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 struct mtx pbuf_mtx; 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 mtx_init(&pbuf_mtx, "pbuf mutex", MTX_DEF); 218 bp = swbuf; 219 /* 220 * Now set up swap and physical I/O buffer headers. 221 */ 222 for (i = 0; i < nswbuf; i++, bp++) { 223 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 224 BUF_LOCKINIT(bp); 225 LIST_INIT(&bp->b_dep); 226 bp->b_rcred = bp->b_wcred = NOCRED; 227 bp->b_xflags = 0; 228 } 229 230 cluster_pbuf_freecnt = nswbuf / 2; 231 232 swapbkva = kmem_alloc_pageable(pager_map, nswbuf * MAXPHYS); 233 if (!swapbkva) 234 panic("Not enough pager_map VM space for physical buffers"); 235 } 236 237 /* 238 * Allocate an instance of a pager of the given type. 239 * Size, protection and offset parameters are passed in for pagers that 240 * need to perform page-level validation (e.g. the device pager). 241 */ 242 vm_object_t 243 vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, 244 vm_prot_t prot, vm_ooffset_t off) 245 { 246 vm_object_t ret; 247 struct pagerops *ops; 248 249 GIANT_REQUIRED; 250 251 ops = pagertab[type]; 252 if (ops) 253 ret = (*ops->pgo_alloc) (handle, size, prot, off); 254 else 255 ret = NULL; 256 return (ret); 257 } 258 259 void 260 vm_pager_deallocate(object) 261 vm_object_t object; 262 { 263 GIANT_REQUIRED; 264 (*pagertab[object->type]->pgo_dealloc) (object); 265 } 266 267 /* 268 * vm_pager_strategy: 269 * 270 * called with no specific spl 271 * Execute strategy routine directly to pager. 272 */ 273 274 void 275 vm_pager_strategy(vm_object_t object, struct bio *bp) 276 { 277 if (pagertab[object->type]->pgo_strategy) { 278 (*pagertab[object->type]->pgo_strategy)(object, bp); 279 } else { 280 bp->bio_flags |= BIO_ERROR; 281 bp->bio_error = ENXIO; 282 biodone(bp); 283 } 284 } 285 286 /* 287 * vm_pager_get_pages() - inline, see vm/vm_pager.h 288 * vm_pager_put_pages() - inline, see vm/vm_pager.h 289 * vm_pager_has_page() - inline, see vm/vm_pager.h 290 * vm_pager_page_inserted() - inline, see vm/vm_pager.h 291 * vm_pager_page_removed() - inline, see vm/vm_pager.h 292 */ 293 294 #if 0 295 /* 296 * vm_pager_sync: 297 * 298 * Called by pageout daemon before going back to sleep. 299 * Gives pagers a chance to clean up any completed async pageing 300 * operations. 301 */ 302 void 303 vm_pager_sync() 304 { 305 struct pagerops **pgops; 306 307 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 308 if (pgops && ((*pgops)->pgo_sync != NULL)) 309 (*(*pgops)->pgo_sync) (); 310 } 311 312 #endif 313 314 vm_offset_t 315 vm_pager_map_page(m) 316 vm_page_t m; 317 { 318 vm_offset_t kva; 319 320 kva = kmem_alloc_wait(pager_map, PAGE_SIZE); 321 pmap_kenter(kva, VM_PAGE_TO_PHYS(m)); 322 return (kva); 323 } 324 325 void 326 vm_pager_unmap_page(kva) 327 vm_offset_t kva; 328 { 329 pmap_kremove(kva); 330 kmem_free_wakeup(pager_map, kva, PAGE_SIZE); 331 } 332 333 vm_object_t 334 vm_pager_object_lookup(pg_list, handle) 335 struct pagerlst *pg_list; 336 void *handle; 337 { 338 vm_object_t object; 339 340 TAILQ_FOREACH(object, pg_list, pager_object_list) 341 if (object->handle == handle) 342 return (object); 343 return (NULL); 344 } 345 346 /* 347 * initialize a physical buffer 348 */ 349 350 static void 351 initpbuf(struct buf *bp) 352 { 353 bp->b_rcred = NOCRED; 354 bp->b_wcred = NOCRED; 355 bp->b_qindex = QUEUE_NONE; 356 bp->b_data = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva; 357 bp->b_kvabase = bp->b_data; 358 bp->b_kvasize = MAXPHYS; 359 bp->b_xflags = 0; 360 bp->b_flags = 0; 361 bp->b_ioflags = 0; 362 bp->b_iodone = NULL; 363 bp->b_error = 0; 364 bp->b_magic = B_MAGIC_BIO; 365 bp->b_op = &buf_ops_bio; 366 BUF_LOCK(bp, LK_EXCLUSIVE); 367 } 368 369 /* 370 * allocate a physical buffer 371 * 372 * There are a limited number (nswbuf) of physical buffers. We need 373 * to make sure that no single subsystem is able to hog all of them, 374 * so each subsystem implements a counter which is typically initialized 375 * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and 376 * increments it on release, and blocks if the counter hits zero. A 377 * subsystem may initialize the counter to -1 to disable the feature, 378 * but it must still be sure to match up all uses of getpbuf() with 379 * relpbuf() using the same variable. 380 * 381 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 382 * relatively soon when the rest of the subsystems get smart about it. XXX 383 */ 384 struct buf * 385 getpbuf(pfreecnt) 386 int *pfreecnt; 387 { 388 int s; 389 struct buf *bp; 390 391 s = splvm(); 392 GIANT_REQUIRED; 393 mtx_lock(&pbuf_mtx); 394 395 for (;;) { 396 if (pfreecnt) { 397 while (*pfreecnt == 0) { 398 msleep(pfreecnt, &pbuf_mtx, PVM, "wswbuf0", 0); 399 } 400 } 401 402 /* get a bp from the swap buffer header pool */ 403 if ((bp = TAILQ_FIRST(&bswlist)) != NULL) 404 break; 405 406 bswneeded = 1; 407 msleep(&bswneeded, &pbuf_mtx, PVM, "wswbuf1", 0); 408 /* loop in case someone else grabbed one */ 409 } 410 TAILQ_REMOVE(&bswlist, bp, b_freelist); 411 if (pfreecnt) 412 --*pfreecnt; 413 mtx_unlock(&pbuf_mtx); 414 splx(s); 415 416 initpbuf(bp); 417 return bp; 418 } 419 420 /* 421 * allocate a physical buffer, if one is available. 422 * 423 * Note that there is no NULL hack here - all subsystems using this 424 * call understand how to use pfreecnt. 425 */ 426 struct buf * 427 trypbuf(pfreecnt) 428 int *pfreecnt; 429 { 430 int s; 431 struct buf *bp; 432 433 s = splvm(); 434 mtx_lock(&pbuf_mtx); 435 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) { 436 mtx_unlock(&pbuf_mtx); 437 splx(s); 438 return NULL; 439 } 440 TAILQ_REMOVE(&bswlist, bp, b_freelist); 441 442 --*pfreecnt; 443 444 mtx_unlock(&pbuf_mtx); 445 splx(s); 446 447 initpbuf(bp); 448 449 return bp; 450 } 451 452 /* 453 * release a physical buffer 454 * 455 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 456 * relatively soon when the rest of the subsystems get smart about it. XXX 457 */ 458 void 459 relpbuf(bp, pfreecnt) 460 struct buf *bp; 461 int *pfreecnt; 462 { 463 int s; 464 465 s = splvm(); 466 mtx_lock(&pbuf_mtx); 467 468 if (bp->b_rcred != NOCRED) { 469 crfree(bp->b_rcred); 470 bp->b_rcred = NOCRED; 471 } 472 if (bp->b_wcred != NOCRED) { 473 crfree(bp->b_wcred); 474 bp->b_wcred = NOCRED; 475 } 476 477 if (bp->b_vp) 478 pbrelvp(bp); 479 480 BUF_UNLOCK(bp); 481 482 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 483 484 if (bswneeded) { 485 bswneeded = 0; 486 wakeup(&bswneeded); 487 } 488 if (pfreecnt) { 489 if (++*pfreecnt == 1) 490 wakeup(pfreecnt); 491 } 492 mtx_unlock(&pbuf_mtx); 493 splx(s); 494 } 495