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/buf.h> 77 #include <sys/ucred.h> 78 #include <sys/malloc.h> 79 #include <sys/proc.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 95 int cluster_pbuf_freecnt = -1; /* unlimited to begin with */ 96 97 static int dead_pager_getpages __P((vm_object_t, vm_page_t *, int, int)); 98 static vm_object_t dead_pager_alloc __P((void *, vm_ooffset_t, vm_prot_t, 99 vm_ooffset_t)); 100 static void dead_pager_putpages __P((vm_object_t, vm_page_t *, int, int, int *)); 101 static boolean_t dead_pager_haspage __P((vm_object_t, vm_pindex_t, int *, int *)); 102 static void dead_pager_dealloc __P((vm_object_t)); 103 104 static int 105 dead_pager_getpages(obj, ma, count, req) 106 vm_object_t obj; 107 vm_page_t *ma; 108 int count; 109 int req; 110 { 111 return VM_PAGER_FAIL; 112 } 113 114 static vm_object_t 115 dead_pager_alloc(handle, size, prot, off) 116 void *handle; 117 vm_ooffset_t size; 118 vm_prot_t prot; 119 vm_ooffset_t off; 120 { 121 return NULL; 122 } 123 124 static void 125 dead_pager_putpages(object, m, count, flags, rtvals) 126 vm_object_t object; 127 vm_page_t *m; 128 int count; 129 int flags; 130 int *rtvals; 131 { 132 int i; 133 134 for (i = 0; i < count; i++) { 135 rtvals[i] = VM_PAGER_AGAIN; 136 } 137 } 138 139 static int 140 dead_pager_haspage(object, pindex, prev, next) 141 vm_object_t object; 142 vm_pindex_t pindex; 143 int *prev; 144 int *next; 145 { 146 if (prev) 147 *prev = 0; 148 if (next) 149 *next = 0; 150 return FALSE; 151 } 152 153 static void 154 dead_pager_dealloc(object) 155 vm_object_t object; 156 { 157 return; 158 } 159 160 static struct pagerops deadpagerops = { 161 NULL, 162 dead_pager_alloc, 163 dead_pager_dealloc, 164 dead_pager_getpages, 165 dead_pager_putpages, 166 dead_pager_haspage, 167 NULL 168 }; 169 170 struct pagerops *pagertab[] = { 171 &defaultpagerops, /* OBJT_DEFAULT */ 172 &swappagerops, /* OBJT_SWAP */ 173 &vnodepagerops, /* OBJT_VNODE */ 174 &devicepagerops, /* OBJT_DEVICE */ 175 &deadpagerops /* OBJT_DEAD */ 176 }; 177 178 int npagers = sizeof(pagertab) / sizeof(pagertab[0]); 179 180 /* 181 * Kernel address space for mapping pages. 182 * Used by pagers where KVAs are needed for IO. 183 * 184 * XXX needs to be large enough to support the number of pending async 185 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size 186 * (MAXPHYS == 64k) if you want to get the most efficiency. 187 */ 188 #define PAGER_MAP_SIZE (8 * 1024 * 1024) 189 190 int pager_map_size = PAGER_MAP_SIZE; 191 vm_map_t pager_map; 192 static int bswneeded; 193 static vm_offset_t swapbkva; /* swap buffers kva */ 194 195 void 196 vm_pager_init() 197 { 198 struct pagerops **pgops; 199 200 /* 201 * Initialize known pagers 202 */ 203 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 204 if (pgops && ((*pgops)->pgo_init != NULL)) 205 (*(*pgops)->pgo_init) (); 206 } 207 208 void 209 vm_pager_bufferinit() 210 { 211 struct buf *bp; 212 int i; 213 214 bp = swbuf; 215 /* 216 * Now set up swap and physical I/O buffer headers. 217 */ 218 for (i = 0; i < nswbuf; i++, bp++) { 219 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 220 BUF_LOCKINIT(bp); 221 LIST_INIT(&bp->b_dep); 222 bp->b_rcred = bp->b_wcred = NOCRED; 223 bp->b_xflags = 0; 224 } 225 226 cluster_pbuf_freecnt = nswbuf / 2; 227 228 swapbkva = kmem_alloc_pageable(pager_map, nswbuf * MAXPHYS); 229 if (!swapbkva) 230 panic("Not enough pager_map VM space for physical buffers"); 231 } 232 233 /* 234 * Allocate an instance of a pager of the given type. 235 * Size, protection and offset parameters are passed in for pagers that 236 * need to perform page-level validation (e.g. the device pager). 237 */ 238 vm_object_t 239 vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, vm_prot_t prot, 240 vm_ooffset_t off) 241 { 242 struct pagerops *ops; 243 244 ops = pagertab[type]; 245 if (ops) 246 return ((*ops->pgo_alloc) (handle, size, prot, off)); 247 return (NULL); 248 } 249 250 void 251 vm_pager_deallocate(object) 252 vm_object_t object; 253 { 254 (*pagertab[object->type]->pgo_dealloc) (object); 255 } 256 257 /* 258 * vm_pager_strategy: 259 * 260 * called with no specific spl 261 * Execute strategy routine directly to pager. 262 */ 263 264 void 265 vm_pager_strategy(vm_object_t object, struct buf *bp) 266 { 267 if (pagertab[object->type]->pgo_strategy) { 268 (*pagertab[object->type]->pgo_strategy)(object, bp); 269 } else { 270 bp->b_ioflags |= BIO_ERROR; 271 bp->b_error = ENXIO; 272 bufdone(bp); 273 } 274 } 275 276 /* 277 * vm_pager_get_pages() - inline, see vm/vm_pager.h 278 * vm_pager_put_pages() - inline, see vm/vm_pager.h 279 * vm_pager_has_page() - inline, see vm/vm_pager.h 280 * vm_pager_page_inserted() - inline, see vm/vm_pager.h 281 * vm_pager_page_removed() - inline, see vm/vm_pager.h 282 */ 283 284 #if 0 285 /* 286 * vm_pager_sync: 287 * 288 * Called by pageout daemon before going back to sleep. 289 * Gives pagers a chance to clean up any completed async pageing 290 * operations. 291 */ 292 void 293 vm_pager_sync() 294 { 295 struct pagerops **pgops; 296 297 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 298 if (pgops && ((*pgops)->pgo_sync != NULL)) 299 (*(*pgops)->pgo_sync) (); 300 } 301 302 #endif 303 304 vm_offset_t 305 vm_pager_map_page(m) 306 vm_page_t m; 307 { 308 vm_offset_t kva; 309 310 kva = kmem_alloc_wait(pager_map, PAGE_SIZE); 311 pmap_kenter(kva, VM_PAGE_TO_PHYS(m)); 312 return (kva); 313 } 314 315 void 316 vm_pager_unmap_page(kva) 317 vm_offset_t kva; 318 { 319 pmap_kremove(kva); 320 kmem_free_wakeup(pager_map, kva, PAGE_SIZE); 321 } 322 323 vm_object_t 324 vm_pager_object_lookup(pg_list, handle) 325 register struct pagerlst *pg_list; 326 void *handle; 327 { 328 register vm_object_t object; 329 330 for (object = TAILQ_FIRST(pg_list); object != NULL; object = TAILQ_NEXT(object,pager_object_list)) 331 if (object->handle == handle) 332 return (object); 333 return (NULL); 334 } 335 336 /* 337 * initialize a physical buffer 338 */ 339 340 static void 341 initpbuf(struct buf *bp) 342 { 343 bp->b_rcred = NOCRED; 344 bp->b_wcred = NOCRED; 345 bp->b_qindex = QUEUE_NONE; 346 bp->b_data = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva; 347 bp->b_kvabase = bp->b_data; 348 bp->b_kvasize = MAXPHYS; 349 bp->b_xflags = 0; 350 bp->b_flags = 0; 351 bp->b_ioflags = 0; 352 bp->b_iodone = NULL; 353 bp->b_error = 0; 354 BUF_LOCK(bp, LK_EXCLUSIVE); 355 } 356 357 /* 358 * allocate a physical buffer 359 * 360 * There are a limited number (nswbuf) of physical buffers. We need 361 * to make sure that no single subsystem is able to hog all of them, 362 * so each subsystem implements a counter which is typically initialized 363 * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and 364 * increments it on release, and blocks if the counter hits zero. A 365 * subsystem may initialize the counter to -1 to disable the feature, 366 * but it must still be sure to match up all uses of getpbuf() with 367 * relpbuf() using the same variable. 368 * 369 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 370 * relatively soon when the rest of the subsystems get smart about it. XXX 371 */ 372 struct buf * 373 getpbuf(pfreecnt) 374 int *pfreecnt; 375 { 376 int s; 377 struct buf *bp; 378 379 s = splvm(); 380 381 for (;;) { 382 if (pfreecnt) { 383 while (*pfreecnt == 0) { 384 tsleep(pfreecnt, PVM, "wswbuf0", 0); 385 } 386 } 387 388 /* get a bp from the swap buffer header pool */ 389 if ((bp = TAILQ_FIRST(&bswlist)) != NULL) 390 break; 391 392 bswneeded = 1; 393 tsleep(&bswneeded, PVM, "wswbuf1", 0); 394 /* loop in case someone else grabbed one */ 395 } 396 TAILQ_REMOVE(&bswlist, bp, b_freelist); 397 if (pfreecnt) 398 --*pfreecnt; 399 splx(s); 400 401 initpbuf(bp); 402 return bp; 403 } 404 405 /* 406 * allocate a physical buffer, if one is available. 407 * 408 * Note that there is no NULL hack here - all subsystems using this 409 * call understand how to use pfreecnt. 410 */ 411 struct buf * 412 trypbuf(pfreecnt) 413 int *pfreecnt; 414 { 415 int s; 416 struct buf *bp; 417 418 s = splvm(); 419 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) { 420 splx(s); 421 return NULL; 422 } 423 TAILQ_REMOVE(&bswlist, bp, b_freelist); 424 425 --*pfreecnt; 426 427 splx(s); 428 429 initpbuf(bp); 430 431 return bp; 432 } 433 434 /* 435 * release a physical buffer 436 * 437 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 438 * relatively soon when the rest of the subsystems get smart about it. XXX 439 */ 440 void 441 relpbuf(bp, pfreecnt) 442 struct buf *bp; 443 int *pfreecnt; 444 { 445 int s; 446 447 s = splvm(); 448 449 if (bp->b_rcred != NOCRED) { 450 crfree(bp->b_rcred); 451 bp->b_rcred = NOCRED; 452 } 453 if (bp->b_wcred != NOCRED) { 454 crfree(bp->b_wcred); 455 bp->b_wcred = NOCRED; 456 } 457 458 if (bp->b_vp) 459 pbrelvp(bp); 460 461 BUF_UNLOCK(bp); 462 463 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 464 465 if (bswneeded) { 466 bswneeded = 0; 467 wakeup(&bswneeded); 468 } 469 if (pfreecnt) { 470 if (++*pfreecnt == 1) 471 wakeup(pfreecnt); 472 } 473 splx(s); 474 } 475 476 /******************************************************** 477 * CHAINING FUNCTIONS * 478 ******************************************************** 479 * 480 * These functions support recursion of I/O operations 481 * on bp's, typically by chaining one or more 'child' bp's 482 * to the parent. Synchronous, asynchronous, and semi-synchronous 483 * chaining is possible. 484 */ 485 486 /* 487 * vm_pager_chain_iodone: 488 * 489 * io completion routine for child bp. Currently we fudge a bit 490 * on dealing with b_resid. Since users of these routines may issue 491 * multiple children simultaneously, sequencing of the error can be lost. 492 */ 493 494 static void 495 vm_pager_chain_iodone(struct buf *nbp) 496 { 497 struct buf *bp; 498 499 if ((bp = nbp->b_chain.parent) != NULL) { 500 if (nbp->b_ioflags & BIO_ERROR) { 501 bp->b_ioflags |= BIO_ERROR; 502 bp->b_error = nbp->b_error; 503 } else if (nbp->b_resid != 0) { 504 bp->b_ioflags |= BIO_ERROR; 505 bp->b_error = EINVAL; 506 } else { 507 bp->b_resid -= nbp->b_bcount; 508 } 509 nbp->b_chain.parent = NULL; 510 --bp->b_chain.count; 511 if (bp->b_flags & B_WANT) { 512 bp->b_flags &= ~B_WANT; 513 wakeup(bp); 514 } 515 if (!bp->b_chain.count && (bp->b_flags & B_AUTOCHAINDONE)) { 516 bp->b_flags &= ~B_AUTOCHAINDONE; 517 if (bp->b_resid != 0 && !(bp->b_ioflags & BIO_ERROR)) { 518 bp->b_ioflags |= BIO_ERROR; 519 bp->b_error = EINVAL; 520 } 521 bufdone(bp); 522 } 523 } 524 nbp->b_flags |= B_DONE; 525 nbp->b_flags &= ~B_ASYNC; 526 relpbuf(nbp, NULL); 527 } 528 529 /* 530 * getchainbuf: 531 * 532 * Obtain a physical buffer and chain it to its parent buffer. When 533 * I/O completes, the parent buffer will be B_SIGNAL'd. Errors are 534 * automatically propagated to the parent 535 */ 536 537 struct buf * 538 getchainbuf(struct buf *bp, struct vnode *vp, int flags) 539 { 540 struct buf *nbp = getpbuf(NULL); 541 542 nbp->b_chain.parent = bp; 543 ++bp->b_chain.count; 544 545 if (bp->b_chain.count > 4) 546 waitchainbuf(bp, 4, 0); 547 548 nbp->b_ioflags = bp->b_ioflags & BIO_ORDERED; 549 nbp->b_flags = flags; 550 nbp->b_rcred = nbp->b_wcred = proc0.p_ucred; 551 nbp->b_iodone = vm_pager_chain_iodone; 552 553 crhold(nbp->b_rcred); 554 crhold(nbp->b_wcred); 555 556 if (vp) 557 pbgetvp(vp, nbp); 558 return(nbp); 559 } 560 561 void 562 flushchainbuf(struct buf *nbp) 563 { 564 if (nbp->b_bcount) { 565 nbp->b_bufsize = nbp->b_bcount; 566 if (nbp->b_iocmd == BIO_WRITE) 567 nbp->b_dirtyend = nbp->b_bcount; 568 BUF_KERNPROC(nbp); 569 BUF_STRATEGY(nbp); 570 } else { 571 bufdone(nbp); 572 } 573 } 574 575 void 576 waitchainbuf(struct buf *bp, int count, int done) 577 { 578 int s; 579 580 s = splbio(); 581 while (bp->b_chain.count > count) { 582 bp->b_flags |= B_WANT; 583 tsleep(bp, PRIBIO + 4, "bpchain", 0); 584 } 585 if (done) { 586 if (bp->b_resid != 0 && !(bp->b_ioflags & BIO_ERROR)) { 587 bp->b_ioflags |= BIO_ERROR; 588 bp->b_error = EINVAL; 589 } 590 bufdone(bp); 591 } 592 splx(s); 593 } 594 595 void 596 autochaindone(struct buf *bp) 597 { 598 int s; 599 600 s = splbio(); 601 if (bp->b_chain.count == 0) 602 bufdone(bp); 603 else 604 bp->b_flags |= B_AUTOCHAINDONE; 605 splx(s); 606 } 607 608