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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * from: @(#)vm_pager.c 8.6 (Berkeley) 1/12/94 33 * 34 * 35 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 36 * All rights reserved. 37 * 38 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 39 * 40 * Permission to use, copy, modify and distribute this software and 41 * its documentation is hereby granted, provided that both the copyright 42 * notice and this permission notice appear in all copies of the 43 * software, derivative works or modified versions, and any portions 44 * thereof, and that both notices appear in supporting documentation. 45 * 46 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 47 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 48 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 49 * 50 * Carnegie Mellon requests users of this software to return to 51 * 52 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 53 * School of Computer Science 54 * Carnegie Mellon University 55 * Pittsburgh PA 15213-3890 56 * 57 * any improvements or extensions that they make and grant Carnegie the 58 * rights to redistribute these changes. 59 */ 60 61 /* 62 * Paging space routine stubs. Emulates a matchmaker-like interface 63 * for builtin pagers. 64 */ 65 66 #include <sys/cdefs.h> 67 __FBSDID("$FreeBSD$"); 68 69 #include <sys/param.h> 70 #include <sys/systm.h> 71 #include <sys/kernel.h> 72 #include <sys/vnode.h> 73 #include <sys/bio.h> 74 #include <sys/buf.h> 75 #include <sys/ucred.h> 76 #include <sys/malloc.h> 77 #include <sys/rwlock.h> 78 79 #include <vm/vm.h> 80 #include <vm/vm_param.h> 81 #include <vm/vm_kern.h> 82 #include <vm/vm_object.h> 83 #include <vm/vm_page.h> 84 #include <vm/vm_pager.h> 85 #include <vm/vm_extern.h> 86 87 int cluster_pbuf_freecnt = -1; /* unlimited to begin with */ 88 89 struct buf *swbuf; 90 91 static int dead_pager_getpages(vm_object_t, vm_page_t *, int, int); 92 static vm_object_t dead_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 93 vm_ooffset_t, struct ucred *); 94 static void dead_pager_putpages(vm_object_t, vm_page_t *, int, int, int *); 95 static boolean_t dead_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 96 static void dead_pager_dealloc(vm_object_t); 97 98 static int 99 dead_pager_getpages(obj, ma, count, req) 100 vm_object_t obj; 101 vm_page_t *ma; 102 int count; 103 int req; 104 { 105 return VM_PAGER_FAIL; 106 } 107 108 static vm_object_t 109 dead_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 110 vm_ooffset_t off, struct ucred *cred) 111 { 112 return NULL; 113 } 114 115 static void 116 dead_pager_putpages(object, m, count, flags, rtvals) 117 vm_object_t object; 118 vm_page_t *m; 119 int count; 120 int flags; 121 int *rtvals; 122 { 123 int i; 124 125 for (i = 0; i < count; i++) { 126 rtvals[i] = VM_PAGER_AGAIN; 127 } 128 } 129 130 static int 131 dead_pager_haspage(object, pindex, prev, next) 132 vm_object_t object; 133 vm_pindex_t pindex; 134 int *prev; 135 int *next; 136 { 137 if (prev) 138 *prev = 0; 139 if (next) 140 *next = 0; 141 return FALSE; 142 } 143 144 static void 145 dead_pager_dealloc(object) 146 vm_object_t object; 147 { 148 return; 149 } 150 151 static struct pagerops deadpagerops = { 152 .pgo_alloc = dead_pager_alloc, 153 .pgo_dealloc = dead_pager_dealloc, 154 .pgo_getpages = dead_pager_getpages, 155 .pgo_putpages = dead_pager_putpages, 156 .pgo_haspage = dead_pager_haspage, 157 }; 158 159 struct pagerops *pagertab[] = { 160 &defaultpagerops, /* OBJT_DEFAULT */ 161 &swappagerops, /* OBJT_SWAP */ 162 &vnodepagerops, /* OBJT_VNODE */ 163 &devicepagerops, /* OBJT_DEVICE */ 164 &physpagerops, /* OBJT_PHYS */ 165 &deadpagerops, /* OBJT_DEAD */ 166 &sgpagerops, /* OBJT_SG */ 167 &mgtdevicepagerops, /* OBJT_MGTDEVICE */ 168 }; 169 170 static const int npagers = sizeof(pagertab) / sizeof(pagertab[0]); 171 172 /* 173 * Kernel address space for mapping pages. 174 * Used by pagers where KVAs are needed for IO. 175 * 176 * XXX needs to be large enough to support the number of pending async 177 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size 178 * (MAXPHYS == 64k) if you want to get the most efficiency. 179 */ 180 struct mtx_padalign pbuf_mtx; 181 static TAILQ_HEAD(swqueue, buf) bswlist; 182 static int bswneeded; 183 vm_offset_t swapbkva; /* swap buffers kva */ 184 185 void 186 vm_pager_init() 187 { 188 struct pagerops **pgops; 189 190 TAILQ_INIT(&bswlist); 191 /* 192 * Initialize known pagers 193 */ 194 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 195 if ((*pgops)->pgo_init != NULL) 196 (*(*pgops)->pgo_init) (); 197 } 198 199 void 200 vm_pager_bufferinit() 201 { 202 struct buf *bp; 203 int i; 204 205 mtx_init(&pbuf_mtx, "pbuf mutex", NULL, MTX_DEF); 206 bp = swbuf; 207 /* 208 * Now set up swap and physical I/O buffer headers. 209 */ 210 for (i = 0; i < nswbuf; i++, bp++) { 211 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 212 BUF_LOCKINIT(bp); 213 LIST_INIT(&bp->b_dep); 214 bp->b_rcred = bp->b_wcred = NOCRED; 215 bp->b_xflags = 0; 216 } 217 218 cluster_pbuf_freecnt = nswbuf / 2; 219 vnode_pbuf_freecnt = nswbuf / 2 + 1; 220 vnode_async_pbuf_freecnt = nswbuf / 2; 221 } 222 223 /* 224 * Allocate an instance of a pager of the given type. 225 * Size, protection and offset parameters are passed in for pagers that 226 * need to perform page-level validation (e.g. the device pager). 227 */ 228 vm_object_t 229 vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, 230 vm_prot_t prot, vm_ooffset_t off, struct ucred *cred) 231 { 232 vm_object_t ret; 233 struct pagerops *ops; 234 235 ops = pagertab[type]; 236 if (ops) 237 ret = (*ops->pgo_alloc) (handle, size, prot, off, cred); 238 else 239 ret = NULL; 240 return (ret); 241 } 242 243 /* 244 * The object must be locked. 245 */ 246 void 247 vm_pager_deallocate(object) 248 vm_object_t object; 249 { 250 251 VM_OBJECT_ASSERT_WLOCKED(object); 252 (*pagertab[object->type]->pgo_dealloc) (object); 253 } 254 255 static void 256 vm_pager_assert_in(vm_object_t object, vm_page_t *m, int count) 257 { 258 #ifdef INVARIANTS 259 260 VM_OBJECT_ASSERT_WLOCKED(object); 261 KASSERT(count > 0, ("%s: 0 count", __func__)); 262 /* 263 * All pages must be busied, not mapped, not fully valid, 264 * not dirty and belong to the proper object. 265 */ 266 for (int i = 0 ; i < count; i++) { 267 vm_page_assert_xbusied(m[i]); 268 KASSERT(!pmap_page_is_mapped(m[i]), 269 ("%s: page %p is mapped", __func__, m[i])); 270 KASSERT(m[i]->valid != VM_PAGE_BITS_ALL, 271 ("%s: request for a valid page %p", __func__, m[i])); 272 KASSERT(m[i]->dirty == 0, 273 ("%s: page %p is dirty", __func__, m[i])); 274 KASSERT(m[i]->object == object, 275 ("%s: wrong object %p/%p", __func__, object, m[i]->object)); 276 } 277 #endif 278 } 279 280 /* 281 * Page in the pages for the object using its associated pager. 282 * The requested page must be fully valid on successful return. 283 */ 284 int 285 vm_pager_get_pages(vm_object_t object, vm_page_t *m, int count, int reqpage) 286 { 287 int r; 288 289 vm_pager_assert_in(object, m, count); 290 291 r = (*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage); 292 if (r != VM_PAGER_OK) 293 return (r); 294 295 /* 296 * If pager has replaced the page, assert that it had 297 * updated the array. Also assert that page is still 298 * busied. 299 */ 300 KASSERT(m[reqpage] == vm_page_lookup(object, m[reqpage]->pindex), 301 ("%s: mismatch page %p pindex %ju", __func__, 302 m[reqpage], (uintmax_t )m[reqpage]->pindex)); 303 vm_page_assert_xbusied(m[reqpage]); 304 305 /* 306 * Pager didn't fill up entire page. Zero out 307 * partially filled data. 308 */ 309 if (m[reqpage]->valid != VM_PAGE_BITS_ALL) 310 vm_page_zero_invalid(m[reqpage], TRUE); 311 312 return (VM_PAGER_OK); 313 } 314 315 int 316 vm_pager_get_pages_async(vm_object_t object, vm_page_t *m, int count, 317 int reqpage, pgo_getpages_iodone_t iodone, void *arg) 318 { 319 320 vm_pager_assert_in(object, m, count); 321 322 return ((*pagertab[object->type]->pgo_getpages_async)(object, m, 323 count, reqpage, iodone, arg)); 324 } 325 326 /* 327 * vm_pager_put_pages() - inline, see vm/vm_pager.h 328 * vm_pager_has_page() - inline, see vm/vm_pager.h 329 */ 330 331 /* 332 * Search the specified pager object list for an object with the 333 * specified handle. If an object with the specified handle is found, 334 * increase its reference count and return it. Otherwise, return NULL. 335 * 336 * The pager object list must be locked. 337 */ 338 vm_object_t 339 vm_pager_object_lookup(struct pagerlst *pg_list, void *handle) 340 { 341 vm_object_t object; 342 343 TAILQ_FOREACH(object, pg_list, pager_object_list) { 344 if (object->handle == handle) { 345 VM_OBJECT_WLOCK(object); 346 if ((object->flags & OBJ_DEAD) == 0) { 347 vm_object_reference_locked(object); 348 VM_OBJECT_WUNLOCK(object); 349 break; 350 } 351 VM_OBJECT_WUNLOCK(object); 352 } 353 } 354 return (object); 355 } 356 357 /* 358 * Free the non-requested pages from the given array. To remove all pages, 359 * caller should provide out of range reqpage number. 360 */ 361 void 362 vm_pager_free_nonreq(vm_object_t object, vm_page_t ma[], int reqpage, 363 int npages, boolean_t object_locked) 364 { 365 enum { UNLOCKED, CALLER_LOCKED, INTERNALLY_LOCKED } locked; 366 int i; 367 368 if (object_locked) { 369 VM_OBJECT_ASSERT_WLOCKED(object); 370 locked = CALLER_LOCKED; 371 } else { 372 VM_OBJECT_ASSERT_UNLOCKED(object); 373 locked = UNLOCKED; 374 } 375 for (i = 0; i < npages; ++i) { 376 if (i != reqpage) { 377 if (locked == UNLOCKED) { 378 VM_OBJECT_WLOCK(object); 379 locked = INTERNALLY_LOCKED; 380 } 381 vm_page_lock(ma[i]); 382 vm_page_free(ma[i]); 383 vm_page_unlock(ma[i]); 384 } 385 } 386 if (locked == INTERNALLY_LOCKED) 387 VM_OBJECT_WUNLOCK(object); 388 } 389 390 /* 391 * initialize a physical buffer 392 */ 393 394 /* 395 * XXX This probably belongs in vfs_bio.c 396 */ 397 static void 398 initpbuf(struct buf *bp) 399 { 400 KASSERT(bp->b_bufobj == NULL, ("initpbuf with bufobj")); 401 KASSERT(bp->b_vp == NULL, ("initpbuf with vp")); 402 bp->b_rcred = NOCRED; 403 bp->b_wcred = NOCRED; 404 bp->b_qindex = 0; /* On no queue (QUEUE_NONE) */ 405 bp->b_kvabase = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva; 406 bp->b_data = bp->b_kvabase; 407 bp->b_kvasize = MAXPHYS; 408 bp->b_flags = 0; 409 bp->b_xflags = 0; 410 bp->b_ioflags = 0; 411 bp->b_iodone = NULL; 412 bp->b_error = 0; 413 BUF_LOCK(bp, LK_EXCLUSIVE, NULL); 414 } 415 416 /* 417 * allocate a physical buffer 418 * 419 * There are a limited number (nswbuf) of physical buffers. We need 420 * to make sure that no single subsystem is able to hog all of them, 421 * so each subsystem implements a counter which is typically initialized 422 * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and 423 * increments it on release, and blocks if the counter hits zero. A 424 * subsystem may initialize the counter to -1 to disable the feature, 425 * but it must still be sure to match up all uses of getpbuf() with 426 * relpbuf() using the same variable. 427 * 428 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 429 * relatively soon when the rest of the subsystems get smart about it. XXX 430 */ 431 struct buf * 432 getpbuf(int *pfreecnt) 433 { 434 struct buf *bp; 435 436 mtx_lock(&pbuf_mtx); 437 438 for (;;) { 439 if (pfreecnt) { 440 while (*pfreecnt == 0) { 441 msleep(pfreecnt, &pbuf_mtx, PVM, "wswbuf0", 0); 442 } 443 } 444 445 /* get a bp from the swap buffer header pool */ 446 if ((bp = TAILQ_FIRST(&bswlist)) != NULL) 447 break; 448 449 bswneeded = 1; 450 msleep(&bswneeded, &pbuf_mtx, PVM, "wswbuf1", 0); 451 /* loop in case someone else grabbed one */ 452 } 453 TAILQ_REMOVE(&bswlist, bp, b_freelist); 454 if (pfreecnt) 455 --*pfreecnt; 456 mtx_unlock(&pbuf_mtx); 457 458 initpbuf(bp); 459 return bp; 460 } 461 462 /* 463 * allocate a physical buffer, if one is available. 464 * 465 * Note that there is no NULL hack here - all subsystems using this 466 * call understand how to use pfreecnt. 467 */ 468 struct buf * 469 trypbuf(int *pfreecnt) 470 { 471 struct buf *bp; 472 473 mtx_lock(&pbuf_mtx); 474 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) { 475 mtx_unlock(&pbuf_mtx); 476 return NULL; 477 } 478 TAILQ_REMOVE(&bswlist, bp, b_freelist); 479 480 --*pfreecnt; 481 482 mtx_unlock(&pbuf_mtx); 483 484 initpbuf(bp); 485 486 return bp; 487 } 488 489 /* 490 * release a physical buffer 491 * 492 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 493 * relatively soon when the rest of the subsystems get smart about it. XXX 494 */ 495 void 496 relpbuf(struct buf *bp, int *pfreecnt) 497 { 498 499 if (bp->b_rcred != NOCRED) { 500 crfree(bp->b_rcred); 501 bp->b_rcred = NOCRED; 502 } 503 if (bp->b_wcred != NOCRED) { 504 crfree(bp->b_wcred); 505 bp->b_wcred = NOCRED; 506 } 507 508 KASSERT(bp->b_vp == NULL, ("relpbuf with vp")); 509 KASSERT(bp->b_bufobj == NULL, ("relpbuf with bufobj")); 510 511 BUF_UNLOCK(bp); 512 513 mtx_lock(&pbuf_mtx); 514 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 515 516 if (bswneeded) { 517 bswneeded = 0; 518 wakeup(&bswneeded); 519 } 520 if (pfreecnt) { 521 if (++*pfreecnt == 1) 522 wakeup(pfreecnt); 523 } 524 mtx_unlock(&pbuf_mtx); 525 } 526 527 /* 528 * Associate a p-buffer with a vnode. 529 * 530 * Also sets B_PAGING flag to indicate that vnode is not fully associated 531 * with the buffer. i.e. the bp has not been linked into the vnode or 532 * ref-counted. 533 */ 534 void 535 pbgetvp(struct vnode *vp, struct buf *bp) 536 { 537 538 KASSERT(bp->b_vp == NULL, ("pbgetvp: not free")); 539 KASSERT(bp->b_bufobj == NULL, ("pbgetvp: not free (bufobj)")); 540 541 bp->b_vp = vp; 542 bp->b_flags |= B_PAGING; 543 bp->b_bufobj = &vp->v_bufobj; 544 } 545 546 /* 547 * Associate a p-buffer with a vnode. 548 * 549 * Also sets B_PAGING flag to indicate that vnode is not fully associated 550 * with the buffer. i.e. the bp has not been linked into the vnode or 551 * ref-counted. 552 */ 553 void 554 pbgetbo(struct bufobj *bo, struct buf *bp) 555 { 556 557 KASSERT(bp->b_vp == NULL, ("pbgetbo: not free (vnode)")); 558 KASSERT(bp->b_bufobj == NULL, ("pbgetbo: not free (bufobj)")); 559 560 bp->b_flags |= B_PAGING; 561 bp->b_bufobj = bo; 562 } 563 564 /* 565 * Disassociate a p-buffer from a vnode. 566 */ 567 void 568 pbrelvp(struct buf *bp) 569 { 570 571 KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL")); 572 KASSERT(bp->b_bufobj != NULL, ("pbrelvp: NULL bufobj")); 573 KASSERT((bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) == 0, 574 ("pbrelvp: pager buf on vnode list.")); 575 576 bp->b_vp = NULL; 577 bp->b_bufobj = NULL; 578 bp->b_flags &= ~B_PAGING; 579 } 580 581 /* 582 * Disassociate a p-buffer from a bufobj. 583 */ 584 void 585 pbrelbo(struct buf *bp) 586 { 587 588 KASSERT(bp->b_vp == NULL, ("pbrelbo: vnode")); 589 KASSERT(bp->b_bufobj != NULL, ("pbrelbo: NULL bufobj")); 590 KASSERT((bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) == 0, 591 ("pbrelbo: pager buf on vnode list.")); 592 593 bp->b_bufobj = NULL; 594 bp->b_flags &= ~B_PAGING; 595 } 596