1 /* $NetBSD: rf_fifo.c,v 1.10 2003/12/30 21:59:03 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 <sys/cdefs.h> 39 __KERNEL_RCSID(0, "$NetBSD: rf_fifo.c,v 1.10 2003/12/30 21:59:03 oster 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 %d\n", 107 (int) elem->queue->numOutstanding, 108 (int) elem->queue->maxOutstanding, 109 (int) elem->queue->row, 110 (int) elem->queue->col); 111 } 112 RF_ASSERT((q->hq_count + q->lq_count) == elem->queue->queueLength); 113 } 114 115 RF_DiskQueueData_t * 116 rf_FifoDequeue(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_DEBUG_QUEUE 140 if (rf_fifoDebug) { 141 printf("raid%d: fifo: DEQ lopri %lx\n", 142 nd->raidPtr->raidid, (long) nd); 143 } 144 #endif 145 } else { 146 RF_ASSERT(q->hq_count == 0 && q->lq_count == 0 && q->hq_tail == NULL && q->lq_tail == NULL); 147 nd = NULL; 148 } 149 return (nd); 150 } 151 152 /* Return ptr to item at head of queue. Used to examine request 153 * info without actually dequeueing the request. 154 */ 155 RF_DiskQueueData_t * 156 rf_FifoPeek(void *q_in) 157 { 158 RF_DiskQueueData_t *headElement = NULL; 159 RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in; 160 161 RF_ASSERT(q); 162 if (q->hq_head) 163 headElement = q->hq_head; 164 else 165 if (q->lq_head) 166 headElement = q->lq_head; 167 return (headElement); 168 } 169 /* We sometimes need to promote a low priority access to a regular priority access. 170 * Currently, this is only used when the user wants to write a stripe which is currently 171 * under reconstruction. 172 * This routine will promote all accesses tagged with the indicated parityStripeID from 173 * the low priority queue to the end of the normal priority queue. 174 * We assume the queue is locked upon entry. 175 */ 176 int 177 rf_FifoPromote(void *q_in, 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