1/*- 2 * Copyright (c) 1997, 1998, 1999 Kenneth D. Merry. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29#include <sys/cdefs.h> 30__FBSDID("$FreeBSD$"); 31 32#include "opt_kdtrace.h" 33 34#include <sys/param.h> 35#include <sys/kernel.h> 36#include <sys/systm.h> 37#include <sys/bio.h> 38#include <sys/devicestat.h> 39#include <sys/sdt.h> 40#include <sys/sysctl.h> 41#include <sys/malloc.h> 42#include <sys/lock.h> 43#include <sys/mutex.h> 44#include <sys/conf.h> 45#include <vm/vm.h> 46#include <vm/pmap.h> 47 48#include <machine/atomic.h> 49 50SDT_PROVIDER_DEFINE(io); 51 52SDT_PROBE_DEFINE2(io, , , start, "struct bio *", "struct devstat *"); 53SDT_PROBE_DEFINE2(io, , , done, "struct bio *", "struct devstat *"); 54SDT_PROBE_DEFINE2(io, , , wait__start, "struct bio *", 55 "struct devstat *"); 56SDT_PROBE_DEFINE2(io, , , wait__done, "struct bio *", 57 "struct devstat *"); 58 59#define DTRACE_DEVSTAT_START() SDT_PROBE2(io, , , start, NULL, ds) 60#define DTRACE_DEVSTAT_BIO_START() SDT_PROBE2(io, , , start, bp, ds) 61#define DTRACE_DEVSTAT_DONE() SDT_PROBE2(io, , , done, NULL, ds) 62#define DTRACE_DEVSTAT_BIO_DONE() SDT_PROBE2(io, , , done, bp, ds) 63#define DTRACE_DEVSTAT_WAIT_START() SDT_PROBE2(io, , , wait__start, NULL, ds) 64#define DTRACE_DEVSTAT_WAIT_DONE() SDT_PROBE2(io, , , wait__done, NULL, ds) 65 66static int devstat_num_devs; 67static long devstat_generation = 1; 68static int devstat_version = DEVSTAT_VERSION; 69static int devstat_current_devnumber; 70static struct mtx devstat_mutex; 71MTX_SYSINIT(devstat_mutex, &devstat_mutex, "devstat", MTX_DEF); 72 73static struct devstatlist device_statq = STAILQ_HEAD_INITIALIZER(device_statq); 74static struct devstat *devstat_alloc(void); 75static void devstat_free(struct devstat *); 76static void devstat_add_entry(struct devstat *ds, const void *dev_name, 77 int unit_number, uint32_t block_size, 78 devstat_support_flags flags, 79 devstat_type_flags device_type, 80 devstat_priority priority); 81 82/* 83 * Allocate a devstat and initialize it 84 */ 85struct devstat * 86devstat_new_entry(const void *dev_name, 87 int unit_number, uint32_t block_size, 88 devstat_support_flags flags, 89 devstat_type_flags device_type, 90 devstat_priority priority) 91{ 92 struct devstat *ds; 93 94 mtx_assert(&devstat_mutex, MA_NOTOWNED); 95 96 ds = devstat_alloc(); 97 mtx_lock(&devstat_mutex); 98 if (unit_number == -1) { 99 ds->unit_number = unit_number; 100 ds->id = dev_name; 101 binuptime(&ds->creation_time); 102 devstat_generation++; 103 } else { 104 devstat_add_entry(ds, dev_name, unit_number, block_size, 105 flags, device_type, priority); 106 } 107 mtx_unlock(&devstat_mutex); 108 return (ds); 109} 110 111/* 112 * Take a malloced and zeroed devstat structure given to us, fill it in 113 * and add it to the queue of devices. 114 */ 115static void 116devstat_add_entry(struct devstat *ds, const void *dev_name, 117 int unit_number, uint32_t block_size, 118 devstat_support_flags flags, 119 devstat_type_flags device_type, 120 devstat_priority priority) 121{ 122 struct devstatlist *devstat_head; 123 struct devstat *ds_tmp; 124 125 mtx_assert(&devstat_mutex, MA_OWNED); 126 devstat_num_devs++; 127 128 devstat_head = &device_statq; 129 130 /* 131 * Priority sort. Each driver passes in its priority when it adds 132 * its devstat entry. Drivers are sorted first by priority, and 133 * then by probe order. 134 * 135 * For the first device, we just insert it, since the priority 136 * doesn't really matter yet. Subsequent devices are inserted into 137 * the list using the order outlined above. 138 */ 139 if (devstat_num_devs == 1) 140 STAILQ_INSERT_TAIL(devstat_head, ds, dev_links); 141 else { 142 STAILQ_FOREACH(ds_tmp, devstat_head, dev_links) { 143 struct devstat *ds_next; 144 145 ds_next = STAILQ_NEXT(ds_tmp, dev_links); 146 147 /* 148 * If we find a break between higher and lower 149 * priority items, and if this item fits in the 150 * break, insert it. This also applies if the 151 * "lower priority item" is the end of the list. 152 */ 153 if ((priority <= ds_tmp->priority) 154 && ((ds_next == NULL) 155 || (priority > ds_next->priority))) { 156 STAILQ_INSERT_AFTER(devstat_head, ds_tmp, ds, 157 dev_links); 158 break; 159 } else if (priority > ds_tmp->priority) { 160 /* 161 * If this is the case, we should be able 162 * to insert ourselves at the head of the 163 * list. If we can't, something is wrong. 164 */ 165 if (ds_tmp == STAILQ_FIRST(devstat_head)) { 166 STAILQ_INSERT_HEAD(devstat_head, 167 ds, dev_links); 168 break; 169 } else { 170 STAILQ_INSERT_TAIL(devstat_head, 171 ds, dev_links); 172 printf("devstat_add_entry: HELP! " 173 "sorting problem detected " 174 "for name %p unit %d\n", 175 dev_name, unit_number); 176 break; 177 } 178 } 179 } 180 } 181 182 ds->device_number = devstat_current_devnumber++; 183 ds->unit_number = unit_number; 184 strlcpy(ds->device_name, dev_name, DEVSTAT_NAME_LEN); 185 ds->block_size = block_size; 186 ds->flags = flags; 187 ds->device_type = device_type; 188 ds->priority = priority; 189 binuptime(&ds->creation_time); 190 devstat_generation++; 191} 192 193/* 194 * Remove a devstat structure from the list of devices. 195 */ 196void 197devstat_remove_entry(struct devstat *ds) 198{ 199 struct devstatlist *devstat_head; 200 201 mtx_assert(&devstat_mutex, MA_NOTOWNED); 202 if (ds == NULL) 203 return; 204 205 mtx_lock(&devstat_mutex); 206 207 devstat_head = &device_statq; 208 209 /* Remove this entry from the devstat queue */ 210 atomic_add_acq_int(&ds->sequence1, 1); 211 if (ds->unit_number != -1) { 212 devstat_num_devs--; 213 STAILQ_REMOVE(devstat_head, ds, devstat, dev_links); 214 } 215 devstat_free(ds); 216 devstat_generation++; 217 mtx_unlock(&devstat_mutex); 218} 219 220/* 221 * Record a transaction start. 222 * 223 * See comments for devstat_end_transaction(). Ordering is very important 224 * here. 225 */ 226void 227devstat_start_transaction(struct devstat *ds, struct bintime *now) 228{ 229 230 mtx_assert(&devstat_mutex, MA_NOTOWNED); 231 232 /* sanity check */ 233 if (ds == NULL) 234 return; 235 236 atomic_add_acq_int(&ds->sequence1, 1); 237 /* 238 * We only want to set the start time when we are going from idle 239 * to busy. The start time is really the start of the latest busy 240 * period. 241 */ 242 if (ds->start_count == ds->end_count) { 243 if (now != NULL) 244 ds->busy_from = *now; 245 else 246 binuptime(&ds->busy_from); 247 } 248 ds->start_count++; 249 atomic_add_rel_int(&ds->sequence0, 1); 250 DTRACE_DEVSTAT_START(); 251} 252 253void 254devstat_start_transaction_bio(struct devstat *ds, struct bio *bp) 255{ 256 257 mtx_assert(&devstat_mutex, MA_NOTOWNED); 258 259 /* sanity check */ 260 if (ds == NULL) 261 return; 262 263 binuptime(&bp->bio_t0); 264 devstat_start_transaction(ds, &bp->bio_t0); 265 DTRACE_DEVSTAT_BIO_START(); 266} 267 268/* 269 * Record the ending of a transaction, and incrment the various counters. 270 * 271 * Ordering in this function, and in devstat_start_transaction() is VERY 272 * important. The idea here is to run without locks, so we are very 273 * careful to only modify some fields on the way "down" (i.e. at 274 * transaction start) and some fields on the way "up" (i.e. at transaction 275 * completion). One exception is busy_from, which we only modify in 276 * devstat_start_transaction() when there are no outstanding transactions, 277 * and thus it can't be modified in devstat_end_transaction() 278 * simultaneously. 279 * 280 * The sequence0 and sequence1 fields are provided to enable an application 281 * spying on the structures with mmap(2) to tell when a structure is in a 282 * consistent state or not. 283 * 284 * For this to work 100% reliably, it is important that the two fields 285 * are at opposite ends of the structure and that they are incremented 286 * in the opposite order of how a memcpy(3) in userland would copy them. 287 * We assume that the copying happens front to back, but there is actually 288 * no way short of writing your own memcpy(3) replacement to guarantee 289 * this will be the case. 290 * 291 * In addition to this, being a kind of locks, they must be updated with 292 * atomic instructions using appropriate memory barriers. 293 */ 294void 295devstat_end_transaction(struct devstat *ds, uint32_t bytes, 296 devstat_tag_type tag_type, devstat_trans_flags flags, 297 struct bintime *now, struct bintime *then) 298{ 299 struct bintime dt, lnow; 300 301 /* sanity check */ 302 if (ds == NULL) 303 return; 304 305 if (now == NULL) { 306 now = &lnow; 307 binuptime(now); 308 } 309 310 atomic_add_acq_int(&ds->sequence1, 1); 311 /* Update byte and operations counts */ 312 ds->bytes[flags] += bytes; 313 ds->operations[flags]++; 314 315 /* 316 * Keep a count of the various tag types sent. 317 */ 318 if ((ds->flags & DEVSTAT_NO_ORDERED_TAGS) == 0 && 319 tag_type != DEVSTAT_TAG_NONE) 320 ds->tag_types[tag_type]++; 321 322 if (then != NULL) { 323 /* Update duration of operations */ 324 dt = *now; 325 bintime_sub(&dt, then); 326 bintime_add(&ds->duration[flags], &dt); 327 } 328 329 /* Accumulate busy time */ 330 dt = *now; 331 bintime_sub(&dt, &ds->busy_from); 332 bintime_add(&ds->busy_time, &dt); 333 ds->busy_from = *now; 334 335 ds->end_count++; 336 atomic_add_rel_int(&ds->sequence0, 1); 337 DTRACE_DEVSTAT_DONE(); 338} 339 340void 341devstat_end_transaction_bio(struct devstat *ds, struct bio *bp) 342{ 343 344 devstat_end_transaction_bio_bt(ds, bp, NULL); 345} 346 347void 348devstat_end_transaction_bio_bt(struct devstat *ds, struct bio *bp, 349 struct bintime *now) 350{ 351 devstat_trans_flags flg; 352 353 /* sanity check */ 354 if (ds == NULL) 355 return; 356 357 if (bp->bio_cmd == BIO_DELETE) 358 flg = DEVSTAT_FREE; 359 else if (bp->bio_cmd == BIO_READ) 360 flg = DEVSTAT_READ; 361 else if (bp->bio_cmd == BIO_WRITE) 362 flg = DEVSTAT_WRITE; 363 else 364 flg = DEVSTAT_NO_DATA; 365 366 devstat_end_transaction(ds, bp->bio_bcount - bp->bio_resid, 367 DEVSTAT_TAG_SIMPLE, flg, now, &bp->bio_t0); 368 DTRACE_DEVSTAT_BIO_DONE(); 369} 370 371/* 372 * This is the sysctl handler for the devstat package. The data pushed out 373 * on the kern.devstat.all sysctl variable consists of the current devstat 374 * generation number, and then an array of devstat structures, one for each 375 * device in the system. 376 * 377 * This is more cryptic that obvious, but basically we neither can nor 378 * want to hold the devstat_mutex for any amount of time, so we grab it 379 * only when we need to and keep an eye on devstat_generation all the time. 380 */ 381static int 382sysctl_devstat(SYSCTL_HANDLER_ARGS) 383{ 384 int error; 385 long mygen; 386 struct devstat *nds; 387 388 mtx_assert(&devstat_mutex, MA_NOTOWNED); 389 390 /* 391 * XXX devstat_generation should really be "volatile" but that 392 * XXX freaks out the sysctl macro below. The places where we 393 * XXX change it and inspect it are bracketed in the mutex which 394 * XXX guarantees us proper write barriers. I don't believe the 395 * XXX compiler is allowed to optimize mygen away across calls 396 * XXX to other functions, so the following is belived to be safe. 397 */ 398 mygen = devstat_generation; 399 400 error = SYSCTL_OUT(req, &mygen, sizeof(mygen)); 401 402 if (devstat_num_devs == 0) 403 return(0); 404 405 if (error != 0) 406 return (error); 407 408 mtx_lock(&devstat_mutex); 409 nds = STAILQ_FIRST(&device_statq); 410 if (mygen != devstat_generation) 411 error = EBUSY; 412 mtx_unlock(&devstat_mutex); 413 414 if (error != 0) 415 return (error); 416 417 for (;nds != NULL;) { 418 error = SYSCTL_OUT(req, nds, sizeof(struct devstat)); 419 if (error != 0) 420 return (error); 421 mtx_lock(&devstat_mutex); 422 if (mygen != devstat_generation) 423 error = EBUSY; 424 else 425 nds = STAILQ_NEXT(nds, dev_links); 426 mtx_unlock(&devstat_mutex); 427 if (error != 0) 428 return (error); 429 } 430 return(error); 431} 432 433/* 434 * Sysctl entries for devstat. The first one is a node that all the rest 435 * hang off of. 436 */ 437static SYSCTL_NODE(_kern, OID_AUTO, devstat, CTLFLAG_RD, NULL, 438 "Device Statistics"); 439 440SYSCTL_PROC(_kern_devstat, OID_AUTO, all, CTLFLAG_RD|CTLTYPE_OPAQUE, 441 NULL, 0, sysctl_devstat, "S,devstat", "All devices in the devstat list"); 442/* 443 * Export the number of devices in the system so that userland utilities 444 * can determine how much memory to allocate to hold all the devices. 445 */ 446SYSCTL_INT(_kern_devstat, OID_AUTO, numdevs, CTLFLAG_RD, 447 &devstat_num_devs, 0, "Number of devices in the devstat list"); 448SYSCTL_LONG(_kern_devstat, OID_AUTO, generation, CTLFLAG_RD, 449 &devstat_generation, 0, "Devstat list generation"); 450SYSCTL_INT(_kern_devstat, OID_AUTO, version, CTLFLAG_RD, 451 &devstat_version, 0, "Devstat list version number"); 452 453/* 454 * Allocator for struct devstat structures. We sub-allocate these from pages 455 * which we get from malloc. These pages are exported for mmap(2)'ing through 456 * a miniature device driver 457 */ 458 459#define statsperpage (PAGE_SIZE / sizeof(struct devstat)) 460 461static d_mmap_t devstat_mmap; 462 463static struct cdevsw devstat_cdevsw = { 464 .d_version = D_VERSION, 465 .d_mmap = devstat_mmap, 466 .d_name = "devstat", 467}; 468 469struct statspage { 470 TAILQ_ENTRY(statspage) list; 471 struct devstat *stat; 472 u_int nfree; 473}; 474 475static TAILQ_HEAD(, statspage) pagelist = TAILQ_HEAD_INITIALIZER(pagelist); 476static MALLOC_DEFINE(M_DEVSTAT, "devstat", "Device statistics"); 477 478static int 479devstat_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr, 480 int nprot, vm_memattr_t *memattr) 481{ 482 struct statspage *spp; 483 484 if (nprot != VM_PROT_READ) 485 return (-1); 486 mtx_lock(&devstat_mutex); 487 TAILQ_FOREACH(spp, &pagelist, list) { 488 if (offset == 0) { 489 *paddr = vtophys(spp->stat); 490 mtx_unlock(&devstat_mutex); 491 return (0); 492 } 493 offset -= PAGE_SIZE; 494 } 495 mtx_unlock(&devstat_mutex); 496 return (-1); 497} 498 499static struct devstat * 500devstat_alloc(void) 501{ 502 struct devstat *dsp; 503 struct statspage *spp, *spp2; 504 u_int u; 505 static int once; 506 507 mtx_assert(&devstat_mutex, MA_NOTOWNED); 508 if (!once) { 509 make_dev_credf(MAKEDEV_ETERNAL | MAKEDEV_CHECKNAME, 510 &devstat_cdevsw, 0, NULL, UID_ROOT, GID_WHEEL, 0444, 511 DEVSTAT_DEVICE_NAME); 512 once = 1; 513 } 514 spp2 = NULL; 515 mtx_lock(&devstat_mutex); 516 for (;;) { 517 TAILQ_FOREACH(spp, &pagelist, list) { 518 if (spp->nfree > 0) 519 break; 520 } 521 if (spp != NULL) 522 break; 523 mtx_unlock(&devstat_mutex); 524 spp2 = malloc(sizeof *spp, M_DEVSTAT, M_ZERO | M_WAITOK); 525 spp2->stat = malloc(PAGE_SIZE, M_DEVSTAT, M_ZERO | M_WAITOK); 526 spp2->nfree = statsperpage; 527 528 /* 529 * If free statspages were added while the lock was released 530 * just reuse them. 531 */ 532 mtx_lock(&devstat_mutex); 533 TAILQ_FOREACH(spp, &pagelist, list) 534 if (spp->nfree > 0) 535 break; 536 if (spp == NULL) { 537 spp = spp2; 538 539 /* 540 * It would make more sense to add the new page at the 541 * head but the order on the list determine the 542 * sequence of the mapping so we can't do that. 543 */ 544 TAILQ_INSERT_TAIL(&pagelist, spp, list); 545 } else 546 break; 547 } 548 dsp = spp->stat; 549 for (u = 0; u < statsperpage; u++) { 550 if (dsp->allocated == 0) 551 break; 552 dsp++; 553 } 554 spp->nfree--; 555 dsp->allocated = 1; 556 mtx_unlock(&devstat_mutex); 557 if (spp2 != NULL && spp2 != spp) { 558 free(spp2->stat, M_DEVSTAT); 559 free(spp2, M_DEVSTAT); 560 } 561 return (dsp); 562} 563 564static void 565devstat_free(struct devstat *dsp) 566{ 567 struct statspage *spp; 568 569 mtx_assert(&devstat_mutex, MA_OWNED); 570 bzero(dsp, sizeof *dsp); 571 TAILQ_FOREACH(spp, &pagelist, list) { 572 if (dsp >= spp->stat && dsp < (spp->stat + statsperpage)) { 573 spp->nfree++; 574 return; 575 } 576 } 577} 578 579SYSCTL_INT(_debug_sizeof, OID_AUTO, devstat, CTLFLAG_RD, 580 SYSCTL_NULL_INT_PTR, sizeof(struct devstat), "sizeof(struct devstat)"); 581