
147 { &vnop_copyfile_desc, (VOPFUNC)err_copyfile }, /* Copyfile */
148 { &vnop_blktooff_desc, (VOPFUNC)spec_blktooff }, /* blktooff */
149 { &vnop_offtoblk_desc, (VOPFUNC)spec_offtoblk }, /* offtoblk */
150 { &vnop_blockmap_desc, (VOPFUNC)spec_blockmap }, /* blockmap */
151 { (struct vnodeop_desc*)NULL, (int(*)())NULL }
152 };
153 struct vnodeopv_desc spec_vnodeop_opv_desc =
154 { &spec_vnodeop_p, spec_vnodeop_entries };
155
156
157 static void set_blocksize(vnode_t, dev_t);
158
159 #define LOWPRI_TIER1_WINDOW_MSECS 25
160 #define LOWPRI_TIER2_WINDOW_MSECS 100
161 #define LOWPRI_TIER3_WINDOW_MSECS 500
162
163 #define LOWPRI_TIER1_IO_PERIOD_MSECS 15
164 #define LOWPRI_TIER2_IO_PERIOD_MSECS 50
165 #define LOWPRI_TIER3_IO_PERIOD_MSECS 200
166
167 #define LOWPRI_TIER1_IO_PERIOD_SSD_MSECS 5
168 #define LOWPRI_TIER2_IO_PERIOD_SSD_MSECS 15
169 #define LOWPRI_TIER3_IO_PERIOD_SSD_MSECS 25
170
171
172 int throttle_windows_msecs[THROTTLE_LEVEL_END + 1] = {
173 0,
174 LOWPRI_TIER1_WINDOW_MSECS,
175 LOWPRI_TIER2_WINDOW_MSECS,
176 LOWPRI_TIER3_WINDOW_MSECS,
177 };
178
179 int throttle_io_period_msecs[THROTTLE_LEVEL_END + 1] = {
180 0,
181 LOWPRI_TIER1_IO_PERIOD_MSECS,
182 LOWPRI_TIER2_IO_PERIOD_MSECS,
183 LOWPRI_TIER3_IO_PERIOD_MSECS,
184 };
185
186 int throttle_io_period_ssd_msecs[THROTTLE_LEVEL_END + 1] = {
187 0,
188 LOWPRI_TIER1_IO_PERIOD_SSD_MSECS,
189 LOWPRI_TIER2_IO_PERIOD_SSD_MSECS,
190 LOWPRI_TIER3_IO_PERIOD_SSD_MSECS,
191 };
192
193
194 int throttled_count[THROTTLE_LEVEL_END + 1];
195
196 struct _throttle_io_info_t {
197 lck_mtx_t throttle_lock;
198
199 struct timeval throttle_last_write_timestamp;
200 struct timeval throttle_min_timer_deadline;
201 struct timeval throttle_window_start_timestamp[THROTTLE_LEVEL_END + 1];
202 struct timeval throttle_last_IO_timestamp[THROTTLE_LEVEL_END + 1];
203 pid_t throttle_last_IO_pid[THROTTLE_LEVEL_END + 1];
204 struct timeval throttle_start_IO_period_timestamp[THROTTLE_LEVEL_END + 1];
205
206 TAILQ_HEAD( , uthread) throttle_uthlist[THROTTLE_LEVEL_END + 1]; /* Lists of throttled uthreads */
207 int throttle_next_wake_level;
208
209 thread_call_t throttle_timer_call;
210 int32_t throttle_timer_ref;
211 int32_t throttle_timer_active;
212
213 int32_t throttle_io_count;
214 int32_t throttle_io_count_begin;
215 int *throttle_io_periods;
216 uint32_t throttle_io_period_num;
217
218 int32_t throttle_refcnt;
219 int32_t throttle_alloc;
220 };
221
222 struct _throttle_io_info_t _throttle_io_info[LOWPRI_MAX_NUM_DEV];
223
224
225 int lowpri_throttle_enabled = 1;
226
227
228
229 static void throttle_info_update_internal(struct _throttle_io_info_t *info, uthread_t ut, int flags, boolean_t isssd);
230 static int throttle_get_thread_throttle_level(uthread_t ut);
231
232 /*
233 * Trivial lookup routine that always fails.
234 */
235 int
236 spec_lookup(struct vnop_lookup_args *ap)
237 {
238
239 *ap->a_vpp = NULL;
240 return (ENOTDIR);
241 }
242
243 static void
244 set_blocksize(struct vnode *vp, dev_t dev)
245 {
246 int (*size)(dev_t);
247 int rsize;
248
249 if ((major(dev) < nblkdev) && (size = bdevsw[major(dev)].d_psize)) {
250 rsize = (*size)(dev);
251 if (rsize <= 0) /* did size fail? */
252 vp->v_specsize = DEV_BSIZE;
253 else
254 vp->v_specsize = rsize;
255 }
256 else
257 vp->v_specsize = DEV_BSIZE;
258 }
259
260 void
261 set_fsblocksize(struct vnode *vp)
262 {
263
264 if (vp->v_type == VBLK) {
265 dev_t dev = (dev_t)vp->v_rdev;
266 int maj = major(dev);
267
268 if ((u_int)maj >= (u_int)nblkdev)
269 return;
270
271 vnode_lock(vp);
272 set_blocksize(vp, dev);
273 vnode_unlock(vp);
274 }
275
276 }
277
278
279 /*
280 * Open a special file.
281 */
282 int
283 spec_open(struct vnop_open_args *ap)
284 {
285 struct proc *p = vfs_context_proc(ap->a_context);
286 kauth_cred_t cred = vfs_context_ucred(ap->a_context);
287 struct vnode *vp = ap->a_vp;
288 dev_t bdev, dev = (dev_t)vp->v_rdev;
289 int maj = major(dev);
290 int error;
291
292 /*
293 * Don't allow open if fs is mounted -nodev.
294 */
295 if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_NODEV))
296 return (ENXIO);
297
298 switch (vp->v_type) {
299
300 case VCHR:
301 if ((u_int)maj >= (u_int)nchrdev)
302 return (ENXIO);
303 if (cred != FSCRED && (ap->a_mode & FWRITE)) {
304 /*
305 * When running in very secure mode, do not allow
306 * opens for writing of any disk character devices.
307 */
308 if (securelevel >= 2 && isdisk(dev, VCHR))
309 return (EPERM);
310 /*
311 * When running in secure mode, do not allow opens
312 * for writing of /dev/mem, /dev/kmem, or character
313 * devices whose corresponding block devices are
314 * currently mounted.
315 */
316 if (securelevel >= 1) {
317 if ((bdev = chrtoblk(dev)) != NODEV && check_mountedon(bdev, VBLK, &error))
318 return (error);
319 if (iskmemdev(dev))
320 return (EPERM);
321 }
322 }
323
324 devsw_lock(dev, S_IFCHR);
325 error = (*cdevsw[maj].d_open)(dev, ap->a_mode, S_IFCHR, p);
326
327 if (error == 0) {
328 vp->v_specinfo->si_opencount++;
329 }
330
331 devsw_unlock(dev, S_IFCHR);
332
333 if (error == 0 && cdevsw[maj].d_type == D_DISK && !vp->v_un.vu_specinfo->si_initted) {
334 int isssd = 0;
335 uint64_t throttle_mask = 0;
336 uint32_t devbsdunit = 0;
337
338 if (VNOP_IOCTL(vp, DKIOCGETTHROTTLEMASK, (caddr_t)&throttle_mask, 0, NULL) == 0) {
339
340 if (throttle_mask != 0 &&
341 VNOP_IOCTL(vp, DKIOCISSOLIDSTATE, (caddr_t)&isssd, 0, ap->a_context) == 0) {
342 /*
343 * as a reasonable approximation, only use the lowest bit of the mask
344 * to generate a disk unit number
345 */
346 devbsdunit = num_trailing_0(throttle_mask);
347
348 vnode_lock(vp);
349
350 vp->v_un.vu_specinfo->si_isssd = isssd;
351 vp->v_un.vu_specinfo->si_devbsdunit = devbsdunit;
352 vp->v_un.vu_specinfo->si_throttle_mask = throttle_mask;
353 vp->v_un.vu_specinfo->si_throttleable = 1;
354 vp->v_un.vu_specinfo->si_initted = 1;
355
356 vnode_unlock(vp);
357 }
358 }
359 if (vp->v_un.vu_specinfo->si_initted == 0) {
360 vnode_lock(vp);
361 vp->v_un.vu_specinfo->si_initted = 1;
362 vnode_unlock(vp);
363 }
364 }
365 return (error);
366
367 case VBLK:
368 if ((u_int)maj >= (u_int)nblkdev)
369 return (ENXIO);
370 /*
371 * When running in very secure mode, do not allow
372 * opens for writing of any disk block devices.
373 */
374 if (securelevel >= 2 && cred != FSCRED &&
375 (ap->a_mode & FWRITE) && bdevsw[maj].d_type == D_DISK)
376 return (EPERM);
377 /*
378 * Do not allow opens of block devices that are
379 * currently mounted.
380 */
381 if ( (error = vfs_mountedon(vp)) )
382 return (error);
383
384 devsw_lock(dev, S_IFBLK);
385 error = (*bdevsw[maj].d_open)(dev, ap->a_mode, S_IFBLK, p);
386 if (!error) {
387 vp->v_specinfo->si_opencount++;
388 }
389 devsw_unlock(dev, S_IFBLK);
390
391 if (!error) {
392 u_int64_t blkcnt;
393 u_int32_t blksize;
394 int setsize = 0;
395 u_int32_t size512 = 512;
396
397
398 if (!VNOP_IOCTL(vp, DKIOCGETBLOCKSIZE, (caddr_t)&blksize, 0, ap->a_context)) {
399 /* Switch to 512 byte sectors (temporarily) */
400
401 if (!VNOP_IOCTL(vp, DKIOCSETBLOCKSIZE, (caddr_t)&size512, FWRITE, ap->a_context)) {
402 /* Get the number of 512 byte physical blocks. */
403 if (!VNOP_IOCTL(vp, DKIOCGETBLOCKCOUNT, (caddr_t)&blkcnt, 0, ap->a_context)) {
404 setsize = 1;
405 }
406 }
407 /* If it doesn't set back, we can't recover */
408 if (VNOP_IOCTL(vp, DKIOCSETBLOCKSIZE, (caddr_t)&blksize, FWRITE, ap->a_context))
409 error = ENXIO;
410 }
411
412
413 vnode_lock(vp);
414 set_blocksize(vp, dev);
415
416 /*
417 * Cache the size in bytes of the block device for later
418 * use by spec_write().
419 */
420 if (setsize)
421 vp->v_specdevsize = blkcnt * (u_int64_t)size512;
422 else
423 vp->v_specdevsize = (u_int64_t)0; /* Default: Can't get */
424
425 vnode_unlock(vp);
426
427 }
428 return(error);
429 default:
430 panic("spec_open type");
431 }
432 return (0);
433 }
434
435 /*
436 * Vnode op for read
437 */
438 int
439 spec_read(struct vnop_read_args *ap)
440 {
441 struct vnode *vp = ap->a_vp;
442 struct uio *uio = ap->a_uio;
443 struct buf *bp;
444 daddr64_t bn, nextbn;
445 long bsize, bscale;
446 int devBlockSize=0;
447 int n, on;
448 int error = 0;
449 dev_t dev;
450
451 #if DIAGNOSTIC
452 if (uio->uio_rw != UIO_READ)
453 panic("spec_read mode");
454 if (UIO_SEG_IS_USER_SPACE(uio->uio_segflg))
455 panic("spec_read proc");
456 #endif
457 if (uio_resid(uio) == 0)
458 return (0);
459
460 switch (vp->v_type) {
461
462 case VCHR:
463 if (cdevsw[major(vp->v_rdev)].d_type == D_DISK && vp->v_un.vu_specinfo->si_throttleable) {
464 struct _throttle_io_info_t *throttle_info;
465
466 throttle_info = &_throttle_io_info[vp->v_un.vu_specinfo->si_devbsdunit];
467
468 throttle_info_update_internal(throttle_info, NULL, 0, vp->v_un.vu_specinfo->si_isssd);
469 }
470 error = (*cdevsw[major(vp->v_rdev)].d_read)
471 (vp->v_rdev, uio, ap->a_ioflag);
472
473 return (error);
474
475 case VBLK:
476 if (uio->uio_offset < 0)
477 return (EINVAL);
478
479 dev = vp->v_rdev;
480
481 devBlockSize = vp->v_specsize;
482
483 if (devBlockSize > PAGE_SIZE)
484 return (EINVAL);
485
486 bscale = PAGE_SIZE / devBlockSize;
487 bsize = bscale * devBlockSize;
488
489 do {
490 on = uio->uio_offset % bsize;
491
492 bn = (daddr64_t)((uio->uio_offset / devBlockSize) &~ (bscale - 1));
493
494 if (vp->v_speclastr + bscale == bn) {
495 nextbn = bn + bscale;
496 error = buf_breadn(vp, bn, (int)bsize, &nextbn,
497 (int *)&bsize, 1, NOCRED, &bp);
498 } else
499 error = buf_bread(vp, bn, (int)bsize, NOCRED, &bp);
500
501 vnode_lock(vp);
502 vp->v_speclastr = bn;
503 vnode_unlock(vp);
504
505 n = bsize - buf_resid(bp);
506 if ((on > n) || error) {
507 if (!error)
508 error = EINVAL;
509 buf_brelse(bp);
510 return (error);
511 }
512 n = min((unsigned)(n - on), uio_resid(uio));
513
514 error = uiomove((char *)buf_dataptr(bp) + on, n, uio);
515 if (n + on == bsize)
516 buf_markaged(bp);
517 buf_brelse(bp);
518 } while (error == 0 && uio_resid(uio) > 0 && n != 0);
519 return (error);
520
521 default:
522 panic("spec_read type");
523 }
524 /* NOTREACHED */
525
526 return (0);
527 }
528
529 /*
530 * Vnode op for write
531 */
532 int
533 spec_write(struct vnop_write_args *ap)
534 {
535 struct vnode *vp = ap->a_vp;
536 struct uio *uio = ap->a_uio;
537 struct buf *bp;
538 daddr64_t bn;
539 int bsize, blkmask, bscale;
540 int io_sync;
541 int devBlockSize=0;
542 int n, on;
543 int error = 0;
544 dev_t dev;
545
546 #if DIAGNOSTIC
547 if (uio->uio_rw != UIO_WRITE)
548 panic("spec_write mode");
549 if (UIO_SEG_IS_USER_SPACE(uio->uio_segflg))
550 panic("spec_write proc");
551 #endif
552
553 switch (vp->v_type) {
554
555 case VCHR:
556 if (cdevsw[major(vp->v_rdev)].d_type == D_DISK && vp->v_un.vu_specinfo->si_throttleable) {
557 struct _throttle_io_info_t *throttle_info;
558
559 throttle_info = &_throttle_io_info[vp->v_un.vu_specinfo->si_devbsdunit];
560
561 throttle_info_update_internal(throttle_info, NULL, 0, vp->v_un.vu_specinfo->si_isssd);
562
563 microuptime(&throttle_info->throttle_last_write_timestamp);
564 }
565 error = (*cdevsw[major(vp->v_rdev)].d_write)
566 (vp->v_rdev, uio, ap->a_ioflag);
567
568 return (error);
569
570 case VBLK:
571 if (uio_resid(uio) == 0)
572 return (0);
573 if (uio->uio_offset < 0)
574 return (EINVAL);
575
576 io_sync = (ap->a_ioflag & IO_SYNC);
577
578 dev = (vp->v_rdev);
579
580 devBlockSize = vp->v_specsize;
581 if (devBlockSize > PAGE_SIZE)
582 return(EINVAL);
583
584 bscale = PAGE_SIZE / devBlockSize;
585 blkmask = bscale - 1;
586 bsize = bscale * devBlockSize;
587
588
589 do {
590 bn = (daddr64_t)((uio->uio_offset / devBlockSize) &~ blkmask);
591 on = uio->uio_offset % bsize;
592
593 n = min((unsigned)(bsize - on), uio_resid(uio));
594
595 /*
596 * Use buf_getblk() as an optimization IFF:
597 *
598 * 1) We are reading exactly a block on a block
599 * aligned boundary
600 * 2) We know the size of the device from spec_open
601 * 3) The read doesn't span the end of the device
602 *
603 * Otherwise, we fall back on buf_bread().
604 */
605 if (n == bsize &&
606 vp->v_specdevsize != (u_int64_t)0 &&
607 (uio->uio_offset + (u_int64_t)n) > vp->v_specdevsize) {
608 /* reduce the size of the read to what is there */
609 n = (uio->uio_offset + (u_int64_t)n) - vp->v_specdevsize;
610 }
611
612 if (n == bsize)
613 bp = buf_getblk(vp, bn, bsize, 0, 0, BLK_WRITE);
614 else
615 error = (int)buf_bread(vp, bn, bsize, NOCRED, &bp);
616
617 /* Translate downstream error for upstream, if needed */
618 if (!error)
619 error = (int)buf_error(bp);
620 if (error) {
621 buf_brelse(bp);
622 return (error);
623 }
624 n = min(n, bsize - buf_resid(bp));
625
626 error = uiomove((char *)buf_dataptr(bp) + on, n, uio);
627 if (error) {
628 buf_brelse(bp);
629 return (error);
630 }
631 buf_markaged(bp);
632
633 if (io_sync)
634 error = buf_bwrite(bp);
635 else {
636 if ((n + on) == bsize)
637 error = buf_bawrite(bp);
638 else
639 error = buf_bdwrite(bp);
640 }
641 } while (error == 0 && uio_resid(uio) > 0 && n != 0);
642 return (error);
643
644 default:
645 panic("spec_write type");
646 }
647 /* NOTREACHED */
648
649 return (0);
650 }
651
652 /*
653 * Device ioctl operation.
654 */
655 int
656 spec_ioctl(struct vnop_ioctl_args *ap)
657 {
658 proc_t p = vfs_context_proc(ap->a_context);
659 dev_t dev = ap->a_vp->v_rdev;
660 int retval = 0;
661
662 KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_IOCTL, 0) | DBG_FUNC_START,
663 (unsigned int)dev, (unsigned int)ap->a_command, (unsigned int)ap->a_fflag, (unsigned int)ap->a_vp->v_type, 0);
664
665 switch (ap->a_vp->v_type) {
666
667 case VCHR:
668 retval = (*cdevsw[major(dev)].d_ioctl)(dev, ap->a_command, ap->a_data,
669 ap->a_fflag, p);
670 break;
671
672 case VBLK:
673 if (kdebug_enable) {
674 if (ap->a_command == DKIOCUNMAP) {
675 dk_unmap_t *unmap;
676 dk_extent_t *extent;
677 uint32_t i;
678
679 unmap = (dk_unmap_t *)ap->a_data;
680 extent = unmap->extents;
681
682 for (i = 0; i < unmap->extentsCount; i++, extent++) {
683 KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_IOCTL, 1) | DBG_FUNC_NONE, dev, extent->offset/ap->a_vp->v_specsize, extent->length, 0, 0);
684 }
685 }
686 }
687 retval = (*bdevsw[major(dev)].d_ioctl)(dev, ap->a_command, ap->a_data, ap->a_fflag, p);
688 break;
689
690 default:
691 panic("spec_ioctl");
692 /* NOTREACHED */
693 }
694 KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_IOCTL, 0) | DBG_FUNC_END,
695 (unsigned int)dev, (unsigned int)ap->a_command, (unsigned int)ap->a_fflag, retval, 0);
696
697 return (retval);
698 }
699
700 int
701 spec_select(struct vnop_select_args *ap)
702 {
703 proc_t p = vfs_context_proc(ap->a_context);
704 dev_t dev;
705
706 switch (ap->a_vp->v_type) {
707
708 default:
709 return (1); /* XXX */
710
711 case VCHR:
712 dev = ap->a_vp->v_rdev;
713 return (*cdevsw[major(dev)].d_select)(dev, ap->a_which, ap->a_wql, p);
714 }
715 }
716
717 static int filt_specattach(struct knote *kn);
718
719 int
720 spec_kqfilter(vnode_t vp, struct knote *kn)
721 {
722 dev_t dev;
723 int err = EINVAL;
724
725 /*
726 * For a few special kinds of devices, we can attach knotes.
727 * Each filter function must check whether the dev type matches it.
728 */
729 dev = vnode_specrdev(vp);
730
731 if (vnode_istty(vp)) {
732 /* We can hook into TTYs... */
733 err = filt_specattach(kn);
734 } else {
735 #if NETWORKING
736 /* Try a bpf device, as defined in bsd/net/bpf.c */
737 err = bpfkqfilter(dev, kn);
738 #endif
739 }
740
741 return err;
742 }
743
744 /*
745 * Synch buffers associated with a block device
746 */
747 int
748 spec_fsync_internal(vnode_t vp, int waitfor, __unused vfs_context_t context)
749 {
750 if (vp->v_type == VCHR)
751 return (0);
752 /*
753 * Flush all dirty buffers associated with a block device.
754 */
755 buf_flushdirtyblks(vp, (waitfor == MNT_WAIT || waitfor == MNT_DWAIT), 0, "spec_fsync");
756
757 return (0);
758 }
759
760 int
761 spec_fsync(struct vnop_fsync_args *ap)
762 {
763 return spec_fsync_internal(ap->a_vp, ap->a_waitfor, ap->a_context);
764 }
765
766
767 /*
768 * Just call the device strategy routine
769 */
770 void throttle_init(void);
771
772
773 #if 0
774 #define DEBUG_ALLOC_THROTTLE_INFO(format, debug_info, args...) \
775 do { \
776 if ((debug_info)->alloc) \
777 printf("%s: "format, __FUNCTION__, ## args); \
778 } while(0)
779
780 #else
781 #define DEBUG_ALLOC_THROTTLE_INFO(format, debug_info, args...)
782 #endif
783
784
785 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier1_window_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_windows_msecs[THROTTLE_LEVEL_TIER1], 0, "");
786 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier2_window_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_windows_msecs[THROTTLE_LEVEL_TIER2], 0, "");
787 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier3_window_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_windows_msecs[THROTTLE_LEVEL_TIER3], 0, "");
788
789 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier1_io_period_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_msecs[THROTTLE_LEVEL_TIER1], 0, "");
790 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier2_io_period_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_msecs[THROTTLE_LEVEL_TIER2], 0, "");
791 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier3_io_period_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_msecs[THROTTLE_LEVEL_TIER3], 0, "");
792
793 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier1_io_period_ssd_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_ssd_msecs[THROTTLE_LEVEL_TIER1], 0, "");
794 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier2_io_period_ssd_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_ssd_msecs[THROTTLE_LEVEL_TIER2], 0, "");
795 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier3_io_period_ssd_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_ssd_msecs[THROTTLE_LEVEL_TIER3], 0, "");
796
797 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_enabled, CTLFLAG_RW | CTLFLAG_LOCKED, &lowpri_throttle_enabled, 0, "");
798
799
800 static lck_grp_t *throttle_mtx_grp;
801 static lck_attr_t *throttle_mtx_attr;
802 static lck_grp_attr_t *throttle_mtx_grp_attr;
803
804
805 /*
806 * throttled I/O helper function
807 * convert the index of the lowest set bit to a device index
808 */
809 int
810 num_trailing_0(uint64_t n)
811 {
812 /*
813 * since in most cases the number of trailing 0s is very small,
814 * we simply counting sequentially from the lowest bit
815 */
816 if (n == 0)
817 return sizeof(n) * 8;
818 int count = 0;
819 while (!ISSET(n, 1)) {
820 n >>= 1;
821 ++count;
822 }
823 return count;
824 }
825
826
827 /*
828 * Release the reference and if the item was allocated and this is the last
829 * reference then free it.
830 *
831 * This routine always returns the old value.
832 */
833 static int
834 throttle_info_rel(struct _throttle_io_info_t *info)
835 {
836 SInt32 oldValue = OSDecrementAtomic(&info->throttle_refcnt);
837
838 DEBUG_ALLOC_THROTTLE_INFO("refcnt = %d info = %p\n",
839 info, (int)(oldValue -1), info );
840
841 /* The reference count just went negative, very bad */
842 if (oldValue == 0)
843 panic("throttle info ref cnt went negative!");
844
845 /*
846 * Once reference count is zero, no one else should be able to take a
847 * reference
848 */
849 if ((info->throttle_refcnt == 0) && (info->throttle_alloc)) {
850 DEBUG_ALLOC_THROTTLE_INFO("Freeing info = %p\n", info);
851
852 lck_mtx_destroy(&info->throttle_lock, throttle_mtx_grp);
853 FREE(info, M_TEMP);
854 }
855 return oldValue;
856 }
857
858
859 /*
860 * Just take a reference on the throttle info structure.
861 *
862 * This routine always returns the old value.
863 */
864 static SInt32
865 throttle_info_ref(struct _throttle_io_info_t *info)
866 {
867 SInt32 oldValue = OSIncrementAtomic(&info->throttle_refcnt);
868
869 DEBUG_ALLOC_THROTTLE_INFO("refcnt = %d info = %p\n",
870 info, (int)(oldValue -1), info );
871 /* Allocated items should never have a reference of zero */
872 if (info->throttle_alloc && (oldValue == 0))
873 panic("Taking a reference without calling create throttle info!\n");
874
875 return oldValue;
876 }
877
878 /*
879 * on entry the throttle_lock is held...
880 * this function is responsible for taking
881 * and dropping the reference on the info
882 * structure which will keep it from going
883 * away while the timer is running if it
884 * happens to have been dynamically allocated by
885 * a network fileystem kext which is now trying
886 * to free it
887 */
888 static uint32_t
889 throttle_timer_start(struct _throttle_io_info_t *info, boolean_t update_io_count, int wakelevel)
890 {
891 struct timeval elapsed;
892 struct timeval now;
893 struct timeval period;
894 uint64_t elapsed_msecs;
895 int throttle_level;
896 int level;
897 int msecs;
898 boolean_t throttled = FALSE;
899 boolean_t need_timer = FALSE;
900
901 microuptime(&now);
902
903 if (update_io_count == TRUE) {
904 info->throttle_io_count_begin = info->throttle_io_count;
905 info->throttle_io_period_num++;
906
907 while (wakelevel >= THROTTLE_LEVEL_THROTTLED)
908 info->throttle_start_IO_period_timestamp[wakelevel--] = now;
909
910 info->throttle_min_timer_deadline = now;
911
912 msecs = info->throttle_io_periods[THROTTLE_LEVEL_THROTTLED];
913 period.tv_sec = msecs / 1000;
914 period.tv_usec = (msecs % 1000) * 1000;
915
916 timevaladd(&info->throttle_min_timer_deadline, &period);
917 }
918 for (throttle_level = THROTTLE_LEVEL_START; throttle_level < THROTTLE_LEVEL_END; throttle_level++) {
919
920 elapsed = now;
921 timevalsub(&elapsed, &info->throttle_window_start_timestamp[throttle_level]);
922 elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
923
924 for (level = throttle_level + 1; level <= THROTTLE_LEVEL_END; level++) {
925
926 if (!TAILQ_EMPTY(&info->throttle_uthlist[level])) {
927
928 if (elapsed_msecs < (uint64_t)throttle_windows_msecs[level]) {
929 /*
930 * we had an I/O occur at a higher priority tier within
931 * this tier's throttle window
932 */
933 throttled = TRUE;
934 }
935 /*
936 * we assume that the windows are the same or longer
937 * as we drop through the throttling tiers... thus
938 * we can stop looking once we run into a tier with
939 * threads to schedule regardless of whether it's
940 * still in its throttling window or not
941 */
942 break;
943 }
944 }
945 if (throttled == TRUE)
946 break;
947 }
948 if (throttled == TRUE) {
949 uint64_t deadline = 0;
950 struct timeval target;
951 struct timeval min_target;
952
953 /*
954 * we've got at least one tier still in a throttled window
955 * so we need a timer running... compute the next deadline
956 * and schedule it
957 */
958 for (level = throttle_level+1; level <= THROTTLE_LEVEL_END; level++) {
959
960 if (TAILQ_EMPTY(&info->throttle_uthlist[level]))
961 continue;
962
963 target = info->throttle_start_IO_period_timestamp[level];
964
965 msecs = info->throttle_io_periods[level];
966 period.tv_sec = msecs / 1000;
967 period.tv_usec = (msecs % 1000) * 1000;
968
969 timevaladd(&target, &period);
970
971 if (need_timer == FALSE || timevalcmp(&target, &min_target, <)) {
972 min_target = target;
973 need_timer = TRUE;
974 }
975 }
976 if (timevalcmp(&info->throttle_min_timer_deadline, &now, >)) {
977 if (timevalcmp(&info->throttle_min_timer_deadline, &min_target, >))
978 min_target = info->throttle_min_timer_deadline;
979 }
980
981 if (info->throttle_timer_active) {
982 if (thread_call_cancel(info->throttle_timer_call) == FALSE) {
983 /*
984 * couldn't kill the timer because it's already
985 * been dispatched, so don't try to start a new
986 * one... once we drop the lock, the timer will
987 * proceed and eventually re-run this function
988 */
989 need_timer = FALSE;
990 } else
991 info->throttle_timer_active = 0;
992 }
993 if (need_timer == TRUE) {
994 /*
995 * This is defined as an int (32-bit) rather than a 64-bit
996 * value because it would need a really big period in the
997 * order of ~500 days to overflow this. So, we let this be
998 * 32-bit which allows us to use the clock_interval_to_deadline()
999 * routine.
1000 */
1001 int target_msecs;
1002
1003 if (info->throttle_timer_ref == 0) {
1004 /*
1005 * take a reference for the timer
1006 */
1007 throttle_info_ref(info);
1008
1009 info->throttle_timer_ref = 1;
1010 }
1011 elapsed = min_target;
1012 timevalsub(&elapsed, &now);
1013 target_msecs = elapsed.tv_sec * 1000 + elapsed.tv_usec / 1000;
1014
1015 if (target_msecs <= 0) {
1016 /*
1017 * we may have computed a deadline slightly in the past
1018 * due to various factors... if so, just set the timer
1019 * to go off in the near future (we don't need to be precise)
1020 */
1021 target_msecs = 1;
1022 }
1023 clock_interval_to_deadline(target_msecs, 1000000, &deadline);
1024
1025 thread_call_enter_delayed(info->throttle_timer_call, deadline);
1026 info->throttle_timer_active = 1;
1027 }
1028 }
1029 return (throttle_level);
1030 }
1031
1032
1033 static void
1034 throttle_timer(struct _throttle_io_info_t *info)
1035 {
1036 uthread_t ut, utlist;
1037 struct timeval elapsed;
1038 struct timeval now;
1039 uint64_t elapsed_msecs;
1040 int throttle_level;
1041 int level;
1042 int wake_level;
1043 caddr_t wake_address = NULL;
1044 boolean_t update_io_count = FALSE;
1045 boolean_t need_wakeup = FALSE;
1046 boolean_t need_release = FALSE;
1047
1048 ut = NULL;
1049 lck_mtx_lock(&info->throttle_lock);
1050
1051 info->throttle_timer_active = 0;
1052 microuptime(&now);
1053
1054 elapsed = now;
1055 timevalsub(&elapsed, &info->throttle_start_IO_period_timestamp[THROTTLE_LEVEL_THROTTLED]);
1056 elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
1057
1058 if (elapsed_msecs >= (uint64_t)info->throttle_io_periods[THROTTLE_LEVEL_THROTTLED]) {
1059
1060 wake_level = info->throttle_next_wake_level;
1061
1062 for (level = THROTTLE_LEVEL_START; level < THROTTLE_LEVEL_END; level++) {
1063
1064 elapsed = now;
1065 timevalsub(&elapsed, &info->throttle_start_IO_period_timestamp[wake_level]);
1066 elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
1067
1068 if (elapsed_msecs >= (uint64_t)info->throttle_io_periods[wake_level] && !TAILQ_EMPTY(&info->throttle_uthlist[wake_level])) {
1069 /*
1070 * we're closing out the current IO period...
1071 * if we have a waiting thread, wake it up
1072 * after we have reset the I/O window info
1073 */
1074 need_wakeup = TRUE;
1075 update_io_count = TRUE;
1076
1077 info->throttle_next_wake_level = wake_level - 1;
1078
1079 if (info->throttle_next_wake_level == THROTTLE_LEVEL_START)
1080 info->throttle_next_wake_level = THROTTLE_LEVEL_END;
1081
1082 break;
1083 }
1084 wake_level--;
1085
1086 if (wake_level == THROTTLE_LEVEL_START)
1087 wake_level = THROTTLE_LEVEL_END;
1088 }
1089 }
1090 if (need_wakeup == TRUE) {
1091 if (!TAILQ_EMPTY(&info->throttle_uthlist[wake_level])) {
1092
1093 ut = (uthread_t)TAILQ_FIRST(&info->throttle_uthlist[wake_level]);
1094 TAILQ_REMOVE(&info->throttle_uthlist[wake_level], ut, uu_throttlelist);
1095 ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
1096
1097 wake_address = (caddr_t)&ut->uu_on_throttlelist;
1098 }
1099 } else
1100 wake_level = THROTTLE_LEVEL_START;
1101
1102 throttle_level = throttle_timer_start(info, update_io_count, wake_level);
1103
1104 if (wake_address != NULL)
1105 wakeup(wake_address);
1106
1107 for (level = THROTTLE_LEVEL_THROTTLED; level <= throttle_level; level++) {
1108
1109 TAILQ_FOREACH_SAFE(ut, &info->throttle_uthlist[level], uu_throttlelist, utlist) {
1110
1111 TAILQ_REMOVE(&info->throttle_uthlist[level], ut, uu_throttlelist);
1112 ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
1113
1114 wakeup(&ut->uu_on_throttlelist);
1115 }
1116 }
1117 if (info->throttle_timer_active == 0 && info->throttle_timer_ref) {
1118 info->throttle_timer_ref = 0;
1119 need_release = TRUE;
1120 }
1121 lck_mtx_unlock(&info->throttle_lock);
1122
1123 if (need_release == TRUE)
1124 throttle_info_rel(info);
1125 }
1126
1127
1128 static int
1129 throttle_add_to_list(struct _throttle_io_info_t *info, uthread_t ut, int mylevel, boolean_t insert_tail)
1130 {
1131 boolean_t start_timer = FALSE;
1132 int level = THROTTLE_LEVEL_START;
1133
1134 if (TAILQ_EMPTY(&info->throttle_uthlist[mylevel])) {
1135 info->throttle_start_IO_period_timestamp[mylevel] = info->throttle_last_IO_timestamp[mylevel];
1136 start_timer = TRUE;
1137 }
1138
1139 if (insert_tail == TRUE)
1140 TAILQ_INSERT_TAIL(&info->throttle_uthlist[mylevel], ut, uu_throttlelist);
1141 else
1142 TAILQ_INSERT_HEAD(&info->throttle_uthlist[mylevel], ut, uu_throttlelist);
1143
1144 ut->uu_on_throttlelist = mylevel;
1145
1146 if (start_timer == TRUE) {
1147 /* we may need to start or rearm the timer */
1148 level = throttle_timer_start(info, FALSE, THROTTLE_LEVEL_START);
1149
1150 if (level == THROTTLE_LEVEL_END) {
1151 if (ut->uu_on_throttlelist >= THROTTLE_LEVEL_THROTTLED) {
1152 TAILQ_REMOVE(&info->throttle_uthlist[ut->uu_on_throttlelist], ut, uu_throttlelist);
1153
1154 ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
1155 }
1156 }
1157 }
1158 return (level);
1159 }
1160
1161 static void
1162 throttle_init_throttle_window(void)
1163 {
1164 int throttle_window_size;
1165
1166 /*
1167 * The hierarchy of throttle window values is as follows:
1168 * - Global defaults
1169 * - Device tree properties
1170 * - Boot-args
1171 * All values are specified in msecs.
1172 */
1173
1174 /* Override global values with device-tree properties */
1175 if (PE_get_default("kern.io_throttle_window_tier1", &throttle_window_size, sizeof(throttle_window_size)))
1176 throttle_windows_msecs[THROTTLE_LEVEL_TIER1] = throttle_window_size;
1177
1178 if (PE_get_default("kern.io_throttle_window_tier2", &throttle_window_size, sizeof(throttle_window_size)))
1179 throttle_windows_msecs[THROTTLE_LEVEL_TIER2] = throttle_window_size;
1180
1181 if (PE_get_default("kern.io_throttle_window_tier3", &throttle_window_size, sizeof(throttle_window_size)))
1182 throttle_windows_msecs[THROTTLE_LEVEL_TIER3] = throttle_window_size;
1183
1184 /* Override with boot-args */
1185 if (PE_parse_boot_argn("io_throttle_window_tier1", &throttle_window_size, sizeof(throttle_window_size)))
1186 throttle_windows_msecs[THROTTLE_LEVEL_TIER1] = throttle_window_size;
1187
1188 if (PE_parse_boot_argn("io_throttle_window_tier2", &throttle_window_size, sizeof(throttle_window_size)))
1189 throttle_windows_msecs[THROTTLE_LEVEL_TIER2] = throttle_window_size;
1190
1191 if (PE_parse_boot_argn("io_throttle_window_tier3", &throttle_window_size, sizeof(throttle_window_size)))
1192 throttle_windows_msecs[THROTTLE_LEVEL_TIER3] = throttle_window_size;
1193 }
1194
1195 static void
1196 throttle_init_throttle_period(struct _throttle_io_info_t *info, boolean_t isssd)
1197 {
1198 int throttle_period_size;
1199
1200 /*
1201 * The hierarchy of throttle period values is as follows:
1202 * - Global defaults
1203 * - Device tree properties
1204 * - Boot-args
1205 * All values are specified in msecs.
1206 */
1207
1208 /* Assign global defaults */
1209 if (isssd == TRUE)
1210 info->throttle_io_periods = &throttle_io_period_ssd_msecs[0];
1211 else
1212 info->throttle_io_periods = &throttle_io_period_msecs[0];
1213
1214 /* Override global values with device-tree properties */
1215 if (PE_get_default("kern.io_throttle_period_tier1", &throttle_period_size, sizeof(throttle_period_size)))
1216 info->throttle_io_periods[THROTTLE_LEVEL_TIER1] = throttle_period_size;
1217
1218 if (PE_get_default("kern.io_throttle_period_tier2", &throttle_period_size, sizeof(throttle_period_size)))
1219 info->throttle_io_periods[THROTTLE_LEVEL_TIER2] = throttle_period_size;
1220
1221 if (PE_get_default("kern.io_throttle_period_tier3", &throttle_period_size, sizeof(throttle_period_size)))
1222 info->throttle_io_periods[THROTTLE_LEVEL_TIER3] = throttle_period_size;
1223
1224 /* Override with boot-args */
1225 if (PE_parse_boot_argn("io_throttle_period_tier1", &throttle_period_size, sizeof(throttle_period_size)))
1226 info->throttle_io_periods[THROTTLE_LEVEL_TIER1] = throttle_period_size;
1227
1228 if (PE_parse_boot_argn("io_throttle_period_tier2", &throttle_period_size, sizeof(throttle_period_size)))
1229 info->throttle_io_periods[THROTTLE_LEVEL_TIER2] = throttle_period_size;
1230
1231 if (PE_parse_boot_argn("io_throttle_period_tier3", &throttle_period_size, sizeof(throttle_period_size)))
1232 info->throttle_io_periods[THROTTLE_LEVEL_TIER3] = throttle_period_size;
1233
1234 }
1235
1236 void
1237 throttle_init(void)
1238 {
1239 struct _throttle_io_info_t *info;
1240 int i;
1241 int level;
1242
1243 /*
1244 * allocate lock group attribute and group
1245 */
1246 throttle_mtx_grp_attr = lck_grp_attr_alloc_init();
1247 throttle_mtx_grp = lck_grp_alloc_init("throttle I/O", throttle_mtx_grp_attr);
1248
1249 /* Update throttle parameters based on device tree configuration */
1250 throttle_init_throttle_window();
1251
1252 /*
1253 * allocate the lock attribute
1254 */
1255 throttle_mtx_attr = lck_attr_alloc_init();
1256
1257 for (i = 0; i < LOWPRI_MAX_NUM_DEV; i++) {
1258 info = &_throttle_io_info[i];
1259
1260 lck_mtx_init(&info->throttle_lock, throttle_mtx_grp, throttle_mtx_attr);
1261 info->throttle_timer_call = thread_call_allocate((thread_call_func_t)throttle_timer, (thread_call_param_t)info);
1262
1263 for (level = 0; level <= THROTTLE_LEVEL_END; level++) {
1264 TAILQ_INIT(&info->throttle_uthlist[level]);
1265 info->throttle_last_IO_pid[level] = 0;
1266 }
1267 info->throttle_next_wake_level = THROTTLE_LEVEL_END;
1268 }
1269 }
1270
1271 void
1272 sys_override_io_throttle(int flag)
1273 {
1274 if (flag == THROTTLE_IO_ENABLE)
1275 lowpri_throttle_enabled = 1;
1276 if (flag == THROTTLE_IO_DISABLE)
1277 lowpri_throttle_enabled = 0;
1278 }
1279
1280 int rethrottle_removed_from_list = 0;
1281 int rethrottle_moved_to_new_list = 0;
1282
1283 /*
1284 * move a throttled thread to the appropriate state based
1285 * on it's new throttle level... throttle_add_to_list will
1286 * reset the timer deadline if necessary... it may also
1287 * leave the thread off of the queue if we're already outside
1288 * the throttle window for the new level
1289 * takes a valid uthread (which may or may not be on the
1290 * throttle queue) as input
1291 *
1292 * NOTE: This is called with the task lock held.
1293 */
1294
1295 void
1296 rethrottle_thread(uthread_t ut)
1297 {
1298 struct _throttle_io_info_t *info;
1299 int my_new_level;
1300
1301 if ((info = ut->uu_throttle_info) == NULL)
1302 return;
1303
1304 lck_mtx_lock(&info->throttle_lock);
1305
1306 if (ut->uu_on_throttlelist >= THROTTLE_LEVEL_THROTTLED) {
1307
1308 my_new_level = throttle_get_thread_throttle_level(ut);
1309
1310 if (my_new_level != ut->uu_on_throttlelist) {
1311
1312 TAILQ_REMOVE(&info->throttle_uthlist[ut->uu_on_throttlelist], ut, uu_throttlelist);
1313 ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
1314
1315 if (my_new_level >= THROTTLE_LEVEL_THROTTLED) {
1316 throttle_add_to_list(info, ut, my_new_level, TRUE);
1317 rethrottle_moved_to_new_list++;
1318 }
1319
1320 /* Thread no longer in window, need to wake it up */
1321 if (ut->uu_on_throttlelist == THROTTLE_LEVEL_NONE) {
1322 wakeup(&ut->uu_on_throttlelist);
1323 rethrottle_removed_from_list++;
1324 }
1325 }
1326 }
1327
1328 lck_mtx_unlock(&info->throttle_lock);
1329 }
1330
1331
1332 /*
1333 * KPI routine
1334 *
1335 * Create and take a reference on a throttle info structure and return a
1336 * pointer for the file system to use when calling throttle_info_update.
1337 * Calling file system must have a matching release for every create.
1338 */
1339 void *
1340 throttle_info_create(void)
1341 {
1342 struct _throttle_io_info_t *info;
1343 int level;
1344
1345 MALLOC(info, struct _throttle_io_info_t *, sizeof(*info), M_TEMP, M_ZERO | M_WAITOK);
1346 /* Should never happen but just in case */
1347 if (info == NULL)
1348 return NULL;
1349 /* Mark that this one was allocated and needs to be freed */
1350 DEBUG_ALLOC_THROTTLE_INFO("Creating info = %p\n", info, info );
1351 info->throttle_alloc = TRUE;
1352
1353 lck_mtx_init(&info->throttle_lock, throttle_mtx_grp, throttle_mtx_attr);
1354 info->throttle_timer_call = thread_call_allocate((thread_call_func_t)throttle_timer, (thread_call_param_t)info);
1355
1356 for (level = 0; level <= THROTTLE_LEVEL_END; level++) {
1357 TAILQ_INIT(&info->throttle_uthlist[level]);
1358 }
1359 info->throttle_next_wake_level = THROTTLE_LEVEL_END;
1360
1361 /* Take a reference */
1362 OSIncrementAtomic(&info->throttle_refcnt);
1363 return info;
1364 }
1365
1366 /*
1367 * KPI routine
1368 *
1369 * Release the throttle info pointer if all the reference are gone. Should be
1370 * called to release reference taken by throttle_info_create
1371 */
1372 void
1373 throttle_info_release(void *throttle_info)
1374 {
1375 DEBUG_ALLOC_THROTTLE_INFO("Releaseing info = %p\n",
1376 (struct _throttle_io_info_t *)throttle_info,
1377 (struct _throttle_io_info_t *)throttle_info);
1378 if (throttle_info) /* Just to be careful */
1379 throttle_info_rel(throttle_info);
1380 }
1381
1382 /*
1383 * KPI routine
1384 *
1385 * File Systems that create an info structure, need to call this routine in
1386 * their mount routine (used by cluster code). File Systems that call this in
1387 * their mount routines must call throttle_info_mount_rel in their unmount
1388 * routines.
1389 */
1390 void
1391 throttle_info_mount_ref(mount_t mp, void *throttle_info)
1392 {
1393 if ((throttle_info == NULL) || (mp == NULL))
1394 return;
1395 throttle_info_ref(throttle_info);
1396
1397 /*
1398 * We already have a reference release it before adding the new one
1399 */
1400 if (mp->mnt_throttle_info)
1401 throttle_info_rel(mp->mnt_throttle_info);
1402 mp->mnt_throttle_info = throttle_info;
1403 }
1404
1405 /*
1406 * Private KPI routine
1407 *
1408 * return a handle for accessing throttle_info given a throttle_mask. The
1409 * handle must be released by throttle_info_rel_by_mask
1410 */
1411 int
1412 throttle_info_ref_by_mask(uint64_t throttle_mask, throttle_info_handle_t *throttle_info_handle)
1413 {
1414 int dev_index;
1415 struct _throttle_io_info_t *info;
1416
1417 if (throttle_info_handle == NULL)
1418 return EINVAL;
1419
1420 dev_index = num_trailing_0(throttle_mask);
1421 info = &_throttle_io_info[dev_index];
1422 throttle_info_ref(info);
1423 *(struct _throttle_io_info_t**)throttle_info_handle = info;
1424
1425 return 0;
1426 }
1427
1428 /*
1429 * Private KPI routine
1430 *
1431 * release the handle obtained by throttle_info_ref_by_mask
1432 */
1433 void
1434 throttle_info_rel_by_mask(throttle_info_handle_t throttle_info_handle)
1435 {
1436 /*
1437 * for now the handle is just a pointer to _throttle_io_info_t
1438 */
1439 throttle_info_rel((struct _throttle_io_info_t*)throttle_info_handle);
1440 }
1441
1442 /*
1443 * KPI routine
1444 *
1445 * File Systems that throttle_info_mount_ref, must call this routine in their
1446 * umount routine.
1447 */
1448 void
1449 throttle_info_mount_rel(mount_t mp)
1450 {
1451 if (mp->mnt_throttle_info)
1452 throttle_info_rel(mp->mnt_throttle_info);
1453 mp->mnt_throttle_info = NULL;
1454 }
1455
1456 void
1457 throttle_info_get_last_io_time(mount_t mp, struct timeval *tv)
1458 {
1459 struct _throttle_io_info_t *info;
1460
1461 if (mp == NULL)
1462 info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
1463 else if (mp->mnt_throttle_info == NULL)
1464 info = &_throttle_io_info[mp->mnt_devbsdunit];
1465 else
1466 info = mp->mnt_throttle_info;
1467
1468 *tv = info->throttle_last_write_timestamp;
1469 }
1470
1471 void
1472 update_last_io_time(mount_t mp)
1473 {
1474 struct _throttle_io_info_t *info;
1475
1476 if (mp == NULL)
1477 info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
1478 else if (mp->mnt_throttle_info == NULL)
1479 info = &_throttle_io_info[mp->mnt_devbsdunit];
1480 else
1481 info = mp->mnt_throttle_info;
1482
1483 microuptime(&info->throttle_last_write_timestamp);
1484 if (mp != NULL)
1485 mp->mnt_last_write_completed_timestamp = info->throttle_last_write_timestamp;
1486 }
1487
1488
1489 int
1490 throttle_get_io_policy(uthread_t *ut)
1491 {
1492 if (ut != NULL)
1493 *ut = get_bsdthread_info(current_thread());
1494
1495 return (proc_get_effective_thread_policy(current_thread(), TASK_POLICY_IO));
1496 }
1497
1498 int
1499 throttle_get_passive_io_policy(uthread_t *ut)
1500 {
1501 if (ut != NULL)
1502 *ut = get_bsdthread_info(current_thread());
1503
1504 return (proc_get_effective_thread_policy(current_thread(), TASK_POLICY_PASSIVE_IO));
1505 }
1506
1507
1508 static int
1509 throttle_get_thread_throttle_level(uthread_t ut)
1510 {
1511 int thread_throttle_level;
1512
1513 if (ut == NULL)
1514 ut = get_bsdthread_info(current_thread());
1515
1516 thread_throttle_level = proc_get_effective_thread_policy(ut->uu_thread, TASK_POLICY_IO);
1517
1518 /* Bootcache misses should always be throttled */
1519 if (ut->uu_throttle_bc == TRUE)
1520 thread_throttle_level = THROTTLE_LEVEL_TIER3;
1521
1522 return (thread_throttle_level);
1523 }
1524
1525
1526 static int
1527 throttle_io_will_be_throttled_internal(void * throttle_info, int * mylevel, int * throttling_level)
1528 {
1529 struct _throttle_io_info_t *info = throttle_info;
1530 struct timeval elapsed;
1531 uint64_t elapsed_msecs;
1532 int thread_throttle_level;
1533 int throttle_level;
1534
1535 if ((thread_throttle_level = throttle_get_thread_throttle_level(NULL)) < THROTTLE_LEVEL_THROTTLED)
1536 return (THROTTLE_DISENGAGED);
1537
1538 for (throttle_level = THROTTLE_LEVEL_START; throttle_level < thread_throttle_level; throttle_level++) {
1539
1540 microuptime(&elapsed);
1541 timevalsub(&elapsed, &info->throttle_window_start_timestamp[throttle_level]);
1542 elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
1543
1544 if (elapsed_msecs < (uint64_t)throttle_windows_msecs[thread_throttle_level])
1545 break;
1546 }
1547 if (throttle_level >= thread_throttle_level) {
1548 /*
1549 * we're beyond all of the throttle windows
1550 * that affect the throttle level of this thread,
1551 * so go ahead and treat as normal I/O
1552 */
1553 return (THROTTLE_DISENGAGED);
1554 }
1555 if (mylevel)
1556 *mylevel = thread_throttle_level;
1557 if (throttling_level)
1558 *throttling_level = throttle_level;
1559
1560 if (info->throttle_io_count != info->throttle_io_count_begin) {
1561 /*
1562 * we've already issued at least one throttleable I/O
1563 * in the current I/O window, so avoid issuing another one
1564 */
1565 return (THROTTLE_NOW);
1566 }
1567 /*
1568 * we're in the throttle window, so
1569 * cut the I/O size back
1570 */
1571 return (THROTTLE_ENGAGED);
1572 }
1573
1574 /*
1575 * If we have a mount point and it has a throttle info pointer then
1576 * use it to do the check, otherwise use the device unit number to find
1577 * the correct throttle info array element.
1578 */
1579 int
1580 throttle_io_will_be_throttled(__unused int lowpri_window_msecs, mount_t mp)
1581 {
1582 void *info;
1583
1584 /*
1585 * Should we just return zero if no mount point
1586 */
1587 if (mp == NULL)
1588 info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
1589 else if (mp->mnt_throttle_info == NULL)
1590 info = &_throttle_io_info[mp->mnt_devbsdunit];
1591 else
1592 info = mp->mnt_throttle_info;
1593
1594 return throttle_io_will_be_throttled_internal(info, NULL, NULL);
1595 }
1596
1597 /*
1598 * Routine to increment I/O throttling counters maintained in the proc
1599 */
1600
1601 static void
1602 throttle_update_proc_stats(pid_t throttling_pid)
1603 {
1604 proc_t throttling_proc;
1605 proc_t throttled_proc = current_proc();
1606
1607 /* The throttled_proc is always the current proc; so we are not concerned with refs */
1608 OSAddAtomic64(1, &(throttled_proc->was_throttled));
1609
1610 /* The throttling pid might have exited by now */
1611 throttling_proc = proc_find(throttling_pid);
1612 if (throttling_proc != PROC_NULL) {
1613 OSAddAtomic64(1, &(throttling_proc->did_throttle));
1614 proc_rele(throttling_proc);
1615 }
1616 }
1617
1618 /*
1619 * Block until woken up by the throttle timer or by a rethrottle call.
1620 * As long as we hold the throttle_lock while querying the throttle tier, we're
1621 * safe against seeing an old throttle tier after a rethrottle.
1622 */
1623 uint32_t
1624 throttle_lowpri_io(int sleep_amount)
1625 {
1626 uthread_t ut;
1627 struct _throttle_io_info_t *info;
1628 int throttle_type = 0;
1629 int mylevel = 0;
1630 int throttling_level = THROTTLE_LEVEL_NONE;
1631 int sleep_cnt = 0;
1632 uint32_t throttle_io_period_num = 0;
1633 boolean_t insert_tail = TRUE;
1634
1635 ut = get_bsdthread_info(current_thread());
1636
1637 if (ut->uu_lowpri_window == 0)
1638 return (0);
1639
1640 info = ut->uu_throttle_info;
1641
1642 if (info == NULL) {
1643 ut->uu_throttle_bc = FALSE;
1644 ut->uu_lowpri_window = 0;
1645 return (0);
1646 }
1647
1648 lck_mtx_lock(&info->throttle_lock);
1649
1650 if (sleep_amount == 0)
1651 goto done;
1652
1653 if (sleep_amount == 1 && ut->uu_throttle_bc == FALSE)
1654 sleep_amount = 0;
1655
1656 throttle_io_period_num = info->throttle_io_period_num;
1657
1658 while ( (throttle_type = throttle_io_will_be_throttled_internal(info, &mylevel, &throttling_level)) ) {
1659
1660 if (throttle_type == THROTTLE_ENGAGED) {
1661 if (sleep_amount == 0)
1662 break;
1663 if (info->throttle_io_period_num < throttle_io_period_num)
1664 break;
1665 if ((info->throttle_io_period_num - throttle_io_period_num) >= (uint32_t)sleep_amount)
1666 break;
1667 }
1668 if (ut->uu_on_throttlelist < THROTTLE_LEVEL_THROTTLED) {
1669 if (throttle_add_to_list(info, ut, mylevel, insert_tail) == THROTTLE_LEVEL_END)
1670 goto done;
1671 }
1672 assert(throttling_level >= THROTTLE_LEVEL_START && throttling_level <= THROTTLE_LEVEL_END);
1673 throttle_update_proc_stats(info->throttle_last_IO_pid[throttling_level]);
1674 KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_THROTTLE, PROCESS_THROTTLED)) | DBG_FUNC_NONE,
1675 info->throttle_last_IO_pid[throttling_level], throttling_level, proc_selfpid(), mylevel, 0);
1676
1677
1678 if (sleep_cnt == 0) {
1679 KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_FSRW, 97)) | DBG_FUNC_START,
1680 throttle_windows_msecs[mylevel], info->throttle_io_periods[mylevel], info->throttle_io_count, 0, 0);
1681 throttled_count[mylevel]++;
1682 }
1683 msleep((caddr_t)&ut->uu_on_throttlelist, &info->throttle_lock, PRIBIO + 1, "throttle_lowpri_io", NULL);
1684
1685 sleep_cnt++;
1686
1687 if (sleep_amount == 0)
1688 insert_tail = FALSE;
1689 else if (info->throttle_io_period_num < throttle_io_period_num ||
1690 (info->throttle_io_period_num - throttle_io_period_num) >= (uint32_t)sleep_amount) {
1691 insert_tail = FALSE;
1692 sleep_amount = 0;
1693 }
1694 }
1695 done:
1696 if (ut->uu_on_throttlelist >= THROTTLE_LEVEL_THROTTLED) {
1697 TAILQ_REMOVE(&info->throttle_uthlist[ut->uu_on_throttlelist], ut, uu_throttlelist);
1698 ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
1699 }
1700
1701 lck_mtx_unlock(&info->throttle_lock);
1702
1703 if (sleep_cnt) {
1704 KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_FSRW, 97)) | DBG_FUNC_END,
1705 throttle_windows_msecs[mylevel], info->throttle_io_periods[mylevel], info->throttle_io_count, 0, 0);
1706 }
1707
1708 throttle_info_rel(info);
1709
1710 ut->uu_throttle_info = NULL;
1711 ut->uu_throttle_bc = FALSE;
1712 ut->uu_lowpri_window = 0;
1713
1714 return (sleep_cnt);
1715 }
1716
1717 /*
1718 * KPI routine
1719 *
1720 * set a kernel thread's IO policy. policy can be:
1721 * IOPOL_NORMAL, IOPOL_THROTTLE, IOPOL_PASSIVE, IOPOL_UTILITY, IOPOL_STANDARD
1722 *
1723 * explanations about these policies are in the man page of setiopolicy_np
1724 */
1725 void throttle_set_thread_io_policy(int policy)
1726 {
1727 proc_set_task_policy(current_task(), current_thread(),
1728 TASK_POLICY_INTERNAL, TASK_POLICY_IOPOL,
1729 policy);
1730 }
1731
1732
1733 static
1734 void throttle_info_reset_window(uthread_t ut)
1735 {
1736 struct _throttle_io_info_t *info;
1737
1738 if ( (info = ut->uu_throttle_info) ) {
1739 throttle_info_rel(info);
1740
1741 ut->uu_throttle_info = NULL;
1742 ut->uu_lowpri_window = 0;
1743 ut->uu_throttle_bc = FALSE;
1744 }
1745 }
1746
1747 static
1748 void throttle_info_set_initial_window(uthread_t ut, struct _throttle_io_info_t *info, boolean_t BC_throttle, boolean_t isssd)
1749 {
1750 if (lowpri_throttle_enabled == 0)
1751 return;
1752
1753 if (info->throttle_io_periods == 0) {
1754 throttle_init_throttle_period(info, isssd);
1755 }
1756 if (ut->uu_throttle_info == NULL) {
1757
1758 ut->uu_throttle_info = info;
1759 throttle_info_ref(info);
1760 DEBUG_ALLOC_THROTTLE_INFO("updating info = %p\n", info, info );
1761
1762 ut->uu_lowpri_window = 1;
1763 ut->uu_throttle_bc = BC_throttle;
1764 }
1765 }
1766
1767
1768 static
1769 void throttle_info_update_internal(struct _throttle_io_info_t *info, uthread_t ut, int flags, boolean_t isssd)
1770 {
1771 int thread_throttle_level;
1772
1773 if (lowpri_throttle_enabled == 0)
1774 return;
1775
1776 if (ut == NULL)
1777 ut = get_bsdthread_info(current_thread());
1778
1779 thread_throttle_level = throttle_get_thread_throttle_level(ut);
1780
1781 if (thread_throttle_level != THROTTLE_LEVEL_NONE) {
1782 if(!ISSET(flags, B_PASSIVE)) {
1783 microuptime(&info->throttle_window_start_timestamp[thread_throttle_level]);
1784 info->throttle_last_IO_pid[thread_throttle_level] = proc_selfpid();
1785 KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_THROTTLE, OPEN_THROTTLE_WINDOW)) | DBG_FUNC_NONE,
1786 current_proc()->p_pid, thread_throttle_level, 0, 0, 0);
1787 }
1788 microuptime(&info->throttle_last_IO_timestamp[thread_throttle_level]);
1789 }
1790
1791
1792 if (thread_throttle_level >= THROTTLE_LEVEL_THROTTLED) {
1793 /*
1794 * I'd really like to do the IOSleep here, but
1795 * we may be holding all kinds of filesystem related locks
1796 * and the pages for this I/O marked 'busy'...
1797 * we don't want to cause a normal task to block on
1798 * one of these locks while we're throttling a task marked
1799 * for low priority I/O... we'll mark the uthread and
1800 * do the delay just before we return from the system
1801 * call that triggered this I/O or from vnode_pagein
1802 */
1803 OSAddAtomic(1, &info->throttle_io_count);
1804
1805 throttle_info_set_initial_window(ut, info, FALSE, isssd);
1806 }
1807 }
1808
1809 void *throttle_info_update_by_mount(mount_t mp)
1810 {
1811 struct _throttle_io_info_t *info;
1812 uthread_t ut;
1813 boolean_t isssd = FALSE;
1814
1815 ut = get_bsdthread_info(current_thread());
1816
1817 if (mp != NULL) {
1818 if ((mp->mnt_kern_flag & MNTK_SSD) && !ignore_is_ssd)
1819 isssd = TRUE;
1820 info = &_throttle_io_info[mp->mnt_devbsdunit];
1821 } else
1822 info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
1823
1824 if (!ut->uu_lowpri_window)
1825 throttle_info_set_initial_window(ut, info, FALSE, isssd);
1826
1827 return info;
1828 }
1829
1830
1831 /*
1832 * KPI routine
1833 *
1834 * this is usually called before every I/O, used for throttled I/O
1835 * book keeping. This routine has low overhead and does not sleep
1836 */
1837 void throttle_info_update(void *throttle_info, int flags)
1838 {
1839 if (throttle_info)
1840 throttle_info_update_internal(throttle_info, NULL, flags, FALSE);
1841 }
1842
1843 /*
1844 * KPI routine
1845 *
1846 * this is usually called before every I/O, used for throttled I/O
1847 * book keeping. This routine has low overhead and does not sleep
1848 */
1849 void throttle_info_update_by_mask(void *throttle_info_handle, int flags)
1850 {
1851 void *throttle_info = throttle_info_handle;
1852
1853 /*
1854 * for now we only use the lowest bit of the throttle mask, so the
1855 * handle is the same as the throttle_info. Later if we store a
1856 * set of throttle infos in the handle, we will want to loop through
1857 * them and call throttle_info_update in a loop
1858 */
1859 throttle_info_update(throttle_info, flags);
1860 }
1861
1862 /*
1863 * KPI routine (private)
1864 * Called to determine if this IO is being throttled to this level so that it can be treated specially
1865 */
1866 int throttle_info_io_will_be_throttled(void * throttle_info, int policy)
1867 {
1868 struct _throttle_io_info_t *info = throttle_info;
1869 struct timeval elapsed;
1870 uint64_t elapsed_msecs;
1871 int throttle_level;
1872 int thread_throttle_level;
1873
1874 switch (policy) {
1875
1876 case IOPOL_THROTTLE:
1877 thread_throttle_level = THROTTLE_LEVEL_TIER3;
1878 break;
1879 case IOPOL_UTILITY:
1880 thread_throttle_level = THROTTLE_LEVEL_TIER2;
1881 break;
1882 case IOPOL_STANDARD:
1883 thread_throttle_level = THROTTLE_LEVEL_TIER1;
1884 break;
1885 default:
1886 thread_throttle_level = THROTTLE_LEVEL_TIER0;
1887 break;
1888 }
1889 for (throttle_level = THROTTLE_LEVEL_START; throttle_level < thread_throttle_level; throttle_level++) {
1890
1891 microuptime(&elapsed);
1892 timevalsub(&elapsed, &info->throttle_window_start_timestamp[throttle_level]);
1893 elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
1894
1895 if (elapsed_msecs < (uint64_t)throttle_windows_msecs[thread_throttle_level])
1896 break;
1897 }
1898 if (throttle_level >= thread_throttle_level) {
1899 /*
1900 * we're beyond all of the throttle windows
1901 * so go ahead and treat as normal I/O
1902 */
1903 return (THROTTLE_DISENGAGED);
1904 }
1905 /*
1906 * we're in the throttle window
1907 */
1908 return (THROTTLE_ENGAGED);
1909 }
1910
1911 int
1912 spec_strategy(struct vnop_strategy_args *ap)
1913 {
1914 buf_t bp;
1915 int bflags;
1916 int io_tier;
1917 int passive;
1918 dev_t bdev;
1919 uthread_t ut;
1920 mount_t mp;
1921 struct bufattr *bap;
1922 int strategy_ret;
1923 struct _throttle_io_info_t *throttle_info;
1924 boolean_t isssd = FALSE;
1925 proc_t curproc = current_proc();
1926
1927 bp = ap->a_bp;
1928 bdev = buf_device(bp);
1929 mp = buf_vnode(bp)->v_mount;
1930 bap = &bp->b_attr;
1931
1932 io_tier = throttle_get_io_policy(&ut);
1933 passive = throttle_get_passive_io_policy(&ut);
1934
1935 if (bp->b_flags & B_META)
1936 bap->ba_flags |= BA_META;
1937
1938 SET_BUFATTR_IO_TIER(bap, io_tier);
1939
1940 if (passive)
1941 bp->b_flags |= B_PASSIVE;
1942
1943 if ((curproc != NULL) && ((curproc->p_flag & P_DELAYIDLESLEEP) == P_DELAYIDLESLEEP))
1944 bap->ba_flags |= BA_DELAYIDLESLEEP;
1945
1946 bflags = bp->b_flags;
1947
1948 if (((bflags & B_READ) == 0) && ((bflags & B_ASYNC) == 0))
1949 bufattr_markquickcomplete(bap);
1950
1951 if (kdebug_enable) {
1952 int code = 0;
1953
1954 if (bflags & B_READ)
1955 code |= DKIO_READ;
1956 if (bflags & B_ASYNC)
1957 code |= DKIO_ASYNC;
1958
1959 if (bflags & B_META)
1960 code |= DKIO_META;
1961 else if (bflags & B_PAGEIO)
1962 code |= DKIO_PAGING;
1963
1964 if (io_tier != 0)
1965 code |= DKIO_THROTTLE;
1966
1967 code |= ((io_tier << DKIO_TIER_SHIFT) & DKIO_TIER_MASK);
1968
1969 if (bflags & B_PASSIVE)
1970 code |= DKIO_PASSIVE;
1971
1972 if (bap->ba_flags & BA_NOCACHE)
1973 code |= DKIO_NOCACHE;
1974
1975 KERNEL_DEBUG_CONSTANT_IST(KDEBUG_COMMON, FSDBG_CODE(DBG_DKRW, code) | DBG_FUNC_NONE,
1976 buf_kernel_addrperm_addr(bp), bdev, (int)buf_blkno(bp), buf_count(bp), 0);
1977 }
1978 if (mp != NULL) {
1979 if ((mp->mnt_kern_flag & MNTK_SSD) && !ignore_is_ssd)
1980 isssd = TRUE;
1981 throttle_info = &_throttle_io_info[mp->mnt_devbsdunit];
1982 } else
1983 throttle_info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
1984
1985 throttle_info_update_internal(throttle_info, ut, bflags, isssd);
1986
1987 if ((bflags & B_READ) == 0) {
1988 microuptime(&throttle_info->throttle_last_write_timestamp);
1989
1990 if (mp) {
1991 mp->mnt_last_write_issued_timestamp = throttle_info->throttle_last_write_timestamp;
1992 INCR_PENDING_IO(buf_count(bp), mp->mnt_pending_write_size);
1993 }
1994 } else if (mp) {
1995 INCR_PENDING_IO(buf_count(bp), mp->mnt_pending_read_size);
1996 }
1997 /*
1998 * The BootCache may give us special information about
1999 * the IO, so it returns special values that we check
2000 * for here.
2001 *
2002 * IO_SATISFIED_BY_CACHE
2003 * The read has been satisfied by the boot cache. Don't
2004 * throttle the thread unnecessarily.
2005 *
2006 * IO_SHOULD_BE_THROTTLED
2007 * The boot cache is playing back a playlist and this IO
2008 * cut through. Throttle it so we're not cutting through
2009 * the boot cache too often.
2010 *
2011 * Note that typical strategy routines are defined with
2012 * a void return so we'll get garbage here. In the
2013 * unlikely case the garbage matches our special return
2014 * value, it's not a big deal since we're only adjusting
2015 * the throttling delay.
2016 */
2017 #define IO_SATISFIED_BY_CACHE ((int)0xcafefeed)
2018 #define IO_SHOULD_BE_THROTTLED ((int)0xcafebeef)
2019 typedef int strategy_fcn_ret_t(struct buf *bp);
2020
2021 strategy_ret = (*(strategy_fcn_ret_t*)bdevsw[major(bdev)].d_strategy)(bp);
2022
2023 if (IO_SATISFIED_BY_CACHE == strategy_ret) {
2024 /*
2025 * If this was a throttled IO satisfied by the boot cache,
2026 * don't delay the thread.
2027 */
2028 throttle_info_reset_window(ut);
2029
2030 } else if (IO_SHOULD_BE_THROTTLED == strategy_ret) {
2031 /*
2032 * If the boot cache indicates this IO should be throttled,
2033 * delay the thread.
2034 */
2035 throttle_info_set_initial_window(ut, throttle_info, TRUE, isssd);
2036 }
2037 return (0);
2038 }
2039
2040
2041 /*
2042 * This is a noop, simply returning what one has been given.
2043 */
2044 int
2045 spec_blockmap(__unused struct vnop_blockmap_args *ap)
2046 {
2047 return (ENOTSUP);
2048 }
2049
2050
2051 /*
2052 * Device close routine
2053 */
2054 int
2055 spec_close(struct vnop_close_args *ap)
2056 {
2057 struct vnode *vp = ap->a_vp;
2058 dev_t dev = vp->v_rdev;
2059 int error = 0;
2060 int flags = ap->a_fflag;
2061 struct proc *p = vfs_context_proc(ap->a_context);
2062 struct session *sessp;
2063 int do_rele = 0;
2064
2065 switch (vp->v_type) {
2066
2067 case VCHR:
2068 /*
2069 * Hack: a tty device that is a controlling terminal
2070 * has a reference from the session structure.
2071 * We cannot easily tell that a character device is
2072 * a controlling terminal, unless it is the closing
2073 * process' controlling terminal. In that case,
2074 * if the reference count is 1 (this is the very
2075 * last close)
2076 */
2077 sessp = proc_session(p);
2078 devsw_lock(dev, S_IFCHR);
2079 if (sessp != SESSION_NULL) {
2080 if (vp == sessp->s_ttyvp && vcount(vp) == 1) {
2081 struct tty *tp;
2082
2083 devsw_unlock(dev, S_IFCHR);
2084 session_lock(sessp);
2085 if (vp == sessp->s_ttyvp) {
2086 tp = SESSION_TP(sessp);
2087 sessp->s_ttyvp = NULL;
2088 sessp->s_ttyvid = 0;
2089 sessp->s_ttyp = TTY_NULL;
2090 sessp->s_ttypgrpid = NO_PID;
2091 do_rele = 1;
2092 }
2093 session_unlock(sessp);
2094
2095 if (do_rele) {
2096 vnode_rele(vp);
2097 if (NULL != tp)
2098 ttyfree(tp);
2099 }
2100 devsw_lock(dev, S_IFCHR);
2101 }
2102 session_rele(sessp);
2103 }
2104
2105 if (--vp->v_specinfo->si_opencount < 0)
2106 panic("negative open count (c, %u, %u)", major(dev), minor(dev));
2107
2108 /*
2109 * close on last reference or on vnode revoke call
2110 */
2111 if (vcount(vp) == 0 || (flags & IO_REVOKE) != 0)
2112 error = cdevsw[major(dev)].d_close(dev, flags, S_IFCHR, p);
2113
2114 devsw_unlock(dev, S_IFCHR);
2115 break;
2116
2117 case VBLK:
2118 /*
2119 * If there is more than one outstanding open, don't
2120 * send the close to the device.
2121 */
2122 devsw_lock(dev, S_IFBLK);
2123 if (vcount(vp) > 1) {
2124 vp->v_specinfo->si_opencount--;
2125 devsw_unlock(dev, S_IFBLK);
2126 return (0);
2127 }
2128 devsw_unlock(dev, S_IFBLK);
2129
2130 /*
2131 * On last close of a block device (that isn't mounted)
2132 * we must invalidate any in core blocks, so that
2133 * we can, for instance, change floppy disks.
2134 */
2135 if ((error = spec_fsync_internal(vp, MNT_WAIT, ap->a_context)))
2136 return (error);
2137
2138 error = buf_invalidateblks(vp, BUF_WRITE_DATA, 0, 0);
2139 if (error)
2140 return (error);
2141
2142 devsw_lock(dev, S_IFBLK);
2143
2144 if (--vp->v_specinfo->si_opencount < 0)
2145 panic("negative open count (b, %u, %u)", major(dev), minor(dev));
2146
2147 if (vcount(vp) == 0)
2148 error = bdevsw[major(dev)].d_close(dev, flags, S_IFBLK, p);
2149
2150 devsw_unlock(dev, S_IFBLK);
2151 break;
2152
2153 default:
2154 panic("spec_close: not special");
2155 return(EBADF);
2156 }
2157
2158 return error;
2159 }
2160
2161 /*
2162 * Return POSIX pathconf information applicable to special devices.
2163 */
2164 int
2165 spec_pathconf(struct vnop_pathconf_args *ap)
2166 {
2167
2168 switch (ap->a_name) {
2169 case _PC_LINK_MAX:
2170 *ap->a_retval = LINK_MAX;
2171 return (0);
2172 case _PC_MAX_CANON:
2173 *ap->a_retval = MAX_CANON;
2174 return (0);
2175 case _PC_MAX_INPUT:
2176 *ap->a_retval = MAX_INPUT;
2177 return (0);
2178 case _PC_PIPE_BUF:
2179 *ap->a_retval = PIPE_BUF;
2180 return (0);
2181 case _PC_CHOWN_RESTRICTED:
2182 *ap->a_retval = 200112; /* _POSIX_CHOWN_RESTRICTED */
2183 return (0);
2184 case _PC_VDISABLE:
2185 *ap->a_retval = _POSIX_VDISABLE;
2186 return (0);
2187 default:
2188 return (EINVAL);
2189 }
2190 /* NOTREACHED */
2191 }
2192
2193 /*
2194 * Special device failed operation
2195 */
2196 int
2197 spec_ebadf(__unused void *dummy)
2198 {
2199
2200 return (EBADF);
2201 }
2202
2203 /* Blktooff derives file offset from logical block number */
2204 int
2205 spec_blktooff(struct vnop_blktooff_args *ap)
2206 {
2207 struct vnode *vp = ap->a_vp;
2208
2209 switch (vp->v_type) {
2210 case VCHR:
2211 *ap->a_offset = (off_t)-1; /* failure */
2212 return (ENOTSUP);
2213
2214 case VBLK:
2215 printf("spec_blktooff: not implemented for VBLK\n");
2216 *ap->a_offset = (off_t)-1; /* failure */
2217 return (ENOTSUP);
2218
2219 default:
2220 panic("spec_blktooff type");
2221 }
2222 /* NOTREACHED */
2223
2224 return (0);
2225 }
2226
2227 /* Offtoblk derives logical block number from file offset */
2228 int
2229 spec_offtoblk(struct vnop_offtoblk_args *ap)
2230 {
2231 struct vnode *vp = ap->a_vp;
2232
2233 switch (vp->v_type) {
2234 case VCHR:
2235 *ap->a_lblkno = (daddr64_t)-1; /* failure */
2236 return (ENOTSUP);
2237
2238 case VBLK:
2239 printf("spec_offtoblk: not implemented for VBLK\n");
2240 *ap->a_lblkno = (daddr64_t)-1; /* failure */
2241 return (ENOTSUP);
2242
2243 default:
2244 panic("spec_offtoblk type");
2245 }
2246 /* NOTREACHED */
2247
2248 return (0);
2249 }
2250
2251 static void filt_specdetach(struct knote *kn);
2252 static int filt_spec(struct knote *kn, long hint);
2253 static unsigned filt_specpeek(struct knote *kn);
2254
2255 struct filterops spec_filtops = {
2256 .f_isfd = 1,
2257 .f_attach = filt_specattach,
2258 .f_detach = filt_specdetach,
2259 .f_event = filt_spec,
2260 .f_peek = filt_specpeek
2261 };
2262
2263 static int
2264 filter_to_seltype(int16_t filter)
2265 {
2266 switch (filter) {
2267 case EVFILT_READ:
2268 return FREAD;
2269 case EVFILT_WRITE:
2270 return FWRITE;
2271 break;
2272 default:
2273 panic("filt_to_seltype(): invalid filter %d\n", filter);
2274 return 0;
2275 }
2276 }
2277
2278 static int
2279 filt_specattach(struct knote *kn)
2280 {
2281 vnode_t vp;
2282 dev_t dev;
2283
2284 vp = (vnode_t)kn->kn_fp->f_fglob->fg_data; /* Already have iocount, and vnode is alive */
2285
2286 assert(vnode_ischr(vp));
2287
2288 dev = vnode_specrdev(vp);
2289
2290 if (major(dev) > nchrdev) {
2291 return ENXIO;
2292 }
2293
2294 if ((cdevsw_flags[major(dev)] & CDEVSW_SELECT_KQUEUE) == 0) {
2295 return EINVAL;
2296 }
2297
2298 /* Resulting wql is safe to unlink even if it has never been linked */
2299 kn->kn_hook = wait_queue_link_allocate();
2300 if (kn->kn_hook == NULL) {
2301 return EAGAIN;
2302 }
2303
2304 kn->kn_fop = &spec_filtops;
2305 kn->kn_hookid = vnode_vid(vp);
2306
2307 knote_markstayqueued(kn);
2308
2309 return 0;
2310 }
2311
2312 static void
2313 filt_specdetach(struct knote *kn)
2314 {
2315 kern_return_t ret;
2316
2317 /*
2318 * Given wait queue link and wait queue set, unlink. This is subtle.
2319 * If the device has been revoked from under us, selclearthread() will
2320 * have removed our link from the kqueue's wait queue set, which
2321 * wait_queue_set_unlink_one() will detect and handle.
2322 */
2323 ret = wait_queue_set_unlink_one(kn->kn_kq->kq_wqs, kn->kn_hook);
2324 if (ret != KERN_SUCCESS) {
2325 panic("filt_specdetach(): failed to unlink wait queue link.");
2326 }
2327
2328 (void)wait_queue_link_free(kn->kn_hook);
2329 kn->kn_hook = NULL;
2330 kn->kn_status &= ~KN_STAYQUEUED;
2331 }
2332
2333 static int
2334 filt_spec(struct knote *kn, long hint)
2335 {
2336 vnode_t vp;
2337 uthread_t uth;
2338 wait_queue_set_t old_wqs;
2339 vfs_context_t ctx;
2340 int selres;
2341 int error;
2342 int use_offset;
2343 dev_t dev;
2344 uint64_t flags;
2345
2346 assert(kn->kn_hook != NULL);
2347
2348 if (hint != 0) {
2349 panic("filt_spec(): nonzero hint?");
2350 }
2351
2352 uth = get_bsdthread_info(current_thread());
2353 ctx = vfs_context_current();
2354 vp = (vnode_t)kn->kn_fp->f_fglob->fg_data;
2355
2356 error = vnode_getwithvid(vp, kn->kn_hookid);
2357 if (error != 0) {
2358 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
2359 return 1;
2360 }
2361
2362 dev = vnode_specrdev(vp);
2363 flags = cdevsw_flags[major(dev)];
2364 use_offset = ((flags & CDEVSW_USE_OFFSET) != 0);
2365 assert((flags & CDEVSW_SELECT_KQUEUE) != 0);
2366
2367 /* Trick selrecord() into hooking kqueue's wait queue set into device wait queue */
2368 old_wqs = uth->uu_wqset;
2369 uth->uu_wqset = kn->kn_kq->kq_wqs;
2370 selres = VNOP_SELECT(vp, filter_to_seltype(kn->kn_filter), 0, kn->kn_hook, ctx);
2371 uth->uu_wqset = old_wqs;
2372
2373 if (use_offset) {
2374 if (kn->kn_fp->f_fglob->fg_offset >= (uint32_t)selres) {
2375 kn->kn_data = 0;
2376 } else {
2377 kn->kn_data = ((uint32_t)selres) - kn->kn_fp->f_fglob->fg_offset;
2378 }
2379 } else {
2380 kn->kn_data = selres;
2381 }
2382
2383 vnode_put(vp);
2384
2385 return (kn->kn_data != 0);
2386 }
2387
2388 static unsigned
2389 filt_specpeek(struct knote *kn)
2390 {
2391 vnode_t vp;
2392 uthread_t uth;
2393 wait_queue_set_t old_wqs;
2394 vfs_context_t ctx;
2395 int error, selres;
2396
2397 uth = get_bsdthread_info(current_thread());
2398 ctx = vfs_context_current();
2399 vp = (vnode_t)kn->kn_fp->f_fglob->fg_data;
2400
2401 error = vnode_getwithvid(vp, kn->kn_hookid);
2402 if (error != 0) {
2403 return 1; /* Just like VNOP_SELECT() on recycled vnode */
2404 }
2405
2406 /*
2407 * Why pass the link here? Because we may not have registered in the past...
2408 */
2409 old_wqs = uth->uu_wqset;
2410 uth->uu_wqset = kn->kn_kq->kq_wqs;
2411 selres = VNOP_SELECT(vp, filter_to_seltype(kn->kn_filter), 0, kn->kn_hook, ctx);
2412 uth->uu_wqset = old_wqs;
2413
2414 vnode_put(vp);
2415 return selres;
2416 }
2417
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