1 /*- 2 * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU) 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * The Mach Operating System project at Carnegie-Mellon University. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * from: @(#)vm_pager.c 8.6 (Berkeley) 1/12/94 35 * 36 * 37 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 38 * All rights reserved. 39 * 40 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 41 * 42 * Permission to use, copy, modify and distribute this software and 43 * its documentation is hereby granted, provided that both the copyright 44 * notice and this permission notice appear in all copies of the 45 * software, derivative works or modified versions, and any portions 46 * thereof, and that both notices appear in supporting documentation. 47 * 48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 51 * 52 * Carnegie Mellon requests users of this software to return to 53 * 54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 55 * School of Computer Science 56 * Carnegie Mellon University 57 * Pittsburgh PA 15213-3890 58 * 59 * any improvements or extensions that they make and grant Carnegie the 60 * rights to redistribute these changes. 61 */ 62 63 /* 64 * Paging space routine stubs. Emulates a matchmaker-like interface 65 * for builtin pagers. 66 */ 67 68 #include <sys/cdefs.h> 69 #include "opt_param.h" 70 71 #include <sys/param.h> 72 #include <sys/systm.h> 73 #include <sys/kernel.h> 74 #include <sys/vnode.h> 75 #include <sys/bio.h> 76 #include <sys/buf.h> 77 #include <sys/ucred.h> 78 #include <sys/malloc.h> 79 #include <sys/rwlock.h> 80 #include <sys/user.h> 81 82 #include <vm/vm.h> 83 #include <vm/vm_param.h> 84 #include <vm/vm_kern.h> 85 #include <vm/vm_object.h> 86 #include <vm/vm_page.h> 87 #include <vm/vm_pager.h> 88 #include <vm/vm_extern.h> 89 #include <vm/uma.h> 90 91 uma_zone_t pbuf_zone; 92 static int pbuf_init(void *, int, int); 93 static int pbuf_ctor(void *, int, void *, int); 94 static void pbuf_dtor(void *, int, void *); 95 96 static int dead_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *); 97 static vm_object_t dead_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 98 vm_ooffset_t, struct ucred *); 99 static void dead_pager_putpages(vm_object_t, vm_page_t *, int, int, int *); 100 static boolean_t dead_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 101 static void dead_pager_dealloc(vm_object_t); 102 static void dead_pager_getvp(vm_object_t, struct vnode **, bool *); 103 104 static int 105 dead_pager_getpages(vm_object_t obj, vm_page_t *ma, int count, int *rbehind, 106 int *rahead) 107 { 108 109 return (VM_PAGER_FAIL); 110 } 111 112 static vm_object_t 113 dead_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 114 vm_ooffset_t off, struct ucred *cred) 115 { 116 117 return (NULL); 118 } 119 120 static void 121 dead_pager_putpages(vm_object_t object, vm_page_t *m, int count, 122 int flags, int *rtvals) 123 { 124 int i; 125 126 for (i = 0; i < count; i++) 127 rtvals[i] = VM_PAGER_AGAIN; 128 } 129 130 static boolean_t 131 dead_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *prev, int *next) 132 { 133 134 if (prev != NULL) 135 *prev = 0; 136 if (next != NULL) 137 *next = 0; 138 return (FALSE); 139 } 140 141 static void 142 dead_pager_dealloc(vm_object_t object) 143 { 144 145 } 146 147 static void 148 dead_pager_getvp(vm_object_t object, struct vnode **vpp, bool *vp_heldp) 149 { 150 /* 151 * For OBJT_DEAD objects, v_writecount was handled in 152 * vnode_pager_dealloc(). 153 */ 154 } 155 156 static const struct pagerops deadpagerops = { 157 .pgo_kvme_type = KVME_TYPE_DEAD, 158 .pgo_alloc = dead_pager_alloc, 159 .pgo_dealloc = dead_pager_dealloc, 160 .pgo_getpages = dead_pager_getpages, 161 .pgo_putpages = dead_pager_putpages, 162 .pgo_haspage = dead_pager_haspage, 163 .pgo_getvp = dead_pager_getvp, 164 }; 165 166 const struct pagerops *pagertab[16] __read_mostly = { 167 [OBJT_SWAP] = &swappagerops, 168 [OBJT_VNODE] = &vnodepagerops, 169 [OBJT_DEVICE] = &devicepagerops, 170 [OBJT_PHYS] = &physpagerops, 171 [OBJT_DEAD] = &deadpagerops, 172 [OBJT_SG] = &sgpagerops, 173 [OBJT_MGTDEVICE] = &mgtdevicepagerops, 174 }; 175 static struct mtx pagertab_lock; 176 177 void 178 vm_pager_init(void) 179 { 180 const struct pagerops **pgops; 181 int i; 182 183 mtx_init(&pagertab_lock, "dynpag", NULL, MTX_DEF); 184 185 /* 186 * Initialize known pagers 187 */ 188 for (i = 0; i < OBJT_FIRST_DYN; i++) { 189 pgops = &pagertab[i]; 190 if (*pgops != NULL && (*pgops)->pgo_init != NULL) 191 (*(*pgops)->pgo_init)(); 192 } 193 } 194 195 static int nswbuf_max; 196 197 void 198 vm_pager_bufferinit(void) 199 { 200 201 /* Main zone for paging bufs. */ 202 pbuf_zone = uma_zcreate("pbuf", 203 sizeof(struct buf) + PBUF_PAGES * sizeof(vm_page_t), 204 pbuf_ctor, pbuf_dtor, pbuf_init, NULL, UMA_ALIGN_CACHE, 205 UMA_ZONE_NOFREE); 206 /* Few systems may still use this zone directly, so it needs a limit. */ 207 nswbuf_max += uma_zone_set_max(pbuf_zone, NSWBUF_MIN); 208 } 209 210 uma_zone_t 211 pbuf_zsecond_create(const char *name, int max) 212 { 213 uma_zone_t zone; 214 215 zone = uma_zsecond_create(name, pbuf_ctor, pbuf_dtor, NULL, NULL, 216 pbuf_zone); 217 218 #ifdef KMSAN 219 /* 220 * Shrink the size of the pbuf pools if KMSAN is enabled, otherwise the 221 * shadows of the large KVA allocations eat up too much memory. 222 */ 223 max /= 3; 224 #endif 225 226 /* 227 * uma_prealloc() rounds up to items per slab. If we would prealloc 228 * immediately on every pbuf_zsecond_create(), we may accumulate too 229 * much of difference between hard limit and prealloced items, which 230 * means wasted memory. 231 */ 232 if (nswbuf_max > 0) 233 nswbuf_max += uma_zone_set_max(zone, max); 234 else 235 uma_prealloc(pbuf_zone, uma_zone_set_max(zone, max)); 236 237 return (zone); 238 } 239 240 static void 241 pbuf_prealloc(void *arg __unused) 242 { 243 244 uma_prealloc(pbuf_zone, nswbuf_max); 245 nswbuf_max = -1; 246 } 247 248 SYSINIT(pbuf, SI_SUB_KTHREAD_BUF, SI_ORDER_ANY, pbuf_prealloc, NULL); 249 250 /* 251 * Allocate an instance of a pager of the given type. 252 * Size, protection and offset parameters are passed in for pagers that 253 * need to perform page-level validation (e.g. the device pager). 254 */ 255 vm_object_t 256 vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, 257 vm_prot_t prot, vm_ooffset_t off, struct ucred *cred) 258 { 259 vm_object_t object; 260 261 MPASS(type < nitems(pagertab)); 262 263 object = (*pagertab[type]->pgo_alloc)(handle, size, prot, off, cred); 264 if (object != NULL) 265 object->type = type; 266 return (object); 267 } 268 269 /* 270 * The object must be locked. 271 */ 272 void 273 vm_pager_deallocate(vm_object_t object) 274 { 275 276 VM_OBJECT_ASSERT_WLOCKED(object); 277 MPASS(object->type < nitems(pagertab)); 278 (*pagertab[object->type]->pgo_dealloc) (object); 279 } 280 281 static void 282 vm_pager_assert_in(vm_object_t object, vm_page_t *m, int count) 283 { 284 #ifdef INVARIANTS 285 286 /* 287 * All pages must be consecutive, busied, not mapped, not fully valid, 288 * not dirty and belong to the proper object. Some pages may be the 289 * bogus page, but the first and last pages must be a real ones. 290 */ 291 292 VM_OBJECT_ASSERT_UNLOCKED(object); 293 VM_OBJECT_ASSERT_PAGING(object); 294 KASSERT(count > 0, ("%s: 0 count", __func__)); 295 for (int i = 0 ; i < count; i++) { 296 if (m[i] == bogus_page) { 297 KASSERT(i != 0 && i != count - 1, 298 ("%s: page %d is the bogus page", __func__, i)); 299 continue; 300 } 301 vm_page_assert_xbusied(m[i]); 302 KASSERT(!pmap_page_is_mapped(m[i]), 303 ("%s: page %p is mapped", __func__, m[i])); 304 KASSERT(m[i]->valid != VM_PAGE_BITS_ALL, 305 ("%s: request for a valid page %p", __func__, m[i])); 306 KASSERT(m[i]->dirty == 0, 307 ("%s: page %p is dirty", __func__, m[i])); 308 KASSERT(m[i]->object == object, 309 ("%s: wrong object %p/%p", __func__, object, m[i]->object)); 310 KASSERT(m[i]->pindex == m[0]->pindex + i, 311 ("%s: page %p isn't consecutive", __func__, m[i])); 312 } 313 #endif 314 } 315 316 /* 317 * Page in the pages for the object using its associated pager. 318 * The requested page must be fully valid on successful return. 319 */ 320 int 321 vm_pager_get_pages(vm_object_t object, vm_page_t *m, int count, int *rbehind, 322 int *rahead) 323 { 324 #ifdef INVARIANTS 325 vm_pindex_t pindex = m[0]->pindex; 326 #endif 327 int r; 328 329 MPASS(object->type < nitems(pagertab)); 330 vm_pager_assert_in(object, m, count); 331 332 r = (*pagertab[object->type]->pgo_getpages)(object, m, count, rbehind, 333 rahead); 334 if (r != VM_PAGER_OK) 335 return (r); 336 337 for (int i = 0; i < count; i++) { 338 /* 339 * If pager has replaced a page, assert that it had 340 * updated the array. 341 */ 342 #ifdef INVARIANTS 343 KASSERT(m[i] == vm_page_relookup(object, pindex++), 344 ("%s: mismatch page %p pindex %ju", __func__, 345 m[i], (uintmax_t )pindex - 1)); 346 #endif 347 348 /* 349 * Zero out partially filled data. 350 */ 351 if (m[i]->valid != VM_PAGE_BITS_ALL) 352 vm_page_zero_invalid(m[i], TRUE); 353 } 354 return (VM_PAGER_OK); 355 } 356 357 int 358 vm_pager_get_pages_async(vm_object_t object, vm_page_t *m, int count, 359 int *rbehind, int *rahead, pgo_getpages_iodone_t iodone, void *arg) 360 { 361 362 MPASS(object->type < nitems(pagertab)); 363 vm_pager_assert_in(object, m, count); 364 365 return ((*pagertab[object->type]->pgo_getpages_async)(object, m, 366 count, rbehind, rahead, iodone, arg)); 367 } 368 369 /* 370 * vm_pager_put_pages() - inline, see vm/vm_pager.h 371 * vm_pager_has_page() - inline, see vm/vm_pager.h 372 */ 373 374 /* 375 * Search the specified pager object list for an object with the 376 * specified handle. If an object with the specified handle is found, 377 * increase its reference count and return it. Otherwise, return NULL. 378 * 379 * The pager object list must be locked. 380 */ 381 vm_object_t 382 vm_pager_object_lookup(struct pagerlst *pg_list, void *handle) 383 { 384 vm_object_t object; 385 386 TAILQ_FOREACH(object, pg_list, pager_object_list) { 387 if (object->handle == handle) { 388 VM_OBJECT_WLOCK(object); 389 if ((object->flags & OBJ_DEAD) == 0) { 390 vm_object_reference_locked(object); 391 VM_OBJECT_WUNLOCK(object); 392 break; 393 } 394 VM_OBJECT_WUNLOCK(object); 395 } 396 } 397 return (object); 398 } 399 400 int 401 vm_pager_alloc_dyn_type(struct pagerops *ops, int base_type) 402 { 403 int res; 404 405 mtx_lock(&pagertab_lock); 406 MPASS(base_type == -1 || 407 (base_type >= OBJT_SWAP && base_type < nitems(pagertab))); 408 for (res = OBJT_FIRST_DYN; res < nitems(pagertab); res++) { 409 if (pagertab[res] == NULL) 410 break; 411 } 412 if (res == nitems(pagertab)) { 413 mtx_unlock(&pagertab_lock); 414 return (-1); 415 } 416 if (base_type != -1) { 417 MPASS(pagertab[base_type] != NULL); 418 #define FIX(n) \ 419 if (ops->pgo_##n == NULL) \ 420 ops->pgo_##n = pagertab[base_type]->pgo_##n 421 FIX(init); 422 FIX(alloc); 423 FIX(dealloc); 424 FIX(getpages); 425 FIX(getpages_async); 426 FIX(putpages); 427 FIX(haspage); 428 FIX(populate); 429 FIX(pageunswapped); 430 FIX(update_writecount); 431 FIX(release_writecount); 432 FIX(set_writeable_dirty); 433 FIX(mightbedirty); 434 FIX(getvp); 435 FIX(freespace); 436 FIX(page_inserted); 437 FIX(page_removed); 438 FIX(can_alloc_page); 439 #undef FIX 440 } 441 pagertab[res] = ops; /* XXXKIB should be rel, but acq is too much */ 442 mtx_unlock(&pagertab_lock); 443 return (res); 444 } 445 446 void 447 vm_pager_free_dyn_type(objtype_t type) 448 { 449 MPASS(type >= OBJT_FIRST_DYN && type < nitems(pagertab)); 450 451 mtx_lock(&pagertab_lock); 452 MPASS(pagertab[type] != NULL); 453 pagertab[type] = NULL; 454 mtx_unlock(&pagertab_lock); 455 } 456 457 static int 458 pbuf_ctor(void *mem, int size, void *arg, int flags) 459 { 460 struct buf *bp = mem; 461 462 bp->b_vp = NULL; 463 bp->b_bufobj = NULL; 464 465 /* copied from initpbuf() */ 466 bp->b_rcred = NOCRED; 467 bp->b_wcred = NOCRED; 468 bp->b_qindex = 0; /* On no queue (QUEUE_NONE) */ 469 bp->b_data = bp->b_kvabase; 470 bp->b_xflags = 0; 471 bp->b_flags = B_MAXPHYS; 472 bp->b_ioflags = 0; 473 bp->b_iodone = NULL; 474 bp->b_error = 0; 475 BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL); 476 477 return (0); 478 } 479 480 static void 481 pbuf_dtor(void *mem, int size, void *arg) 482 { 483 struct buf *bp = mem; 484 485 if (bp->b_rcred != NOCRED) { 486 crfree(bp->b_rcred); 487 bp->b_rcred = NOCRED; 488 } 489 if (bp->b_wcred != NOCRED) { 490 crfree(bp->b_wcred); 491 bp->b_wcred = NOCRED; 492 } 493 494 BUF_UNLOCK(bp); 495 } 496 497 static const char pbuf_wmesg[] = "pbufwait"; 498 499 static int 500 pbuf_init(void *mem, int size, int flags) 501 { 502 struct buf *bp = mem; 503 504 TSENTER(); 505 506 bp->b_kvabase = (void *)kva_alloc(ptoa(PBUF_PAGES)); 507 if (bp->b_kvabase == NULL) 508 return (ENOMEM); 509 bp->b_kvasize = ptoa(PBUF_PAGES); 510 BUF_LOCKINIT(bp, pbuf_wmesg); 511 LIST_INIT(&bp->b_dep); 512 bp->b_rcred = bp->b_wcred = NOCRED; 513 bp->b_xflags = 0; 514 515 TSEXIT(); 516 517 return (0); 518 } 519 520 /* 521 * Associate a p-buffer with a vnode. 522 * 523 * Also sets B_PAGING flag to indicate that vnode is not fully associated 524 * with the buffer. i.e. the bp has not been linked into the vnode or 525 * ref-counted. 526 */ 527 void 528 pbgetvp(struct vnode *vp, struct buf *bp) 529 { 530 531 KASSERT(bp->b_vp == NULL, ("pbgetvp: not free")); 532 KASSERT(bp->b_bufobj == NULL, ("pbgetvp: not free (bufobj)")); 533 534 bp->b_vp = vp; 535 bp->b_flags |= B_PAGING; 536 bp->b_bufobj = &vp->v_bufobj; 537 } 538 539 /* 540 * Associate a p-buffer with a vnode. 541 * 542 * Also sets B_PAGING flag to indicate that vnode is not fully associated 543 * with the buffer. i.e. the bp has not been linked into the vnode or 544 * ref-counted. 545 */ 546 void 547 pbgetbo(struct bufobj *bo, struct buf *bp) 548 { 549 550 KASSERT(bp->b_vp == NULL, ("pbgetbo: not free (vnode)")); 551 KASSERT(bp->b_bufobj == NULL, ("pbgetbo: not free (bufobj)")); 552 553 bp->b_flags |= B_PAGING; 554 bp->b_bufobj = bo; 555 } 556 557 /* 558 * Disassociate a p-buffer from a vnode. 559 */ 560 void 561 pbrelvp(struct buf *bp) 562 { 563 564 KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL")); 565 KASSERT(bp->b_bufobj != NULL, ("pbrelvp: NULL bufobj")); 566 KASSERT((bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) == 0, 567 ("pbrelvp: pager buf on vnode list.")); 568 569 bp->b_vp = NULL; 570 bp->b_bufobj = NULL; 571 bp->b_flags &= ~B_PAGING; 572 } 573 574 /* 575 * Disassociate a p-buffer from a bufobj. 576 */ 577 void 578 pbrelbo(struct buf *bp) 579 { 580 581 KASSERT(bp->b_vp == NULL, ("pbrelbo: vnode")); 582 KASSERT(bp->b_bufobj != NULL, ("pbrelbo: NULL bufobj")); 583 KASSERT((bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) == 0, 584 ("pbrelbo: pager buf on vnode list.")); 585 586 bp->b_bufobj = NULL; 587 bp->b_flags &= ~B_PAGING; 588 } 589 590 void 591 vm_object_set_writeable_dirty(vm_object_t object) 592 { 593 pgo_set_writeable_dirty_t *method; 594 595 MPASS(object->type < nitems(pagertab)); 596 597 method = pagertab[object->type]->pgo_set_writeable_dirty; 598 if (method != NULL) 599 method(object); 600 } 601 602 bool 603 vm_object_mightbedirty(vm_object_t object) 604 { 605 pgo_mightbedirty_t *method; 606 607 MPASS(object->type < nitems(pagertab)); 608 609 method = pagertab[object->type]->pgo_mightbedirty; 610 if (method == NULL) 611 return (false); 612 return (method(object)); 613 } 614 615 /* 616 * Return the kvme type of the given object. 617 * If vpp is not NULL, set it to the object's vm_object_vnode() or NULL. 618 */ 619 int 620 vm_object_kvme_type(vm_object_t object, struct vnode **vpp) 621 { 622 VM_OBJECT_ASSERT_LOCKED(object); 623 MPASS(object->type < nitems(pagertab)); 624 625 if (vpp != NULL) 626 *vpp = vm_object_vnode(object); 627 return (pagertab[object->type]->pgo_kvme_type); 628 } 629