1 /*
2 * Copyright (c) 2000-2019 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 <machine/machine_routines.h>
85 #include <miscfs/specfs/specdev.h>
86 #include <vfs/vfs_support.h>
87 #include <vfs/vfs_disk_conditioner.h>
88
89 #include <kern/assert.h>
90 #include <kern/task.h>
91 #include <kern/sched_prim.h>
92 #include <kern/thread.h>
93 #include <kern/policy_internal.h>
94 #include <kern/timer_call.h>
95 #include <kern/waitq.h>
96
97 #include <pexpert/pexpert.h>
98
99 #include <sys/kdebug.h>
100 #include <libkern/section_keywords.h>
101
102 #if CONFIG_IO_COMPRESSION_STATS
103 #include <vfs/vfs_io_compression_stats.h>
104 #endif /* CONFIG_IO_COMPRESSION_STATS */
105
106 #if CONFIG_IOSCHED
107 #include <vm/vm_pageout_xnu.h>
108 #include <vm/vm_object_xnu.h>
109 #endif /* CONFIG_IOSCHED */
110
111 /* XXX following three prototypes should be in a header file somewhere */
112 extern dev_t chrtoblk(dev_t dev);
113 extern boolean_t iskmemdev(dev_t dev);
114 extern int bpfkqfilter(dev_t dev, struct knote *kn);
115 extern int ptsd_kqfilter(dev_t, struct knote *);
116 extern int ptmx_kqfilter(dev_t, struct knote *);
117 #if CONFIG_PHYS_WRITE_ACCT
118 uint64_t kernel_pm_writes; // to track the sync writes occurring during power management transitions
119 #endif /* CONFIG_PHYS_WRITE_ACCT */
120
121
122 struct vnode *speclisth[SPECHSZ];
123
124 /* symbolic sleep message strings for devices */
125 char devopn[] = "devopn";
126 char devio[] = "devio";
127 char devwait[] = "devwait";
128 char devin[] = "devin";
129 char devout[] = "devout";
130 char devioc[] = "devioc";
131 char devcls[] = "devcls";
132
133 #define VOPFUNC int (*)(void *)
134
135 int(**spec_vnodeop_p)(void *);
136 const struct vnodeopv_entry_desc spec_vnodeop_entries[] = {
137 { .opve_op = &vnop_default_desc, .opve_impl = (VOPFUNC)(void (*)(void))vn_default_error },
138 { .opve_op = &vnop_lookup_desc, .opve_impl = (VOPFUNC)spec_lookup }, /* lookup */
139 { .opve_op = &vnop_create_desc, .opve_impl = (VOPFUNC)err_create }, /* create */
140 { .opve_op = &vnop_mknod_desc, .opve_impl = (VOPFUNC)err_mknod }, /* mknod */
141 { .opve_op = &vnop_open_desc, .opve_impl = (VOPFUNC)spec_open }, /* open */
142 { .opve_op = &vnop_close_desc, .opve_impl = (VOPFUNC)spec_close }, /* close */
143 { .opve_op = &vnop_access_desc, .opve_impl = (VOPFUNC)spec_access }, /* access */
144 { .opve_op = &vnop_getattr_desc, .opve_impl = (VOPFUNC)spec_getattr }, /* getattr */
145 { .opve_op = &vnop_setattr_desc, .opve_impl = (VOPFUNC)spec_setattr }, /* setattr */
146 { .opve_op = &vnop_read_desc, .opve_impl = (VOPFUNC)spec_read }, /* read */
147 { .opve_op = &vnop_write_desc, .opve_impl = (VOPFUNC)spec_write }, /* write */
148 { .opve_op = &vnop_ioctl_desc, .opve_impl = (VOPFUNC)spec_ioctl }, /* ioctl */
149 { .opve_op = &vnop_select_desc, .opve_impl = (VOPFUNC)spec_select }, /* select */
150 { .opve_op = &vnop_revoke_desc, .opve_impl = (VOPFUNC)nop_revoke }, /* revoke */
151 { .opve_op = &vnop_mmap_desc, .opve_impl = (VOPFUNC)err_mmap }, /* mmap */
152 { .opve_op = &vnop_fsync_desc, .opve_impl = (VOPFUNC)spec_fsync }, /* fsync */
153 { .opve_op = &vnop_remove_desc, .opve_impl = (VOPFUNC)err_remove }, /* remove */
154 { .opve_op = &vnop_link_desc, .opve_impl = (VOPFUNC)err_link }, /* link */
155 { .opve_op = &vnop_rename_desc, .opve_impl = (VOPFUNC)err_rename }, /* rename */
156 { .opve_op = &vnop_mkdir_desc, .opve_impl = (VOPFUNC)err_mkdir }, /* mkdir */
157 { .opve_op = &vnop_rmdir_desc, .opve_impl = (VOPFUNC)err_rmdir }, /* rmdir */
158 { .opve_op = &vnop_symlink_desc, .opve_impl = (VOPFUNC)err_symlink }, /* symlink */
159 { .opve_op = &vnop_readdir_desc, .opve_impl = (VOPFUNC)err_readdir }, /* readdir */
160 { .opve_op = &vnop_readlink_desc, .opve_impl = (VOPFUNC)err_readlink }, /* readlink */
161 { .opve_op = &vnop_inactive_desc, .opve_impl = (VOPFUNC)nop_inactive }, /* inactive */
162 { .opve_op = &vnop_reclaim_desc, .opve_impl = (VOPFUNC)nop_reclaim }, /* reclaim */
163 { .opve_op = &vnop_strategy_desc, .opve_impl = (VOPFUNC)spec_strategy }, /* strategy */
164 { .opve_op = &vnop_pathconf_desc, .opve_impl = (VOPFUNC)spec_pathconf }, /* pathconf */
165 { .opve_op = &vnop_advlock_desc, .opve_impl = (VOPFUNC)err_advlock }, /* advlock */
166 { .opve_op = &vnop_bwrite_desc, .opve_impl = (VOPFUNC)spec_bwrite }, /* bwrite */
167 { .opve_op = &vnop_pagein_desc, .opve_impl = (VOPFUNC)err_pagein }, /* Pagein */
168 { .opve_op = &vnop_pageout_desc, .opve_impl = (VOPFUNC)err_pageout }, /* Pageout */
169 { .opve_op = &vnop_copyfile_desc, .opve_impl = (VOPFUNC)err_copyfile }, /* Copyfile */
170 { .opve_op = &vnop_blktooff_desc, .opve_impl = (VOPFUNC)spec_blktooff }, /* blktooff */
171 { .opve_op = &vnop_offtoblk_desc, .opve_impl = (VOPFUNC)spec_offtoblk }, /* offtoblk */
172 { .opve_op = &vnop_blockmap_desc, .opve_impl = (VOPFUNC)spec_blockmap }, /* blockmap */
173 { .opve_op = (struct vnodeop_desc*)NULL, .opve_impl = (int (*)(void *))NULL }
174 };
175 const struct vnodeopv_desc spec_vnodeop_opv_desc =
176 { .opv_desc_vector_p = &spec_vnodeop_p, .opv_desc_ops = spec_vnodeop_entries };
177
178
179 static void set_blocksize(vnode_t, dev_t);
180
181 #define LOWPRI_TIER1_WINDOW_MSECS 25
182 #define LOWPRI_TIER2_WINDOW_MSECS 100
183 #define LOWPRI_TIER3_WINDOW_MSECS 500
184
185 #define LOWPRI_TIER1_IO_PERIOD_MSECS 40
186 #define LOWPRI_TIER2_IO_PERIOD_MSECS 85
187 #define LOWPRI_TIER3_IO_PERIOD_MSECS 200
188
189 #define LOWPRI_TIER1_IO_PERIOD_SSD_MSECS 5
190 #define LOWPRI_TIER2_IO_PERIOD_SSD_MSECS 15
191 #define LOWPRI_TIER3_IO_PERIOD_SSD_MSECS 25
192
193
194 int throttle_windows_msecs[THROTTLE_LEVEL_END + 1] = {
195 0,
196 LOWPRI_TIER1_WINDOW_MSECS,
197 LOWPRI_TIER2_WINDOW_MSECS,
198 LOWPRI_TIER3_WINDOW_MSECS,
199 };
200
201 int throttle_io_period_msecs[THROTTLE_LEVEL_END + 1] = {
202 0,
203 LOWPRI_TIER1_IO_PERIOD_MSECS,
204 LOWPRI_TIER2_IO_PERIOD_MSECS,
205 LOWPRI_TIER3_IO_PERIOD_MSECS,
206 };
207
208 int throttle_io_period_ssd_msecs[THROTTLE_LEVEL_END + 1] = {
209 0,
210 LOWPRI_TIER1_IO_PERIOD_SSD_MSECS,
211 LOWPRI_TIER2_IO_PERIOD_SSD_MSECS,
212 LOWPRI_TIER3_IO_PERIOD_SSD_MSECS,
213 };
214
215
216 int throttled_count[THROTTLE_LEVEL_END + 1];
217
218 struct _throttle_io_info_t {
219 lck_mtx_t throttle_lock;
220
221 struct timeval throttle_last_write_timestamp;
222 struct timeval throttle_min_timer_deadline;
223 struct timeval throttle_window_start_timestamp[THROTTLE_LEVEL_END + 1]; /* window starts at both the beginning and completion of an I/O */
224 struct timeval throttle_last_IO_timestamp[THROTTLE_LEVEL_END + 1];
225 pid_t throttle_last_IO_pid[THROTTLE_LEVEL_END + 1];
226 struct timeval throttle_start_IO_period_timestamp[THROTTLE_LEVEL_END + 1];
227 int32_t throttle_inflight_count[THROTTLE_LEVEL_END + 1];
228
229 TAILQ_HEAD(, uthread) throttle_uthlist[THROTTLE_LEVEL_END + 1]; /* Lists of throttled uthreads */
230 int throttle_next_wake_level;
231
232 thread_call_t throttle_timer_call;
233 int32_t throttle_timer_ref;
234 int32_t throttle_timer_active;
235
236 int32_t throttle_io_count;
237 int32_t throttle_io_count_begin;
238 int *throttle_io_periods;
239 uint32_t throttle_io_period_num;
240
241 int32_t throttle_refcnt;
242 int32_t throttle_alloc;
243 int32_t throttle_disabled;
244 int32_t throttle_is_fusion_with_priority;
245 };
246
247 struct _throttle_io_info_t _throttle_io_info[LOWPRI_MAX_NUM_DEV];
248
249
250 int lowpri_throttle_enabled = 1;
251
252 static int spec_close_internal(struct vnode *vp, dev_t dev, int flags, vfs_context_t ctx);
253
254 static void throttle_info_end_io_internal(struct _throttle_io_info_t *info, int throttle_level);
255 static int throttle_info_update_internal(struct _throttle_io_info_t *info, uthread_t ut, int flags, boolean_t isssd, boolean_t inflight, struct bufattr *bap);
256 static int throttle_get_thread_throttle_level(uthread_t ut);
257 static int throttle_get_thread_throttle_level_internal(uthread_t ut, int io_tier);
258 void throttle_info_mount_reset_period(mount_t mp, int isssd);
259
260 /*
261 * Trivial lookup routine that always fails.
262 */
263 int
spec_lookup(struct vnop_lookup_args * ap)264 spec_lookup(struct vnop_lookup_args *ap)
265 {
266 *ap->a_vpp = NULL;
267 return ENOTDIR;
268 }
269
270 static void
set_blocksize(struct vnode * vp,dev_t dev)271 set_blocksize(struct vnode *vp, dev_t dev)
272 {
273 int (*size)(dev_t);
274 int rsize;
275
276 if ((major(dev) < nblkdev) && (size = bdevsw[major(dev)].d_psize)) {
277 rsize = (*size)(dev);
278 if (rsize <= 0) { /* did size fail? */
279 vp->v_specsize = DEV_BSIZE;
280 } else {
281 vp->v_specsize = rsize;
282 }
283 } else {
284 vp->v_specsize = DEV_BSIZE;
285 }
286 }
287
288 void
set_fsblocksize(struct vnode * vp)289 set_fsblocksize(struct vnode *vp)
290 {
291 if (vp->v_type == VBLK) {
292 dev_t dev = (dev_t)vp->v_rdev;
293 int maj = major(dev);
294
295 if ((u_int)maj >= (u_int)nblkdev) {
296 return;
297 }
298
299 vnode_lock(vp);
300 set_blocksize(vp, dev);
301 vnode_unlock(vp);
302 }
303 }
304
305 static void
spec_init_bsdunit(vnode_t vp,vfs_context_t ctx,const char * caller)306 spec_init_bsdunit(vnode_t vp, vfs_context_t ctx, const char* caller)
307 {
308 int isssd = 0;
309 uint64_t throttle_mask = 0;
310 uint32_t devbsdunit = 0;
311
312 if (VNOP_IOCTL(vp, DKIOCISSOLIDSTATE, (caddr_t)&isssd, 0, ctx)) {
313 isssd = 0;
314 }
315 if (VNOP_IOCTL(vp, DKIOCGETTHROTTLEMASK, (caddr_t)&throttle_mask, 0, NULL)) {
316 throttle_mask = 0;
317 }
318
319 if (throttle_mask != 0) {
320 /*
321 * as a reasonable approximation, only use the lowest bit of the mask
322 * to generate a disk unit number
323 */
324 devbsdunit = num_trailing_0(throttle_mask);
325 } else {
326 devbsdunit = 0;
327 }
328
329 if (vp->v_un.vu_specinfo->si_initted == 0) {
330 vnode_lock(vp);
331 if (vp->v_un.vu_specinfo->si_initted == 0) {
332 vp->v_un.vu_specinfo->si_isssd = isssd ? 1 : 0;
333 vp->v_un.vu_specinfo->si_devbsdunit = devbsdunit;
334 vp->v_un.vu_specinfo->si_throttle_mask = throttle_mask;
335 vp->v_un.vu_specinfo->si_throttleable = 1;
336 vp->v_un.vu_specinfo->si_initted = 1;
337 }
338 vnode_unlock(vp);
339 printf("%s : si_devbsdunit initialized to (%d), throttle_mask is (0x%llx), isssd is (%d)\n",
340 caller, vp->v_un.vu_specinfo->si_devbsdunit,
341 vp->v_un.vu_specinfo->si_throttle_mask,
342 vp->v_un.vu_specinfo->si_isssd);
343 }
344 }
345
346 #define SPEC_INIT_BSDUNIT(vp, ctx) spec_init_bsdunit((vp), (ctx), __FUNCTION__)
347
348 /*
349 * Open a special file.
350 */
351 int
spec_open(struct vnop_open_args * ap)352 spec_open(struct vnop_open_args *ap)
353 {
354 struct proc *p = vfs_context_proc(ap->a_context);
355 kauth_cred_t cred = vfs_context_ucred(ap->a_context);
356 struct vnode *vp = ap->a_vp;
357 dev_t bdev, dev = (dev_t)vp->v_rdev;
358 int maj = major(dev);
359 int error;
360
361 /*
362 * Don't allow open if fs is mounted -nodev.
363 */
364 if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_NODEV)) {
365 return ENXIO;
366 }
367
368 switch (vp->v_type) {
369 case VCHR:
370 if ((u_int)maj >= (u_int)nchrdev) {
371 return ENXIO;
372 }
373 if (cred != FSCRED && (ap->a_mode & FWRITE)) {
374 #if 0
375 /*
376 * When running in very secure mode, do not allow
377 * opens for writing of any disk character devices.
378 */
379 if (securelevel >= 2 && isdisk(dev, VCHR)) {
380 return EPERM;
381 }
382 #endif
383
384 /* Never allow writing to /dev/mem or /dev/kmem */
385 if (iskmemdev(dev)) {
386 return EPERM;
387 }
388 /*
389 * When running in secure mode, do not allow opens for
390 * writing of character devices whose corresponding block
391 * devices are currently mounted.
392 */
393 if (securelevel >= 1) {
394 if ((bdev = chrtoblk(dev)) != NODEV && check_mountedon(bdev, VBLK, &error)) {
395 return error;
396 }
397 }
398 }
399
400 devsw_lock(dev, S_IFCHR);
401 error = (*cdevsw[maj].d_open)(dev, ap->a_mode, S_IFCHR, p);
402
403 if (error == 0) {
404 vp->v_specinfo->si_opencount++;
405 }
406
407 devsw_unlock(dev, S_IFCHR);
408
409 if (error == 0 && cdevsw[maj].d_type == D_DISK && !vp->v_un.vu_specinfo->si_initted) {
410 int isssd = 0;
411 uint64_t throttle_mask = 0;
412 uint32_t devbsdunit = 0;
413
414 if (VNOP_IOCTL(vp, DKIOCGETTHROTTLEMASK, (caddr_t)&throttle_mask, 0, NULL) == 0) {
415 if (throttle_mask != 0 &&
416 VNOP_IOCTL(vp, DKIOCISSOLIDSTATE, (caddr_t)&isssd, 0, ap->a_context) == 0) {
417 /*
418 * as a reasonable approximation, only use the lowest bit of the mask
419 * to generate a disk unit number
420 */
421 devbsdunit = num_trailing_0(throttle_mask);
422
423 vnode_lock(vp);
424
425 vp->v_un.vu_specinfo->si_isssd = isssd ? 1 : 0;
426 vp->v_un.vu_specinfo->si_devbsdunit = devbsdunit;
427 vp->v_un.vu_specinfo->si_throttle_mask = throttle_mask;
428 vp->v_un.vu_specinfo->si_throttleable = 1;
429 vp->v_un.vu_specinfo->si_initted = 1;
430
431 vnode_unlock(vp);
432 }
433 }
434 if (vp->v_un.vu_specinfo->si_initted == 0) {
435 vnode_lock(vp);
436 vp->v_un.vu_specinfo->si_initted = 1;
437 vnode_unlock(vp);
438 }
439 }
440 return error;
441
442 case VBLK:
443 if ((u_int)maj >= (u_int)nblkdev) {
444 return ENXIO;
445 }
446 /*
447 * When running in very secure mode, do not allow
448 * opens for writing of any disk block devices.
449 */
450 if (securelevel >= 2 && cred != FSCRED &&
451 (ap->a_mode & FWRITE) && bdevsw[maj].d_type == D_DISK) {
452 return EPERM;
453 }
454 /*
455 * Do not allow opens of block devices that are
456 * currently mounted.
457 */
458 if ((error = vfs_mountedon(vp))) {
459 return error;
460 }
461
462 devsw_lock(dev, S_IFBLK);
463 error = (*bdevsw[maj].d_open)(dev, ap->a_mode, S_IFBLK, p);
464 if (!error) {
465 vp->v_specinfo->si_opencount++;
466 }
467 devsw_unlock(dev, S_IFBLK);
468
469 if (!error) {
470 u_int64_t blkcnt;
471 u_int32_t blksize;
472 int setsize = 0;
473 u_int32_t size512 = 512;
474
475 if (bdevsw[maj].d_type == D_DISK && !vp->v_un.vu_specinfo->si_initted) {
476 SPEC_INIT_BSDUNIT(vp, ap->a_context);
477 }
478
479 if (!VNOP_IOCTL(vp, DKIOCGETBLOCKSIZE, (caddr_t)&blksize, 0, ap->a_context)) {
480 /* Switch to 512 byte sectors (temporarily) */
481
482 if (!VNOP_IOCTL(vp, DKIOCSETBLOCKSIZE, (caddr_t)&size512, FWRITE, ap->a_context)) {
483 /* Get the number of 512 byte physical blocks. */
484 if (!VNOP_IOCTL(vp, DKIOCGETBLOCKCOUNT, (caddr_t)&blkcnt, 0, ap->a_context)) {
485 setsize = 1;
486 }
487 }
488 /* If it doesn't set back, we can't recover */
489 if (VNOP_IOCTL(vp, DKIOCSETBLOCKSIZE, (caddr_t)&blksize, FWRITE, ap->a_context)) {
490 /* Perform an explicit close on the block device, as the device is already open */
491 spec_close_internal(vp, dev, ap->a_mode, ap->a_context);
492
493 error = ENXIO;
494 }
495 }
496
497
498 vnode_lock(vp);
499 set_blocksize(vp, dev);
500
501 /*
502 * Cache the size in bytes of the block device for later
503 * use by spec_write().
504 */
505 if (setsize) {
506 vp->v_specdevsize = blkcnt * (u_int64_t)size512;
507 } else {
508 vp->v_specdevsize = (u_int64_t)0; /* Default: Can't get */
509 }
510 vnode_unlock(vp);
511 }
512 return error;
513 default:
514 panic("spec_open type");
515 }
516 return 0;
517 }
518
519 /*
520 * Vnode op for read
521 */
522 int
spec_read(struct vnop_read_args * ap)523 spec_read(struct vnop_read_args *ap)
524 {
525 struct vnode *vp = ap->a_vp;
526 struct uio *uio = ap->a_uio;
527 struct buf *bp;
528 daddr64_t bn, nextbn;
529 long bscale;
530 int devBlockSize = 0;
531 size_t bsize, n, on;
532 int error = 0;
533 dev_t dev;
534
535 #if DIAGNOSTIC
536 if (uio->uio_rw != UIO_READ) {
537 panic("spec_read mode");
538 }
539 if (UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) {
540 panic("spec_read proc");
541 }
542 #endif
543 if (uio_resid(uio) == 0) {
544 return 0;
545 }
546
547 switch (vp->v_type) {
548 case VCHR:
549 {
550 struct _throttle_io_info_t *throttle_info = NULL;
551 int thread_throttle_level;
552 uint64_t blkno = 0;
553 uint32_t iolen = 0;
554 int ddisk = 0;
555 int ktrace_code = DKIO_READ;
556 devBlockSize = vp->v_specsize;
557 uintptr_t our_id = 0;
558
559 if (cdevsw[major(vp->v_rdev)].d_type == D_DISK) {
560 ddisk = 1;
561 }
562
563 if (ddisk && vp->v_un.vu_specinfo->si_throttleable) {
564 throttle_info = &_throttle_io_info[vp->v_un.vu_specinfo->si_devbsdunit];
565 thread_throttle_level = throttle_info_update_internal(throttle_info, NULL, 0, vp->v_un.vu_specinfo->si_isssd, TRUE, NULL);
566 }
567
568 if (kdebug_enable && ddisk) {
569 if (devBlockSize == 0) {
570 devBlockSize = 512; // default sector size
571 }
572
573 if (uio_offset(uio) && devBlockSize) {
574 blkno = ((uint64_t) uio_offset(uio) / ((uint64_t)devBlockSize));
575 }
576 iolen = (int) uio_resid(uio);
577 our_id = (uintptr_t)thread_tid(current_thread());
578 KERNEL_DEBUG_CONSTANT_IST(KDEBUG_COMMON,
579 (FSDBG_CODE(DBG_DKRW, ktrace_code)) | DBG_FUNC_NONE, our_id,
580 vp->v_rdev, blkno, iolen, 0);
581 }
582
583 error = (*cdevsw[major(vp->v_rdev)].d_read)
584 (vp->v_rdev, uio, ap->a_ioflag);
585
586
587 if (kdebug_enable && ddisk) {
588 uint32_t residual = (uint32_t)uio_resid(uio);
589 ktrace_code |= DKIO_DONE;
590 KERNEL_DEBUG_CONSTANT_IST(KDEBUG_COMMON,
591 (FSDBG_CODE(DBG_DKRW, ktrace_code)) | DBG_FUNC_NONE, our_id,
592 (uintptr_t)VM_KERNEL_ADDRPERM(vp), residual, error, 0);
593 }
594
595 if (throttle_info) {
596 throttle_info_end_io_internal(throttle_info, thread_throttle_level);
597 }
598
599 return error;
600 }
601
602 case VBLK:
603 if (uio->uio_offset < 0) {
604 return EINVAL;
605 }
606
607 dev = vp->v_rdev;
608
609 devBlockSize = vp->v_specsize;
610
611 if (devBlockSize > PAGE_SIZE) {
612 return EINVAL;
613 }
614
615 bscale = PAGE_SIZE / devBlockSize;
616 bsize = bscale * devBlockSize;
617
618 do {
619 on = uio->uio_offset % bsize;
620
621 bn = (daddr64_t)((uio->uio_offset / devBlockSize) & ~(bscale - 1));
622
623 if (vp->v_speclastr + bscale == bn) {
624 nextbn = bn + bscale;
625 error = buf_breadn(vp, bn, (int)bsize, &nextbn,
626 (int *)&bsize, 1, NOCRED, &bp);
627 } else {
628 error = buf_bread(vp, bn, (int)bsize, NOCRED, &bp);
629 }
630
631 vnode_lock(vp);
632 vp->v_speclastr = bn;
633 vnode_unlock(vp);
634
635 n = bsize - buf_resid(bp);
636 if ((on > n) || error) {
637 if (!error) {
638 error = EINVAL;
639 }
640 buf_brelse(bp);
641 return error;
642 }
643 n = MIN((n - on), (size_t)uio_resid(uio));
644
645 error = uiomove((char *)buf_dataptr(bp) + on, (int)n, uio);
646 if (n + on == bsize) {
647 buf_markaged(bp);
648 }
649 buf_brelse(bp);
650 } while (error == 0 && uio_resid(uio) > 0 && n != 0);
651 return error;
652
653 default:
654 panic("spec_read type");
655 }
656 /* NOTREACHED */
657
658 return 0;
659 }
660
661 /*
662 * Vnode op for write
663 */
664 int
spec_write(struct vnop_write_args * ap)665 spec_write(struct vnop_write_args *ap)
666 {
667 struct vnode *vp = ap->a_vp;
668 struct uio *uio = ap->a_uio;
669 struct buf *bp;
670 daddr64_t bn;
671 int blkmask, bscale;
672 int io_sync;
673 int devBlockSize = 0;
674 size_t bsize, n, on;
675 int error = 0;
676 dev_t dev;
677
678 #if DIAGNOSTIC
679 if (uio->uio_rw != UIO_WRITE) {
680 panic("spec_write mode");
681 }
682 if (UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) {
683 panic("spec_write proc");
684 }
685 #endif
686
687 switch (vp->v_type) {
688 case VCHR:
689 {
690 struct _throttle_io_info_t *throttle_info = NULL;
691 int thread_throttle_level;
692 dev = vp->v_rdev;
693 devBlockSize = vp->v_specsize;
694 uint32_t iolen = 0;
695 uint64_t blkno = 0;
696 int ddisk = 0;
697 int ktrace_code = 0; // write is implied; read must be OR'd in.
698 uintptr_t our_id = 0;
699
700 if (cdevsw[major(dev)].d_type == D_DISK) {
701 ddisk = 1;
702 }
703
704 if (ddisk && vp->v_un.vu_specinfo->si_throttleable) {
705 throttle_info = &_throttle_io_info[vp->v_un.vu_specinfo->si_devbsdunit];
706
707 thread_throttle_level = throttle_info_update_internal(throttle_info, NULL, 0, vp->v_un.vu_specinfo->si_isssd, TRUE, NULL);
708
709 microuptime(&throttle_info->throttle_last_write_timestamp);
710 }
711
712 if (kdebug_enable && ddisk) {
713 if (devBlockSize == 0) {
714 devBlockSize = 512; // default sector size
715 }
716 if ((uio_offset(uio) != 0) && devBlockSize) {
717 blkno = ((uint64_t)uio_offset(uio)) / ((uint64_t)devBlockSize);
718 }
719 iolen = (int)uio_resid(uio);
720 our_id = (uintptr_t)thread_tid(current_thread());
721 KERNEL_DEBUG_CONSTANT_IST(KDEBUG_COMMON,
722 (FSDBG_CODE(DBG_DKRW, ktrace_code)) | DBG_FUNC_NONE, our_id,
723 vp->v_rdev, blkno, iolen, 0);
724 }
725 error = (*cdevsw[major(vp->v_rdev)].d_write)
726 (vp->v_rdev, uio, ap->a_ioflag);
727
728 if (kdebug_enable && ddisk) {
729 //emit the I/O completion
730 uint32_t residual = (uint32_t)uio_resid(uio);
731 ktrace_code |= DKIO_DONE;
732 KERNEL_DEBUG_CONSTANT_IST(KDEBUG_COMMON,
733 (FSDBG_CODE(DBG_DKRW, ktrace_code)) | DBG_FUNC_NONE, our_id,
734 (uintptr_t)VM_KERNEL_ADDRPERM(vp), residual, error, 0);
735 }
736
737 if (throttle_info) {
738 throttle_info_end_io_internal(throttle_info, thread_throttle_level);
739 }
740
741 return error;
742 }
743
744 case VBLK:
745 if (uio_resid(uio) == 0) {
746 return 0;
747 }
748 if (uio->uio_offset < 0) {
749 return EINVAL;
750 }
751
752 io_sync = (ap->a_ioflag & IO_SYNC);
753
754 dev = (vp->v_rdev);
755
756 devBlockSize = vp->v_specsize;
757 if (devBlockSize > PAGE_SIZE) {
758 return EINVAL;
759 }
760
761 bscale = PAGE_SIZE / devBlockSize;
762 blkmask = bscale - 1;
763 bsize = bscale * devBlockSize;
764
765
766 do {
767 bn = (daddr64_t)((uio->uio_offset / devBlockSize) & ~blkmask);
768 on = uio->uio_offset % bsize;
769
770 n = MIN((bsize - on), (size_t)uio_resid(uio));
771
772 /*
773 * Use buf_getblk() as an optimization IFF:
774 *
775 * 1) We are reading exactly a block on a block
776 * aligned boundary
777 * 2) We know the size of the device from spec_open
778 * 3) The read doesn't span the end of the device
779 *
780 * Otherwise, we fall back on buf_bread().
781 */
782 if (n == bsize &&
783 vp->v_specdevsize != (u_int64_t)0 &&
784 (uio->uio_offset + (u_int64_t)n) > vp->v_specdevsize) {
785 /* reduce the size of the read to what is there */
786 n = (uio->uio_offset + (u_int64_t)n) - vp->v_specdevsize;
787 }
788
789 if (n == bsize) {
790 bp = buf_getblk(vp, bn, (int)bsize, 0, 0, BLK_WRITE);
791 } else {
792 error = (int)buf_bread(vp, bn, (int)bsize, NOCRED, &bp);
793 }
794
795 /* Translate downstream error for upstream, if needed */
796 if (!error) {
797 error = (int)buf_error(bp);
798 }
799 if (error) {
800 buf_brelse(bp);
801 return error;
802 }
803 n = MIN(n, bsize - buf_resid(bp));
804
805 error = uiomove((char *)buf_dataptr(bp) + on, (int)n, uio);
806 if (error) {
807 buf_brelse(bp);
808 return error;
809 }
810 buf_markaged(bp);
811
812 if (io_sync) {
813 error = buf_bwrite(bp);
814 } else {
815 if ((n + on) == bsize) {
816 error = buf_bawrite(bp);
817 } else {
818 error = buf_bdwrite(bp);
819 }
820 }
821 } while (error == 0 && uio_resid(uio) > 0 && n != 0);
822 return error;
823
824 default:
825 panic("spec_write type");
826 }
827 /* NOTREACHED */
828
829 return 0;
830 }
831
832 /*
833 * Device ioctl operation.
834 */
835 int
spec_ioctl(struct vnop_ioctl_args * ap)836 spec_ioctl(struct vnop_ioctl_args *ap)
837 {
838 proc_t p = vfs_context_proc(ap->a_context);
839 dev_t dev = ap->a_vp->v_rdev;
840 int retval = 0;
841
842 KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_IOCTL, 0) | DBG_FUNC_START,
843 dev, ap->a_command, ap->a_fflag, ap->a_vp->v_type, 0);
844
845 switch (ap->a_vp->v_type) {
846 case VCHR:
847 retval = (*cdevsw[major(dev)].d_ioctl)(dev, ap->a_command, ap->a_data,
848 ap->a_fflag, p);
849 break;
850
851 case VBLK:
852 retval = (*bdevsw[major(dev)].d_ioctl)(dev, ap->a_command, ap->a_data, ap->a_fflag, p);
853 if (!retval && ap->a_command == DKIOCSETBLOCKSIZE) {
854 ap->a_vp->v_specsize = *(uint32_t *)ap->a_data;
855 }
856 break;
857
858 default:
859 panic("spec_ioctl");
860 /* NOTREACHED */
861 }
862 KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_IOCTL, 0) | DBG_FUNC_END,
863 dev, ap->a_command, ap->a_fflag, retval, 0);
864
865 return retval;
866 }
867
868 int
spec_select(struct vnop_select_args * ap)869 spec_select(struct vnop_select_args *ap)
870 {
871 proc_t p = vfs_context_proc(ap->a_context);
872 dev_t dev;
873
874 switch (ap->a_vp->v_type) {
875 default:
876 return 1; /* XXX */
877
878 case VCHR:
879 dev = ap->a_vp->v_rdev;
880 return (*cdevsw[major(dev)].d_select)(dev, ap->a_which, ap->a_wql, p);
881 }
882 }
883
884 int
spec_kqfilter(vnode_t vp,struct knote * kn,struct kevent_qos_s * kev)885 spec_kqfilter(vnode_t vp, struct knote *kn, struct kevent_qos_s *kev)
886 {
887 dev_t dev;
888
889 assert(vnode_ischr(vp));
890
891 dev = vnode_specrdev(vp);
892
893 #if NETWORKING
894 /*
895 * Try a bpf device, as defined in bsd/net/bpf.c
896 * If it doesn't error out the attach, then it
897 * claimed it. Otherwise, fall through and try
898 * other attaches.
899 */
900 int32_t tmp_flags = kn->kn_flags;
901 int64_t tmp_sdata = kn->kn_sdata;
902 int res;
903
904 res = bpfkqfilter(dev, kn);
905 if ((kn->kn_flags & EV_ERROR) == 0) {
906 return res;
907 }
908 kn->kn_flags = tmp_flags;
909 kn->kn_sdata = tmp_sdata;
910 #endif
911
912 if (major(dev) >= nchrdev) {
913 knote_set_error(kn, ENXIO);
914 return 0;
915 }
916
917 kn->kn_vnode_kqok = !!(cdevsw_flags[major(dev)] & CDEVSW_SELECT_KQUEUE);
918 kn->kn_vnode_use_ofst = !!(cdevsw_flags[major(dev)] & CDEVSW_USE_OFFSET);
919
920 if (cdevsw_flags[major(dev)] & CDEVSW_IS_PTS) {
921 kn->kn_filtid = EVFILTID_PTSD;
922 return ptsd_kqfilter(dev, kn);
923 } else if (cdevsw_flags[major(dev)] & CDEVSW_IS_PTC) {
924 kn->kn_filtid = EVFILTID_PTMX;
925 return ptmx_kqfilter(dev, kn);
926 } else if (cdevsw[major(dev)].d_type == D_TTY && kn->kn_vnode_kqok) {
927 /*
928 * TTYs from drivers that use struct ttys use their own filter
929 * routines. The PTC driver doesn't use the tty for character
930 * counts, so it must go through the select fallback.
931 */
932 kn->kn_filtid = EVFILTID_TTY;
933 } else {
934 /* Try to attach to other char special devices */
935 kn->kn_filtid = EVFILTID_SPEC;
936 }
937
938 return knote_fops(kn)->f_attach(kn, kev);
939 }
940
941 /*
942 * Synch buffers associated with a block device
943 */
944 int
spec_fsync_internal(vnode_t vp,int waitfor,__unused vfs_context_t context)945 spec_fsync_internal(vnode_t vp, int waitfor, __unused vfs_context_t context)
946 {
947 if (vp->v_type == VCHR) {
948 return 0;
949 }
950 /*
951 * Flush all dirty buffers associated with a block device.
952 */
953 buf_flushdirtyblks(vp, (waitfor == MNT_WAIT || waitfor == MNT_DWAIT), 0, "spec_fsync");
954
955 return 0;
956 }
957
958 int
spec_fsync(struct vnop_fsync_args * ap)959 spec_fsync(struct vnop_fsync_args *ap)
960 {
961 return spec_fsync_internal(ap->a_vp, ap->a_waitfor, ap->a_context);
962 }
963
964
965 /*
966 * Just call the device strategy routine
967 */
968 void throttle_init(void);
969
970
971 #if 0
972 #define DEBUG_ALLOC_THROTTLE_INFO(format, debug_info, args...) \
973 do { \
974 if ((debug_info)->alloc) \
975 printf("%s: "format, __FUNCTION__, ## args); \
976 } while(0)
977
978 #else
979 #define DEBUG_ALLOC_THROTTLE_INFO(format, debug_info, args...)
980 #endif
981
982
983 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier1_window_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_windows_msecs[THROTTLE_LEVEL_TIER1], 0, "");
984 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier2_window_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_windows_msecs[THROTTLE_LEVEL_TIER2], 0, "");
985 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier3_window_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_windows_msecs[THROTTLE_LEVEL_TIER3], 0, "");
986
987 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier1_io_period_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_msecs[THROTTLE_LEVEL_TIER1], 0, "");
988 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier2_io_period_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_msecs[THROTTLE_LEVEL_TIER2], 0, "");
989 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier3_io_period_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_msecs[THROTTLE_LEVEL_TIER3], 0, "");
990
991 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, "");
992 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, "");
993 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, "");
994
995 SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_enabled, CTLFLAG_RW | CTLFLAG_LOCKED, &lowpri_throttle_enabled, 0, "");
996
997
998 static LCK_GRP_DECLARE(throttle_lock_grp, "throttle I/O");
999
1000
1001 /*
1002 * throttled I/O helper function
1003 * convert the index of the lowest set bit to a device index
1004 */
1005 int
num_trailing_0(uint64_t n)1006 num_trailing_0(uint64_t n)
1007 {
1008 /*
1009 * since in most cases the number of trailing 0s is very small,
1010 * we simply counting sequentially from the lowest bit
1011 */
1012 if (n == 0) {
1013 return sizeof(n) * 8;
1014 }
1015 int count = 0;
1016 while (!ISSET(n, 1)) {
1017 n >>= 1;
1018 ++count;
1019 }
1020 return count;
1021 }
1022
1023
1024 /*
1025 * Release the reference and if the item was allocated and this is the last
1026 * reference then free it.
1027 *
1028 * This routine always returns the old value.
1029 */
1030 static int
throttle_info_rel(struct _throttle_io_info_t * info)1031 throttle_info_rel(struct _throttle_io_info_t *info)
1032 {
1033 SInt32 oldValue = OSDecrementAtomic(&info->throttle_refcnt);
1034
1035 DEBUG_ALLOC_THROTTLE_INFO("refcnt = %d info = %p\n",
1036 info, (int)(oldValue - 1), info );
1037
1038 /* The reference count just went negative, very bad */
1039 if (oldValue == 0) {
1040 panic("throttle info ref cnt went negative!");
1041 }
1042
1043 /*
1044 * Once reference count is zero, no one else should be able to take a
1045 * reference
1046 */
1047 if ((oldValue == 1) && (info->throttle_alloc)) {
1048 DEBUG_ALLOC_THROTTLE_INFO("Freeing info = %p\n", info);
1049
1050 lck_mtx_destroy(&info->throttle_lock, &throttle_lock_grp);
1051 kfree_type(struct _throttle_io_info_t, info);
1052 }
1053 return oldValue;
1054 }
1055
1056
1057 /*
1058 * Just take a reference on the throttle info structure.
1059 *
1060 * This routine always returns the old value.
1061 */
1062 static SInt32
throttle_info_ref(struct _throttle_io_info_t * info)1063 throttle_info_ref(struct _throttle_io_info_t *info)
1064 {
1065 SInt32 oldValue = OSIncrementAtomic(&info->throttle_refcnt);
1066
1067 DEBUG_ALLOC_THROTTLE_INFO("refcnt = %d info = %p\n",
1068 info, (int)(oldValue - 1), info );
1069 /* Allocated items should never have a reference of zero */
1070 if (info->throttle_alloc && (oldValue == 0)) {
1071 panic("Taking a reference without calling create throttle info!");
1072 }
1073
1074 return oldValue;
1075 }
1076
1077 /*
1078 * on entry the throttle_lock is held...
1079 * this function is responsible for taking
1080 * and dropping the reference on the info
1081 * structure which will keep it from going
1082 * away while the timer is running if it
1083 * happens to have been dynamically allocated by
1084 * a network fileystem kext which is now trying
1085 * to free it
1086 */
1087 static uint32_t
throttle_timer_start(struct _throttle_io_info_t * info,boolean_t update_io_count,int wakelevel)1088 throttle_timer_start(struct _throttle_io_info_t *info, boolean_t update_io_count, int wakelevel)
1089 {
1090 struct timeval elapsed;
1091 struct timeval now;
1092 struct timeval period;
1093 uint64_t elapsed_msecs;
1094 int throttle_level;
1095 int level;
1096 int msecs;
1097 boolean_t throttled = FALSE;
1098 boolean_t need_timer = FALSE;
1099
1100 microuptime(&now);
1101
1102 if (update_io_count == TRUE) {
1103 info->throttle_io_count_begin = info->throttle_io_count;
1104 info->throttle_io_period_num++;
1105
1106 while (wakelevel >= THROTTLE_LEVEL_THROTTLED) {
1107 info->throttle_start_IO_period_timestamp[wakelevel--] = now;
1108 }
1109
1110 info->throttle_min_timer_deadline = now;
1111
1112 msecs = info->throttle_io_periods[THROTTLE_LEVEL_THROTTLED];
1113 period.tv_sec = msecs / 1000;
1114 period.tv_usec = (msecs % 1000) * 1000;
1115
1116 timevaladd(&info->throttle_min_timer_deadline, &period);
1117 }
1118 for (throttle_level = THROTTLE_LEVEL_START; throttle_level < THROTTLE_LEVEL_END; throttle_level++) {
1119 elapsed = now;
1120 timevalsub(&elapsed, &info->throttle_window_start_timestamp[throttle_level]);
1121 elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
1122
1123 for (level = throttle_level + 1; level <= THROTTLE_LEVEL_END; level++) {
1124 if (!TAILQ_EMPTY(&info->throttle_uthlist[level])) {
1125 if (elapsed_msecs < (uint64_t)throttle_windows_msecs[level] || info->throttle_inflight_count[throttle_level]) {
1126 /*
1127 * we had an I/O occur at a higher priority tier within
1128 * this tier's throttle window
1129 */
1130 throttled = TRUE;
1131 }
1132 /*
1133 * we assume that the windows are the same or longer
1134 * as we drop through the throttling tiers... thus
1135 * we can stop looking once we run into a tier with
1136 * threads to schedule regardless of whether it's
1137 * still in its throttling window or not
1138 */
1139 break;
1140 }
1141 }
1142 if (throttled == TRUE) {
1143 break;
1144 }
1145 }
1146 if (throttled == TRUE) {
1147 uint64_t deadline = 0;
1148 struct timeval target;
1149 struct timeval min_target;
1150
1151 /*
1152 * we've got at least one tier still in a throttled window
1153 * so we need a timer running... compute the next deadline
1154 * and schedule it
1155 */
1156 for (level = throttle_level + 1; level <= THROTTLE_LEVEL_END; level++) {
1157 if (TAILQ_EMPTY(&info->throttle_uthlist[level])) {
1158 continue;
1159 }
1160
1161 target = info->throttle_start_IO_period_timestamp[level];
1162
1163 msecs = info->throttle_io_periods[level];
1164 period.tv_sec = msecs / 1000;
1165 period.tv_usec = (msecs % 1000) * 1000;
1166
1167 timevaladd(&target, &period);
1168
1169 if (need_timer == FALSE || timevalcmp(&target, &min_target, <)) {
1170 min_target = target;
1171 need_timer = TRUE;
1172 }
1173 }
1174 if (timevalcmp(&info->throttle_min_timer_deadline, &now, >)) {
1175 if (timevalcmp(&info->throttle_min_timer_deadline, &min_target, >)) {
1176 min_target = info->throttle_min_timer_deadline;
1177 }
1178 }
1179
1180 if (info->throttle_timer_active) {
1181 if (thread_call_cancel(info->throttle_timer_call) == FALSE) {
1182 /*
1183 * couldn't kill the timer because it's already
1184 * been dispatched, so don't try to start a new
1185 * one... once we drop the lock, the timer will
1186 * proceed and eventually re-run this function
1187 */
1188 need_timer = FALSE;
1189 } else {
1190 info->throttle_timer_active = 0;
1191 }
1192 }
1193 if (need_timer == TRUE) {
1194 /*
1195 * This is defined as an int (32-bit) rather than a 64-bit
1196 * value because it would need a really big period in the
1197 * order of ~500 days to overflow this. So, we let this be
1198 * 32-bit which allows us to use the clock_interval_to_deadline()
1199 * routine.
1200 */
1201 int target_msecs;
1202
1203 if (info->throttle_timer_ref == 0) {
1204 /*
1205 * take a reference for the timer
1206 */
1207 throttle_info_ref(info);
1208
1209 info->throttle_timer_ref = 1;
1210 }
1211 elapsed = min_target;
1212 timevalsub(&elapsed, &now);
1213 target_msecs = (int)(elapsed.tv_sec * 1000 + elapsed.tv_usec / 1000);
1214
1215 if (target_msecs <= 0) {
1216 /*
1217 * we may have computed a deadline slightly in the past
1218 * due to various factors... if so, just set the timer
1219 * to go off in the near future (we don't need to be precise)
1220 */
1221 target_msecs = 1;
1222 }
1223 clock_interval_to_deadline(target_msecs, 1000000, &deadline);
1224
1225 thread_call_enter_delayed(info->throttle_timer_call, deadline);
1226 info->throttle_timer_active = 1;
1227 }
1228 }
1229 return throttle_level;
1230 }
1231
1232
1233 static void
throttle_timer(struct _throttle_io_info_t * info,__unused thread_call_param_t p)1234 throttle_timer(struct _throttle_io_info_t *info, __unused thread_call_param_t p)
1235 {
1236 uthread_t ut, utlist;
1237 struct timeval elapsed;
1238 struct timeval now;
1239 uint64_t elapsed_msecs;
1240 int throttle_level;
1241 int level;
1242 int wake_level;
1243 caddr_t wake_address = NULL;
1244 boolean_t update_io_count = FALSE;
1245 boolean_t need_wakeup = FALSE;
1246 boolean_t need_release = FALSE;
1247
1248 ut = NULL;
1249 lck_mtx_lock(&info->throttle_lock);
1250
1251 info->throttle_timer_active = 0;
1252 microuptime(&now);
1253
1254 elapsed = now;
1255 timevalsub(&elapsed, &info->throttle_start_IO_period_timestamp[THROTTLE_LEVEL_THROTTLED]);
1256 elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
1257
1258 if (elapsed_msecs >= (uint64_t)info->throttle_io_periods[THROTTLE_LEVEL_THROTTLED]) {
1259 wake_level = info->throttle_next_wake_level;
1260
1261 for (level = THROTTLE_LEVEL_START; level < THROTTLE_LEVEL_END; level++) {
1262 elapsed = now;
1263 timevalsub(&elapsed, &info->throttle_start_IO_period_timestamp[wake_level]);
1264 elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
1265
1266 if (elapsed_msecs >= (uint64_t)info->throttle_io_periods[wake_level] && !TAILQ_EMPTY(&info->throttle_uthlist[wake_level])) {
1267 /*
1268 * we're closing out the current IO period...
1269 * if we have a waiting thread, wake it up
1270 * after we have reset the I/O window info
1271 */
1272 need_wakeup = TRUE;
1273 update_io_count = TRUE;
1274
1275 info->throttle_next_wake_level = wake_level - 1;
1276
1277 if (info->throttle_next_wake_level == THROTTLE_LEVEL_START) {
1278 info->throttle_next_wake_level = THROTTLE_LEVEL_END;
1279 }
1280
1281 break;
1282 }
1283 wake_level--;
1284
1285 if (wake_level == THROTTLE_LEVEL_START) {
1286 wake_level = THROTTLE_LEVEL_END;
1287 }
1288 }
1289 }
1290 if (need_wakeup == TRUE) {
1291 if (!TAILQ_EMPTY(&info->throttle_uthlist[wake_level])) {
1292 ut = (uthread_t)TAILQ_FIRST(&info->throttle_uthlist[wake_level]);
1293 TAILQ_REMOVE(&info->throttle_uthlist[wake_level], ut, uu_throttlelist);
1294 ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
1295 ut->uu_is_throttled = false;
1296
1297 wake_address = (caddr_t)&ut->uu_on_throttlelist;
1298 }
1299 } else {
1300 wake_level = THROTTLE_LEVEL_START;
1301 }
1302
1303 throttle_level = throttle_timer_start(info, update_io_count, wake_level);
1304
1305 if (wake_address != NULL) {
1306 wakeup(wake_address);
1307 }
1308
1309 for (level = THROTTLE_LEVEL_THROTTLED; level <= throttle_level; level++) {
1310 TAILQ_FOREACH_SAFE(ut, &info->throttle_uthlist[level], uu_throttlelist, utlist) {
1311 TAILQ_REMOVE(&info->throttle_uthlist[level], ut, uu_throttlelist);
1312 ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
1313 ut->uu_is_throttled = false;
1314
1315 wakeup(&ut->uu_on_throttlelist);
1316 }
1317 }
1318 if (info->throttle_timer_active == 0 && info->throttle_timer_ref) {
1319 info->throttle_timer_ref = 0;
1320 need_release = TRUE;
1321 }
1322 lck_mtx_unlock(&info->throttle_lock);
1323
1324 if (need_release == TRUE) {
1325 throttle_info_rel(info);
1326 }
1327 }
1328
1329
1330 static int
throttle_add_to_list(struct _throttle_io_info_t * info,uthread_t ut,int mylevel,boolean_t insert_tail)1331 throttle_add_to_list(struct _throttle_io_info_t *info, uthread_t ut, int mylevel, boolean_t insert_tail)
1332 {
1333 boolean_t start_timer = FALSE;
1334 int level = THROTTLE_LEVEL_START;
1335
1336 if (TAILQ_EMPTY(&info->throttle_uthlist[mylevel])) {
1337 info->throttle_start_IO_period_timestamp[mylevel] = info->throttle_last_IO_timestamp[mylevel];
1338 start_timer = TRUE;
1339 }
1340
1341 if (insert_tail == TRUE) {
1342 TAILQ_INSERT_TAIL(&info->throttle_uthlist[mylevel], ut, uu_throttlelist);
1343 } else {
1344 TAILQ_INSERT_HEAD(&info->throttle_uthlist[mylevel], ut, uu_throttlelist);
1345 }
1346
1347 ut->uu_on_throttlelist = (int8_t)mylevel;
1348
1349 if (start_timer == TRUE) {
1350 /* we may need to start or rearm the timer */
1351 level = throttle_timer_start(info, FALSE, THROTTLE_LEVEL_START);
1352
1353 if (level == THROTTLE_LEVEL_END) {
1354 if (ut->uu_on_throttlelist >= THROTTLE_LEVEL_THROTTLED) {
1355 TAILQ_REMOVE(&info->throttle_uthlist[ut->uu_on_throttlelist], ut, uu_throttlelist);
1356
1357 ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
1358 }
1359 }
1360 }
1361 return level;
1362 }
1363
1364 static void
throttle_init_throttle_window(void)1365 throttle_init_throttle_window(void)
1366 {
1367 int throttle_window_size;
1368
1369 /*
1370 * The hierarchy of throttle window values is as follows:
1371 * - Global defaults
1372 * - Device tree properties
1373 * - Boot-args
1374 * All values are specified in msecs.
1375 */
1376
1377 #if (XNU_TARGET_OS_OSX && __arm64__)
1378 /*
1379 * IO Tier EDT overrides are meant for
1380 * some arm platforms but not for
1381 * macs.
1382 */
1383 #else /* (XNU_TARGET_OS_OSX && __arm64__) */
1384 /* Override global values with device-tree properties */
1385 if (PE_get_default("kern.io_throttle_window_tier1", &throttle_window_size, sizeof(throttle_window_size))) {
1386 throttle_windows_msecs[THROTTLE_LEVEL_TIER1] = throttle_window_size;
1387 }
1388
1389 if (PE_get_default("kern.io_throttle_window_tier2", &throttle_window_size, sizeof(throttle_window_size))) {
1390 throttle_windows_msecs[THROTTLE_LEVEL_TIER2] = throttle_window_size;
1391 }
1392
1393 if (PE_get_default("kern.io_throttle_window_tier3", &throttle_window_size, sizeof(throttle_window_size))) {
1394 throttle_windows_msecs[THROTTLE_LEVEL_TIER3] = throttle_window_size;
1395 }
1396 #endif /* (XNU_TARGET_OS_OSX && __arm64__) */
1397
1398 /* Override with boot-args */
1399 if (PE_parse_boot_argn("io_throttle_window_tier1", &throttle_window_size, sizeof(throttle_window_size))) {
1400 throttle_windows_msecs[THROTTLE_LEVEL_TIER1] = throttle_window_size;
1401 }
1402
1403 if (PE_parse_boot_argn("io_throttle_window_tier2", &throttle_window_size, sizeof(throttle_window_size))) {
1404 throttle_windows_msecs[THROTTLE_LEVEL_TIER2] = throttle_window_size;
1405 }
1406
1407 if (PE_parse_boot_argn("io_throttle_window_tier3", &throttle_window_size, sizeof(throttle_window_size))) {
1408 throttle_windows_msecs[THROTTLE_LEVEL_TIER3] = throttle_window_size;
1409 }
1410 }
1411
1412 static void
throttle_init_throttle_period(struct _throttle_io_info_t * info,boolean_t isssd)1413 throttle_init_throttle_period(struct _throttle_io_info_t *info, boolean_t isssd)
1414 {
1415 int throttle_period_size;
1416
1417 /*
1418 * The hierarchy of throttle period values is as follows:
1419 * - Global defaults
1420 * - Device tree properties
1421 * - Boot-args
1422 * All values are specified in msecs.
1423 */
1424
1425 /* Assign global defaults */
1426 if ((isssd == TRUE) && (info->throttle_is_fusion_with_priority == 0)) {
1427 info->throttle_io_periods = &throttle_io_period_ssd_msecs[0];
1428 } else {
1429 info->throttle_io_periods = &throttle_io_period_msecs[0];
1430 }
1431
1432 #if (XNU_TARGET_OS_OSX && __arm64__)
1433 /*
1434 * IO Tier EDT overrides are meant for
1435 * some arm platforms but not for
1436 * macs.
1437 */
1438 #else /* (XNU_TARGET_OS_OSX && __arm64__) */
1439 /* Override global values with device-tree properties */
1440 if (PE_get_default("kern.io_throttle_period_tier1", &throttle_period_size, sizeof(throttle_period_size))) {
1441 info->throttle_io_periods[THROTTLE_LEVEL_TIER1] = throttle_period_size;
1442 }
1443
1444 if (PE_get_default("kern.io_throttle_period_tier2", &throttle_period_size, sizeof(throttle_period_size))) {
1445 info->throttle_io_periods[THROTTLE_LEVEL_TIER2] = throttle_period_size;
1446 }
1447
1448 if (PE_get_default("kern.io_throttle_period_tier3", &throttle_period_size, sizeof(throttle_period_size))) {
1449 info->throttle_io_periods[THROTTLE_LEVEL_TIER3] = throttle_period_size;
1450 }
1451 #endif /* (XNU_TARGET_OS_OSX && __arm64__) */
1452
1453 /* Override with boot-args */
1454 if (PE_parse_boot_argn("io_throttle_period_tier1", &throttle_period_size, sizeof(throttle_period_size))) {
1455 info->throttle_io_periods[THROTTLE_LEVEL_TIER1] = throttle_period_size;
1456 }
1457
1458 if (PE_parse_boot_argn("io_throttle_period_tier2", &throttle_period_size, sizeof(throttle_period_size))) {
1459 info->throttle_io_periods[THROTTLE_LEVEL_TIER2] = throttle_period_size;
1460 }
1461
1462 if (PE_parse_boot_argn("io_throttle_period_tier3", &throttle_period_size, sizeof(throttle_period_size))) {
1463 info->throttle_io_periods[THROTTLE_LEVEL_TIER3] = throttle_period_size;
1464 }
1465 }
1466
1467 #if CONFIG_IOSCHED
1468 int iosched_enabled = 1;
1469 #endif
1470
1471 void
throttle_init(void)1472 throttle_init(void)
1473 {
1474 struct _throttle_io_info_t *info;
1475 int i;
1476 int level;
1477 #if CONFIG_IOSCHED
1478 int iosched;
1479 #endif
1480
1481 /* Update throttle parameters based on device tree configuration */
1482 throttle_init_throttle_window();
1483
1484 for (i = 0; i < LOWPRI_MAX_NUM_DEV; i++) {
1485 info = &_throttle_io_info[i];
1486
1487 lck_mtx_init(&info->throttle_lock, &throttle_lock_grp, LCK_ATTR_NULL);
1488 info->throttle_timer_call = thread_call_allocate((thread_call_func_t)throttle_timer, (thread_call_param_t)info);
1489
1490 for (level = 0; level <= THROTTLE_LEVEL_END; level++) {
1491 TAILQ_INIT(&info->throttle_uthlist[level]);
1492 info->throttle_last_IO_pid[level] = 0;
1493 info->throttle_inflight_count[level] = 0;
1494 }
1495 info->throttle_next_wake_level = THROTTLE_LEVEL_END;
1496 info->throttle_disabled = 0;
1497 info->throttle_is_fusion_with_priority = 0;
1498 }
1499 #if CONFIG_IOSCHED
1500 if (PE_parse_boot_argn("iosched", &iosched, sizeof(iosched))) {
1501 iosched_enabled = iosched;
1502 }
1503 if (iosched_enabled) {
1504 /* Initialize I/O Reprioritization mechanism */
1505 vm_io_reprioritize_init();
1506 }
1507 #endif
1508 }
1509
1510 void
sys_override_io_throttle(boolean_t enable_override)1511 sys_override_io_throttle(boolean_t enable_override)
1512 {
1513 if (enable_override) {
1514 lowpri_throttle_enabled = 0;
1515 } else {
1516 lowpri_throttle_enabled = 1;
1517 }
1518 }
1519
1520 int rethrottle_wakeups = 0;
1521
1522 /*
1523 * the uu_rethrottle_lock is used to synchronize this function
1524 * with "throttle_lowpri_io" which is where a throttled thread
1525 * will block... that function will grab this lock before beginning
1526 * it's decision making process concerning the need to block, and
1527 * hold it through the assert_wait. When that thread is awakened
1528 * for any reason (timer or rethrottle), it will reacquire the
1529 * uu_rethrottle_lock before determining if it really is ok for
1530 * it to now run. This is the point at which the thread could
1531 * enter a different throttling queue and reblock or return from
1532 * the throttle w/o having waited out it's entire throttle if
1533 * the rethrottle has now moved it out of any currently
1534 * active throttle window.
1535 *
1536 *
1537 * NOTES:
1538 * 1 - This may be called with the task lock held.
1539 * 2 - This may be called with preemption and interrupts disabled
1540 * in the kqueue wakeup path so we can't take the throttle_lock which is a mutex
1541 * 3 - This cannot safely dereference uu_throttle_info, as it may
1542 * get deallocated out from under us
1543 */
1544
1545 void
rethrottle_thread(uthread_t ut)1546 rethrottle_thread(uthread_t ut)
1547 {
1548 /*
1549 * If uthread doesn't have throttle state, then there's no chance
1550 * of it needing a rethrottle.
1551 */
1552 if (ut->uu_throttle_info == NULL) {
1553 return;
1554 }
1555
1556 boolean_t s = ml_set_interrupts_enabled(FALSE);
1557 lck_spin_lock(&ut->uu_rethrottle_lock);
1558
1559 if (!ut->uu_is_throttled) {
1560 ut->uu_was_rethrottled = true;
1561 } else {
1562 int my_new_level = throttle_get_thread_throttle_level(ut);
1563
1564 if (my_new_level != ut->uu_on_throttlelist) {
1565 /*
1566 * ut is currently blocked (as indicated by
1567 * ut->uu_is_throttled == true)
1568 * and we're changing it's throttle level, so
1569 * we need to wake it up.
1570 */
1571 ut->uu_is_throttled = false;
1572 wakeup(&ut->uu_on_throttlelist);
1573
1574 rethrottle_wakeups++;
1575 KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_FSRW, 102)),
1576 uthread_tid(ut), ut->uu_on_throttlelist, my_new_level, 0, 0);
1577 }
1578 }
1579 lck_spin_unlock(&ut->uu_rethrottle_lock);
1580 ml_set_interrupts_enabled(s);
1581 }
1582
1583
1584 /*
1585 * KPI routine
1586 *
1587 * Create and take a reference on a throttle info structure and return a
1588 * pointer for the file system to use when calling throttle_info_update.
1589 * Calling file system must have a matching release for every create.
1590 */
1591 void *
throttle_info_create(void)1592 throttle_info_create(void)
1593 {
1594 struct _throttle_io_info_t *info;
1595 int level;
1596
1597 info = kalloc_type(struct _throttle_io_info_t,
1598 Z_ZERO | Z_WAITOK | Z_NOFAIL);
1599 /* Mark that this one was allocated and needs to be freed */
1600 DEBUG_ALLOC_THROTTLE_INFO("Creating info = %p\n", info, info );
1601 info->throttle_alloc = TRUE;
1602
1603 lck_mtx_init(&info->throttle_lock, &throttle_lock_grp, LCK_ATTR_NULL);
1604 info->throttle_timer_call = thread_call_allocate((thread_call_func_t)throttle_timer, (thread_call_param_t)info);
1605
1606 for (level = 0; level <= THROTTLE_LEVEL_END; level++) {
1607 TAILQ_INIT(&info->throttle_uthlist[level]);
1608 }
1609 info->throttle_next_wake_level = THROTTLE_LEVEL_END;
1610
1611 /* Take a reference */
1612 OSIncrementAtomic(&info->throttle_refcnt);
1613 return info;
1614 }
1615
1616 /*
1617 * KPI routine
1618 *
1619 * Release the throttle info pointer if all the reference are gone. Should be
1620 * called to release reference taken by throttle_info_create
1621 */
1622 void
throttle_info_release(void * throttle_info)1623 throttle_info_release(void *throttle_info)
1624 {
1625 DEBUG_ALLOC_THROTTLE_INFO("Releaseing info = %p\n",
1626 (struct _throttle_io_info_t *)throttle_info,
1627 (struct _throttle_io_info_t *)throttle_info);
1628 if (throttle_info) { /* Just to be careful */
1629 throttle_info_rel(throttle_info);
1630 }
1631 }
1632
1633 /*
1634 * KPI routine
1635 *
1636 * File Systems that create an info structure, need to call this routine in
1637 * their mount routine (used by cluster code). File Systems that call this in
1638 * their mount routines must call throttle_info_mount_rel in their unmount
1639 * routines.
1640 */
1641 void
throttle_info_mount_ref(mount_t mp,void * throttle_info)1642 throttle_info_mount_ref(mount_t mp, void *throttle_info)
1643 {
1644 if ((throttle_info == NULL) || (mp == NULL)) {
1645 return;
1646 }
1647 throttle_info_ref(throttle_info);
1648
1649 /*
1650 * We already have a reference release it before adding the new one
1651 */
1652 if (mp->mnt_throttle_info) {
1653 throttle_info_rel(mp->mnt_throttle_info);
1654 }
1655 mp->mnt_throttle_info = throttle_info;
1656 }
1657
1658 /*
1659 * Private KPI routine
1660 *
1661 * return a handle for accessing throttle_info given a throttle_mask. The
1662 * handle must be released by throttle_info_rel_by_mask
1663 */
1664 int
throttle_info_ref_by_mask(uint64_t throttle_mask,throttle_info_handle_t * throttle_info_handle)1665 throttle_info_ref_by_mask(uint64_t throttle_mask, throttle_info_handle_t *throttle_info_handle)
1666 {
1667 int dev_index;
1668 struct _throttle_io_info_t *info;
1669
1670 /*
1671 * The 'throttle_mask' is not expected to be 0 otherwise num_trailing_0()
1672 * would return value of 64 and this will cause '_throttle_io_info' to
1673 * go out of bounds as '_throttle_io_info' is only LOWPRI_MAX_NUM_DEV (64)
1674 * elements long.
1675 */
1676 if (throttle_info_handle == NULL || throttle_mask == 0) {
1677 return EINVAL;
1678 }
1679
1680 dev_index = num_trailing_0(throttle_mask);
1681 info = &_throttle_io_info[dev_index];
1682 throttle_info_ref(info);
1683 *(struct _throttle_io_info_t**)throttle_info_handle = info;
1684
1685 return 0;
1686 }
1687
1688 /*
1689 * Private KPI routine
1690 *
1691 * release the handle obtained by throttle_info_ref_by_mask
1692 */
1693 void
throttle_info_rel_by_mask(throttle_info_handle_t throttle_info_handle)1694 throttle_info_rel_by_mask(throttle_info_handle_t throttle_info_handle)
1695 {
1696 /*
1697 * for now the handle is just a pointer to _throttle_io_info_t
1698 */
1699 throttle_info_rel((struct _throttle_io_info_t*)throttle_info_handle);
1700 }
1701
1702 /*
1703 * KPI routine
1704 *
1705 * File Systems that throttle_info_mount_ref, must call this routine in their
1706 * umount routine.
1707 */
1708 void
throttle_info_mount_rel(mount_t mp)1709 throttle_info_mount_rel(mount_t mp)
1710 {
1711 if (mp->mnt_throttle_info) {
1712 throttle_info_rel(mp->mnt_throttle_info);
1713 }
1714 mp->mnt_throttle_info = NULL;
1715 }
1716
1717 /*
1718 * Reset throttling periods for the given mount point
1719 *
1720 * private interface used by disk conditioner to reset
1721 * throttling periods when 'is_ssd' status changes
1722 */
1723 void
throttle_info_mount_reset_period(mount_t mp,int isssd)1724 throttle_info_mount_reset_period(mount_t mp, int isssd)
1725 {
1726 struct _throttle_io_info_t *info;
1727
1728 if (mp == NULL) {
1729 info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
1730 } else if (mp->mnt_throttle_info == NULL) {
1731 info = &_throttle_io_info[mp->mnt_devbsdunit];
1732 } else {
1733 info = mp->mnt_throttle_info;
1734 }
1735
1736 throttle_init_throttle_period(info, isssd);
1737 }
1738
1739 void
throttle_info_get_last_io_time(mount_t mp,struct timeval * tv)1740 throttle_info_get_last_io_time(mount_t mp, struct timeval *tv)
1741 {
1742 struct _throttle_io_info_t *info;
1743
1744 if (mp == NULL) {
1745 info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
1746 } else if (mp->mnt_throttle_info == NULL) {
1747 info = &_throttle_io_info[mp->mnt_devbsdunit];
1748 } else {
1749 info = mp->mnt_throttle_info;
1750 }
1751
1752 *tv = info->throttle_last_write_timestamp;
1753 }
1754
1755 void
update_last_io_time(mount_t mp)1756 update_last_io_time(mount_t mp)
1757 {
1758 struct _throttle_io_info_t *info;
1759
1760 if (mp == NULL) {
1761 info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
1762 } else if (mp->mnt_throttle_info == NULL) {
1763 info = &_throttle_io_info[mp->mnt_devbsdunit];
1764 } else {
1765 info = mp->mnt_throttle_info;
1766 }
1767
1768 microuptime(&info->throttle_last_write_timestamp);
1769 if (mp != NULL) {
1770 mp->mnt_last_write_completed_timestamp = info->throttle_last_write_timestamp;
1771 }
1772 }
1773
1774 int
throttle_get_io_policy(uthread_t * ut)1775 throttle_get_io_policy(uthread_t *ut)
1776 {
1777 if (ut != NULL) {
1778 *ut = current_uthread();
1779 }
1780
1781 return proc_get_effective_thread_policy(current_thread(), TASK_POLICY_IO);
1782 }
1783
1784 int
throttle_get_passive_io_policy(uthread_t * ut)1785 throttle_get_passive_io_policy(uthread_t *ut)
1786 {
1787 if (ut != NULL) {
1788 *ut = current_uthread();
1789 }
1790
1791 return proc_get_effective_thread_policy(current_thread(), TASK_POLICY_PASSIVE_IO);
1792 }
1793
1794
1795 static int
throttle_get_thread_throttle_level(uthread_t ut)1796 throttle_get_thread_throttle_level(uthread_t ut)
1797 {
1798 uthread_t *ut_p = (ut == NULL) ? &ut : NULL;
1799 int io_tier = throttle_get_io_policy(ut_p);
1800
1801 return throttle_get_thread_throttle_level_internal(ut, io_tier);
1802 }
1803
1804 /*
1805 * Return a throttle level given an existing I/O tier (such as returned by throttle_get_io_policy)
1806 */
1807 static int
throttle_get_thread_throttle_level_internal(uthread_t ut,int io_tier)1808 throttle_get_thread_throttle_level_internal(uthread_t ut, int io_tier)
1809 {
1810 int thread_throttle_level = io_tier;
1811 int user_idle_level;
1812
1813 assert(ut != NULL);
1814
1815 /* Bootcache misses should always be throttled */
1816 if (ut->uu_throttle_bc) {
1817 thread_throttle_level = THROTTLE_LEVEL_TIER3;
1818 }
1819
1820 /*
1821 * Issue tier3 I/O as tier2 when the user is idle
1822 * to allow maintenance tasks to make more progress.
1823 *
1824 * Assume any positive idle level is enough... for now it's
1825 * only ever 0 or 128 but this is not defined anywhere.
1826 */
1827 if (thread_throttle_level >= THROTTLE_LEVEL_TIER3) {
1828 user_idle_level = timer_get_user_idle_level();
1829 if (user_idle_level > 0) {
1830 thread_throttle_level--;
1831 }
1832 }
1833
1834 return thread_throttle_level;
1835 }
1836
1837 /*
1838 * I/O will be throttled if either of the following are true:
1839 * - Higher tiers have in-flight I/O
1840 * - The time delta since the last start/completion of a higher tier is within the throttle window interval
1841 *
1842 * In-flight I/O is bookended by throttle_info_update_internal/throttle_info_end_io_internal
1843 */
1844 static int
throttle_io_will_be_throttled_internal(void * throttle_info,int * mylevel,int * throttling_level)1845 throttle_io_will_be_throttled_internal(void * throttle_info, int * mylevel, int * throttling_level)
1846 {
1847 struct _throttle_io_info_t *info = throttle_info;
1848 struct timeval elapsed;
1849 struct timeval now;
1850 uint64_t elapsed_msecs;
1851 int thread_throttle_level;
1852 int throttle_level;
1853
1854 if ((thread_throttle_level = throttle_get_thread_throttle_level(NULL)) < THROTTLE_LEVEL_THROTTLED) {
1855 return THROTTLE_DISENGAGED;
1856 }
1857
1858 microuptime(&now);
1859
1860 for (throttle_level = THROTTLE_LEVEL_START; throttle_level < thread_throttle_level; throttle_level++) {
1861 if (info->throttle_inflight_count[throttle_level]) {
1862 break;
1863 }
1864 elapsed = now;
1865 timevalsub(&elapsed, &info->throttle_window_start_timestamp[throttle_level]);
1866 elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
1867
1868 if (elapsed_msecs < (uint64_t)throttle_windows_msecs[thread_throttle_level]) {
1869 break;
1870 }
1871 }
1872 if (throttle_level >= thread_throttle_level) {
1873 /*
1874 * we're beyond all of the throttle windows
1875 * that affect the throttle level of this thread,
1876 * so go ahead and treat as normal I/O
1877 */
1878 return THROTTLE_DISENGAGED;
1879 }
1880 if (mylevel) {
1881 *mylevel = thread_throttle_level;
1882 }
1883 if (throttling_level) {
1884 *throttling_level = throttle_level;
1885 }
1886
1887 if (info->throttle_io_count != info->throttle_io_count_begin) {
1888 /*
1889 * we've already issued at least one throttleable I/O
1890 * in the current I/O window, so avoid issuing another one
1891 */
1892 return THROTTLE_NOW;
1893 }
1894 /*
1895 * we're in the throttle window, so
1896 * cut the I/O size back
1897 */
1898 return THROTTLE_ENGAGED;
1899 }
1900
1901 /*
1902 * If we have a mount point and it has a throttle info pointer then
1903 * use it to do the check, otherwise use the device unit number to find
1904 * the correct throttle info array element.
1905 */
1906 int
throttle_io_will_be_throttled(__unused int lowpri_window_msecs,mount_t mp)1907 throttle_io_will_be_throttled(__unused int lowpri_window_msecs, mount_t mp)
1908 {
1909 struct _throttle_io_info_t *info;
1910
1911 /*
1912 * Should we just return zero if no mount point
1913 */
1914 if (mp == NULL) {
1915 info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
1916 } else if (mp->mnt_throttle_info == NULL) {
1917 info = &_throttle_io_info[mp->mnt_devbsdunit];
1918 } else {
1919 info = mp->mnt_throttle_info;
1920 }
1921
1922 if (info->throttle_is_fusion_with_priority) {
1923 uthread_t ut = current_uthread();
1924 if (ut->uu_lowpri_window == 0) {
1925 return THROTTLE_DISENGAGED;
1926 }
1927 }
1928
1929 if (info->throttle_disabled) {
1930 return THROTTLE_DISENGAGED;
1931 } else {
1932 return throttle_io_will_be_throttled_internal(info, NULL, NULL);
1933 }
1934 }
1935
1936 /*
1937 * Routine to increment I/O throttling counters maintained in the proc
1938 */
1939
1940 static void
throttle_update_proc_stats(pid_t throttling_pid,int count)1941 throttle_update_proc_stats(pid_t throttling_pid, int count)
1942 {
1943 proc_t throttling_proc;
1944 proc_t throttled_proc = current_proc();
1945
1946 /* The throttled_proc is always the current proc; so we are not concerned with refs */
1947 OSAddAtomic64(count, &(throttled_proc->was_throttled));
1948
1949 /* The throttling pid might have exited by now */
1950 throttling_proc = proc_find(throttling_pid);
1951 if (throttling_proc != PROC_NULL) {
1952 OSAddAtomic64(count, &(throttling_proc->did_throttle));
1953 proc_rele(throttling_proc);
1954 }
1955 }
1956
1957 /*
1958 * Block until woken up by the throttle timer or by a rethrottle call.
1959 * As long as we hold the throttle_lock while querying the throttle tier, we're
1960 * safe against seeing an old throttle tier after a rethrottle.
1961 */
1962 uint32_t
throttle_lowpri_io(int sleep_amount)1963 throttle_lowpri_io(int sleep_amount)
1964 {
1965 uthread_t ut;
1966 struct _throttle_io_info_t *info;
1967 int throttle_type = 0;
1968 int mylevel = 0;
1969 int throttling_level = THROTTLE_LEVEL_NONE;
1970 int sleep_cnt = 0;
1971 uint32_t throttle_io_period_num = 0;
1972 boolean_t insert_tail = TRUE;
1973 boolean_t s;
1974
1975 ut = current_uthread();
1976
1977 if (ut->uu_lowpri_window == 0) {
1978 return 0;
1979 }
1980 if (current_thread_in_kernel_fault()) {
1981 /* do not throttle kernel faults */
1982 return 0;
1983 }
1984
1985 info = ut->uu_throttle_info;
1986
1987 if (info == NULL) {
1988 ut->uu_throttle_bc = false;
1989 ut->uu_lowpri_window = 0;
1990 return 0;
1991 }
1992 lck_mtx_lock(&info->throttle_lock);
1993 assert(ut->uu_on_throttlelist < THROTTLE_LEVEL_THROTTLED);
1994
1995 if (sleep_amount == 0) {
1996 goto done;
1997 }
1998
1999 if (sleep_amount == 1 && !ut->uu_throttle_bc) {
2000 sleep_amount = 0;
2001 }
2002
2003 throttle_io_period_num = info->throttle_io_period_num;
2004
2005 ut->uu_was_rethrottled = false;
2006
2007 while ((throttle_type = throttle_io_will_be_throttled_internal(info, &mylevel, &throttling_level))) {
2008 if (throttle_type == THROTTLE_ENGAGED) {
2009 if (sleep_amount == 0) {
2010 break;
2011 }
2012 if (info->throttle_io_period_num < throttle_io_period_num) {
2013 break;
2014 }
2015 if ((info->throttle_io_period_num - throttle_io_period_num) >= (uint32_t)sleep_amount) {
2016 break;
2017 }
2018 }
2019 /*
2020 * keep the same position in the list if "rethrottle_thread" changes our throttle level and
2021 * then puts us back to the original level before we get a chance to run
2022 */
2023 if (ut->uu_on_throttlelist >= THROTTLE_LEVEL_THROTTLED && ut->uu_on_throttlelist != mylevel) {
2024 /*
2025 * must have been awakened via "rethrottle_thread" (the timer pulls us off the list)
2026 * and we've changed our throttling level, so pull ourselves off of the appropriate list
2027 * and make sure we get put on the tail of the new list since we're starting anew w/r to
2028 * the throttling engine
2029 */
2030 TAILQ_REMOVE(&info->throttle_uthlist[ut->uu_on_throttlelist], ut, uu_throttlelist);
2031 ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
2032 insert_tail = TRUE;
2033 }
2034 if (ut->uu_on_throttlelist < THROTTLE_LEVEL_THROTTLED) {
2035 if (throttle_add_to_list(info, ut, mylevel, insert_tail) == THROTTLE_LEVEL_END) {
2036 goto done;
2037 }
2038 }
2039 assert(throttling_level >= THROTTLE_LEVEL_START && throttling_level <= THROTTLE_LEVEL_END);
2040
2041 s = ml_set_interrupts_enabled(FALSE);
2042 lck_spin_lock(&ut->uu_rethrottle_lock);
2043
2044 /*
2045 * this is the critical section w/r to our interaction
2046 * with "rethrottle_thread"
2047 */
2048 if (ut->uu_was_rethrottled) {
2049 lck_spin_unlock(&ut->uu_rethrottle_lock);
2050 ml_set_interrupts_enabled(s);
2051 lck_mtx_yield(&info->throttle_lock);
2052
2053 KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_FSRW, 103)),
2054 uthread_tid(ut), ut->uu_on_throttlelist, 0, 0, 0);
2055
2056 ut->uu_was_rethrottled = false;
2057 continue;
2058 }
2059 KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_THROTTLE, PROCESS_THROTTLED)) | DBG_FUNC_NONE,
2060 info->throttle_last_IO_pid[throttling_level], throttling_level, proc_selfpid(), mylevel, 0);
2061
2062 if (sleep_cnt == 0) {
2063 KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_FSRW, 97)) | DBG_FUNC_START,
2064 throttle_windows_msecs[mylevel], info->throttle_io_periods[mylevel], info->throttle_io_count, 0, 0);
2065 throttled_count[mylevel]++;
2066 }
2067 ut->uu_wmesg = "throttle_lowpri_io";
2068
2069 assert_wait((caddr_t)&ut->uu_on_throttlelist, THREAD_UNINT);
2070
2071 ut->uu_is_throttled = true;
2072 lck_spin_unlock(&ut->uu_rethrottle_lock);
2073 ml_set_interrupts_enabled(s);
2074
2075 lck_mtx_unlock(&info->throttle_lock);
2076
2077 thread_block(THREAD_CONTINUE_NULL);
2078
2079 ut->uu_wmesg = NULL;
2080
2081 ut->uu_is_throttled = false;
2082 ut->uu_was_rethrottled = false;
2083
2084 lck_mtx_lock(&info->throttle_lock);
2085
2086 sleep_cnt++;
2087
2088 if (sleep_amount == 0) {
2089 insert_tail = FALSE;
2090 } else if (info->throttle_io_period_num < throttle_io_period_num ||
2091 (info->throttle_io_period_num - throttle_io_period_num) >= (uint32_t)sleep_amount) {
2092 insert_tail = FALSE;
2093 sleep_amount = 0;
2094 }
2095 }
2096 done:
2097 if (ut->uu_on_throttlelist >= THROTTLE_LEVEL_THROTTLED) {
2098 TAILQ_REMOVE(&info->throttle_uthlist[ut->uu_on_throttlelist], ut, uu_throttlelist);
2099 ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
2100 }
2101 lck_mtx_unlock(&info->throttle_lock);
2102
2103 if (sleep_cnt) {
2104 KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_FSRW, 97)) | DBG_FUNC_END,
2105 throttle_windows_msecs[mylevel], info->throttle_io_periods[mylevel], info->throttle_io_count, 0, 0);
2106 /*
2107 * We update the stats for the last pid which opened a throttle window for the throttled thread.
2108 * This might not be completely accurate since the multiple throttles seen by the lower tier pid
2109 * might have been caused by various higher prio pids. However, updating these stats accurately
2110 * means doing a proc_find while holding the throttle lock which leads to deadlock.
2111 */
2112 throttle_update_proc_stats(info->throttle_last_IO_pid[throttling_level], sleep_cnt);
2113 }
2114
2115 ut->uu_throttle_info = NULL;
2116 ut->uu_throttle_bc = false;
2117 ut->uu_lowpri_window = 0;
2118
2119 throttle_info_rel(info);
2120
2121 return sleep_cnt;
2122 }
2123
2124 /*
2125 * returns TRUE if the throttle_lowpri_io called with the same sleep_amount would've slept
2126 * This function mimics the most of the throttle_lowpri_io checks but without actual sleeping
2127 */
2128 int
throttle_lowpri_io_will_be_throttled(int sleep_amount)2129 throttle_lowpri_io_will_be_throttled(int sleep_amount)
2130 {
2131 if (sleep_amount == 0) {
2132 return FALSE;
2133 }
2134
2135 uthread_t ut = current_uthread();
2136 if (ut->uu_lowpri_window == 0) {
2137 return FALSE;
2138 }
2139
2140 struct _throttle_io_info_t *info = ut->uu_throttle_info;
2141 if (info == NULL) {
2142 return FALSE;
2143 }
2144
2145 lck_mtx_lock(&info->throttle_lock);
2146 assert(ut->uu_on_throttlelist < THROTTLE_LEVEL_THROTTLED);
2147
2148 if (sleep_amount == 1 && !ut->uu_throttle_bc) {
2149 sleep_amount = 0;
2150 }
2151
2152 int result = FALSE;
2153
2154 int throttle_type = throttle_io_will_be_throttled_internal(info, NULL, NULL);
2155 if (throttle_type > THROTTLE_DISENGAGED) {
2156 result = TRUE;
2157 if ((throttle_type == THROTTLE_ENGAGED) && (sleep_amount == 0)) {
2158 result = FALSE;
2159 }
2160 }
2161
2162 lck_mtx_unlock(&info->throttle_lock);
2163
2164 return result;
2165 }
2166
2167
2168 /*
2169 * KPI routine
2170 *
2171 * set a kernel thread's IO policy. policy can be:
2172 * IOPOL_NORMAL, IOPOL_THROTTLE, IOPOL_PASSIVE, IOPOL_UTILITY, IOPOL_STANDARD
2173 *
2174 * explanations about these policies are in the man page of setiopolicy_np
2175 */
2176 void
throttle_set_thread_io_policy(int policy)2177 throttle_set_thread_io_policy(int policy)
2178 {
2179 proc_set_thread_policy(current_thread(), TASK_POLICY_INTERNAL, TASK_POLICY_IOPOL, policy);
2180 }
2181
2182 int
throttle_get_thread_effective_io_policy()2183 throttle_get_thread_effective_io_policy()
2184 {
2185 return proc_get_effective_thread_policy(current_thread(), TASK_POLICY_IO);
2186 }
2187
2188 int
throttle_thread_io_tier_above_metadata(void)2189 throttle_thread_io_tier_above_metadata(void)
2190 {
2191 return throttle_get_thread_effective_io_policy() < IOSCHED_METADATA_TIER;
2192 }
2193
2194 void
throttle_info_reset_window(uthread_t ut)2195 throttle_info_reset_window(uthread_t ut)
2196 {
2197 struct _throttle_io_info_t *info;
2198
2199 if (ut == NULL) {
2200 ut = current_uthread();
2201 }
2202
2203 if ((info = ut->uu_throttle_info)) {
2204 throttle_info_rel(info);
2205
2206 ut->uu_throttle_info = NULL;
2207 ut->uu_lowpri_window = 0;
2208 ut->uu_throttle_bc = false;
2209 }
2210 }
2211
2212 static
2213 void
throttle_info_set_initial_window(uthread_t ut,struct _throttle_io_info_t * info,boolean_t BC_throttle,boolean_t isssd)2214 throttle_info_set_initial_window(uthread_t ut, struct _throttle_io_info_t *info, boolean_t BC_throttle, boolean_t isssd)
2215 {
2216 if (lowpri_throttle_enabled == 0 || info->throttle_disabled) {
2217 return;
2218 }
2219
2220 if (info->throttle_io_periods == 0) {
2221 throttle_init_throttle_period(info, isssd);
2222 }
2223 if (ut->uu_throttle_info == NULL) {
2224 ut->uu_throttle_info = info;
2225 throttle_info_ref(info);
2226 DEBUG_ALLOC_THROTTLE_INFO("updating info = %p\n", info, info );
2227
2228 ut->uu_lowpri_window = 1;
2229 ut->uu_throttle_bc = BC_throttle;
2230 }
2231 }
2232
2233 /*
2234 * Update inflight IO count and throttling window
2235 * Should be called when an IO is done
2236 *
2237 * Only affects IO that was sent through spec_strategy
2238 */
2239 void
throttle_info_end_io(buf_t bp)2240 throttle_info_end_io(buf_t bp)
2241 {
2242 vnode_t vp;
2243 mount_t mp;
2244 struct bufattr *bap;
2245 struct _throttle_io_info_t *info;
2246 int io_tier;
2247
2248 bap = &bp->b_attr;
2249 if (!ISSET(bap->ba_flags, BA_STRATEGY_TRACKED_IO)) {
2250 return;
2251 }
2252 CLR(bap->ba_flags, BA_STRATEGY_TRACKED_IO);
2253
2254 vp = buf_vnode(bp);
2255 mp = vp->v_mount;
2256
2257 if (vp && (vp->v_type == VBLK || vp->v_type == VCHR)) {
2258 info = &_throttle_io_info[vp->v_un.vu_specinfo->si_devbsdunit];
2259 } else if (mp != NULL) {
2260 info = &_throttle_io_info[mp->mnt_devbsdunit];
2261 } else {
2262 info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
2263 }
2264
2265 io_tier = GET_BUFATTR_IO_TIER(bap);
2266 if (ISSET(bap->ba_flags, BA_IO_TIER_UPGRADE)) {
2267 io_tier--;
2268 }
2269
2270 throttle_info_end_io_internal(info, io_tier);
2271 }
2272
2273 /*
2274 * Decrement inflight count initially incremented by throttle_info_update_internal
2275 */
2276 static
2277 void
throttle_info_end_io_internal(struct _throttle_io_info_t * info,int throttle_level)2278 throttle_info_end_io_internal(struct _throttle_io_info_t *info, int throttle_level)
2279 {
2280 if (throttle_level == THROTTLE_LEVEL_NONE) {
2281 return;
2282 }
2283
2284 microuptime(&info->throttle_window_start_timestamp[throttle_level]);
2285 OSDecrementAtomic(&info->throttle_inflight_count[throttle_level]);
2286 assert(info->throttle_inflight_count[throttle_level] >= 0);
2287 }
2288
2289 /*
2290 * If inflight is TRUE and bap is NULL then the caller is responsible for calling
2291 * throttle_info_end_io_internal to avoid leaking in-flight I/O.
2292 */
2293 static
2294 int
throttle_info_update_internal(struct _throttle_io_info_t * info,uthread_t ut,int flags,boolean_t isssd,boolean_t inflight,struct bufattr * bap)2295 throttle_info_update_internal(struct _throttle_io_info_t *info, uthread_t ut, int flags, boolean_t isssd, boolean_t inflight, struct bufattr *bap)
2296 {
2297 int thread_throttle_level;
2298
2299 if (lowpri_throttle_enabled == 0 || info->throttle_disabled) {
2300 return THROTTLE_LEVEL_NONE;
2301 }
2302
2303 if (ut == NULL) {
2304 ut = current_uthread();
2305 }
2306
2307 if (bap && inflight && !ut->uu_throttle_bc) {
2308 thread_throttle_level = GET_BUFATTR_IO_TIER(bap);
2309 if (ISSET(bap->ba_flags, BA_IO_TIER_UPGRADE)) {
2310 thread_throttle_level--;
2311 }
2312 } else {
2313 thread_throttle_level = throttle_get_thread_throttle_level(ut);
2314 }
2315
2316 if (thread_throttle_level != THROTTLE_LEVEL_NONE) {
2317 if (!ISSET(flags, B_PASSIVE)) {
2318 info->throttle_last_IO_pid[thread_throttle_level] = proc_selfpid();
2319 if (inflight && !ut->uu_throttle_bc) {
2320 if (NULL != bap) {
2321 SET(bap->ba_flags, BA_STRATEGY_TRACKED_IO);
2322 }
2323 OSIncrementAtomic(&info->throttle_inflight_count[thread_throttle_level]);
2324 } else {
2325 microuptime(&info->throttle_window_start_timestamp[thread_throttle_level]);
2326 }
2327 KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_THROTTLE, OPEN_THROTTLE_WINDOW)) | DBG_FUNC_NONE,
2328 proc_getpid(current_proc()), thread_throttle_level, 0, 0, 0);
2329 }
2330 microuptime(&info->throttle_last_IO_timestamp[thread_throttle_level]);
2331 }
2332
2333
2334 if (thread_throttle_level >= THROTTLE_LEVEL_THROTTLED) {
2335 /*
2336 * I'd really like to do the IOSleep here, but
2337 * we may be holding all kinds of filesystem related locks
2338 * and the pages for this I/O marked 'busy'...
2339 * we don't want to cause a normal task to block on
2340 * one of these locks while we're throttling a task marked
2341 * for low priority I/O... we'll mark the uthread and
2342 * do the delay just before we return from the system
2343 * call that triggered this I/O or from vnode_pagein
2344 */
2345 OSAddAtomic(1, &info->throttle_io_count);
2346
2347 throttle_info_set_initial_window(ut, info, FALSE, isssd);
2348 }
2349
2350 return thread_throttle_level;
2351 }
2352
2353 void *
throttle_info_update_by_mount(mount_t mp)2354 throttle_info_update_by_mount(mount_t mp)
2355 {
2356 struct _throttle_io_info_t *info;
2357 uthread_t ut;
2358 boolean_t isssd = FALSE;
2359
2360 ut = current_uthread();
2361
2362 if (mp != NULL) {
2363 if (disk_conditioner_mount_is_ssd(mp)) {
2364 isssd = TRUE;
2365 }
2366 info = &_throttle_io_info[mp->mnt_devbsdunit];
2367 } else {
2368 info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
2369 }
2370
2371 if (!ut->uu_lowpri_window) {
2372 throttle_info_set_initial_window(ut, info, FALSE, isssd);
2373 }
2374
2375 return info;
2376 }
2377
2378
2379 /*
2380 * KPI routine
2381 *
2382 * this is usually called before every I/O, used for throttled I/O
2383 * book keeping. This routine has low overhead and does not sleep
2384 */
2385 void
throttle_info_update(void * throttle_info,int flags)2386 throttle_info_update(void *throttle_info, int flags)
2387 {
2388 if (throttle_info) {
2389 throttle_info_update_internal(throttle_info, NULL, flags, FALSE, FALSE, NULL);
2390 }
2391 }
2392
2393 /*
2394 * KPI routine (private)
2395 *
2396 * similar to throttle_info_update() but takes an additional argument to
2397 * indicate if the backing device type is SSD or not.
2398 */
2399 void
throttle_info_update_with_type(void * throttle_info,int flags,boolean_t isssd)2400 throttle_info_update_with_type(void *throttle_info, int flags, boolean_t isssd)
2401 {
2402 if (throttle_info) {
2403 throttle_info_update_internal(throttle_info, NULL, flags, isssd, FALSE, NULL);
2404 }
2405 }
2406
2407 /*
2408 * KPI routine
2409 *
2410 * this is usually called before every I/O, used for throttled I/O
2411 * book keeping. This routine has low overhead and does not sleep
2412 */
2413 void
throttle_info_update_by_mask(void * throttle_info_handle,int flags)2414 throttle_info_update_by_mask(void *throttle_info_handle, int flags)
2415 {
2416 void *throttle_info = throttle_info_handle;
2417
2418 /*
2419 * for now we only use the lowest bit of the throttle mask, so the
2420 * handle is the same as the throttle_info. Later if we store a
2421 * set of throttle infos in the handle, we will want to loop through
2422 * them and call throttle_info_update in a loop
2423 */
2424 throttle_info_update(throttle_info, flags);
2425 }
2426 /*
2427 * KPI routine
2428 *
2429 * This routine marks the throttle info as disabled. Used for mount points which
2430 * support I/O scheduling.
2431 */
2432
2433 void
throttle_info_disable_throttle(int devno,boolean_t isfusion)2434 throttle_info_disable_throttle(int devno, boolean_t isfusion)
2435 {
2436 struct _throttle_io_info_t *info;
2437
2438 if (devno < 0 || devno >= LOWPRI_MAX_NUM_DEV) {
2439 panic("Illegal devno (%d) passed into throttle_info_disable_throttle()", devno);
2440 }
2441
2442 info = &_throttle_io_info[devno];
2443 // don't disable software throttling on devices that are part of a fusion device
2444 // and override the software throttle periods to use HDD periods
2445 if (isfusion) {
2446 info->throttle_is_fusion_with_priority = isfusion;
2447 throttle_init_throttle_period(info, FALSE);
2448 }
2449 info->throttle_disabled = !info->throttle_is_fusion_with_priority;
2450 return;
2451 }
2452
2453
2454 /*
2455 * KPI routine (private)
2456 * Called to determine if this IO is being throttled to this level so that it can be treated specially
2457 */
2458 int
throttle_info_io_will_be_throttled(void * throttle_info,int policy)2459 throttle_info_io_will_be_throttled(void * throttle_info, int policy)
2460 {
2461 struct _throttle_io_info_t *info = throttle_info;
2462 struct timeval elapsed;
2463 uint64_t elapsed_msecs;
2464 int throttle_level;
2465 int thread_throttle_level;
2466
2467 switch (policy) {
2468 case IOPOL_THROTTLE:
2469 thread_throttle_level = THROTTLE_LEVEL_TIER3;
2470 break;
2471 case IOPOL_UTILITY:
2472 thread_throttle_level = THROTTLE_LEVEL_TIER2;
2473 break;
2474 case IOPOL_STANDARD:
2475 thread_throttle_level = THROTTLE_LEVEL_TIER1;
2476 break;
2477 default:
2478 thread_throttle_level = THROTTLE_LEVEL_TIER0;
2479 break;
2480 }
2481 for (throttle_level = THROTTLE_LEVEL_START; throttle_level < thread_throttle_level; throttle_level++) {
2482 if (info->throttle_inflight_count[throttle_level]) {
2483 break;
2484 }
2485
2486 microuptime(&elapsed);
2487 timevalsub(&elapsed, &info->throttle_window_start_timestamp[throttle_level]);
2488 elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
2489
2490 if (elapsed_msecs < (uint64_t)throttle_windows_msecs[thread_throttle_level]) {
2491 break;
2492 }
2493 }
2494 if (throttle_level >= thread_throttle_level) {
2495 /*
2496 * we're beyond all of the throttle windows
2497 * so go ahead and treat as normal I/O
2498 */
2499 return THROTTLE_DISENGAGED;
2500 }
2501 /*
2502 * we're in the throttle window
2503 */
2504 return THROTTLE_ENGAGED;
2505 }
2506
2507 int
throttle_lowpri_window(void)2508 throttle_lowpri_window(void)
2509 {
2510 return current_uthread()->uu_lowpri_window;
2511 }
2512
2513 #if CONFIG_PHYS_WRITE_ACCT
2514 extern thread_t pm_sync_thread;
2515 #endif /* CONFIG_PHYS_WRITE_ACCT */
2516
2517 int
spec_strategy(struct vnop_strategy_args * ap)2518 spec_strategy(struct vnop_strategy_args *ap)
2519 {
2520 buf_t bp;
2521 int bflags;
2522 int io_tier;
2523 int passive;
2524 dev_t bdev;
2525 uthread_t ut;
2526 vnode_t vp;
2527 mount_t mp;
2528 struct bufattr *bap;
2529 int strategy_ret;
2530 struct _throttle_io_info_t *throttle_info;
2531 boolean_t isssd = FALSE;
2532 boolean_t inflight = FALSE;
2533 boolean_t upgrade = FALSE;
2534 int code = 0;
2535
2536 #if CONFIG_DELAY_IDLE_SLEEP
2537 proc_t curproc = current_proc();
2538 #endif /* CONFIG_DELAY_IDLE_SLEEP */
2539
2540 bp = ap->a_bp;
2541 bdev = buf_device(bp);
2542 vp = buf_vnode(bp);
2543 mp = vp ? vp->v_mount : NULL;
2544 bap = &bp->b_attr;
2545
2546 #if CONFIG_PHYS_WRITE_ACCT
2547 if (current_thread() == pm_sync_thread) {
2548 OSAddAtomic64(buf_count(bp), (SInt64 *)&(kernel_pm_writes));
2549 }
2550 #endif /* CONFIG_PHYS_WRITE_ACCT */
2551
2552 #if CONFIG_IOSCHED
2553 if (bp->b_flags & B_CLUSTER) {
2554 io_tier = upl_get_cached_tier(bp->b_upl);
2555
2556 if (io_tier == -1) {
2557 io_tier = throttle_get_io_policy(&ut);
2558 }
2559 #if DEVELOPMENT || DEBUG
2560 else {
2561 int my_io_tier = throttle_get_io_policy(&ut);
2562
2563 if (io_tier != my_io_tier) {
2564 KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_THROTTLE, IO_TIER_UPL_MISMATCH)) | DBG_FUNC_NONE, buf_kernel_addrperm_addr(bp), my_io_tier, io_tier, 0, 0);
2565 }
2566 }
2567 #endif
2568 } else {
2569 io_tier = throttle_get_io_policy(&ut);
2570 }
2571 #else
2572 io_tier = throttle_get_io_policy(&ut);
2573 #endif
2574 passive = throttle_get_passive_io_policy(&ut);
2575
2576 /*
2577 * Mark if the I/O was upgraded by throttle_get_thread_throttle_level
2578 * while preserving the original issued tier (throttle_get_io_policy
2579 * does not return upgraded tiers)
2580 */
2581 if (mp && io_tier > throttle_get_thread_throttle_level_internal(ut, io_tier)) {
2582 #if CONFIG_IOSCHED
2583 if (!(mp->mnt_ioflags & MNT_IOFLAGS_IOSCHED_SUPPORTED)) {
2584 upgrade = TRUE;
2585 }
2586 #else /* CONFIG_IOSCHED */
2587 upgrade = TRUE;
2588 #endif /* CONFIG_IOSCHED */
2589 }
2590
2591 if (bp->b_flags & B_META) {
2592 bap->ba_flags |= BA_META;
2593 }
2594
2595 #if CONFIG_IOSCHED
2596 /*
2597 * For metadata reads, ceil the I/O tier to IOSCHED_METADATA_EXPEDITED_TIER if they are expedited, otherwise
2598 * ceil it to IOSCHED_METADATA_TIER. Mark them passive if the I/O tier was upgraded.
2599 * For metadata writes, set the I/O tier to IOSCHED_METADATA_EXPEDITED_TIER if they are expedited. Otherwise
2600 * set it to IOSCHED_METADATA_TIER. In addition, mark them as passive.
2601 */
2602 if (bap->ba_flags & BA_META) {
2603 if ((mp && (mp->mnt_ioflags & MNT_IOFLAGS_IOSCHED_SUPPORTED)) || (bap->ba_flags & BA_IO_SCHEDULED)) {
2604 if (bp->b_flags & B_READ) {
2605 if ((bap->ba_flags & BA_EXPEDITED_META_IO) && (io_tier > IOSCHED_METADATA_EXPEDITED_TIER)) {
2606 io_tier = IOSCHED_METADATA_EXPEDITED_TIER;
2607 passive = 1;
2608 } else if (io_tier > IOSCHED_METADATA_TIER) {
2609 io_tier = IOSCHED_METADATA_TIER;
2610 passive = 1;
2611 }
2612 } else {
2613 if (bap->ba_flags & BA_EXPEDITED_META_IO) {
2614 io_tier = IOSCHED_METADATA_EXPEDITED_TIER;
2615 } else {
2616 io_tier = IOSCHED_METADATA_TIER;
2617 }
2618 passive = 1;
2619 }
2620 }
2621 }
2622 #endif /* CONFIG_IOSCHED */
2623
2624 SET_BUFATTR_IO_TIER(bap, io_tier);
2625
2626 if (passive) {
2627 bp->b_flags |= B_PASSIVE;
2628 bap->ba_flags |= BA_PASSIVE;
2629 }
2630
2631 #if CONFIG_DELAY_IDLE_SLEEP
2632 if ((curproc != NULL) && ((curproc->p_flag & P_DELAYIDLESLEEP) == P_DELAYIDLESLEEP)) {
2633 bap->ba_flags |= BA_DELAYIDLESLEEP;
2634 }
2635 #endif /* CONFIG_DELAY_IDLE_SLEEP */
2636
2637 bflags = bp->b_flags;
2638
2639 if (((bflags & B_READ) == 0) && ((bflags & B_ASYNC) == 0)) {
2640 bufattr_markquickcomplete(bap);
2641 }
2642
2643 if (bflags & B_READ) {
2644 code |= DKIO_READ;
2645 }
2646 if (bflags & B_ASYNC) {
2647 code |= DKIO_ASYNC;
2648 }
2649
2650 if (bap->ba_flags & BA_META) {
2651 code |= DKIO_META;
2652 } else if (bflags & B_PAGEIO) {
2653 code |= DKIO_PAGING;
2654 }
2655
2656 if (io_tier != 0) {
2657 code |= DKIO_THROTTLE;
2658 }
2659
2660 code |= ((io_tier << DKIO_TIER_SHIFT) & DKIO_TIER_MASK);
2661
2662 if (bflags & B_PASSIVE) {
2663 code |= DKIO_PASSIVE;
2664 }
2665
2666 if (bap->ba_flags & BA_NOCACHE) {
2667 code |= DKIO_NOCACHE;
2668 }
2669
2670 if (upgrade) {
2671 code |= DKIO_TIER_UPGRADE;
2672 SET(bap->ba_flags, BA_IO_TIER_UPGRADE);
2673 }
2674
2675 if (kdebug_enable) {
2676 KERNEL_DEBUG_CONSTANT_IST(KDEBUG_COMMON, FSDBG_CODE(DBG_DKRW, code) | DBG_FUNC_NONE,
2677 buf_kernel_addrperm_addr(bp), bdev, buf_blkno(bp), buf_count(bp), 0);
2678 }
2679
2680 #if CONFIG_IO_COMPRESSION_STATS
2681 // Do not run IO Compression Stats when a privilege thread is active
2682 if (!is_vm_privileged() && !is_external_pageout_thread()) {
2683 io_compression_stats(bp);
2684 }
2685 #endif /* CONFIG_IO_COMPRESSION_STATS */
2686 thread_update_io_stats(current_thread(), buf_count(bp), code);
2687
2688 if (vp && (vp->v_type == VBLK || vp->v_type == VCHR)) {
2689 if (!vp->v_un.vu_specinfo->si_initted) {
2690 SPEC_INIT_BSDUNIT(vp, vfs_context_current());
2691 }
2692 if (vp->v_un.vu_specinfo->si_devbsdunit > (LOWPRI_MAX_NUM_DEV - 1)) {
2693 panic("Invalid value (%d) for si_devbsdunit for vnode %p",
2694 vp->v_un.vu_specinfo->si_devbsdunit, vp);
2695 }
2696 if (vp->v_un.vu_specinfo->si_isssd > 1) {
2697 panic("Invalid value (%d) for si_isssd for vnode %p",
2698 vp->v_un.vu_specinfo->si_isssd, vp);
2699 }
2700 throttle_info = &_throttle_io_info[vp->v_un.vu_specinfo->si_devbsdunit];
2701 isssd = vp->v_un.vu_specinfo->si_isssd;
2702 } else if (mp != NULL) {
2703 if (disk_conditioner_mount_is_ssd(mp)) {
2704 isssd = TRUE;
2705 }
2706 /*
2707 * Partially initialized mounts don't have a final devbsdunit and should not be tracked.
2708 * Verify that devbsdunit is initialized (non-zero) or that 0 is the correct initialized value
2709 * (mnt_throttle_mask is initialized and num_trailing_0 would be 0)
2710 */
2711 if (mp->mnt_devbsdunit || (mp->mnt_throttle_mask != LOWPRI_MAX_NUM_DEV - 1 && mp->mnt_throttle_mask & 0x1)) {
2712 inflight = TRUE;
2713 }
2714 throttle_info = &_throttle_io_info[mp->mnt_devbsdunit];
2715 } else {
2716 throttle_info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
2717 }
2718
2719 throttle_info_update_internal(throttle_info, ut, bflags, isssd, inflight, bap);
2720
2721 if ((bflags & B_READ) == 0) {
2722 microuptime(&throttle_info->throttle_last_write_timestamp);
2723
2724 if (!(vp && (vp->v_type == VBLK || vp->v_type == VCHR)) && mp) {
2725 mp->mnt_last_write_issued_timestamp = throttle_info->throttle_last_write_timestamp;
2726 INCR_PENDING_IO(buf_count(bp), mp->mnt_pending_write_size);
2727 }
2728 } else if (!(vp && (vp->v_type == VBLK || vp->v_type == VCHR)) && mp) {
2729 INCR_PENDING_IO(buf_count(bp), mp->mnt_pending_read_size);
2730 }
2731 /*
2732 * The BootCache may give us special information about
2733 * the IO, so it returns special values that we check
2734 * for here.
2735 *
2736 * IO_SATISFIED_BY_CACHE
2737 * The read has been satisfied by the boot cache. Don't
2738 * throttle the thread unnecessarily.
2739 *
2740 * IO_SHOULD_BE_THROTTLED
2741 * The boot cache is playing back a playlist and this IO
2742 * cut through. Throttle it so we're not cutting through
2743 * the boot cache too often.
2744 *
2745 * Note that typical strategy routines are defined with
2746 * a void return so we'll get garbage here. In the
2747 * unlikely case the garbage matches our special return
2748 * value, it's not a big deal since we're only adjusting
2749 * the throttling delay.
2750 */
2751 #define IO_SATISFIED_BY_CACHE ((int)0xcafefeed)
2752 #define IO_SHOULD_BE_THROTTLED ((int)0xcafebeef)
2753 #pragma clang diagnostic push
2754 #pragma clang diagnostic ignored "-Wcast-function-type"
2755
2756 typedef int strategy_fcn_ret_t(struct buf *bp);
2757
2758 strategy_ret = (*(strategy_fcn_ret_t*)bdevsw[major(bdev)].d_strategy)(bp);
2759
2760 #pragma clang diagnostic pop
2761
2762 // disk conditioner needs to track when this I/O actually starts
2763 // which means track it after `strategy` which may include delays
2764 // from inflight I/Os
2765 microuptime(&bp->b_timestamp_tv);
2766
2767 if (IO_SATISFIED_BY_CACHE == strategy_ret) {
2768 /*
2769 * If this was a throttled IO satisfied by the boot cache,
2770 * don't delay the thread.
2771 */
2772 throttle_info_reset_window(ut);
2773 } else if (IO_SHOULD_BE_THROTTLED == strategy_ret) {
2774 /*
2775 * If the boot cache indicates this IO should be throttled,
2776 * delay the thread.
2777 */
2778 throttle_info_set_initial_window(ut, throttle_info, TRUE, isssd);
2779 }
2780 return 0;
2781 }
2782
2783
2784 /*
2785 * This is a noop, simply returning what one has been given.
2786 */
2787 int
spec_blockmap(__unused struct vnop_blockmap_args * ap)2788 spec_blockmap(__unused struct vnop_blockmap_args *ap)
2789 {
2790 return ENOTSUP;
2791 }
2792
2793 static int
spec_close_internal(struct vnode * vp,dev_t dev,int flags,vfs_context_t ctx)2794 spec_close_internal(struct vnode *vp, dev_t dev, int flags, vfs_context_t ctx)
2795 {
2796 int error = 0;
2797 struct proc *p = vfs_context_proc(ctx);
2798 struct session *sessp;
2799 struct pgrp *pg;
2800
2801 switch (vp->v_type) {
2802 case VCHR:
2803 /*
2804 * Hack: a tty device that is a controlling terminal
2805 * has a reference from the session structure.
2806 * We cannot easily tell that a character device is
2807 * a controlling terminal, unless it is the closing
2808 * process' controlling terminal. In that case,
2809 * if the reference count is 1 (this is the very
2810 * last close)
2811 */
2812 pg = proc_pgrp(p, &sessp);
2813 devsw_lock(dev, S_IFCHR);
2814 if (sessp != SESSION_NULL) {
2815 if (vp == sessp->s_ttyvp && vcount(vp) == 1) {
2816 struct tty *tp = TTY_NULL;
2817
2818 devsw_unlock(dev, S_IFCHR);
2819 session_lock(sessp);
2820 if (vp == sessp->s_ttyvp) {
2821 tp = session_clear_tty_locked(sessp);
2822 }
2823 session_unlock(sessp);
2824
2825 if (tp != TTY_NULL) {
2826 ttyfree(tp);
2827 }
2828 devsw_lock(dev, S_IFCHR);
2829 }
2830 }
2831 pgrp_rele(pg);
2832
2833 if (--vp->v_specinfo->si_opencount < 0) {
2834 panic("negative open count (c, %u, %u)", major(dev), minor(dev));
2835 }
2836
2837 /*
2838 * close on last reference or on vnode revoke call
2839 */
2840 if (vcount(vp) == 0 || (flags & IO_REVOKE) != 0) {
2841 error = cdevsw[major(dev)].d_close(dev, flags, S_IFCHR, p);
2842 }
2843
2844 devsw_unlock(dev, S_IFCHR);
2845 break;
2846
2847 case VBLK:
2848 /*
2849 * If there is more than one outstanding open, don't
2850 * send the close to the device.
2851 */
2852 devsw_lock(dev, S_IFBLK);
2853 if (vcount(vp) > 1) {
2854 vp->v_specinfo->si_opencount--;
2855 devsw_unlock(dev, S_IFBLK);
2856 return 0;
2857 }
2858 devsw_unlock(dev, S_IFBLK);
2859
2860 /*
2861 * On last close of a block device (that isn't mounted)
2862 * we must invalidate any in core blocks, so that
2863 * we can, for instance, change floppy disks.
2864 */
2865 if ((error = spec_fsync_internal(vp, MNT_WAIT, ctx))) {
2866 return error;
2867 }
2868
2869 error = buf_invalidateblks(vp, BUF_WRITE_DATA, 0, 0);
2870 if (error) {
2871 return error;
2872 }
2873
2874 devsw_lock(dev, S_IFBLK);
2875
2876 if (--vp->v_specinfo->si_opencount < 0) {
2877 panic("negative open count (b, %u, %u)", major(dev), minor(dev));
2878 }
2879
2880 if (vcount(vp) == 0) {
2881 error = bdevsw[major(dev)].d_close(dev, flags, S_IFBLK, p);
2882 }
2883
2884 devsw_unlock(dev, S_IFBLK);
2885 break;
2886
2887 default:
2888 panic("spec_close: not special");
2889 return EBADF;
2890 }
2891
2892 return error;
2893 }
2894
2895 /*
2896 * Device close routine
2897 */
2898 int
spec_close(struct vnop_close_args * ap)2899 spec_close(struct vnop_close_args *ap)
2900 {
2901 return spec_close_internal(ap->a_vp, ap->a_vp->v_rdev, ap->a_fflag, ap->a_context);
2902 }
2903
2904 /*
2905 * Return POSIX pathconf information applicable to special devices.
2906 */
2907 int
spec_pathconf(struct vnop_pathconf_args * ap)2908 spec_pathconf(struct vnop_pathconf_args *ap)
2909 {
2910 switch (ap->a_name) {
2911 case _PC_LINK_MAX:
2912 *ap->a_retval = LINK_MAX;
2913 return 0;
2914 case _PC_MAX_CANON:
2915 *ap->a_retval = MAX_CANON;
2916 return 0;
2917 case _PC_MAX_INPUT:
2918 *ap->a_retval = MAX_INPUT;
2919 return 0;
2920 case _PC_PIPE_BUF:
2921 *ap->a_retval = PIPE_BUF;
2922 return 0;
2923 case _PC_CHOWN_RESTRICTED:
2924 *ap->a_retval = 200112; /* _POSIX_CHOWN_RESTRICTED */
2925 return 0;
2926 case _PC_VDISABLE:
2927 *ap->a_retval = _POSIX_VDISABLE;
2928 return 0;
2929 default:
2930 return EINVAL;
2931 }
2932 /* NOTREACHED */
2933 }
2934
2935 /*
2936 * Special device failed operation
2937 */
2938 int
spec_ebadf(__unused void * dummy)2939 spec_ebadf(__unused void *dummy)
2940 {
2941 return EBADF;
2942 }
2943
2944 /* Blktooff derives file offset from logical block number */
2945 int
spec_blktooff(struct vnop_blktooff_args * ap)2946 spec_blktooff(struct vnop_blktooff_args *ap)
2947 {
2948 struct vnode *vp = ap->a_vp;
2949
2950 switch (vp->v_type) {
2951 case VCHR:
2952 *ap->a_offset = (off_t)-1; /* failure */
2953 return ENOTSUP;
2954
2955 case VBLK:
2956 printf("spec_blktooff: not implemented for VBLK\n");
2957 *ap->a_offset = (off_t)-1; /* failure */
2958 return ENOTSUP;
2959
2960 default:
2961 panic("spec_blktooff type");
2962 }
2963 /* NOTREACHED */
2964
2965 return 0;
2966 }
2967
2968 /* Offtoblk derives logical block number from file offset */
2969 int
spec_offtoblk(struct vnop_offtoblk_args * ap)2970 spec_offtoblk(struct vnop_offtoblk_args *ap)
2971 {
2972 struct vnode *vp = ap->a_vp;
2973
2974 switch (vp->v_type) {
2975 case VCHR:
2976 *ap->a_lblkno = (daddr64_t)-1; /* failure */
2977 return ENOTSUP;
2978
2979 case VBLK:
2980 printf("spec_offtoblk: not implemented for VBLK\n");
2981 *ap->a_lblkno = (daddr64_t)-1; /* failure */
2982 return ENOTSUP;
2983
2984 default:
2985 panic("spec_offtoblk type");
2986 }
2987 /* NOTREACHED */
2988
2989 return 0;
2990 }
2991
2992 static int filt_specattach(struct knote *kn, struct kevent_qos_s *kev);
2993 static void filt_specdetach(struct knote *kn);
2994 static int filt_specevent(struct knote *kn, long hint);
2995 static int filt_spectouch(struct knote *kn, struct kevent_qos_s *kev);
2996 static int filt_specprocess(struct knote *kn, struct kevent_qos_s *kev);
2997
2998 SECURITY_READ_ONLY_EARLY(struct filterops) spec_filtops = {
2999 .f_isfd = 1,
3000 .f_attach = filt_specattach,
3001 .f_detach = filt_specdetach,
3002 .f_event = filt_specevent,
3003 .f_touch = filt_spectouch,
3004 .f_process = filt_specprocess,
3005 };
3006
3007 static void
filt_spec_make_eof(struct knote * kn)3008 filt_spec_make_eof(struct knote *kn)
3009 {
3010 /*
3011 * The spec filter might touch kn_flags from f_event
3012 * without holding "the primitive lock", so make it atomic.
3013 */
3014 os_atomic_or(&kn->kn_flags, EV_EOF | EV_ONESHOT, relaxed);
3015 }
3016
3017 static int
filt_spec_common(struct knote * kn,struct kevent_qos_s * kev,bool attach)3018 filt_spec_common(struct knote *kn, struct kevent_qos_s *kev, bool attach)
3019 {
3020 uthread_t uth = current_uthread();
3021 vfs_context_t ctx = vfs_context_current();
3022 vnode_t vp = (vnode_t)fp_get_data(kn->kn_fp);
3023 __block bool selrecorded = false;
3024 struct select_set *old_wqs;
3025 int64_t data = 0;
3026 int ret, selret;
3027
3028 if (kn->kn_flags & EV_EOF) {
3029 ret = FILTER_ACTIVE;
3030 goto out;
3031 }
3032
3033 if (!attach && vnode_getwithvid(vp, vnode_vid(vp)) != 0) {
3034 filt_spec_make_eof(kn);
3035 ret = FILTER_ACTIVE;
3036 goto out;
3037 }
3038
3039 selspec_record_hook_t cb = ^(struct selinfo *si) {
3040 selspec_attach(kn, si);
3041 selrecorded = true;
3042 };
3043
3044 old_wqs = uth->uu_selset;
3045 uth->uu_selset = SELSPEC_RECORD_MARKER;
3046 selret = VNOP_SELECT(vp, knote_get_seltype(kn), 0, cb, ctx);
3047 uth->uu_selset = old_wqs;
3048
3049 if (!attach) {
3050 vnode_put(vp);
3051 }
3052
3053 if (!selrecorded && selret == 0) {
3054 /*
3055 * The device indicated that there's no data to read,
3056 * but didn't call `selrecord`.
3057 *
3058 * Nothing will be notified of changes to this vnode,
3059 * so return an error back to user space on attach,
3060 * or pretend the knote disappeared for other cases,
3061 * to make it clear that the knote is not attached.
3062 */
3063 if (attach) {
3064 knote_set_error(kn, ENODEV);
3065 return 0;
3066 }
3067
3068 filt_spec_make_eof(kn);
3069 ret = FILTER_ACTIVE;
3070 goto out;
3071 }
3072
3073 if (kn->kn_vnode_use_ofst) {
3074 if (kn->kn_fp->fp_glob->fg_offset >= (uint32_t)selret) {
3075 data = 0;
3076 } else {
3077 data = ((uint32_t)selret) - kn->kn_fp->fp_glob->fg_offset;
3078 }
3079 } else {
3080 data = selret;
3081 }
3082
3083 if (data >= knote_low_watermark(kn)) {
3084 ret = FILTER_ACTIVE;
3085 } else {
3086 ret = 0;
3087 }
3088 out:
3089 if (ret) {
3090 knote_fill_kevent(kn, kev, data);
3091 }
3092 return ret;
3093 }
3094
3095 static int
filt_specattach(struct knote * kn,__unused struct kevent_qos_s * kev)3096 filt_specattach(struct knote *kn, __unused struct kevent_qos_s *kev)
3097 {
3098 vnode_t vp = (vnode_t)fp_get_data(kn->kn_fp); /* Already have iocount, and vnode is alive */
3099 dev_t dev;
3100
3101 assert(vnode_ischr(vp));
3102
3103 dev = vnode_specrdev(vp);
3104
3105 /*
3106 * For a few special kinds of devices, we can attach knotes with
3107 * no restrictions because their "select" vectors return the amount
3108 * of data available. Others require an explicit NOTE_LOWAT with
3109 * data of 1, indicating that the caller doesn't care about actual
3110 * data counts, just an indication that the device has data.
3111 */
3112 if (!kn->kn_vnode_kqok &&
3113 ((kn->kn_sfflags & NOTE_LOWAT) == 0 || kn->kn_sdata != 1)) {
3114 knote_set_error(kn, EINVAL);
3115 return 0;
3116 }
3117
3118 return filt_spec_common(kn, kev, true);
3119 }
3120
3121 static void
filt_specdetach(struct knote * kn)3122 filt_specdetach(struct knote *kn)
3123 {
3124 selspec_detach(kn);
3125 }
3126
3127 static int
filt_specevent(struct knote * kn,long hint)3128 filt_specevent(struct knote *kn, long hint)
3129 {
3130 /* Due to selwakeup_internal() on SI_SELSPEC */
3131 assert(KNOTE_IS_AUTODETACHED(kn));
3132 knote_kn_hook_set_raw(kn, NULL);
3133
3134 /* called by selwakeup with the selspec_lock lock held */
3135 if (hint & NOTE_REVOKE) {
3136 filt_spec_make_eof(kn);
3137 }
3138 return FILTER_ACTIVE;
3139 }
3140
3141 static int
filt_spectouch(struct knote * kn,struct kevent_qos_s * kev)3142 filt_spectouch(struct knote *kn, struct kevent_qos_s *kev)
3143 {
3144 kn->kn_sdata = kev->data;
3145 kn->kn_sfflags = kev->fflags;
3146
3147 return filt_spec_common(kn, kev, false);
3148 }
3149
3150 static int
filt_specprocess(struct knote * kn,struct kevent_qos_s * kev)3151 filt_specprocess(struct knote *kn, struct kevent_qos_s *kev)
3152 {
3153 return filt_spec_common(kn, kev, false);
3154 }
3155