| 1 | /* $NetBSD: rf_sstf.c,v 1.16 2009/03/14 15:36:20 dsl Exp $ */ |
| 2 | /* |
| 3 | * Copyright (c) 1995 Carnegie-Mellon University. |
| 4 | * All rights reserved. |
| 5 | * |
| 6 | * Author: Jim Zelenka |
| 7 | * |
| 8 | * Permission to use, copy, modify and distribute this software and |
| 9 | * its documentation is hereby granted, provided that both the copyright |
| 10 | * notice and this permission notice appear in all copies of the |
| 11 | * software, derivative works or modified versions, and any portions |
| 12 | * thereof, and that both notices appear in supporting documentation. |
| 13 | * |
| 14 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" |
| 15 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND |
| 16 | * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. |
| 17 | * |
| 18 | * Carnegie Mellon requests users of this software to return to |
| 19 | * |
| 20 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU |
| 21 | * School of Computer Science |
| 22 | * Carnegie Mellon University |
| 23 | * Pittsburgh PA 15213-3890 |
| 24 | * |
| 25 | * any improvements or extensions that they make and grant Carnegie the |
| 26 | * rights to redistribute these changes. |
| 27 | */ |
| 28 | |
| 29 | /******************************************************************************* |
| 30 | * |
| 31 | * sstf.c -- prioritized shortest seek time first disk queueing code |
| 32 | * |
| 33 | ******************************************************************************/ |
| 34 | |
| 35 | #include <sys/cdefs.h> |
| 36 | __KERNEL_RCSID(0, "$NetBSD: rf_sstf.c,v 1.16 2009/03/14 15:36:20 dsl Exp $" ); |
| 37 | |
| 38 | #include <dev/raidframe/raidframevar.h> |
| 39 | |
| 40 | #include "rf_alloclist.h" |
| 41 | #include "rf_stripelocks.h" |
| 42 | #include "rf_layout.h" |
| 43 | #include "rf_diskqueue.h" |
| 44 | #include "rf_sstf.h" |
| 45 | #include "rf_debugMem.h" |
| 46 | #include "rf_general.h" |
| 47 | #include "rf_options.h" |
| 48 | #include "rf_raid.h" |
| 49 | |
| 50 | #define DIR_LEFT 1 |
| 51 | #define DIR_RIGHT 2 |
| 52 | #define DIR_EITHER 3 |
| 53 | |
| 54 | #define SNUM_DIFF(_a_,_b_) (((_a_)>(_b_))?((_a_)-(_b_)):((_b_)-(_a_))) |
| 55 | |
| 56 | #define QSUM(_sstfq_) (((_sstfq_)->lopri.qlen)+((_sstfq_)->left.qlen)+((_sstfq_)->right.qlen)) |
| 57 | |
| 58 | |
| 59 | static void |
| 60 | do_sstf_ord_q(RF_DiskQueueData_t **, |
| 61 | RF_DiskQueueData_t **, |
| 62 | RF_DiskQueueData_t *); |
| 63 | |
| 64 | static RF_DiskQueueData_t * |
| 65 | closest_to_arm(RF_SstfQ_t *, |
| 66 | RF_SectorNum_t, |
| 67 | int *, |
| 68 | int); |
| 69 | static void do_dequeue(RF_SstfQ_t *, RF_DiskQueueData_t *); |
| 70 | |
| 71 | |
| 72 | static void |
| 73 | do_sstf_ord_q(RF_DiskQueueData_t **queuep, RF_DiskQueueData_t **tailp, RF_DiskQueueData_t *req) |
| 74 | { |
| 75 | RF_DiskQueueData_t *r, *s; |
| 76 | |
| 77 | if (*queuep == NULL) { |
| 78 | *queuep = req; |
| 79 | *tailp = req; |
| 80 | req->next = NULL; |
| 81 | req->prev = NULL; |
| 82 | return; |
| 83 | } |
| 84 | if (req->sectorOffset <= (*queuep)->sectorOffset) { |
| 85 | req->next = *queuep; |
| 86 | req->prev = NULL; |
| 87 | (*queuep)->prev = req; |
| 88 | *queuep = req; |
| 89 | return; |
| 90 | } |
| 91 | if (req->sectorOffset > (*tailp)->sectorOffset) { |
| 92 | /* optimization */ |
| 93 | r = NULL; |
| 94 | s = *tailp; |
| 95 | goto q_at_end; |
| 96 | } |
| 97 | for (s = NULL, r = *queuep; r; s = r, r = r->next) { |
| 98 | if (r->sectorOffset >= req->sectorOffset) { |
| 99 | /* insert after s, before r */ |
| 100 | RF_ASSERT(s); |
| 101 | req->next = r; |
| 102 | r->prev = req; |
| 103 | s->next = req; |
| 104 | req->prev = s; |
| 105 | return; |
| 106 | } |
| 107 | } |
| 108 | q_at_end: |
| 109 | /* insert after s, at end of queue */ |
| 110 | RF_ASSERT(r == NULL); |
| 111 | RF_ASSERT(s); |
| 112 | RF_ASSERT(s == (*tailp)); |
| 113 | req->next = NULL; |
| 114 | req->prev = s; |
| 115 | s->next = req; |
| 116 | *tailp = req; |
| 117 | } |
| 118 | /* for removing from head-of-queue */ |
| 119 | #define DO_HEAD_DEQ(_r_,_q_) { \ |
| 120 | _r_ = (_q_)->queue; \ |
| 121 | RF_ASSERT((_r_) != NULL); \ |
| 122 | (_q_)->queue = (_r_)->next; \ |
| 123 | (_q_)->qlen--; \ |
| 124 | if ((_q_)->qlen == 0) { \ |
| 125 | RF_ASSERT((_r_) == (_q_)->qtail); \ |
| 126 | RF_ASSERT((_q_)->queue == NULL); \ |
| 127 | (_q_)->qtail = NULL; \ |
| 128 | } \ |
| 129 | else { \ |
| 130 | RF_ASSERT((_q_)->queue->prev == (_r_)); \ |
| 131 | (_q_)->queue->prev = NULL; \ |
| 132 | } \ |
| 133 | } |
| 134 | |
| 135 | /* for removing from end-of-queue */ |
| 136 | #define DO_TAIL_DEQ(_r_,_q_) { \ |
| 137 | _r_ = (_q_)->qtail; \ |
| 138 | RF_ASSERT((_r_) != NULL); \ |
| 139 | (_q_)->qtail = (_r_)->prev; \ |
| 140 | (_q_)->qlen--; \ |
| 141 | if ((_q_)->qlen == 0) { \ |
| 142 | RF_ASSERT((_r_) == (_q_)->queue); \ |
| 143 | RF_ASSERT((_q_)->qtail == NULL); \ |
| 144 | (_q_)->queue = NULL; \ |
| 145 | } \ |
| 146 | else { \ |
| 147 | RF_ASSERT((_q_)->qtail->next == (_r_)); \ |
| 148 | (_q_)->qtail->next = NULL; \ |
| 149 | } \ |
| 150 | } |
| 151 | |
| 152 | #define DO_BEST_DEQ(_l_,_r_,_q_) { \ |
| 153 | if (SNUM_DIFF((_q_)->queue->sectorOffset,_l_) \ |
| 154 | < SNUM_DIFF((_q_)->qtail->sectorOffset,_l_)) \ |
| 155 | { \ |
| 156 | DO_HEAD_DEQ(_r_,_q_); \ |
| 157 | } \ |
| 158 | else { \ |
| 159 | DO_TAIL_DEQ(_r_,_q_); \ |
| 160 | } \ |
| 161 | } |
| 162 | |
| 163 | static RF_DiskQueueData_t * |
| 164 | closest_to_arm(RF_SstfQ_t *queue, RF_SectorNum_t arm_pos, int *dir, int allow_reverse) |
| 165 | { |
| 166 | RF_SectorNum_t best_pos_l = 0, this_pos_l = 0, last_pos = 0; |
| 167 | RF_SectorNum_t best_pos_r = 0, this_pos_r = 0; |
| 168 | RF_DiskQueueData_t *r, *best_l, *best_r; |
| 169 | |
| 170 | best_r = best_l = NULL; |
| 171 | for (r = queue->queue; r; r = r->next) { |
| 172 | if (r->sectorOffset < arm_pos) { |
| 173 | if (best_l == NULL) { |
| 174 | best_l = r; |
| 175 | last_pos = best_pos_l = this_pos_l; |
| 176 | } else { |
| 177 | this_pos_l = arm_pos - r->sectorOffset; |
| 178 | if (this_pos_l < best_pos_l) { |
| 179 | best_l = r; |
| 180 | last_pos = best_pos_l = this_pos_l; |
| 181 | } else { |
| 182 | last_pos = this_pos_l; |
| 183 | } |
| 184 | } |
| 185 | } else { |
| 186 | if (best_r == NULL) { |
| 187 | best_r = r; |
| 188 | last_pos = best_pos_r = this_pos_r; |
| 189 | } else { |
| 190 | this_pos_r = r->sectorOffset - arm_pos; |
| 191 | if (this_pos_r < best_pos_r) { |
| 192 | best_r = r; |
| 193 | last_pos = best_pos_r = this_pos_r; |
| 194 | } else { |
| 195 | last_pos = this_pos_r; |
| 196 | } |
| 197 | if (this_pos_r > last_pos) { |
| 198 | /* getting farther away */ |
| 199 | break; |
| 200 | } |
| 201 | } |
| 202 | } |
| 203 | } |
| 204 | if ((best_r == NULL) && (best_l == NULL)) |
| 205 | return (NULL); |
| 206 | if ((*dir == DIR_RIGHT) && best_r) |
| 207 | return (best_r); |
| 208 | if ((*dir == DIR_LEFT) && best_l) |
| 209 | return (best_l); |
| 210 | if (*dir == DIR_EITHER) { |
| 211 | if (best_l == NULL) |
| 212 | return (best_r); |
| 213 | if (best_r == NULL) |
| 214 | return (best_l); |
| 215 | if (best_pos_r < best_pos_l) |
| 216 | return (best_r); |
| 217 | else |
| 218 | return (best_l); |
| 219 | } |
| 220 | /* |
| 221 | * Nothing in the direction we want to go. Reverse or |
| 222 | * reset the arm. We know we have an I/O in the other |
| 223 | * direction. |
| 224 | */ |
| 225 | if (allow_reverse) { |
| 226 | if (*dir == DIR_RIGHT) { |
| 227 | *dir = DIR_LEFT; |
| 228 | return (best_l); |
| 229 | } else { |
| 230 | *dir = DIR_RIGHT; |
| 231 | return (best_r); |
| 232 | } |
| 233 | } |
| 234 | /* |
| 235 | * Reset (beginning of queue). |
| 236 | */ |
| 237 | RF_ASSERT(*dir == DIR_RIGHT); |
| 238 | return (queue->queue); |
| 239 | } |
| 240 | |
| 241 | void * |
| 242 | rf_SstfCreate( |
| 243 | RF_SectorCount_t sect_per_disk, |
| 244 | RF_AllocListElem_t *cl_list, |
| 245 | RF_ShutdownList_t **listp) |
| 246 | { |
| 247 | RF_Sstf_t *sstfq; |
| 248 | |
| 249 | RF_MallocAndAdd(sstfq, sizeof(RF_Sstf_t), (RF_Sstf_t *), cl_list); |
| 250 | sstfq->dir = DIR_EITHER; |
| 251 | sstfq->allow_reverse = 1; |
| 252 | return ((void *) sstfq); |
| 253 | } |
| 254 | |
| 255 | void * |
| 256 | rf_ScanCreate( |
| 257 | RF_SectorCount_t sect_per_disk, |
| 258 | RF_AllocListElem_t *cl_list, |
| 259 | RF_ShutdownList_t **listp) |
| 260 | { |
| 261 | RF_Sstf_t *scanq; |
| 262 | |
| 263 | RF_MallocAndAdd(scanq, sizeof(RF_Sstf_t), (RF_Sstf_t *), cl_list); |
| 264 | scanq->dir = DIR_RIGHT; |
| 265 | scanq->allow_reverse = 1; |
| 266 | return ((void *) scanq); |
| 267 | } |
| 268 | |
| 269 | void * |
| 270 | rf_CscanCreate( |
| 271 | RF_SectorCount_t sect_per_disk, |
| 272 | RF_AllocListElem_t *cl_list, |
| 273 | RF_ShutdownList_t **listp) |
| 274 | { |
| 275 | RF_Sstf_t *cscanq; |
| 276 | |
| 277 | RF_MallocAndAdd(cscanq, sizeof(RF_Sstf_t), (RF_Sstf_t *), cl_list); |
| 278 | cscanq->dir = DIR_RIGHT; |
| 279 | return ((void *) cscanq); |
| 280 | } |
| 281 | |
| 282 | void |
| 283 | rf_SstfEnqueue(void *qptr, RF_DiskQueueData_t *req, int priority) |
| 284 | { |
| 285 | RF_Sstf_t *sstfq; |
| 286 | |
| 287 | sstfq = (RF_Sstf_t *) qptr; |
| 288 | |
| 289 | if (priority == RF_IO_LOW_PRIORITY) { |
| 290 | #if RF_DEBUG_QUEUE |
| 291 | if (rf_sstfDebug || rf_scanDebug || rf_cscanDebug) { |
| 292 | RF_DiskQueue_t *dq; |
| 293 | dq = (RF_DiskQueue_t *) req->queue; |
| 294 | printf("raid%d: ENQ lopri %d queues are %d,%d,%d\n" , |
| 295 | req->raidPtr->raidid, |
| 296 | dq->col, |
| 297 | sstfq->left.qlen, sstfq->right.qlen, |
| 298 | sstfq->lopri.qlen); |
| 299 | } |
| 300 | #endif |
| 301 | do_sstf_ord_q(&sstfq->lopri.queue, &sstfq->lopri.qtail, req); |
| 302 | sstfq->lopri.qlen++; |
| 303 | } else { |
| 304 | if (req->sectorOffset < sstfq->last_sector) { |
| 305 | do_sstf_ord_q(&sstfq->left.queue, &sstfq->left.qtail, req); |
| 306 | sstfq->left.qlen++; |
| 307 | } else { |
| 308 | do_sstf_ord_q(&sstfq->right.queue, &sstfq->right.qtail, req); |
| 309 | sstfq->right.qlen++; |
| 310 | } |
| 311 | } |
| 312 | } |
| 313 | |
| 314 | static void |
| 315 | do_dequeue(RF_SstfQ_t *queue, RF_DiskQueueData_t *req) |
| 316 | { |
| 317 | RF_DiskQueueData_t *req2; |
| 318 | |
| 319 | #if RF_DEBUG_QUEUE |
| 320 | if (rf_sstfDebug || rf_scanDebug || rf_cscanDebug) { |
| 321 | printf("raid%d: do_dequeue\n" , req->raidPtr->raidid); |
| 322 | } |
| 323 | #endif |
| 324 | if (req == queue->queue) { |
| 325 | DO_HEAD_DEQ(req2, queue); |
| 326 | RF_ASSERT(req2 == req); |
| 327 | } else |
| 328 | if (req == queue->qtail) { |
| 329 | DO_TAIL_DEQ(req2, queue); |
| 330 | RF_ASSERT(req2 == req); |
| 331 | } else { |
| 332 | /* dequeue from middle of list */ |
| 333 | RF_ASSERT(req->next); |
| 334 | RF_ASSERT(req->prev); |
| 335 | queue->qlen--; |
| 336 | req->next->prev = req->prev; |
| 337 | req->prev->next = req->next; |
| 338 | req->next = req->prev = NULL; |
| 339 | } |
| 340 | } |
| 341 | |
| 342 | RF_DiskQueueData_t * |
| 343 | rf_SstfDequeue(void *qptr) |
| 344 | { |
| 345 | RF_DiskQueueData_t *req = NULL; |
| 346 | RF_Sstf_t *sstfq; |
| 347 | |
| 348 | sstfq = (RF_Sstf_t *) qptr; |
| 349 | |
| 350 | #if RF_DEBUG_QUEUE |
| 351 | if (rf_sstfDebug) { |
| 352 | RF_DiskQueue_t *dq; |
| 353 | dq = (RF_DiskQueue_t *) req->queue; |
| 354 | RF_ASSERT(QSUM(sstfq) == dq->queueLength); |
| 355 | printf("raid%d: sstf: Dequeue %d queues are %d,%d,%d\n" , |
| 356 | req->raidPtr->raidid, dq->col, |
| 357 | sstfq->left.qlen, sstfq->right.qlen, sstfq->lopri.qlen); |
| 358 | } |
| 359 | #endif |
| 360 | if (sstfq->left.queue == NULL) { |
| 361 | RF_ASSERT(sstfq->left.qlen == 0); |
| 362 | if (sstfq->right.queue == NULL) { |
| 363 | RF_ASSERT(sstfq->right.qlen == 0); |
| 364 | if (sstfq->lopri.queue == NULL) { |
| 365 | RF_ASSERT(sstfq->lopri.qlen == 0); |
| 366 | return (NULL); |
| 367 | } |
| 368 | #if RF_DEBUG_QUEUE |
| 369 | if (rf_sstfDebug) { |
| 370 | printf("raid%d: sstf: check for close lopri" , |
| 371 | req->raidPtr->raidid); |
| 372 | } |
| 373 | #endif |
| 374 | req = closest_to_arm(&sstfq->lopri, sstfq->last_sector, |
| 375 | &sstfq->dir, sstfq->allow_reverse); |
| 376 | #if RF_DEBUG_QUEUE |
| 377 | if (rf_sstfDebug) { |
| 378 | printf("raid%d: sstf: closest_to_arm said %lx" , |
| 379 | req->raidPtr->raidid, (long) req); |
| 380 | } |
| 381 | #endif |
| 382 | if (req == NULL) |
| 383 | return (NULL); |
| 384 | do_dequeue(&sstfq->lopri, req); |
| 385 | } else { |
| 386 | DO_BEST_DEQ(sstfq->last_sector, req, &sstfq->right); |
| 387 | } |
| 388 | } else { |
| 389 | if (sstfq->right.queue == NULL) { |
| 390 | RF_ASSERT(sstfq->right.qlen == 0); |
| 391 | DO_BEST_DEQ(sstfq->last_sector, req, &sstfq->left); |
| 392 | } else { |
| 393 | if (SNUM_DIFF(sstfq->last_sector, sstfq->right.queue->sectorOffset) |
| 394 | < SNUM_DIFF(sstfq->last_sector, sstfq->left.qtail->sectorOffset)) { |
| 395 | DO_HEAD_DEQ(req, &sstfq->right); |
| 396 | } else { |
| 397 | DO_TAIL_DEQ(req, &sstfq->left); |
| 398 | } |
| 399 | } |
| 400 | } |
| 401 | RF_ASSERT(req); |
| 402 | sstfq->last_sector = req->sectorOffset; |
| 403 | return (req); |
| 404 | } |
| 405 | |
| 406 | RF_DiskQueueData_t * |
| 407 | rf_ScanDequeue(void *qptr) |
| 408 | { |
| 409 | RF_DiskQueueData_t *req = NULL; |
| 410 | RF_Sstf_t *scanq; |
| 411 | |
| 412 | scanq = (RF_Sstf_t *) qptr; |
| 413 | |
| 414 | #if RF_DEBUG_QUEUE |
| 415 | if (rf_scanDebug) { |
| 416 | RF_DiskQueue_t *dq; |
| 417 | dq = (RF_DiskQueue_t *) req->queue; |
| 418 | RF_ASSERT(QSUM(scanq) == dq->queueLength); |
| 419 | printf("raid%d: scan: Dequeue %d queues are %d,%d,%d\n" , |
| 420 | req->raidPtr->raidid, dq->col, |
| 421 | scanq->left.qlen, scanq->right.qlen, scanq->lopri.qlen); |
| 422 | } |
| 423 | #endif |
| 424 | if (scanq->left.queue == NULL) { |
| 425 | RF_ASSERT(scanq->left.qlen == 0); |
| 426 | if (scanq->right.queue == NULL) { |
| 427 | RF_ASSERT(scanq->right.qlen == 0); |
| 428 | if (scanq->lopri.queue == NULL) { |
| 429 | RF_ASSERT(scanq->lopri.qlen == 0); |
| 430 | return (NULL); |
| 431 | } |
| 432 | req = closest_to_arm(&scanq->lopri, scanq->last_sector, |
| 433 | &scanq->dir, scanq->allow_reverse); |
| 434 | if (req == NULL) |
| 435 | return (NULL); |
| 436 | do_dequeue(&scanq->lopri, req); |
| 437 | } else { |
| 438 | scanq->dir = DIR_RIGHT; |
| 439 | DO_HEAD_DEQ(req, &scanq->right); |
| 440 | } |
| 441 | } else |
| 442 | if (scanq->right.queue == NULL) { |
| 443 | RF_ASSERT(scanq->right.qlen == 0); |
| 444 | RF_ASSERT(scanq->left.queue); |
| 445 | scanq->dir = DIR_LEFT; |
| 446 | DO_TAIL_DEQ(req, &scanq->left); |
| 447 | } else { |
| 448 | RF_ASSERT(scanq->right.queue); |
| 449 | RF_ASSERT(scanq->left.queue); |
| 450 | if (scanq->dir == DIR_RIGHT) { |
| 451 | DO_HEAD_DEQ(req, &scanq->right); |
| 452 | } else { |
| 453 | DO_TAIL_DEQ(req, &scanq->left); |
| 454 | } |
| 455 | } |
| 456 | RF_ASSERT(req); |
| 457 | scanq->last_sector = req->sectorOffset; |
| 458 | return (req); |
| 459 | } |
| 460 | |
| 461 | RF_DiskQueueData_t * |
| 462 | rf_CscanDequeue(void *qptr) |
| 463 | { |
| 464 | RF_DiskQueueData_t *req = NULL; |
| 465 | RF_Sstf_t *cscanq; |
| 466 | |
| 467 | cscanq = (RF_Sstf_t *) qptr; |
| 468 | |
| 469 | RF_ASSERT(cscanq->dir == DIR_RIGHT); |
| 470 | #if RF_DEBUG_QUEUE |
| 471 | if (rf_cscanDebug) { |
| 472 | RF_DiskQueue_t *dq; |
| 473 | dq = (RF_DiskQueue_t *) req->queue; |
| 474 | RF_ASSERT(QSUM(cscanq) == dq->queueLength); |
| 475 | printf("raid%d: scan: Dequeue %d queues are %d,%d,%d\n" , |
| 476 | req->raidPtr->raidid, dq->col, |
| 477 | cscanq->left.qlen, cscanq->right.qlen, |
| 478 | cscanq->lopri.qlen); |
| 479 | } |
| 480 | #endif |
| 481 | if (cscanq->right.queue) { |
| 482 | DO_HEAD_DEQ(req, &cscanq->right); |
| 483 | } else { |
| 484 | RF_ASSERT(cscanq->right.qlen == 0); |
| 485 | if (cscanq->left.queue == NULL) { |
| 486 | RF_ASSERT(cscanq->left.qlen == 0); |
| 487 | if (cscanq->lopri.queue == NULL) { |
| 488 | RF_ASSERT(cscanq->lopri.qlen == 0); |
| 489 | return (NULL); |
| 490 | } |
| 491 | req = closest_to_arm(&cscanq->lopri, cscanq->last_sector, |
| 492 | &cscanq->dir, cscanq->allow_reverse); |
| 493 | if (req == NULL) |
| 494 | return (NULL); |
| 495 | do_dequeue(&cscanq->lopri, req); |
| 496 | } else { |
| 497 | /* |
| 498 | * There's I/Os to the left of the arm. Swing |
| 499 | * on back (swap queues). |
| 500 | */ |
| 501 | cscanq->right = cscanq->left; |
| 502 | cscanq->left.qlen = 0; |
| 503 | cscanq->left.queue = cscanq->left.qtail = NULL; |
| 504 | DO_HEAD_DEQ(req, &cscanq->right); |
| 505 | } |
| 506 | } |
| 507 | RF_ASSERT(req); |
| 508 | cscanq->last_sector = req->sectorOffset; |
| 509 | return (req); |
| 510 | } |
| 511 | |
| 512 | RF_DiskQueueData_t * |
| 513 | rf_SstfPeek(void *qptr) |
| 514 | { |
| 515 | RF_DiskQueueData_t *req; |
| 516 | RF_Sstf_t *sstfq; |
| 517 | |
| 518 | sstfq = (RF_Sstf_t *) qptr; |
| 519 | |
| 520 | if ((sstfq->left.queue == NULL) && (sstfq->right.queue == NULL)) { |
| 521 | req = closest_to_arm(&sstfq->lopri, sstfq->last_sector, &sstfq->dir, |
| 522 | sstfq->allow_reverse); |
| 523 | } else { |
| 524 | if (sstfq->left.queue == NULL) |
| 525 | req = sstfq->right.queue; |
| 526 | else { |
| 527 | if (sstfq->right.queue == NULL) |
| 528 | req = sstfq->left.queue; |
| 529 | else { |
| 530 | if (SNUM_DIFF(sstfq->last_sector, sstfq->right.queue->sectorOffset) |
| 531 | < SNUM_DIFF(sstfq->last_sector, sstfq->left.qtail->sectorOffset)) { |
| 532 | req = sstfq->right.queue; |
| 533 | } else { |
| 534 | req = sstfq->left.qtail; |
| 535 | } |
| 536 | } |
| 537 | } |
| 538 | } |
| 539 | if (req == NULL) { |
| 540 | RF_ASSERT(QSUM(sstfq) == 0); |
| 541 | } |
| 542 | return (req); |
| 543 | } |
| 544 | |
| 545 | RF_DiskQueueData_t * |
| 546 | rf_ScanPeek(void *qptr) |
| 547 | { |
| 548 | RF_DiskQueueData_t *req; |
| 549 | RF_Sstf_t *scanq; |
| 550 | int dir; |
| 551 | |
| 552 | scanq = (RF_Sstf_t *) qptr; |
| 553 | dir = scanq->dir; |
| 554 | |
| 555 | if (scanq->left.queue == NULL) { |
| 556 | RF_ASSERT(scanq->left.qlen == 0); |
| 557 | if (scanq->right.queue == NULL) { |
| 558 | RF_ASSERT(scanq->right.qlen == 0); |
| 559 | if (scanq->lopri.queue == NULL) { |
| 560 | RF_ASSERT(scanq->lopri.qlen == 0); |
| 561 | return (NULL); |
| 562 | } |
| 563 | req = closest_to_arm(&scanq->lopri, scanq->last_sector, |
| 564 | &dir, scanq->allow_reverse); |
| 565 | } else { |
| 566 | req = scanq->right.queue; |
| 567 | } |
| 568 | } else |
| 569 | if (scanq->right.queue == NULL) { |
| 570 | RF_ASSERT(scanq->right.qlen == 0); |
| 571 | RF_ASSERT(scanq->left.queue); |
| 572 | req = scanq->left.qtail; |
| 573 | } else { |
| 574 | RF_ASSERT(scanq->right.queue); |
| 575 | RF_ASSERT(scanq->left.queue); |
| 576 | if (scanq->dir == DIR_RIGHT) { |
| 577 | req = scanq->right.queue; |
| 578 | } else { |
| 579 | req = scanq->left.qtail; |
| 580 | } |
| 581 | } |
| 582 | if (req == NULL) { |
| 583 | RF_ASSERT(QSUM(scanq) == 0); |
| 584 | } |
| 585 | return (req); |
| 586 | } |
| 587 | |
| 588 | RF_DiskQueueData_t * |
| 589 | rf_CscanPeek(void *qptr) |
| 590 | { |
| 591 | RF_DiskQueueData_t *req; |
| 592 | RF_Sstf_t *cscanq; |
| 593 | |
| 594 | cscanq = (RF_Sstf_t *) qptr; |
| 595 | |
| 596 | RF_ASSERT(cscanq->dir == DIR_RIGHT); |
| 597 | if (cscanq->right.queue) { |
| 598 | req = cscanq->right.queue; |
| 599 | } else { |
| 600 | RF_ASSERT(cscanq->right.qlen == 0); |
| 601 | if (cscanq->left.queue == NULL) { |
| 602 | RF_ASSERT(cscanq->left.qlen == 0); |
| 603 | if (cscanq->lopri.queue == NULL) { |
| 604 | RF_ASSERT(cscanq->lopri.qlen == 0); |
| 605 | return (NULL); |
| 606 | } |
| 607 | req = closest_to_arm(&cscanq->lopri, cscanq->last_sector, |
| 608 | &cscanq->dir, cscanq->allow_reverse); |
| 609 | } else { |
| 610 | /* |
| 611 | * There's I/Os to the left of the arm. We'll end |
| 612 | * up swinging on back. |
| 613 | */ |
| 614 | req = cscanq->left.queue; |
| 615 | } |
| 616 | } |
| 617 | if (req == NULL) { |
| 618 | RF_ASSERT(QSUM(cscanq) == 0); |
| 619 | } |
| 620 | return (req); |
| 621 | } |
| 622 | |
| 623 | int |
| 624 | rf_SstfPromote(void *qptr, RF_StripeNum_t parityStripeID, RF_ReconUnitNum_t which_ru) |
| 625 | { |
| 626 | RF_DiskQueueData_t *r, *next; |
| 627 | RF_Sstf_t *sstfq; |
| 628 | int n; |
| 629 | |
| 630 | sstfq = (RF_Sstf_t *) qptr; |
| 631 | |
| 632 | n = 0; |
| 633 | for (r = sstfq->lopri.queue; r; r = next) { |
| 634 | next = r->next; |
| 635 | #if RF_DEBUG_QUEUE |
| 636 | if (rf_sstfDebug || rf_scanDebug || rf_cscanDebug) { |
| 637 | printf("raid%d: check promote %lx\n" , |
| 638 | r->raidPtr->raidid, (long) r); |
| 639 | } |
| 640 | #endif |
| 641 | if ((r->parityStripeID == parityStripeID) |
| 642 | && (r->which_ru == which_ru)) { |
| 643 | do_dequeue(&sstfq->lopri, r); |
| 644 | rf_SstfEnqueue(qptr, r, RF_IO_NORMAL_PRIORITY); |
| 645 | n++; |
| 646 | } |
| 647 | } |
| 648 | #if RF_DEBUG_QUEUE |
| 649 | if (rf_sstfDebug || rf_scanDebug || rf_cscanDebug) { |
| 650 | printf("raid%d: promoted %d matching I/Os queues are %d,%d,%d\n" , |
| 651 | r->raidPtr->raidid, n, sstfq->left.qlen, |
| 652 | sstfq->right.qlen, sstfq->lopri.qlen); |
| 653 | } |
| 654 | #endif |
| 655 | return (n); |
| 656 | } |
| 657 | |