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 #include <sys/proc.h> 81 82 #include <vm/vm.h> 83 #include <vm/vm_param.h> 84 #include <vm/vm_object.h> 85 #include <vm/vm_page.h> 86 #include <vm/vm_pager.h> 87 #include <vm/vm_extern.h> 88 89 MALLOC_DEFINE(M_VMPGDATA, "VM pgdata", "XXX: VM pager private data"); 90 91 extern struct pagerops defaultpagerops; 92 extern struct pagerops swappagerops; 93 extern struct pagerops vnodepagerops; 94 extern struct pagerops devicepagerops; 95 extern struct pagerops physpagerops; 96 97 int cluster_pbuf_freecnt = -1; /* unlimited to begin with */ 98 99 static int dead_pager_getpages __P((vm_object_t, vm_page_t *, int, int)); 100 static vm_object_t dead_pager_alloc __P((void *, vm_ooffset_t, vm_prot_t, 101 vm_ooffset_t)); 102 static void dead_pager_putpages __P((vm_object_t, vm_page_t *, int, int, int *)); 103 static boolean_t dead_pager_haspage __P((vm_object_t, vm_pindex_t, int *, int *)); 104 static void dead_pager_dealloc __P((vm_object_t)); 105 106 static int 107 dead_pager_getpages(obj, ma, count, req) 108 vm_object_t obj; 109 vm_page_t *ma; 110 int count; 111 int req; 112 { 113 return VM_PAGER_FAIL; 114 } 115 116 static vm_object_t 117 dead_pager_alloc(handle, size, prot, off) 118 void *handle; 119 vm_ooffset_t size; 120 vm_prot_t prot; 121 vm_ooffset_t off; 122 { 123 return NULL; 124 } 125 126 static void 127 dead_pager_putpages(object, m, count, flags, rtvals) 128 vm_object_t object; 129 vm_page_t *m; 130 int count; 131 int flags; 132 int *rtvals; 133 { 134 int i; 135 136 for (i = 0; i < count; i++) { 137 rtvals[i] = VM_PAGER_AGAIN; 138 } 139 } 140 141 static int 142 dead_pager_haspage(object, pindex, prev, next) 143 vm_object_t object; 144 vm_pindex_t pindex; 145 int *prev; 146 int *next; 147 { 148 if (prev) 149 *prev = 0; 150 if (next) 151 *next = 0; 152 return FALSE; 153 } 154 155 static void 156 dead_pager_dealloc(object) 157 vm_object_t object; 158 { 159 return; 160 } 161 162 static struct pagerops deadpagerops = { 163 NULL, 164 dead_pager_alloc, 165 dead_pager_dealloc, 166 dead_pager_getpages, 167 dead_pager_putpages, 168 dead_pager_haspage, 169 NULL 170 }; 171 172 struct pagerops *pagertab[] = { 173 &defaultpagerops, /* OBJT_DEFAULT */ 174 &swappagerops, /* OBJT_SWAP */ 175 &vnodepagerops, /* OBJT_VNODE */ 176 &devicepagerops, /* OBJT_DEVICE */ 177 &physpagerops, /* OBJT_PHYS */ 178 &deadpagerops /* OBJT_DEAD */ 179 }; 180 181 int npagers = sizeof(pagertab) / sizeof(pagertab[0]); 182 183 /* 184 * Kernel address space for mapping pages. 185 * Used by pagers where KVAs are needed for IO. 186 * 187 * XXX needs to be large enough to support the number of pending async 188 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size 189 * (MAXPHYS == 64k) if you want to get the most efficiency. 190 */ 191 #define PAGER_MAP_SIZE (8 * 1024 * 1024) 192 193 int pager_map_size = PAGER_MAP_SIZE; 194 vm_map_t pager_map; 195 static int bswneeded; 196 static vm_offset_t swapbkva; /* swap buffers kva */ 197 198 void 199 vm_pager_init() 200 { 201 struct pagerops **pgops; 202 203 /* 204 * Initialize known pagers 205 */ 206 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 207 if (pgops && ((*pgops)->pgo_init != NULL)) 208 (*(*pgops)->pgo_init) (); 209 } 210 211 void 212 vm_pager_bufferinit() 213 { 214 struct buf *bp; 215 int i; 216 217 bp = swbuf; 218 /* 219 * Now set up swap and physical I/O buffer headers. 220 */ 221 for (i = 0; i < nswbuf; i++, bp++) { 222 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 223 BUF_LOCKINIT(bp); 224 LIST_INIT(&bp->b_dep); 225 bp->b_rcred = bp->b_wcred = NOCRED; 226 bp->b_xflags = 0; 227 } 228 229 cluster_pbuf_freecnt = nswbuf / 2; 230 231 swapbkva = kmem_alloc_pageable(pager_map, nswbuf * MAXPHYS); 232 if (!swapbkva) 233 panic("Not enough pager_map VM space for physical buffers"); 234 } 235 236 /* 237 * Allocate an instance of a pager of the given type. 238 * Size, protection and offset parameters are passed in for pagers that 239 * need to perform page-level validation (e.g. the device pager). 240 */ 241 vm_object_t 242 vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, vm_prot_t prot, 243 vm_ooffset_t off) 244 { 245 struct pagerops *ops; 246 247 ops = pagertab[type]; 248 if (ops) 249 return ((*ops->pgo_alloc) (handle, size, prot, off)); 250 return (NULL); 251 } 252 253 void 254 vm_pager_deallocate(object) 255 vm_object_t object; 256 { 257 (*pagertab[object->type]->pgo_dealloc) (object); 258 } 259 260 /* 261 * vm_pager_strategy: 262 * 263 * called with no specific spl 264 * Execute strategy routine directly to pager. 265 */ 266 267 void 268 vm_pager_strategy(vm_object_t object, struct bio *bp) 269 { 270 if (pagertab[object->type]->pgo_strategy) { 271 (*pagertab[object->type]->pgo_strategy)(object, bp); 272 } else { 273 bp->bio_flags |= BIO_ERROR; 274 bp->bio_error = ENXIO; 275 biodone(bp); 276 } 277 } 278 279 /* 280 * vm_pager_get_pages() - inline, see vm/vm_pager.h 281 * vm_pager_put_pages() - inline, see vm/vm_pager.h 282 * vm_pager_has_page() - inline, see vm/vm_pager.h 283 * vm_pager_page_inserted() - inline, see vm/vm_pager.h 284 * vm_pager_page_removed() - inline, see vm/vm_pager.h 285 */ 286 287 #if 0 288 /* 289 * vm_pager_sync: 290 * 291 * Called by pageout daemon before going back to sleep. 292 * Gives pagers a chance to clean up any completed async pageing 293 * operations. 294 */ 295 void 296 vm_pager_sync() 297 { 298 struct pagerops **pgops; 299 300 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 301 if (pgops && ((*pgops)->pgo_sync != NULL)) 302 (*(*pgops)->pgo_sync) (); 303 } 304 305 #endif 306 307 vm_offset_t 308 vm_pager_map_page(m) 309 vm_page_t m; 310 { 311 vm_offset_t kva; 312 313 kva = kmem_alloc_wait(pager_map, PAGE_SIZE); 314 pmap_kenter(kva, VM_PAGE_TO_PHYS(m)); 315 return (kva); 316 } 317 318 void 319 vm_pager_unmap_page(kva) 320 vm_offset_t kva; 321 { 322 pmap_kremove(kva); 323 kmem_free_wakeup(pager_map, kva, PAGE_SIZE); 324 } 325 326 vm_object_t 327 vm_pager_object_lookup(pg_list, handle) 328 register struct pagerlst *pg_list; 329 void *handle; 330 { 331 register vm_object_t object; 332 333 for (object = TAILQ_FIRST(pg_list); object != NULL; object = TAILQ_NEXT(object,pager_object_list)) 334 if (object->handle == handle) 335 return (object); 336 return (NULL); 337 } 338 339 /* 340 * initialize a physical buffer 341 */ 342 343 static void 344 initpbuf(struct buf *bp) 345 { 346 bp->b_rcred = NOCRED; 347 bp->b_wcred = NOCRED; 348 bp->b_qindex = QUEUE_NONE; 349 bp->b_data = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva; 350 bp->b_kvabase = bp->b_data; 351 bp->b_kvasize = MAXPHYS; 352 bp->b_xflags = 0; 353 bp->b_flags = 0; 354 bp->b_ioflags = 0; 355 bp->b_iodone = NULL; 356 bp->b_error = 0; 357 BUF_LOCK(bp, LK_EXCLUSIVE); 358 } 359 360 /* 361 * allocate a physical buffer 362 * 363 * There are a limited number (nswbuf) of physical buffers. We need 364 * to make sure that no single subsystem is able to hog all of them, 365 * so each subsystem implements a counter which is typically initialized 366 * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and 367 * increments it on release, and blocks if the counter hits zero. A 368 * subsystem may initialize the counter to -1 to disable the feature, 369 * but it must still be sure to match up all uses of getpbuf() with 370 * relpbuf() using the same variable. 371 * 372 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 373 * relatively soon when the rest of the subsystems get smart about it. XXX 374 */ 375 struct buf * 376 getpbuf(pfreecnt) 377 int *pfreecnt; 378 { 379 int s; 380 struct buf *bp; 381 382 s = splvm(); 383 384 for (;;) { 385 if (pfreecnt) { 386 while (*pfreecnt == 0) { 387 tsleep(pfreecnt, PVM, "wswbuf0", 0); 388 } 389 } 390 391 /* get a bp from the swap buffer header pool */ 392 if ((bp = TAILQ_FIRST(&bswlist)) != NULL) 393 break; 394 395 bswneeded = 1; 396 tsleep(&bswneeded, PVM, "wswbuf1", 0); 397 /* loop in case someone else grabbed one */ 398 } 399 TAILQ_REMOVE(&bswlist, bp, b_freelist); 400 if (pfreecnt) 401 --*pfreecnt; 402 splx(s); 403 404 initpbuf(bp); 405 return bp; 406 } 407 408 /* 409 * allocate a physical buffer, if one is available. 410 * 411 * Note that there is no NULL hack here - all subsystems using this 412 * call understand how to use pfreecnt. 413 */ 414 struct buf * 415 trypbuf(pfreecnt) 416 int *pfreecnt; 417 { 418 int s; 419 struct buf *bp; 420 421 s = splvm(); 422 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) { 423 splx(s); 424 return NULL; 425 } 426 TAILQ_REMOVE(&bswlist, bp, b_freelist); 427 428 --*pfreecnt; 429 430 splx(s); 431 432 initpbuf(bp); 433 434 return bp; 435 } 436 437 /* 438 * release a physical buffer 439 * 440 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 441 * relatively soon when the rest of the subsystems get smart about it. XXX 442 */ 443 void 444 relpbuf(bp, pfreecnt) 445 struct buf *bp; 446 int *pfreecnt; 447 { 448 int s; 449 450 s = splvm(); 451 452 if (bp->b_rcred != NOCRED) { 453 crfree(bp->b_rcred); 454 bp->b_rcred = NOCRED; 455 } 456 if (bp->b_wcred != NOCRED) { 457 crfree(bp->b_wcred); 458 bp->b_wcred = NOCRED; 459 } 460 461 if (bp->b_vp) 462 pbrelvp(bp); 463 464 BUF_UNLOCK(bp); 465 466 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 467 468 if (bswneeded) { 469 bswneeded = 0; 470 wakeup(&bswneeded); 471 } 472 if (pfreecnt) { 473 if (++*pfreecnt == 1) 474 wakeup(pfreecnt); 475 } 476 splx(s); 477 } 478