vm_pager.c revision 33108
1/* 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * The Mach Operating System project at Carnegie-Mellon University. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#)vm_pager.c 8.6 (Berkeley) 1/12/94 37 * 38 * 39 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 40 * All rights reserved. 41 * 42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 43 * 44 * Permission to use, copy, modify and distribute this software and 45 * its documentation is hereby granted, provided that both the copyright 46 * notice and this permission notice appear in all copies of the 47 * software, derivative works or modified versions, and any portions 48 * thereof, and that both notices appear in supporting documentation. 49 * 50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 53 * 54 * Carnegie Mellon requests users of this software to return to 55 * 56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 57 * School of Computer Science 58 * Carnegie Mellon University 59 * Pittsburgh PA 15213-3890 60 * 61 * any improvements or extensions that they make and grant Carnegie the 62 * rights to redistribute these changes. 63 * 64 * $Id: vm_pager.c,v 1.32 1998/01/24 02:01:46 dyson Exp $ 65 */ 66 67/* 68 * Paging space routine stubs. Emulates a matchmaker-like interface 69 * for builtin pagers. 70 */ 71 72#include "opt_diagnostic.h" 73 74#include <sys/param.h> 75#include <sys/systm.h> 76#include <sys/buf.h> 77#include <sys/ucred.h> 78#include <sys/malloc.h> 79 80#include <vm/vm.h> 81#include <vm/vm_param.h> 82#include <vm/vm_prot.h> 83#include <vm/vm_object.h> 84#include <vm/vm_page.h> 85#include <vm/vm_pager.h> 86#include <vm/vm_extern.h> 87 88MALLOC_DEFINE(M_VMPGDATA, "VM pgdata", "XXX: VM pager private data"); 89 90extern struct pagerops defaultpagerops; 91extern struct pagerops swappagerops; 92extern struct pagerops vnodepagerops; 93extern struct pagerops devicepagerops; 94 95static struct pagerops *pagertab[] = { 96 &defaultpagerops, /* OBJT_DEFAULT */ 97 &swappagerops, /* OBJT_SWAP */ 98 &vnodepagerops, /* OBJT_VNODE */ 99 &devicepagerops, /* OBJT_DEVICE */ 100}; 101static int npagers = sizeof(pagertab) / sizeof(pagertab[0]); 102 103/* 104 * Kernel address space for mapping pages. 105 * Used by pagers where KVAs are needed for IO. 106 * 107 * XXX needs to be large enough to support the number of pending async 108 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size 109 * (MAXPHYS == 64k) if you want to get the most efficiency. 110 */ 111#define PAGER_MAP_SIZE (8 * 1024 * 1024) 112 113int pager_map_size = PAGER_MAP_SIZE; 114vm_map_t pager_map; 115static int bswneeded; 116static vm_offset_t swapbkva; /* swap buffers kva */ 117 118void 119vm_pager_init() 120{ 121 struct pagerops **pgops; 122 123 /* 124 * Initialize known pagers 125 */ 126 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 127 if (pgops && ((*pgops)->pgo_init != NULL)) 128 (*(*pgops)->pgo_init) (); 129} 130 131void 132vm_pager_bufferinit() 133{ 134 struct buf *bp; 135 int i; 136 137 bp = swbuf; 138 /* 139 * Now set up swap and physical I/O buffer headers. 140 */ 141 for (i = 0; i < nswbuf; i++, bp++) { 142 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 143 bp->b_rcred = bp->b_wcred = NOCRED; 144 bp->b_vnbufs.le_next = NOLIST; 145 } 146 147 swapbkva = kmem_alloc_pageable(pager_map, nswbuf * MAXPHYS); 148 if (!swapbkva) 149 panic("Not enough pager_map VM space for physical buffers"); 150} 151 152/* 153 * Allocate an instance of a pager of the given type. 154 * Size, protection and offset parameters are passed in for pagers that 155 * need to perform page-level validation (e.g. the device pager). 156 */ 157vm_object_t 158vm_pager_allocate(objtype_t type, void *handle, vm_size_t size, vm_prot_t prot, 159 vm_ooffset_t off) 160{ 161 struct pagerops *ops; 162 163 ops = pagertab[type]; 164 if (ops) 165 return ((*ops->pgo_alloc) (handle, size, prot, off)); 166 return (NULL); 167} 168 169void 170vm_pager_deallocate(object) 171 vm_object_t object; 172{ 173 (*pagertab[object->type]->pgo_dealloc) (object); 174} 175 176 177int 178vm_pager_get_pages(object, m, count, reqpage) 179 vm_object_t object; 180 vm_page_t *m; 181 int count; 182 int reqpage; 183{ 184 return ((*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage)); 185} 186 187int 188vm_pager_put_pages(object, m, count, sync, rtvals) 189 vm_object_t object; 190 vm_page_t *m; 191 int count; 192 boolean_t sync; 193 int *rtvals; 194{ 195 return ((*pagertab[object->type]->pgo_putpages)(object, m, count, sync, rtvals)); 196} 197 198boolean_t 199vm_pager_has_page(object, offset, before, after) 200 vm_object_t object; 201 vm_pindex_t offset; 202 int *before; 203 int *after; 204{ 205 return ((*pagertab[object->type]->pgo_haspage) (object, offset, before, after)); 206} 207 208/* 209 * Called by pageout daemon before going back to sleep. 210 * Gives pagers a chance to clean up any completed async pageing operations. 211 */ 212void 213vm_pager_sync() 214{ 215 struct pagerops **pgops; 216 217 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 218 if (pgops && ((*pgops)->pgo_sync != NULL)) 219 (*(*pgops)->pgo_sync) (); 220} 221 222vm_offset_t 223vm_pager_map_page(m) 224 vm_page_t m; 225{ 226 vm_offset_t kva; 227 228 kva = kmem_alloc_wait(pager_map, PAGE_SIZE); 229 pmap_kenter(kva, VM_PAGE_TO_PHYS(m)); 230 return (kva); 231} 232 233void 234vm_pager_unmap_page(kva) 235 vm_offset_t kva; 236{ 237 pmap_kremove(kva); 238 kmem_free_wakeup(pager_map, kva, PAGE_SIZE); 239} 240 241vm_object_t 242vm_pager_object_lookup(pg_list, handle) 243 register struct pagerlst *pg_list; 244 void *handle; 245{ 246 register vm_object_t object; 247 248 for (object = TAILQ_FIRST(pg_list); object != NULL; object = TAILQ_NEXT(object,pager_object_list)) 249 if (object->handle == handle) 250 return (object); 251 return (NULL); 252} 253 254/* 255 * initialize a physical buffer 256 */ 257 258static void 259initpbuf(struct buf *bp) { 260 bzero(bp, sizeof *bp); 261 bp->b_rcred = NOCRED; 262 bp->b_wcred = NOCRED; 263 bp->b_qindex = QUEUE_NONE; 264 bp->b_data = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva; 265 bp->b_kvabase = bp->b_data; 266 bp->b_kvasize = MAXPHYS; 267 bp->b_vnbufs.le_next = NOLIST; 268} 269 270/* 271 * allocate a physical buffer 272 */ 273struct buf * 274getpbuf() 275{ 276 int s; 277 struct buf *bp; 278 279 s = splbio(); 280 /* get a bp from the swap buffer header pool */ 281 while ((bp = TAILQ_FIRST(&bswlist)) == NULL) { 282 bswneeded = 1; 283 tsleep(&bswneeded, PVM, "wswbuf", 0); 284 } 285 TAILQ_REMOVE(&bswlist, bp, b_freelist); 286 splx(s); 287 288 initpbuf(bp); 289 return bp; 290} 291 292/* 293 * allocate a physical buffer, if one is available 294 */ 295struct buf * 296trypbuf() 297{ 298 int s; 299 struct buf *bp; 300 301 s = splbio(); 302 if ((bp = TAILQ_FIRST(&bswlist)) == NULL) { 303 splx(s); 304 return NULL; 305 } 306 TAILQ_REMOVE(&bswlist, bp, b_freelist); 307 splx(s); 308 309 initpbuf(bp); 310 311 return bp; 312} 313 314/* 315 * release a physical buffer 316 */ 317void 318relpbuf(bp) 319 struct buf *bp; 320{ 321 int s; 322 323 s = splbio(); 324 325 if (bp->b_rcred != NOCRED) { 326 crfree(bp->b_rcred); 327 bp->b_rcred = NOCRED; 328 } 329 if (bp->b_wcred != NOCRED) { 330 crfree(bp->b_wcred); 331 bp->b_wcred = NOCRED; 332 } 333 if (bp->b_vp) 334 pbrelvp(bp); 335 336 if (bp->b_flags & B_WANTED) 337 wakeup(bp); 338 339 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 340 341 if (bswneeded) { 342 bswneeded = 0; 343 wakeup(&bswneeded); 344 } 345 splx(s); 346} 347