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 | |