| 1 | /* $NetBSD: rf_cvscan.c,v 1.16 2011/08/31 18:31:02 plunky Exp $ */ |
| 2 | /* |
| 3 | * Copyright (c) 1995 Carnegie-Mellon University. |
| 4 | * All rights reserved. |
| 5 | * |
| 6 | * Author: Mark Holland |
| 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 | * cvscan.c -- prioritized cvscan disk queueing code. |
| 32 | * |
| 33 | * Nov 9, 1994, adapted from raidSim version (MCH) |
| 34 | * |
| 35 | ******************************************************************************/ |
| 36 | |
| 37 | #include <sys/cdefs.h> |
| 38 | __KERNEL_RCSID(0, "$NetBSD: rf_cvscan.c,v 1.16 2011/08/31 18:31:02 plunky Exp $" ); |
| 39 | |
| 40 | #include <dev/raidframe/raidframevar.h> |
| 41 | #include "rf_alloclist.h" |
| 42 | #include "rf_stripelocks.h" |
| 43 | #include "rf_layout.h" |
| 44 | #include "rf_diskqueue.h" |
| 45 | #include "rf_cvscan.h" |
| 46 | #include "rf_debugMem.h" |
| 47 | #include "rf_general.h" |
| 48 | |
| 49 | #define DO_CHECK_STATE(_hdr_) CheckCvscanState((_hdr_)) |
| 50 | |
| 51 | #define pri_ok(p) ( ((p) == RF_IO_NORMAL_PRIORITY) || ((p) == RF_IO_LOW_PRIORITY)) |
| 52 | |
| 53 | static void |
| 54 | CheckCvscanState(RF_CvscanHeader_t *hdr) |
| 55 | { |
| 56 | long i, key; |
| 57 | RF_DiskQueueData_t *tmp; |
| 58 | |
| 59 | if (hdr->left != NULL) |
| 60 | RF_ASSERT(hdr->left->sectorOffset < hdr->cur_block); |
| 61 | for (key = hdr->cur_block, i = 0, tmp = hdr->left; |
| 62 | tmp != NULL; |
| 63 | key = tmp->sectorOffset, i++, tmp = tmp->next) |
| 64 | RF_ASSERT(tmp->sectorOffset <= key |
| 65 | && tmp->priority == hdr->nxt_priority && pri_ok(tmp->priority)); |
| 66 | RF_ASSERT(i == hdr->left_cnt); |
| 67 | |
| 68 | for (key = hdr->cur_block, i = 0, tmp = hdr->right; |
| 69 | tmp != NULL; |
| 70 | key = tmp->sectorOffset, i++, tmp = tmp->next) { |
| 71 | RF_ASSERT(key <= tmp->sectorOffset); |
| 72 | RF_ASSERT(tmp->priority == hdr->nxt_priority); |
| 73 | RF_ASSERT(pri_ok(tmp->priority)); |
| 74 | } |
| 75 | RF_ASSERT(i == hdr->right_cnt); |
| 76 | |
| 77 | for (key = hdr->nxt_priority - 1, tmp = hdr->burner; |
| 78 | tmp != NULL; |
| 79 | key = tmp->priority, tmp = tmp->next) { |
| 80 | RF_ASSERT(tmp); |
| 81 | RF_ASSERT(hdr); |
| 82 | RF_ASSERT(pri_ok(tmp->priority)); |
| 83 | RF_ASSERT(key >= tmp->priority); |
| 84 | RF_ASSERT(tmp->priority < hdr->nxt_priority); |
| 85 | } |
| 86 | } |
| 87 | |
| 88 | |
| 89 | |
| 90 | static void |
| 91 | PriorityInsert(RF_DiskQueueData_t **list_ptr, RF_DiskQueueData_t *req) |
| 92 | { |
| 93 | /* * insert block pointed to by req in to list whose first * entry is |
| 94 | * pointed to by the pointer that list_ptr points to * ie., list_ptr |
| 95 | * is a grandparent of the first entry */ |
| 96 | |
| 97 | for (; (*list_ptr) != NULL && (*list_ptr)->priority > req->priority; |
| 98 | list_ptr = &((*list_ptr)->next)) { |
| 99 | } |
| 100 | req->next = (*list_ptr); |
| 101 | (*list_ptr) = req; |
| 102 | } |
| 103 | |
| 104 | |
| 105 | |
| 106 | static void |
| 107 | ReqInsert(RF_DiskQueueData_t **list_ptr, RF_DiskQueueData_t *req, RF_CvscanArmDir_t order) |
| 108 | { |
| 109 | /* * insert block pointed to by req in to list whose first * entry is |
| 110 | * pointed to by the pointer that list_ptr points to * ie., list_ptr |
| 111 | * is a grandparent of the first entry */ |
| 112 | |
| 113 | for (; (*list_ptr) != NULL && |
| 114 | ((order == rf_cvscan_RIGHT && (*list_ptr)->sectorOffset <= req->sectorOffset) |
| 115 | || (order == rf_cvscan_LEFT && (*list_ptr)->sectorOffset > req->sectorOffset)); |
| 116 | list_ptr = &((*list_ptr)->next)) { |
| 117 | } |
| 118 | req->next = (*list_ptr); |
| 119 | (*list_ptr) = req; |
| 120 | } |
| 121 | |
| 122 | |
| 123 | |
| 124 | static RF_DiskQueueData_t * |
| 125 | ReqDequeue(RF_DiskQueueData_t **list_ptr) |
| 126 | { |
| 127 | RF_DiskQueueData_t *ret = (*list_ptr); |
| 128 | if ((*list_ptr) != NULL) { |
| 129 | (*list_ptr) = (*list_ptr)->next; |
| 130 | } |
| 131 | return (ret); |
| 132 | } |
| 133 | |
| 134 | |
| 135 | |
| 136 | static void |
| 137 | ReBalance(RF_CvscanHeader_t *hdr) |
| 138 | { |
| 139 | /* DO_CHECK_STATE(hdr); */ |
| 140 | while (hdr->right != NULL |
| 141 | && hdr->right->sectorOffset < hdr->cur_block) { |
| 142 | hdr->right_cnt--; |
| 143 | hdr->left_cnt++; |
| 144 | ReqInsert(&hdr->left, ReqDequeue(&hdr->right), rf_cvscan_LEFT); |
| 145 | } |
| 146 | /* DO_CHECK_STATE(hdr); */ |
| 147 | } |
| 148 | |
| 149 | |
| 150 | |
| 151 | static void |
| 152 | Transfer(RF_DiskQueueData_t **to_list_ptr, RF_DiskQueueData_t **from_list_ptr) |
| 153 | { |
| 154 | RF_DiskQueueData_t *gp; |
| 155 | for (gp = (*from_list_ptr); gp != NULL;) { |
| 156 | RF_DiskQueueData_t *p = gp->next; |
| 157 | PriorityInsert(to_list_ptr, gp); |
| 158 | gp = p; |
| 159 | } |
| 160 | (*from_list_ptr) = NULL; |
| 161 | } |
| 162 | |
| 163 | |
| 164 | |
| 165 | static void |
| 166 | RealEnqueue(RF_CvscanHeader_t *hdr, RF_DiskQueueData_t *req) |
| 167 | { |
| 168 | RF_ASSERT(req->priority == RF_IO_NORMAL_PRIORITY || req->priority == RF_IO_LOW_PRIORITY); |
| 169 | |
| 170 | DO_CHECK_STATE(hdr); |
| 171 | if (hdr->left_cnt == 0 && hdr->right_cnt == 0) { |
| 172 | hdr->nxt_priority = req->priority; |
| 173 | } |
| 174 | if (req->priority > hdr->nxt_priority) { |
| 175 | /* |
| 176 | ** dump all other outstanding requests on the back burner |
| 177 | */ |
| 178 | Transfer(&hdr->burner, &hdr->left); |
| 179 | Transfer(&hdr->burner, &hdr->right); |
| 180 | hdr->left_cnt = 0; |
| 181 | hdr->right_cnt = 0; |
| 182 | hdr->nxt_priority = req->priority; |
| 183 | } |
| 184 | if (req->priority < hdr->nxt_priority) { |
| 185 | /* |
| 186 | ** yet another low priority task! |
| 187 | */ |
| 188 | PriorityInsert(&hdr->burner, req); |
| 189 | } else { |
| 190 | if (req->sectorOffset < hdr->cur_block) { |
| 191 | /* this request is to the left of the current arms */ |
| 192 | ReqInsert(&hdr->left, req, rf_cvscan_LEFT); |
| 193 | hdr->left_cnt++; |
| 194 | } else { |
| 195 | /* this request is to the right of the current arms */ |
| 196 | ReqInsert(&hdr->right, req, rf_cvscan_RIGHT); |
| 197 | hdr->right_cnt++; |
| 198 | } |
| 199 | } |
| 200 | DO_CHECK_STATE(hdr); |
| 201 | } |
| 202 | |
| 203 | |
| 204 | |
| 205 | void |
| 206 | rf_CvscanEnqueue(void *q_in, RF_DiskQueueData_t * elem, int priority) |
| 207 | { |
| 208 | RF_CvscanHeader_t *hdr = (RF_CvscanHeader_t *) q_in; |
| 209 | RealEnqueue(hdr, elem /* req */ ); |
| 210 | } |
| 211 | |
| 212 | |
| 213 | |
| 214 | RF_DiskQueueData_t * |
| 215 | rf_CvscanDequeue(void *q_in) |
| 216 | { |
| 217 | RF_CvscanHeader_t *hdr = (RF_CvscanHeader_t *) q_in; |
| 218 | long range, i, sum_dist_left, sum_dist_right; |
| 219 | RF_DiskQueueData_t *ret; |
| 220 | RF_DiskQueueData_t *tmp; |
| 221 | |
| 222 | DO_CHECK_STATE(hdr); |
| 223 | |
| 224 | if (hdr->left_cnt == 0 && hdr->right_cnt == 0) |
| 225 | return (NULL); |
| 226 | |
| 227 | range = RF_MIN(hdr->range_for_avg, RF_MIN(hdr->left_cnt, hdr->right_cnt)); |
| 228 | for (i = 0, tmp = hdr->left, sum_dist_left = |
| 229 | ((hdr->direction == rf_cvscan_RIGHT) ? range * hdr->change_penalty : 0); |
| 230 | tmp != NULL && i < range; |
| 231 | tmp = tmp->next, i++) { |
| 232 | sum_dist_left += hdr->cur_block - tmp->sectorOffset; |
| 233 | } |
| 234 | for (i = 0, tmp = hdr->right, sum_dist_right = |
| 235 | ((hdr->direction == rf_cvscan_LEFT) ? range * hdr->change_penalty : 0); |
| 236 | tmp != NULL && i < range; |
| 237 | tmp = tmp->next, i++) { |
| 238 | sum_dist_right += tmp->sectorOffset - hdr->cur_block; |
| 239 | } |
| 240 | |
| 241 | if (hdr->right_cnt == 0 || sum_dist_left < sum_dist_right) { |
| 242 | hdr->direction = rf_cvscan_LEFT; |
| 243 | hdr->cur_block = hdr->left->sectorOffset + hdr->left->numSector; |
| 244 | hdr->left_cnt = RF_MAX(hdr->left_cnt - 1, 0); |
| 245 | tmp = hdr->left; |
| 246 | ret = (ReqDequeue(&hdr->left)) /*->parent*/ ; |
| 247 | } else { |
| 248 | hdr->direction = rf_cvscan_RIGHT; |
| 249 | hdr->cur_block = hdr->right->sectorOffset + hdr->right->numSector; |
| 250 | hdr->right_cnt = RF_MAX(hdr->right_cnt - 1, 0); |
| 251 | tmp = hdr->right; |
| 252 | ret = (ReqDequeue(&hdr->right)) /*->parent*/ ; |
| 253 | } |
| 254 | ReBalance(hdr); |
| 255 | |
| 256 | if (hdr->left_cnt == 0 && hdr->right_cnt == 0 |
| 257 | && hdr->burner != NULL) { |
| 258 | /* |
| 259 | ** restore low priority requests for next dequeue |
| 260 | */ |
| 261 | RF_DiskQueueData_t *burner = hdr->burner; |
| 262 | hdr->nxt_priority = burner->priority; |
| 263 | while (burner != NULL |
| 264 | && burner->priority == hdr->nxt_priority) { |
| 265 | RF_DiskQueueData_t *next = burner->next; |
| 266 | RealEnqueue(hdr, burner); |
| 267 | burner = next; |
| 268 | } |
| 269 | hdr->burner = burner; |
| 270 | } |
| 271 | DO_CHECK_STATE(hdr); |
| 272 | return (ret); |
| 273 | } |
| 274 | |
| 275 | |
| 276 | |
| 277 | RF_DiskQueueData_t * |
| 278 | rf_CvscanPeek(void *q_in) |
| 279 | { |
| 280 | RF_CvscanHeader_t *hdr = (RF_CvscanHeader_t *) q_in; |
| 281 | long range, i, sum_dist_left, sum_dist_right; |
| 282 | RF_DiskQueueData_t *tmp, *headElement; |
| 283 | |
| 284 | DO_CHECK_STATE(hdr); |
| 285 | |
| 286 | if (hdr->left_cnt == 0 && hdr->right_cnt == 0) |
| 287 | headElement = NULL; |
| 288 | else { |
| 289 | range = RF_MIN(hdr->range_for_avg, RF_MIN(hdr->left_cnt, hdr->right_cnt)); |
| 290 | for (i = 0, tmp = hdr->left, sum_dist_left = |
| 291 | ((hdr->direction == rf_cvscan_RIGHT) ? range * hdr->change_penalty : 0); |
| 292 | tmp != NULL && i < range; |
| 293 | tmp = tmp->next, i++) { |
| 294 | sum_dist_left += hdr->cur_block - tmp->sectorOffset; |
| 295 | } |
| 296 | for (i = 0, tmp = hdr->right, sum_dist_right = |
| 297 | ((hdr->direction == rf_cvscan_LEFT) ? range * hdr->change_penalty : 0); |
| 298 | tmp != NULL && i < range; |
| 299 | tmp = tmp->next, i++) { |
| 300 | sum_dist_right += tmp->sectorOffset - hdr->cur_block; |
| 301 | } |
| 302 | |
| 303 | if (hdr->right_cnt == 0 || sum_dist_left < sum_dist_right) |
| 304 | headElement = hdr->left; |
| 305 | else |
| 306 | headElement = hdr->right; |
| 307 | } |
| 308 | return (headElement); |
| 309 | } |
| 310 | |
| 311 | |
| 312 | |
| 313 | /* |
| 314 | ** CVSCAN( 1, 0 ) is Shortest Seek Time First (SSTF) |
| 315 | ** lowest average response time |
| 316 | ** CVSCAN( 1, infinity ) is SCAN |
| 317 | ** lowest response time standard deviation |
| 318 | */ |
| 319 | |
| 320 | void * |
| 321 | rf_CvscanCreate(RF_SectorCount_t sectPerDisk, |
| 322 | RF_AllocListElem_t *clList, |
| 323 | RF_ShutdownList_t **listp) |
| 324 | { |
| 325 | RF_CvscanHeader_t *hdr; |
| 326 | long range = 2; /* Currently no mechanism to change these */ |
| 327 | long penalty = sectPerDisk / 5; |
| 328 | |
| 329 | RF_MallocAndAdd(hdr, sizeof(RF_CvscanHeader_t), (RF_CvscanHeader_t *), clList); |
| 330 | memset((char *) hdr, 0, sizeof(RF_CvscanHeader_t)); |
| 331 | hdr->range_for_avg = RF_MAX(range, 1); |
| 332 | hdr->change_penalty = RF_MAX(penalty, 0); |
| 333 | hdr->direction = rf_cvscan_RIGHT; |
| 334 | hdr->cur_block = 0; |
| 335 | hdr->left_cnt = hdr->right_cnt = 0; |
| 336 | hdr->left = hdr->right = NULL; |
| 337 | hdr->burner = NULL; |
| 338 | DO_CHECK_STATE(hdr); |
| 339 | |
| 340 | return ((void *) hdr); |
| 341 | } |
| 342 | |
| 343 | |
| 344 | #if defined(__NetBSD__) && defined(_KERNEL) |
| 345 | /* PrintCvscanQueue is not used, so we ignore it... */ |
| 346 | #else |
| 347 | static void |
| 348 | PrintCvscanQueue(RF_CvscanHeader_t *hdr) |
| 349 | { |
| 350 | RF_DiskQueueData_t *tmp; |
| 351 | |
| 352 | printf("CVSCAN(%d,%d) at %d going %s\n" , |
| 353 | (int) hdr->range_for_avg, |
| 354 | (int) hdr->change_penalty, |
| 355 | (int) hdr->cur_block, |
| 356 | (hdr->direction == rf_cvscan_LEFT) ? "LEFT" : "RIGHT" ); |
| 357 | printf("\tLeft(%d): " , hdr->left_cnt); |
| 358 | for (tmp = hdr->left; tmp != NULL; tmp = tmp->next) |
| 359 | printf("(%d,%ld,%d) " , |
| 360 | (int) tmp->sectorOffset, |
| 361 | (long) (tmp->sectorOffset + tmp->numSector), |
| 362 | tmp->priority); |
| 363 | printf("\n" ); |
| 364 | printf("\tRight(%d): " , hdr->right_cnt); |
| 365 | for (tmp = hdr->right; tmp != NULL; tmp = tmp->next) |
| 366 | printf("(%d,%ld,%d) " , |
| 367 | (int) tmp->sectorOffset, |
| 368 | (long) (tmp->sectorOffset + tmp->numSector), |
| 369 | tmp->priority); |
| 370 | printf("\n" ); |
| 371 | printf("\tBurner: " ); |
| 372 | for (tmp = hdr->burner; tmp != NULL; tmp = tmp->next) |
| 373 | printf("(%d,%ld,%d) " , |
| 374 | (int) tmp->sectorOffset, |
| 375 | (long) (tmp->sectorOffset + tmp->numSector), |
| 376 | tmp->priority); |
| 377 | printf("\n" ); |
| 378 | } |
| 379 | #endif |
| 380 | |
| 381 | |
| 382 | /* promotes reconstruction accesses for the given stripeID to normal priority. |
| 383 | * returns 1 if an access was found and zero otherwise. Normally, we should |
| 384 | * only have one or zero entries in the burner queue, so execution time should |
| 385 | * be short. |
| 386 | */ |
| 387 | int |
| 388 | rf_CvscanPromote(void *q_in, RF_StripeNum_t parityStripeID, |
| 389 | RF_ReconUnitNum_t which_ru) |
| 390 | { |
| 391 | RF_CvscanHeader_t *hdr = (RF_CvscanHeader_t *) q_in; |
| 392 | RF_DiskQueueData_t *trailer = NULL, *tmp = hdr->burner, *tlist = NULL; |
| 393 | int retval = 0; |
| 394 | |
| 395 | DO_CHECK_STATE(hdr); |
| 396 | while (tmp) { /* handle entries at the front of the list */ |
| 397 | if (tmp->parityStripeID == parityStripeID && tmp->which_ru == which_ru) { |
| 398 | hdr->burner = tmp->next; |
| 399 | tmp->priority = RF_IO_NORMAL_PRIORITY; |
| 400 | tmp->next = tlist; |
| 401 | tlist = tmp; |
| 402 | tmp = hdr->burner; |
| 403 | } else |
| 404 | break; |
| 405 | } |
| 406 | if (tmp) { |
| 407 | trailer = tmp; |
| 408 | tmp = tmp->next; |
| 409 | } |
| 410 | while (tmp) { /* handle entries on the rest of the list */ |
| 411 | if (tmp->parityStripeID == parityStripeID && tmp->which_ru == which_ru) { |
| 412 | trailer->next = tmp->next; |
| 413 | tmp->priority = RF_IO_NORMAL_PRIORITY; |
| 414 | tmp->next = tlist; |
| 415 | tlist = tmp; /* insert on a temp queue */ |
| 416 | tmp = trailer->next; |
| 417 | } else { |
| 418 | trailer = tmp; |
| 419 | tmp = tmp->next; |
| 420 | } |
| 421 | } |
| 422 | while (tlist) { |
| 423 | retval++; |
| 424 | tmp = tlist->next; |
| 425 | RealEnqueue(hdr, tlist); |
| 426 | tlist = tmp; |
| 427 | } |
| 428 | RF_ASSERT(retval == 0 || retval == 1); |
| 429 | DO_CHECK_STATE((RF_CvscanHeader_t *) q_in); |
| 430 | return (retval); |
| 431 | } |
| 432 | |