1 /* $NetBSD: rf_fifo.c,v 1.5 2000/03/04 03:27:13 oster 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 "rf_types.h" 39 #include "rf_alloclist.h" 40 #include "rf_stripelocks.h" 41 #include "rf_layout.h" 42 #include "rf_diskqueue.h" 43 #include "rf_fifo.h" 44 #include "rf_debugMem.h" 45 #include "rf_general.h" 46 #include "rf_options.h" 47 #include "rf_raid.h" 48 #include "rf_types.h" 49 50 /* just malloc a header, zero it (via calloc), and return it */ 51 /*ARGSUSED*/ 52 void * 53 rf_FifoCreate(sectPerDisk, clList, listp) 54 RF_SectorCount_t sectPerDisk; 55 RF_AllocListElem_t *clList; 56 RF_ShutdownList_t **listp; 57 { 58 RF_FifoHeader_t *q; 59 60 RF_CallocAndAdd(q, 1, sizeof(RF_FifoHeader_t), (RF_FifoHeader_t *), clList); 61 q->hq_count = q->lq_count = 0; 62 return ((void *) q); 63 } 64 65 void 66 rf_FifoEnqueue(q_in, elem, priority) 67 void *q_in; 68 RF_DiskQueueData_t *elem; 69 int priority; 70 { 71 RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in; 72 73 RF_ASSERT(priority == RF_IO_NORMAL_PRIORITY || priority == RF_IO_LOW_PRIORITY); 74 75 elem->next = NULL; 76 if (priority == RF_IO_NORMAL_PRIORITY) { 77 if (!q->hq_tail) { 78 RF_ASSERT(q->hq_count == 0 && q->hq_head == NULL); 79 q->hq_head = q->hq_tail = elem; 80 } else { 81 RF_ASSERT(q->hq_count != 0 && q->hq_head != NULL); 82 q->hq_tail->next = elem; 83 q->hq_tail = elem; 84 } 85 q->hq_count++; 86 } else { 87 RF_ASSERT(elem->next == NULL); 88 if (rf_fifoDebug) { 89 printf("raid%d: fifo: ENQ lopri\n", 90 elem->raidPtr->raidid); 91 } 92 if (!q->lq_tail) { 93 RF_ASSERT(q->lq_count == 0 && q->lq_head == NULL); 94 q->lq_head = q->lq_tail = elem; 95 } else { 96 RF_ASSERT(q->lq_count != 0 && q->lq_head != NULL); 97 q->lq_tail->next = elem; 98 q->lq_tail = elem; 99 } 100 q->lq_count++; 101 } 102 if ((q->hq_count + q->lq_count) != elem->queue->queueLength) { 103 printf("Queue lengths differ!: %d %d %d\n", 104 q->hq_count, q->lq_count, (int) elem->queue->queueLength); 105 printf("%d %d %d %d\n", 106 (int) elem->queue->numOutstanding, 107 (int) elem->queue->maxOutstanding, 108 (int) elem->queue->row, 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(q_in) 116 void *q_in; 117 { 118 RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in; 119 RF_DiskQueueData_t *nd; 120 121 RF_ASSERT(q); 122 if (q->hq_head) { 123 RF_ASSERT(q->hq_count != 0 && q->hq_tail != NULL); 124 nd = q->hq_head; 125 q->hq_head = q->hq_head->next; 126 if (!q->hq_head) 127 q->hq_tail = NULL; 128 nd->next = NULL; 129 q->hq_count--; 130 } else 131 if (q->lq_head) { 132 RF_ASSERT(q->lq_count != 0 && q->lq_tail != NULL); 133 nd = q->lq_head; 134 q->lq_head = q->lq_head->next; 135 if (!q->lq_head) 136 q->lq_tail = NULL; 137 nd->next = NULL; 138 q->lq_count--; 139 if (rf_fifoDebug) { 140 printf("raid%d: fifo: DEQ lopri %lx\n", 141 nd->raidPtr->raidid, (long) nd); 142 } 143 } else { 144 RF_ASSERT(q->hq_count == 0 && q->lq_count == 0 && q->hq_tail == NULL && q->lq_tail == NULL); 145 nd = NULL; 146 } 147 return (nd); 148 } 149 150 /* Return ptr to item at head of queue. Used to examine request 151 * info without actually dequeueing the request. 152 */ 153 RF_DiskQueueData_t * 154 rf_FifoPeek(void *q_in) 155 { 156 RF_DiskQueueData_t *headElement = NULL; 157 RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in; 158 159 RF_ASSERT(q); 160 if (q->hq_head) 161 headElement = q->hq_head; 162 else 163 if (q->lq_head) 164 headElement = q->lq_head; 165 return (headElement); 166 } 167 /* We sometimes need to promote a low priority access to a regular priority access. 168 * Currently, this is only used when the user wants to write a stripe which is currently 169 * under reconstruction. 170 * This routine will promote all accesses tagged with the indicated parityStripeID from 171 * the low priority queue to the end of the normal priority queue. 172 * We assume the queue is locked upon entry. 173 */ 174 int 175 rf_FifoPromote(q_in, parityStripeID, which_ru) 176 void *q_in; 177 RF_StripeNum_t parityStripeID; 178 RF_ReconUnitNum_t which_ru; 179 { 180 RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in; 181 RF_DiskQueueData_t *lp = q->lq_head, *pt = NULL; /* lp = lo-pri queue 182 * pointer, pt = trailer */ 183 int retval = 0; 184 185 while (lp) { 186 187 /* search for the indicated parity stripe in the low-pri queue */ 188 if (lp->parityStripeID == parityStripeID && lp->which_ru == which_ru) { 189 /* printf("FifoPromote: promoting access for psid 190 * %ld\n",parityStripeID); */ 191 if (pt) 192 pt->next = lp->next; /* delete an entry other 193 * than the first */ 194 else 195 q->lq_head = lp->next; /* delete the head entry */ 196 197 if (!q->lq_head) 198 q->lq_tail = NULL; /* we deleted the only 199 * entry */ 200 else 201 if (lp == q->lq_tail) 202 q->lq_tail = pt; /* we deleted the tail 203 * entry */ 204 205 lp->next = NULL; 206 q->lq_count--; 207 208 if (q->hq_tail) { 209 q->hq_tail->next = lp; 210 q->hq_tail = lp; 211 } 212 /* append to hi-priority queue */ 213 else { 214 q->hq_head = q->hq_tail = lp; 215 } 216 q->hq_count++; 217 218 /* UpdateShortestSeekFinishTimeForced(lp->requestPtr, 219 * lp->diskState); *//* deal with this later, if ever */ 220 221 lp = (pt) ? pt->next : q->lq_head; /* reset low-pri pointer 222 * and continue */ 223 retval++; 224 225 } else { 226 pt = lp; 227 lp = lp->next; 228 } 229 } 230 231 /* sanity check. delete this if you ever put more than one entry in 232 * the low-pri queue */ 233 RF_ASSERT(retval == 0 || retval == 1); 234 return (retval); 235 } 236