bufq_disksort.c revision 1.1.2.5
1 1.1.2.5 skrll /* $NetBSD: bufq_disksort.c,v 1.1.2.5 2005/11/10 14:09:44 skrll Exp $ */ 2 1.1.2.2 skrll /* NetBSD: subr_disk.c,v 1.61 2004/09/25 03:30:44 thorpej Exp */ 3 1.1.2.2 skrll 4 1.1.2.2 skrll /*- 5 1.1.2.2 skrll * Copyright (c) 1996, 1997, 1999, 2000 The NetBSD Foundation, Inc. 6 1.1.2.2 skrll * All rights reserved. 7 1.1.2.2 skrll * 8 1.1.2.2 skrll * This code is derived from software contributed to The NetBSD Foundation 9 1.1.2.2 skrll * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 10 1.1.2.2 skrll * NASA Ames Research Center. 11 1.1.2.2 skrll * 12 1.1.2.2 skrll * Redistribution and use in source and binary forms, with or without 13 1.1.2.2 skrll * modification, are permitted provided that the following conditions 14 1.1.2.2 skrll * are met: 15 1.1.2.2 skrll * 1. Redistributions of source code must retain the above copyright 16 1.1.2.2 skrll * notice, this list of conditions and the following disclaimer. 17 1.1.2.2 skrll * 2. Redistributions in binary form must reproduce the above copyright 18 1.1.2.2 skrll * notice, this list of conditions and the following disclaimer in the 19 1.1.2.2 skrll * documentation and/or other materials provided with the distribution. 20 1.1.2.2 skrll * 3. All advertising materials mentioning features or use of this software 21 1.1.2.2 skrll * must display the following acknowledgement: 22 1.1.2.2 skrll * This product includes software developed by the NetBSD 23 1.1.2.2 skrll * Foundation, Inc. and its contributors. 24 1.1.2.2 skrll * 4. Neither the name of The NetBSD Foundation nor the names of its 25 1.1.2.2 skrll * contributors may be used to endorse or promote products derived 26 1.1.2.2 skrll * from this software without specific prior written permission. 27 1.1.2.2 skrll * 28 1.1.2.2 skrll * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 29 1.1.2.2 skrll * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 30 1.1.2.2 skrll * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 31 1.1.2.2 skrll * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 32 1.1.2.2 skrll * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 33 1.1.2.2 skrll * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 34 1.1.2.2 skrll * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 35 1.1.2.2 skrll * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 36 1.1.2.2 skrll * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 37 1.1.2.2 skrll * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 38 1.1.2.2 skrll * POSSIBILITY OF SUCH DAMAGE. 39 1.1.2.2 skrll */ 40 1.1.2.2 skrll 41 1.1.2.2 skrll /* 42 1.1.2.2 skrll * Copyright (c) 1982, 1986, 1988, 1993 43 1.1.2.2 skrll * The Regents of the University of California. All rights reserved. 44 1.1.2.2 skrll * (c) UNIX System Laboratories, Inc. 45 1.1.2.2 skrll * All or some portions of this file are derived from material licensed 46 1.1.2.2 skrll * to the University of California by American Telephone and Telegraph 47 1.1.2.2 skrll * Co. or Unix System Laboratories, Inc. and are reproduced herein with 48 1.1.2.2 skrll * the permission of UNIX System Laboratories, Inc. 49 1.1.2.2 skrll * 50 1.1.2.2 skrll * Redistribution and use in source and binary forms, with or without 51 1.1.2.2 skrll * modification, are permitted provided that the following conditions 52 1.1.2.2 skrll * are met: 53 1.1.2.2 skrll * 1. Redistributions of source code must retain the above copyright 54 1.1.2.2 skrll * notice, this list of conditions and the following disclaimer. 55 1.1.2.2 skrll * 2. Redistributions in binary form must reproduce the above copyright 56 1.1.2.2 skrll * notice, this list of conditions and the following disclaimer in the 57 1.1.2.2 skrll * documentation and/or other materials provided with the distribution. 58 1.1.2.2 skrll * 3. Neither the name of the University nor the names of its contributors 59 1.1.2.2 skrll * may be used to endorse or promote products derived from this software 60 1.1.2.2 skrll * without specific prior written permission. 61 1.1.2.2 skrll * 62 1.1.2.2 skrll * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 63 1.1.2.2 skrll * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 64 1.1.2.2 skrll * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 65 1.1.2.2 skrll * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 66 1.1.2.2 skrll * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 67 1.1.2.2 skrll * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 68 1.1.2.2 skrll * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 69 1.1.2.2 skrll * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 70 1.1.2.2 skrll * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 71 1.1.2.2 skrll * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 72 1.1.2.2 skrll * SUCH DAMAGE. 73 1.1.2.2 skrll * 74 1.1.2.2 skrll * @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94 75 1.1.2.2 skrll */ 76 1.1.2.2 skrll 77 1.1.2.2 skrll #include <sys/cdefs.h> 78 1.1.2.5 skrll __KERNEL_RCSID(0, "$NetBSD: bufq_disksort.c,v 1.1.2.5 2005/11/10 14:09:44 skrll Exp $"); 79 1.1.2.2 skrll 80 1.1.2.2 skrll #include <sys/param.h> 81 1.1.2.2 skrll #include <sys/systm.h> 82 1.1.2.2 skrll #include <sys/buf.h> 83 1.1.2.3 skrll #include <sys/bufq.h> 84 1.1.2.5 skrll #include <sys/bufq_impl.h> 85 1.1.2.2 skrll #include <sys/malloc.h> 86 1.1.2.2 skrll 87 1.1.2.2 skrll /* 88 1.1.2.2 skrll * Seek sort for disks. 89 1.1.2.2 skrll * 90 1.1.2.2 skrll * There are actually two queues, sorted in ascendening order. The first 91 1.1.2.2 skrll * queue holds those requests which are positioned after the current block; 92 1.1.2.2 skrll * the second holds requests which came in after their position was passed. 93 1.1.2.2 skrll * Thus we implement a one-way scan, retracting after reaching the end of 94 1.1.2.2 skrll * the drive to the first request on the second queue, at which time it 95 1.1.2.2 skrll * becomes the first queue. 96 1.1.2.2 skrll * 97 1.1.2.2 skrll * A one-way scan is natural because of the way UNIX read-ahead blocks are 98 1.1.2.2 skrll * allocated. 99 1.1.2.2 skrll */ 100 1.1.2.2 skrll 101 1.1.2.2 skrll struct bufq_disksort { 102 1.1.2.2 skrll TAILQ_HEAD(, buf) bq_head; /* actual list of buffers */ 103 1.1.2.2 skrll }; 104 1.1.2.2 skrll 105 1.1.2.4 skrll static void bufq_disksort_init(struct bufq_state *); 106 1.1.2.4 skrll static void bufq_disksort_put(struct bufq_state *, struct buf *); 107 1.1.2.4 skrll static struct buf *bufq_disksort_get(struct bufq_state *, int); 108 1.1.2.4 skrll 109 1.1.2.5 skrll BUFQ_DEFINE(disksort, 20, bufq_disksort_init); 110 1.1.2.4 skrll 111 1.1.2.2 skrll static void 112 1.1.2.2 skrll bufq_disksort_put(struct bufq_state *bufq, struct buf *bp) 113 1.1.2.2 skrll { 114 1.1.2.5 skrll struct bufq_disksort *disksort = bufq_private(bufq); 115 1.1.2.2 skrll struct buf *bq, *nbq; 116 1.1.2.2 skrll int sortby; 117 1.1.2.2 skrll 118 1.1.2.2 skrll sortby = bufq->bq_flags & BUFQ_SORT_MASK; 119 1.1.2.2 skrll 120 1.1.2.2 skrll bq = TAILQ_FIRST(&disksort->bq_head); 121 1.1.2.2 skrll 122 1.1.2.2 skrll /* 123 1.1.2.2 skrll * If the queue is empty it's easy; we just go on the end. 124 1.1.2.2 skrll */ 125 1.1.2.2 skrll if (bq == NULL) { 126 1.1.2.2 skrll TAILQ_INSERT_TAIL(&disksort->bq_head, bp, b_actq); 127 1.1.2.2 skrll return; 128 1.1.2.2 skrll } 129 1.1.2.2 skrll 130 1.1.2.2 skrll /* 131 1.1.2.2 skrll * If we lie before the currently active request, then we 132 1.1.2.2 skrll * must locate the second request list and add ourselves to it. 133 1.1.2.2 skrll */ 134 1.1.2.2 skrll if (buf_inorder(bp, bq, sortby)) { 135 1.1.2.2 skrll while ((nbq = TAILQ_NEXT(bq, b_actq)) != NULL) { 136 1.1.2.2 skrll /* 137 1.1.2.2 skrll * Check for an ``inversion'' in the normally ascending 138 1.1.2.2 skrll * block numbers, indicating the start of the second 139 1.1.2.2 skrll * request list. 140 1.1.2.2 skrll */ 141 1.1.2.2 skrll if (buf_inorder(nbq, bq, sortby)) { 142 1.1.2.2 skrll /* 143 1.1.2.2 skrll * Search the second request list for the first 144 1.1.2.2 skrll * request at a larger block number. We go 145 1.1.2.2 skrll * after that; if there is no such request, we 146 1.1.2.2 skrll * go at the end. 147 1.1.2.2 skrll */ 148 1.1.2.2 skrll do { 149 1.1.2.2 skrll if (buf_inorder(bp, nbq, sortby)) 150 1.1.2.2 skrll goto insert; 151 1.1.2.2 skrll bq = nbq; 152 1.1.2.2 skrll } while ((nbq = 153 1.1.2.2 skrll TAILQ_NEXT(bq, b_actq)) != NULL); 154 1.1.2.2 skrll goto insert; /* after last */ 155 1.1.2.2 skrll } 156 1.1.2.2 skrll bq = nbq; 157 1.1.2.2 skrll } 158 1.1.2.2 skrll /* 159 1.1.2.2 skrll * No inversions... we will go after the last, and 160 1.1.2.2 skrll * be the first request in the second request list. 161 1.1.2.2 skrll */ 162 1.1.2.2 skrll goto insert; 163 1.1.2.2 skrll } 164 1.1.2.2 skrll /* 165 1.1.2.2 skrll * Request is at/after the current request... 166 1.1.2.2 skrll * sort in the first request list. 167 1.1.2.2 skrll */ 168 1.1.2.2 skrll while ((nbq = TAILQ_NEXT(bq, b_actq)) != NULL) { 169 1.1.2.2 skrll /* 170 1.1.2.2 skrll * We want to go after the current request if there is an 171 1.1.2.2 skrll * inversion after it (i.e. it is the end of the first 172 1.1.2.2 skrll * request list), or if the next request is a larger cylinder 173 1.1.2.2 skrll * than our request. 174 1.1.2.2 skrll */ 175 1.1.2.2 skrll if (buf_inorder(nbq, bq, sortby) || 176 1.1.2.2 skrll buf_inorder(bp, nbq, sortby)) 177 1.1.2.2 skrll goto insert; 178 1.1.2.2 skrll bq = nbq; 179 1.1.2.2 skrll } 180 1.1.2.2 skrll /* 181 1.1.2.2 skrll * Neither a second list nor a larger request... we go at the end of 182 1.1.2.2 skrll * the first list, which is the same as the end of the whole schebang. 183 1.1.2.2 skrll */ 184 1.1.2.2 skrll insert: TAILQ_INSERT_AFTER(&disksort->bq_head, bq, bp, b_actq); 185 1.1.2.2 skrll } 186 1.1.2.2 skrll 187 1.1.2.2 skrll static struct buf * 188 1.1.2.2 skrll bufq_disksort_get(struct bufq_state *bufq, int remove) 189 1.1.2.2 skrll { 190 1.1.2.2 skrll struct bufq_disksort *disksort = bufq->bq_private; 191 1.1.2.2 skrll struct buf *bp; 192 1.1.2.2 skrll 193 1.1.2.2 skrll bp = TAILQ_FIRST(&disksort->bq_head); 194 1.1.2.2 skrll 195 1.1.2.2 skrll if (bp != NULL && remove) 196 1.1.2.2 skrll TAILQ_REMOVE(&disksort->bq_head, bp, b_actq); 197 1.1.2.2 skrll 198 1.1.2.2 skrll return (bp); 199 1.1.2.2 skrll } 200 1.1.2.2 skrll 201 1.1.2.4 skrll static void 202 1.1.2.2 skrll bufq_disksort_init(struct bufq_state *bufq) 203 1.1.2.2 skrll { 204 1.1.2.2 skrll struct bufq_disksort *disksort; 205 1.1.2.2 skrll 206 1.1.2.2 skrll bufq->bq_get = bufq_disksort_get; 207 1.1.2.2 skrll bufq->bq_put = bufq_disksort_put; 208 1.1.2.5 skrll bufq->bq_private = malloc(sizeof(struct bufq_disksort), 209 1.1.2.5 skrll M_DEVBUF, M_ZERO); 210 1.1.2.2 skrll disksort = (struct bufq_disksort *)bufq->bq_private; 211 1.1.2.2 skrll TAILQ_INIT(&disksort->bq_head); 212 1.1.2.2 skrll } 213
Indexes created Sun Sep 28 16:09:52 GMT 2025