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 * $FreeBSD$ 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/kernel.h> 75 #include <sys/vnode.h> 76 #include <sys/bio.h> 77 #include <sys/buf.h> 78 #include <sys/ucred.h> 79 #include <sys/malloc.h> 80 81 #include <vm/vm.h> 82 #include <vm/vm_param.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 88 MALLOC_DEFINE(M_VMPGDATA, "VM pgdata", "XXX: VM pager private data"); 89 90 extern struct pagerops defaultpagerops; 91 extern struct pagerops swappagerops; 92 extern struct pagerops vnodepagerops; 93 extern struct pagerops devicepagerops; 94 extern struct pagerops physpagerops; 95 96 int cluster_pbuf_freecnt = -1; /* unlimited to begin with */ 97 98 static int dead_pager_getpages __P((vm_object_t, vm_page_t *, int, int)); 99 static vm_object_t dead_pager_alloc __P((void *, vm_ooffset_t, vm_prot_t, 100 vm_ooffset_t)); 101 static void dead_pager_putpages __P((vm_object_t, vm_page_t *, int, int, int *)); 102 static boolean_t dead_pager_haspage __P((vm_object_t, vm_pindex_t, int *, int *)); 103 static void dead_pager_dealloc __P((vm_object_t)); 104 105 static int 106 dead_pager_getpages(obj, ma, count, req) 107 vm_object_t obj; 108 vm_page_t *ma; 109 int count; 110 int req; 111 { 112 return VM_PAGER_FAIL; 113 } 114 115 static vm_object_t 116 dead_pager_alloc(handle, size, prot, off) 117 void *handle; 118 vm_ooffset_t size; 119 vm_prot_t prot; 120 vm_ooffset_t off; 121 { 122 return NULL; 123 } 124 125 static void 126 dead_pager_putpages(object, m, count, flags, rtvals) 127 vm_object_t object; 128 vm_page_t *m; 129 int count; 130 int flags; 131 int *rtvals; 132 { 133 int i; 134 135 for (i = 0; i < count; i++) { 136 rtvals[i] = VM_PAGER_AGAIN; 137 } 138 } 139 140 static int 141 dead_pager_haspage(object, pindex, prev, next) 142 vm_object_t object; 143 vm_pindex_t pindex; 144 int *prev; 145 int *next; 146 { 147 if (prev) 148 *prev = 0; 149 if (next) 150 *next = 0; 151 return FALSE; 152 } 153 154 static void 155 dead_pager_dealloc(object) 156 vm_object_t object; 157 { 158 return; 159 } 160 161 static struct pagerops deadpagerops = { 162 NULL, 163 dead_pager_alloc, 164 dead_pager_dealloc, 165 dead_pager_getpages, 166 dead_pager_putpages, 167 dead_pager_haspage, 168 NULL 169 }; 170 171 struct pagerops *pagertab[] = { 172 &defaultpagerops, /* OBJT_DEFAULT */ 173 &swappagerops, /* OBJT_SWAP */ 174 &vnodepagerops, /* OBJT_VNODE */ 175 &devicepagerops, /* OBJT_DEVICE */ 176 &physpagerops, /* OBJT_PHYS */ 177 &deadpagerops /* OBJT_DEAD */ 178 }; 179 180 int npagers = sizeof(pagertab) / sizeof(pagertab[0]); 181 182 /* 183 * Kernel address space for mapping pages. 184 * Used by pagers where KVAs are needed for IO. 185 * 186 * XXX needs to be large enough to support the number of pending async 187 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size 188 * (MAXPHYS == 64k) if you want to get the most efficiency. 189 */ 190 #define PAGER_MAP_SIZE (8 * 1024 * 1024) 191 192 int pager_map_size = PAGER_MAP_SIZE; 193 vm_map_t pager_map; 194 static int bswneeded; 195 static vm_offset_t swapbkva; /* swap buffers kva */ 196 197 void 198 vm_pager_init() 199 { 200 struct pagerops **pgops; 201 202 /* 203 * Initialize known pagers 204 */ 205 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 206 if (pgops && ((*pgops)->pgo_init != NULL)) 207 (*(*pgops)->pgo_init) (); 208 } 209 210 void 211 vm_pager_bufferinit() 212 { 213 struct buf *bp; 214 int i; 215 216 bp = swbuf; 217 /* 218 * Now set up swap and physical I/O buffer headers. 219 */ 220 for (i = 0; i < nswbuf; i++, bp++) { 221 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 222 BUF_LOCKINIT(bp); 223 LIST_INIT(&bp->b_dep); 224 bp->b_rcred = bp->b_wcred = NOCRED; 225 bp->b_xflags = 0; 226 } 227 228 cluster_pbuf_freecnt = nswbuf / 2; 229 230 swapbkva = kmem_alloc_pageable(pager_map, nswbuf * MAXPHYS); 231 if (!swapbkva) 232 panic("Not enough pager_map VM space for physical buffers"); 233 } 234 235 /* 236 * Allocate an instance of a pager of the given type. 237 * Size, protection and offset parameters are passed in for pagers that 238 * need to perform page-level validation (e.g. the device pager). 239 */ 240 vm_object_t 241 vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, vm_prot_t prot, 242 vm_ooffset_t off) 243 { 244 struct pagerops *ops; 245 246 ops = pagertab[type]; 247 if (ops) 248 return ((*ops->pgo_alloc) (handle, size, prot, off)); 249 return (NULL); 250 } 251 252 void 253 vm_pager_deallocate(object) 254 vm_object_t object; 255 { 256 (*pagertab[object->type]->pgo_dealloc) (object); 257 } 258 259 /* 260 * vm_pager_strategy: 261 * 262 * called with no specific spl 263 * Execute strategy routine directly to pager. 264 */ 265 266 void 267 vm_pager_strategy(vm_object_t object, struct bio *bp) 268 { 269 if (pagertab[object->type]->pgo_strategy) { 270 (*pagertab[object->type]->pgo_strategy)(object, bp); 271 } else { 272 bp->bio_flags |= BIO_ERROR; 273 bp->bio_error = ENXIO; 274 biodone(bp); 275 } 276 } 277 278 /* 279 * vm_pager_get_pages() - inline, see vm/vm_pager.h 280 * vm_pager_put_pages() - inline, see vm/vm_pager.h 281 * vm_pager_has_page() - inline, see vm/vm_pager.h 282 * vm_pager_page_inserted() - inline, see vm/vm_pager.h 283 * vm_pager_page_removed() - inline, see vm/vm_pager.h 284 */ 285 286 #if 0 287 /* 288 * vm_pager_sync: 289 * 290 * Called by pageout daemon before going back to sleep. 291 * Gives pagers a chance to clean up any completed async pageing 292 * operations. 293 */ 294 void 295 vm_pager_sync() 296 { 297 struct pagerops **pgops; 298 299 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 300 if (pgops && ((*pgops)->pgo_sync != NULL)) 301 (*(*pgops)->pgo_sync) (); 302 } 303 304 #endif 305 306 vm_offset_t 307 vm_pager_map_page(m) 308 vm_page_t m; 309 { 310 vm_offset_t kva; 311 312 kva = kmem_alloc_wait(pager_map, PAGE_SIZE); 313 pmap_kenter(kva, VM_PAGE_TO_PHYS(m)); 314 return (kva); 315 } 316 317 void 318 vm_pager_unmap_page(kva) 319 vm_offset_t kva; 320 { 321 pmap_kremove(kva); 322 kmem_free_wakeup(pager_map, kva, PAGE_SIZE); 323 } 324 325 vm_object_t 326 vm_pager_object_lookup(pg_list, handle) 327 register struct pagerlst *pg_list; 328 void *handle; 329 { 330 register vm_object_t object; 331 332 for (object = TAILQ_FIRST(pg_list); object != NULL; object = TAILQ_NEXT(object,pager_object_list)) 333 if (object->handle == handle) 334 return (object); 335 return (NULL); 336 } 337 338 /* 339 * initialize a physical buffer 340 */ 341 342 static void 343 initpbuf(struct buf *bp) 344 { 345 bp->b_rcred = NOCRED; 346 bp->b_wcred = NOCRED; 347 bp->b_qindex = QUEUE_NONE; 348 bp->b_data = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva; 349 bp->b_kvabase = bp->b_data; 350 bp->b_kvasize = MAXPHYS; 351 bp->b_xflags = 0; 352 bp->b_flags = 0; 353 bp->b_ioflags = 0; 354 bp->b_iodone = NULL; 355 bp->b_error = 0; 356 BUF_LOCK(bp, LK_EXCLUSIVE); 357 } 358 359 /* 360 * allocate a physical buffer 361 * 362 * There are a limited number (nswbuf) of physical buffers. We need 363 * to make sure that no single subsystem is able to hog all of them, 364 * so each subsystem implements a counter which is typically initialized 365 * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and 366 * increments it on release, and blocks if the counter hits zero. A 367 * subsystem may initialize the counter to -1 to disable the feature, 368 * but it must still be sure to match up all uses of getpbuf() with 369 * relpbuf() using the same variable. 370 * 371 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 372 * relatively soon when the rest of the subsystems get smart about it. XXX 373 */ 374 struct buf * 375 getpbuf(pfreecnt) 376 int *pfreecnt; 377 { 378 int s; 379 struct buf *bp; 380 381 s = splvm(); 382 383 for (;;) { 384 if (pfreecnt) { 385 while (*pfreecnt == 0) { 386 tsleep(pfreecnt, PVM, "wswbuf0", 0); 387 } 388 } 389 390 /* get a bp from the swap buffer header pool */ 391 if ((bp = TAILQ_FIRST(&bswlist)) != NULL) 392 break; 393 394 bswneeded = 1; 395 tsleep(&bswneeded, PVM, "wswbuf1", 0); 396 /* loop in case someone else grabbed one */ 397 } 398 TAILQ_REMOVE(&bswlist, bp, b_freelist); 399 if (pfreecnt) 400 --*pfreecnt; 401 splx(s); 402 403 initpbuf(bp); 404 return bp; 405 } 406 407 /* 408 * allocate a physical buffer, if one is available. 409 * 410 * Note that there is no NULL hack here - all subsystems using this 411 * call understand how to use pfreecnt. 412 */ 413 struct buf * 414 trypbuf(pfreecnt) 415 int *pfreecnt; 416 { 417 int s; 418 struct buf *bp; 419 420 s = splvm(); 421 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) { 422 splx(s); 423 return NULL; 424 } 425 TAILQ_REMOVE(&bswlist, bp, b_freelist); 426 427 --*pfreecnt; 428 429 splx(s); 430 431 initpbuf(bp); 432 433 return bp; 434 } 435 436 /* 437 * release a physical buffer 438 * 439 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 440 * relatively soon when the rest of the subsystems get smart about it. XXX 441 */ 442 void 443 relpbuf(bp, pfreecnt) 444 struct buf *bp; 445 int *pfreecnt; 446 { 447 int s; 448 449 s = splvm(); 450 451 if (bp->b_rcred != NOCRED) { 452 crfree(bp->b_rcred); 453 bp->b_rcred = NOCRED; 454 } 455 if (bp->b_wcred != NOCRED) { 456 crfree(bp->b_wcred); 457 bp->b_wcred = NOCRED; 458 } 459 460 if (bp->b_vp) 461 pbrelvp(bp); 462 463 BUF_UNLOCK(bp); 464 465 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 466 467 if (bswneeded) { 468 bswneeded = 0; 469 wakeup(&bswneeded); 470 } 471 if (pfreecnt) { 472 if (++*pfreecnt == 1) 473 wakeup(pfreecnt); 474 } 475 splx(s); 476 } 477