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 1.24 1996/09/08 20:44:49 dyson Exp $ 65 */ 66 67 /* 68 * Paging space routine stubs. Emulates a matchmaker-like interface 69 * for builtin pagers. 70 */ 71 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/proc.h> 75 #include <sys/malloc.h> 76 #include <sys/buf.h> 77 #include <sys/ucred.h> 78 79 #include <vm/vm.h> 80 #include <vm/vm_param.h> 81 #include <vm/vm_prot.h> 82 #include <vm/vm_object.h> 83 #include <vm/vm_page.h> 84 #include <vm/vm_kern.h> 85 #include <vm/vm_pager.h> 86 #include <vm/vm_extern.h> 87 88 extern struct pagerops defaultpagerops; 89 extern struct pagerops swappagerops; 90 extern struct pagerops vnodepagerops; 91 extern struct pagerops devicepagerops; 92 93 static struct pagerops *pagertab[] = { 94 &defaultpagerops, /* OBJT_DEFAULT */ 95 &swappagerops, /* OBJT_SWAP */ 96 &vnodepagerops, /* OBJT_VNODE */ 97 &devicepagerops, /* OBJT_DEVICE */ 98 }; 99 static int npagers = sizeof(pagertab) / sizeof(pagertab[0]); 100 101 /* 102 * Kernel address space for mapping pages. 103 * Used by pagers where KVAs are needed for IO. 104 * 105 * XXX needs to be large enough to support the number of pending async 106 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size 107 * (MAXPHYS == 64k) if you want to get the most efficiency. 108 */ 109 #define PAGER_MAP_SIZE (8 * 1024 * 1024) 110 111 int pager_map_size = PAGER_MAP_SIZE; 112 vm_map_t pager_map; 113 static int bswneeded; 114 static vm_offset_t swapbkva; /* swap buffers kva */ 115 116 void 117 vm_pager_init() 118 { 119 struct pagerops **pgops; 120 121 /* 122 * Initialize known pagers 123 */ 124 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 125 if (pgops && ((*pgops)->pgo_init != NULL)) 126 (*(*pgops)->pgo_init) (); 127 } 128 129 void 130 vm_pager_bufferinit() 131 { 132 struct buf *bp; 133 int i; 134 135 bp = swbuf; 136 /* 137 * Now set up swap and physical I/O buffer headers. 138 */ 139 for (i = 0; i < nswbuf - 1; i++, bp++) { 140 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 141 bp->b_rcred = bp->b_wcred = NOCRED; 142 bp->b_vnbufs.le_next = NOLIST; 143 } 144 bp->b_rcred = bp->b_wcred = NOCRED; 145 bp->b_vnbufs.le_next = NOLIST; 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 */ 157 vm_object_t 158 vm_pager_allocate(type, handle, size, prot, off) 159 objtype_t type; 160 void *handle; 161 vm_size_t size; 162 vm_prot_t prot; 163 vm_ooffset_t off; 164 { 165 struct pagerops *ops; 166 167 ops = pagertab[type]; 168 if (ops) 169 return ((*ops->pgo_alloc) (handle, size, prot, off)); 170 return (NULL); 171 } 172 173 void 174 vm_pager_deallocate(object) 175 vm_object_t object; 176 { 177 (*pagertab[object->type]->pgo_dealloc) (object); 178 } 179 180 181 int 182 vm_pager_get_pages(object, m, count, reqpage) 183 vm_object_t object; 184 vm_page_t *m; 185 int count; 186 int reqpage; 187 { 188 return ((*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage)); 189 } 190 191 int 192 vm_pager_put_pages(object, m, count, sync, rtvals) 193 vm_object_t object; 194 vm_page_t *m; 195 int count; 196 boolean_t sync; 197 int *rtvals; 198 { 199 return ((*pagertab[object->type]->pgo_putpages)(object, m, count, sync, rtvals)); 200 } 201 202 boolean_t 203 vm_pager_has_page(object, offset, before, after) 204 vm_object_t object; 205 vm_pindex_t offset; 206 int *before; 207 int *after; 208 { 209 return ((*pagertab[object->type]->pgo_haspage) (object, offset, before, after)); 210 } 211 212 /* 213 * Called by pageout daemon before going back to sleep. 214 * Gives pagers a chance to clean up any completed async pageing operations. 215 */ 216 void 217 vm_pager_sync() 218 { 219 struct pagerops **pgops; 220 221 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 222 if (pgops && ((*pgops)->pgo_sync != NULL)) 223 (*(*pgops)->pgo_sync) (); 224 } 225 226 vm_offset_t 227 vm_pager_map_page(m) 228 vm_page_t m; 229 { 230 vm_offset_t kva; 231 232 kva = kmem_alloc_wait(pager_map, PAGE_SIZE); 233 pmap_kenter(kva, VM_PAGE_TO_PHYS(m)); 234 return (kva); 235 } 236 237 void 238 vm_pager_unmap_page(kva) 239 vm_offset_t kva; 240 { 241 pmap_kremove(kva); 242 kmem_free_wakeup(pager_map, kva, PAGE_SIZE); 243 } 244 245 vm_object_t 246 vm_pager_object_lookup(pg_list, handle) 247 register struct pagerlst *pg_list; 248 void *handle; 249 { 250 register vm_object_t object; 251 252 for (object = TAILQ_FIRST(pg_list); object != NULL; object = TAILQ_NEXT(object,pager_object_list)) 253 if (object->handle == handle) 254 return (object); 255 return (NULL); 256 } 257 258 /* 259 * This routine loses a reference to the object - 260 * thus a reference must be gained before calling. 261 */ 262 int 263 pager_cache(object, should_cache) 264 vm_object_t object; 265 boolean_t should_cache; 266 { 267 if (object == NULL) 268 return (KERN_INVALID_ARGUMENT); 269 270 if (should_cache) 271 object->flags |= OBJ_CANPERSIST; 272 else 273 object->flags &= ~OBJ_CANPERSIST; 274 275 vm_object_deallocate(object); 276 277 return (KERN_SUCCESS); 278 } 279 280 /* 281 * initialize a physical buffer 282 */ 283 284 static void 285 initpbuf(struct buf *bp) { 286 bzero(bp, sizeof *bp); 287 bp->b_rcred = NOCRED; 288 bp->b_wcred = NOCRED; 289 bp->b_qindex = QUEUE_NONE; 290 bp->b_data = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva; 291 bp->b_kvabase = bp->b_data; 292 bp->b_kvasize = MAXPHYS; 293 bp->b_vnbufs.le_next = NOLIST; 294 } 295 296 /* 297 * allocate a physical buffer 298 */ 299 struct buf * 300 getpbuf() 301 { 302 int s; 303 struct buf *bp; 304 305 s = splbio(); 306 /* get a bp from the swap buffer header pool */ 307 while ((bp = TAILQ_FIRST(&bswlist)) == NULL) { 308 bswneeded = 1; 309 tsleep(&bswneeded, PVM, "wswbuf", 0); 310 } 311 TAILQ_REMOVE(&bswlist, bp, b_freelist); 312 splx(s); 313 314 initpbuf(bp); 315 return bp; 316 } 317 318 /* 319 * allocate a physical buffer, if one is available 320 */ 321 struct buf * 322 trypbuf() 323 { 324 int s; 325 struct buf *bp; 326 327 s = splbio(); 328 if ((bp = TAILQ_FIRST(&bswlist)) == NULL) { 329 splx(s); 330 return NULL; 331 } 332 TAILQ_REMOVE(&bswlist, bp, b_freelist); 333 splx(s); 334 335 initpbuf(bp); 336 337 return bp; 338 } 339 340 /* 341 * release a physical buffer 342 */ 343 void 344 relpbuf(bp) 345 struct buf *bp; 346 { 347 int s; 348 349 s = splbio(); 350 351 if (bp->b_rcred != NOCRED) { 352 crfree(bp->b_rcred); 353 bp->b_rcred = NOCRED; 354 } 355 if (bp->b_wcred != NOCRED) { 356 crfree(bp->b_wcred); 357 bp->b_wcred = NOCRED; 358 } 359 if (bp->b_vp) 360 pbrelvp(bp); 361 362 if (bp->b_flags & B_WANTED) 363 wakeup(bp); 364 365 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 366 367 if (bswneeded) { 368 bswneeded = 0; 369 wakeup(&bswneeded); 370 } 371 splx(s); 372 } 373