| 1 | /* $NetBSD: rf_fifo.c,v 1.15 2006/11/16 01:33:23 christos 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 | * rf_fifo.c -- prioritized fifo queue code. |
| 32 | * There are only two priority levels: hi and lo. |
| 33 | * |
| 34 | * Aug 4, 1994, adapted from raidSim version (MCH) |
| 35 | * |
| 36 | ***************************************************/ |
| 37 | |
| 38 | #include <sys/cdefs.h> |
| 39 | __KERNEL_RCSID(0, "$NetBSD: rf_fifo.c,v 1.15 2006/11/16 01:33:23 christos Exp $" ); |
| 40 | |
| 41 | #include <dev/raidframe/raidframevar.h> |
| 42 | |
| 43 | #include "rf_alloclist.h" |
| 44 | #include "rf_stripelocks.h" |
| 45 | #include "rf_layout.h" |
| 46 | #include "rf_diskqueue.h" |
| 47 | #include "rf_fifo.h" |
| 48 | #include "rf_debugMem.h" |
| 49 | #include "rf_general.h" |
| 50 | #include "rf_options.h" |
| 51 | #include "rf_raid.h" |
| 52 | |
| 53 | /* just malloc a header, zero it (via calloc), and return it */ |
| 54 | /*ARGSUSED*/ |
| 55 | void * |
| 56 | rf_FifoCreate(RF_SectorCount_t sectPerDisk, RF_AllocListElem_t *clList, |
| 57 | RF_ShutdownList_t **listp) |
| 58 | { |
| 59 | RF_FifoHeader_t *q; |
| 60 | |
| 61 | RF_MallocAndAdd(q, sizeof(RF_FifoHeader_t), |
| 62 | (RF_FifoHeader_t *), clList); |
| 63 | q->hq_count = q->lq_count = 0; |
| 64 | return ((void *) q); |
| 65 | } |
| 66 | |
| 67 | void |
| 68 | rf_FifoEnqueue(void *q_in, RF_DiskQueueData_t *elem, int priority) |
| 69 | { |
| 70 | RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in; |
| 71 | |
| 72 | RF_ASSERT(priority == RF_IO_NORMAL_PRIORITY || priority == RF_IO_LOW_PRIORITY); |
| 73 | |
| 74 | elem->next = NULL; |
| 75 | if (priority == RF_IO_NORMAL_PRIORITY) { |
| 76 | if (!q->hq_tail) { |
| 77 | RF_ASSERT(q->hq_count == 0 && q->hq_head == NULL); |
| 78 | q->hq_head = q->hq_tail = elem; |
| 79 | } else { |
| 80 | RF_ASSERT(q->hq_count != 0 && q->hq_head != NULL); |
| 81 | q->hq_tail->next = elem; |
| 82 | q->hq_tail = elem; |
| 83 | } |
| 84 | q->hq_count++; |
| 85 | } else { |
| 86 | RF_ASSERT(elem->next == NULL); |
| 87 | #if RF_DEBUG_QUEUE |
| 88 | if (rf_fifoDebug) { |
| 89 | printf("raid%d: fifo: ENQ lopri\n" , |
| 90 | elem->raidPtr->raidid); |
| 91 | } |
| 92 | #endif |
| 93 | if (!q->lq_tail) { |
| 94 | RF_ASSERT(q->lq_count == 0 && q->lq_head == NULL); |
| 95 | q->lq_head = q->lq_tail = elem; |
| 96 | } else { |
| 97 | RF_ASSERT(q->lq_count != 0 && q->lq_head != NULL); |
| 98 | q->lq_tail->next = elem; |
| 99 | q->lq_tail = elem; |
| 100 | } |
| 101 | q->lq_count++; |
| 102 | } |
| 103 | if ((q->hq_count + q->lq_count) != elem->queue->queueLength) { |
| 104 | printf("Queue lengths differ!: %d %d %d\n" , |
| 105 | q->hq_count, q->lq_count, (int) elem->queue->queueLength); |
| 106 | printf("%d %d %d\n" , |
| 107 | (int) elem->queue->numOutstanding, |
| 108 | (int) elem->queue->maxOutstanding, |
| 109 | (int) elem->queue->col); |
| 110 | } |
| 111 | RF_ASSERT((q->hq_count + q->lq_count) == elem->queue->queueLength); |
| 112 | } |
| 113 | |
| 114 | RF_DiskQueueData_t * |
| 115 | rf_FifoDequeue(void *q_in) |
| 116 | { |
| 117 | RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in; |
| 118 | RF_DiskQueueData_t *nd; |
| 119 | |
| 120 | RF_ASSERT(q); |
| 121 | if (q->hq_head) { |
| 122 | RF_ASSERT(q->hq_count != 0 && q->hq_tail != NULL); |
| 123 | nd = q->hq_head; |
| 124 | q->hq_head = q->hq_head->next; |
| 125 | if (!q->hq_head) |
| 126 | q->hq_tail = NULL; |
| 127 | nd->next = NULL; |
| 128 | q->hq_count--; |
| 129 | } else |
| 130 | if (q->lq_head) { |
| 131 | RF_ASSERT(q->lq_count != 0 && q->lq_tail != NULL); |
| 132 | nd = q->lq_head; |
| 133 | q->lq_head = q->lq_head->next; |
| 134 | if (!q->lq_head) |
| 135 | q->lq_tail = NULL; |
| 136 | nd->next = NULL; |
| 137 | q->lq_count--; |
| 138 | #if RF_DEBUG_QUEUE |
| 139 | if (rf_fifoDebug) { |
| 140 | printf("raid%d: fifo: DEQ lopri %lx\n" , |
| 141 | nd->raidPtr->raidid, (long) nd); |
| 142 | } |
| 143 | #endif |
| 144 | } else { |
| 145 | RF_ASSERT(q->hq_count == 0 && q->lq_count == 0 && q->hq_tail == NULL && q->lq_tail == NULL); |
| 146 | nd = NULL; |
| 147 | } |
| 148 | return (nd); |
| 149 | } |
| 150 | |
| 151 | /* Return ptr to item at head of queue. Used to examine request |
| 152 | * info without actually dequeueing the request. |
| 153 | */ |
| 154 | RF_DiskQueueData_t * |
| 155 | rf_FifoPeek(void *q_in) |
| 156 | { |
| 157 | RF_DiskQueueData_t *headElement = NULL; |
| 158 | RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in; |
| 159 | |
| 160 | RF_ASSERT(q); |
| 161 | if (q->hq_head) |
| 162 | headElement = q->hq_head; |
| 163 | else |
| 164 | if (q->lq_head) |
| 165 | headElement = q->lq_head; |
| 166 | return (headElement); |
| 167 | } |
| 168 | /* We sometimes need to promote a low priority access to a regular priority access. |
| 169 | * Currently, this is only used when the user wants to write a stripe which is currently |
| 170 | * under reconstruction. |
| 171 | * This routine will promote all accesses tagged with the indicated parityStripeID from |
| 172 | * the low priority queue to the end of the normal priority queue. |
| 173 | * We assume the queue is locked upon entry. |
| 174 | */ |
| 175 | int |
| 176 | rf_FifoPromote(void *q_in, RF_StripeNum_t parityStripeID, |
| 177 | RF_ReconUnitNum_t which_ru) |
| 178 | { |
| 179 | RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in; |
| 180 | RF_DiskQueueData_t *lp = q->lq_head, *pt = NULL; /* lp = lo-pri queue |
| 181 | * pointer, pt = trailer */ |
| 182 | int retval = 0; |
| 183 | |
| 184 | while (lp) { |
| 185 | |
| 186 | /* search for the indicated parity stripe in the low-pri queue */ |
| 187 | if (lp->parityStripeID == parityStripeID && lp->which_ru == which_ru) { |
| 188 | /* printf("FifoPromote: promoting access for psid |
| 189 | * %ld\n",parityStripeID); */ |
| 190 | if (pt) |
| 191 | pt->next = lp->next; /* delete an entry other |
| 192 | * than the first */ |
| 193 | else |
| 194 | q->lq_head = lp->next; /* delete the head entry */ |
| 195 | |
| 196 | if (!q->lq_head) |
| 197 | q->lq_tail = NULL; /* we deleted the only |
| 198 | * entry */ |
| 199 | else |
| 200 | if (lp == q->lq_tail) |
| 201 | q->lq_tail = pt; /* we deleted the tail |
| 202 | * entry */ |
| 203 | |
| 204 | lp->next = NULL; |
| 205 | q->lq_count--; |
| 206 | |
| 207 | if (q->hq_tail) { |
| 208 | q->hq_tail->next = lp; |
| 209 | q->hq_tail = lp; |
| 210 | } |
| 211 | /* append to hi-priority queue */ |
| 212 | else { |
| 213 | q->hq_head = q->hq_tail = lp; |
| 214 | } |
| 215 | q->hq_count++; |
| 216 | |
| 217 | /* UpdateShortestSeekFinishTimeForced(lp->requestPtr, |
| 218 | * lp->diskState); *//* deal with this later, if ever */ |
| 219 | |
| 220 | lp = (pt) ? pt->next : q->lq_head; /* reset low-pri pointer |
| 221 | * and continue */ |
| 222 | retval++; |
| 223 | |
| 224 | } else { |
| 225 | pt = lp; |
| 226 | lp = lp->next; |
| 227 | } |
| 228 | } |
| 229 | |
| 230 | /* sanity check. delete this if you ever put more than one entry in |
| 231 | * the low-pri queue */ |
| 232 | RF_ASSERT(retval == 0 || retval == 1); |
| 233 | return (retval); |
| 234 | } |
| 235 | |