1 /* $NetBSD: rf_fifo.c,v 1.17 2021/07/23 20:18:24 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 1.17 2021/07/23 20:18:24 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 *
rf_FifoCreate(RF_SectorCount_t sectPerDisk,RF_AllocListElem_t * clList,RF_ShutdownList_t ** listp)56 rf_FifoCreate(RF_SectorCount_t sectPerDisk, RF_AllocListElem_t *clList,
57 RF_ShutdownList_t **listp)
58 {
59 RF_FifoHeader_t *q;
60
61 q = RF_MallocAndAdd(sizeof(*q), clList);
62 q->hq_count = q->lq_count = 0;
63 return ((void *) q);
64 }
65
66 void
rf_FifoEnqueue(void * q_in,RF_DiskQueueData_t * elem,int priority)67 rf_FifoEnqueue(void *q_in, RF_DiskQueueData_t *elem, int priority)
68 {
69 RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in;
70
71 RF_ASSERT(priority == RF_IO_NORMAL_PRIORITY || priority == RF_IO_LOW_PRIORITY);
72
73 elem->next = NULL;
74 if (priority == RF_IO_NORMAL_PRIORITY) {
75 if (!q->hq_tail) {
76 RF_ASSERT(q->hq_count == 0 && q->hq_head == NULL);
77 q->hq_head = q->hq_tail = elem;
78 } else {
79 RF_ASSERT(q->hq_count != 0 && q->hq_head != NULL);
80 q->hq_tail->next = elem;
81 q->hq_tail = elem;
82 }
83 q->hq_count++;
84 } else {
85 RF_ASSERT(elem->next == NULL);
86 #if RF_DEBUG_QUEUE
87 if (rf_fifoDebug) {
88 printf("raid%d: fifo: ENQ lopri\n",
89 elem->raidPtr->raidid);
90 }
91 #endif
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\n",
106 (int) elem->queue->numOutstanding,
107 (int) elem->queue->maxOutstanding,
108 (int) elem->queue->col);
109 }
110 RF_ASSERT((q->hq_count + q->lq_count) == elem->queue->queueLength);
111 }
112
113 RF_DiskQueueData_t *
rf_FifoDequeue(void * q_in)114 rf_FifoDequeue(void *q_in)
115 {
116 RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in;
117 RF_DiskQueueData_t *nd;
118
119 RF_ASSERT(q);
120 if (q->hq_head) {
121 RF_ASSERT(q->hq_count != 0 && q->hq_tail != NULL);
122 nd = q->hq_head;
123 q->hq_head = q->hq_head->next;
124 if (!q->hq_head)
125 q->hq_tail = NULL;
126 nd->next = NULL;
127 q->hq_count--;
128 } else
129 if (q->lq_head) {
130 RF_ASSERT(q->lq_count != 0 && q->lq_tail != NULL);
131 nd = q->lq_head;
132 q->lq_head = q->lq_head->next;
133 if (!q->lq_head)
134 q->lq_tail = NULL;
135 nd->next = NULL;
136 q->lq_count--;
137 #if RF_DEBUG_QUEUE
138 if (rf_fifoDebug) {
139 printf("raid%d: fifo: DEQ lopri %lx\n",
140 nd->raidPtr->raidid, (long) nd);
141 }
142 #endif
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 /* We sometimes need to promote a low priority access to a regular priority access.
151 * Currently, this is only used when the user wants to write a stripe which is currently
152 * under reconstruction.
153 * This routine will promote all accesses tagged with the indicated parityStripeID from
154 * the low priority queue to the end of the normal priority queue.
155 * We assume the queue is locked upon entry.
156 */
157 int
rf_FifoPromote(void * q_in,RF_StripeNum_t parityStripeID,RF_ReconUnitNum_t which_ru)158 rf_FifoPromote(void *q_in, RF_StripeNum_t parityStripeID,
159 RF_ReconUnitNum_t which_ru)
160 {
161 RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in;
162 RF_DiskQueueData_t *lp = q->lq_head, *pt = NULL; /* lp = lo-pri queue
163 * pointer, pt = trailer */
164 int retval = 0;
165
166 while (lp) {
167
168 /* search for the indicated parity stripe in the low-pri queue */
169 if (lp->parityStripeID == parityStripeID && lp->which_ru == which_ru) {
170 /* printf("FifoPromote: promoting access for psid
171 * %ld\n",parityStripeID); */
172 if (pt)
173 pt->next = lp->next; /* delete an entry other
174 * than the first */
175 else
176 q->lq_head = lp->next; /* delete the head entry */
177
178 if (!q->lq_head)
179 q->lq_tail = NULL; /* we deleted the only
180 * entry */
181 else
182 if (lp == q->lq_tail)
183 q->lq_tail = pt; /* we deleted the tail
184 * entry */
185
186 lp->next = NULL;
187 q->lq_count--;
188
189 if (q->hq_tail) {
190 q->hq_tail->next = lp;
191 q->hq_tail = lp;
192 }
193 /* append to hi-priority queue */
194 else {
195 q->hq_head = q->hq_tail = lp;
196 }
197 q->hq_count++;
198
199 /* UpdateShortestSeekFinishTimeForced(lp->requestPtr,
200 * lp->diskState); *//* deal with this later, if ever */
201
202 lp = (pt) ? pt->next : q->lq_head; /* reset low-pri pointer
203 * and continue */
204 retval++;
205
206 } else {
207 pt = lp;
208 lp = lp->next;
209 }
210 }
211
212 /* sanity check. delete this if you ever put more than one entry in
213 * the low-pri queue */
214 RF_ASSERT(retval == 0 || retval == 1);
215 return (retval);
216 }
217