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 * 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 #include "opt_param.h" 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 #include <sys/user.h> 79 80 #include <vm/vm.h> 81 #include <vm/vm_param.h> 82 #include <vm/vm_kern.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 #include <vm/uma.h> 88 89 uma_zone_t pbuf_zone; 90 static int pbuf_init(void *, int, int); 91 static int pbuf_ctor(void *, int, void *, int); 92 static void pbuf_dtor(void *, int, void *); 93 94 static int dead_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *); 95 static vm_object_t dead_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 96 vm_ooffset_t, struct ucred *); 97 static void dead_pager_putpages(vm_object_t, vm_page_t *, int, int, int *); 98 static boolean_t dead_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 99 static void dead_pager_dealloc(vm_object_t); 100 static void dead_pager_getvp(vm_object_t, struct vnode **, bool *); 101 102 static int 103 dead_pager_getpages(vm_object_t obj, vm_page_t *ma, int count, int *rbehind, 104 int *rahead) 105 { 106 107 return (VM_PAGER_FAIL); 108 } 109 110 static vm_object_t 111 dead_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 112 vm_ooffset_t off, struct ucred *cred) 113 { 114 115 return (NULL); 116 } 117 118 static void 119 dead_pager_putpages(vm_object_t object, vm_page_t *m, int count, 120 int flags, int *rtvals) 121 { 122 int i; 123 124 for (i = 0; i < count; i++) 125 rtvals[i] = VM_PAGER_AGAIN; 126 } 127 128 static boolean_t 129 dead_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *prev, int *next) 130 { 131 132 if (prev != NULL) 133 *prev = 0; 134 if (next != NULL) 135 *next = 0; 136 return (FALSE); 137 } 138 139 static void 140 dead_pager_dealloc(vm_object_t object) 141 { 142 143 } 144 145 static void 146 dead_pager_getvp(vm_object_t object, struct vnode **vpp, bool *vp_heldp) 147 { 148 /* 149 * For OBJT_DEAD objects, v_writecount was handled in 150 * vnode_pager_dealloc(). 151 */ 152 } 153 154 static const struct pagerops deadpagerops = { 155 .pgo_kvme_type = KVME_TYPE_DEAD, 156 .pgo_alloc = dead_pager_alloc, 157 .pgo_dealloc = dead_pager_dealloc, 158 .pgo_getpages = dead_pager_getpages, 159 .pgo_putpages = dead_pager_putpages, 160 .pgo_haspage = dead_pager_haspage, 161 .pgo_getvp = dead_pager_getvp, 162 }; 163 164 const struct pagerops *pagertab[16] __read_mostly = { 165 [OBJT_SWAP] = &swappagerops, 166 [OBJT_VNODE] = &vnodepagerops, 167 [OBJT_DEVICE] = &devicepagerops, 168 [OBJT_PHYS] = &physpagerops, 169 [OBJT_DEAD] = &deadpagerops, 170 [OBJT_SG] = &sgpagerops, 171 [OBJT_MGTDEVICE] = &mgtdevicepagerops, 172 }; 173 static struct mtx pagertab_lock; 174 175 void 176 vm_pager_init(void) 177 { 178 const struct pagerops **pgops; 179 int i; 180 181 mtx_init(&pagertab_lock, "dynpag", NULL, MTX_DEF); 182 183 /* 184 * Initialize known pagers 185 */ 186 for (i = 0; i < OBJT_FIRST_DYN; i++) { 187 pgops = &pagertab[i]; 188 if (*pgops != NULL && (*pgops)->pgo_init != NULL) 189 (*(*pgops)->pgo_init)(); 190 } 191 } 192 193 static int nswbuf_max; 194 195 void 196 vm_pager_bufferinit(void) 197 { 198 199 /* Main zone for paging bufs. */ 200 pbuf_zone = uma_zcreate("pbuf", 201 sizeof(struct buf) + PBUF_PAGES * sizeof(vm_page_t), 202 pbuf_ctor, pbuf_dtor, pbuf_init, NULL, UMA_ALIGN_CACHE, 203 UMA_ZONE_NOFREE); 204 /* Few systems may still use this zone directly, so it needs a limit. */ 205 nswbuf_max += uma_zone_set_max(pbuf_zone, NSWBUF_MIN); 206 } 207 208 uma_zone_t 209 pbuf_zsecond_create(const char *name, int max) 210 { 211 uma_zone_t zone; 212 213 zone = uma_zsecond_create(name, pbuf_ctor, pbuf_dtor, NULL, NULL, 214 pbuf_zone); 215 216 #ifdef KMSAN 217 /* 218 * Shrink the size of the pbuf pools if KMSAN is enabled, otherwise the 219 * shadows of the large KVA allocations eat up too much memory. 220 */ 221 max /= 3; 222 #endif 223 224 /* 225 * uma_prealloc() rounds up to items per slab. If we would prealloc 226 * immediately on every pbuf_zsecond_create(), we may accumulate too 227 * much of difference between hard limit and prealloced items, which 228 * means wasted memory. 229 */ 230 if (nswbuf_max > 0) 231 nswbuf_max += uma_zone_set_max(zone, max); 232 else 233 uma_prealloc(pbuf_zone, uma_zone_set_max(zone, max)); 234 235 return (zone); 236 } 237 238 static void 239 pbuf_prealloc(void *arg __unused) 240 { 241 242 uma_prealloc(pbuf_zone, nswbuf_max); 243 nswbuf_max = -1; 244 } 245 246 SYSINIT(pbuf, SI_SUB_KTHREAD_BUF, SI_ORDER_ANY, pbuf_prealloc, NULL); 247 248 /* 249 * Allocate an instance of a pager of the given type. 250 * Size, protection and offset parameters are passed in for pagers that 251 * need to perform page-level validation (e.g. the device pager). 252 */ 253 vm_object_t 254 vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, 255 vm_prot_t prot, vm_ooffset_t off, struct ucred *cred) 256 { 257 vm_object_t object; 258 259 MPASS(type < nitems(pagertab)); 260 261 object = (*pagertab[type]->pgo_alloc)(handle, size, prot, off, cred); 262 if (object != NULL) 263 object->type = type; 264 return (object); 265 } 266 267 /* 268 * The object must be locked. 269 */ 270 void 271 vm_pager_deallocate(vm_object_t object) 272 { 273 274 VM_OBJECT_ASSERT_WLOCKED(object); 275 MPASS(object->type < nitems(pagertab)); 276 (*pagertab[object->type]->pgo_dealloc) (object); 277 } 278 279 static void 280 vm_pager_assert_in(vm_object_t object, vm_page_t *m, int count) 281 { 282 #ifdef INVARIANTS 283 284 /* 285 * All pages must be consecutive, busied, not mapped, not fully valid, 286 * not dirty and belong to the proper object. Some pages may be the 287 * bogus page, but the first and last pages must be a real ones. 288 */ 289 290 VM_OBJECT_ASSERT_UNLOCKED(object); 291 VM_OBJECT_ASSERT_PAGING(object); 292 KASSERT(count > 0, ("%s: 0 count", __func__)); 293 for (int i = 0 ; i < count; i++) { 294 if (m[i] == bogus_page) { 295 KASSERT(i != 0 && i != count - 1, 296 ("%s: page %d is the bogus page", __func__, i)); 297 continue; 298 } 299 vm_page_assert_xbusied(m[i]); 300 KASSERT(!pmap_page_is_mapped(m[i]), 301 ("%s: page %p is mapped", __func__, m[i])); 302 KASSERT(m[i]->valid != VM_PAGE_BITS_ALL, 303 ("%s: request for a valid page %p", __func__, m[i])); 304 KASSERT(m[i]->dirty == 0, 305 ("%s: page %p is dirty", __func__, m[i])); 306 KASSERT(m[i]->object == object, 307 ("%s: wrong object %p/%p", __func__, object, m[i]->object)); 308 KASSERT(m[i]->pindex == m[0]->pindex + i, 309 ("%s: page %p isn't consecutive", __func__, m[i])); 310 } 311 #endif 312 } 313 314 /* 315 * Page in the pages for the object using its associated pager. 316 * The requested page must be fully valid on successful return. 317 */ 318 int 319 vm_pager_get_pages(vm_object_t object, vm_page_t *m, int count, int *rbehind, 320 int *rahead) 321 { 322 #ifdef INVARIANTS 323 vm_pindex_t pindex = m[0]->pindex; 324 #endif 325 int r; 326 327 MPASS(object->type < nitems(pagertab)); 328 vm_pager_assert_in(object, m, count); 329 330 r = (*pagertab[object->type]->pgo_getpages)(object, m, count, rbehind, 331 rahead); 332 if (r != VM_PAGER_OK) 333 return (r); 334 335 for (int i = 0; i < count; i++) { 336 /* 337 * If pager has replaced a page, assert that it had 338 * updated the array. 339 */ 340 #ifdef INVARIANTS 341 KASSERT(m[i] == vm_page_relookup(object, pindex++), 342 ("%s: mismatch page %p pindex %ju", __func__, 343 m[i], (uintmax_t )pindex - 1)); 344 #endif 345 346 /* 347 * Zero out partially filled data. 348 */ 349 if (m[i]->valid != VM_PAGE_BITS_ALL) 350 vm_page_zero_invalid(m[i], TRUE); 351 } 352 return (VM_PAGER_OK); 353 } 354 355 int 356 vm_pager_get_pages_async(vm_object_t object, vm_page_t *m, int count, 357 int *rbehind, int *rahead, pgo_getpages_iodone_t iodone, void *arg) 358 { 359 360 MPASS(object->type < nitems(pagertab)); 361 vm_pager_assert_in(object, m, count); 362 363 return ((*pagertab[object->type]->pgo_getpages_async)(object, m, 364 count, rbehind, rahead, iodone, arg)); 365 } 366 367 /* 368 * vm_pager_put_pages() - inline, see vm/vm_pager.h 369 * vm_pager_has_page() - inline, see vm/vm_pager.h 370 */ 371 372 /* 373 * Search the specified pager object list for an object with the 374 * specified handle. If an object with the specified handle is found, 375 * increase its reference count and return it. Otherwise, return NULL. 376 * 377 * The pager object list must be locked. 378 */ 379 vm_object_t 380 vm_pager_object_lookup(struct pagerlst *pg_list, void *handle) 381 { 382 vm_object_t object; 383 384 TAILQ_FOREACH(object, pg_list, pager_object_list) { 385 if (object->handle == handle) { 386 VM_OBJECT_WLOCK(object); 387 if ((object->flags & OBJ_DEAD) == 0) { 388 vm_object_reference_locked(object); 389 VM_OBJECT_WUNLOCK(object); 390 break; 391 } 392 VM_OBJECT_WUNLOCK(object); 393 } 394 } 395 return (object); 396 } 397 398 int 399 vm_pager_alloc_dyn_type(struct pagerops *ops, int base_type) 400 { 401 int res; 402 403 mtx_lock(&pagertab_lock); 404 MPASS(base_type == -1 || 405 (base_type >= OBJT_SWAP && base_type < nitems(pagertab))); 406 for (res = OBJT_FIRST_DYN; res < nitems(pagertab); res++) { 407 if (pagertab[res] == NULL) 408 break; 409 } 410 if (res == nitems(pagertab)) { 411 mtx_unlock(&pagertab_lock); 412 return (-1); 413 } 414 if (base_type != -1) { 415 MPASS(pagertab[base_type] != NULL); 416 #define FIX(n) \ 417 if (ops->pgo_##n == NULL) \ 418 ops->pgo_##n = pagertab[base_type]->pgo_##n 419 FIX(init); 420 FIX(alloc); 421 FIX(dealloc); 422 FIX(getpages); 423 FIX(getpages_async); 424 FIX(putpages); 425 FIX(haspage); 426 FIX(populate); 427 FIX(pageunswapped); 428 FIX(update_writecount); 429 FIX(release_writecount); 430 FIX(set_writeable_dirty); 431 FIX(mightbedirty); 432 FIX(getvp); 433 FIX(freespace); 434 FIX(page_inserted); 435 FIX(page_removed); 436 FIX(can_alloc_page); 437 #undef FIX 438 } 439 pagertab[res] = ops; /* XXXKIB should be rel, but acq is too much */ 440 mtx_unlock(&pagertab_lock); 441 return (res); 442 } 443 444 void 445 vm_pager_free_dyn_type(objtype_t type) 446 { 447 MPASS(type >= OBJT_FIRST_DYN && type < nitems(pagertab)); 448 449 mtx_lock(&pagertab_lock); 450 MPASS(pagertab[type] != NULL); 451 pagertab[type] = NULL; 452 mtx_unlock(&pagertab_lock); 453 } 454 455 static int 456 pbuf_ctor(void *mem, int size, void *arg, int flags) 457 { 458 struct buf *bp = mem; 459 460 bp->b_vp = NULL; 461 bp->b_bufobj = NULL; 462 463 /* copied from initpbuf() */ 464 bp->b_rcred = NOCRED; 465 bp->b_wcred = NOCRED; 466 bp->b_qindex = 0; /* On no queue (QUEUE_NONE) */ 467 bp->b_data = bp->b_kvabase; 468 bp->b_xflags = 0; 469 bp->b_flags = B_MAXPHYS; 470 bp->b_ioflags = 0; 471 bp->b_iodone = NULL; 472 bp->b_error = 0; 473 BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWITNESS, NULL); 474 475 return (0); 476 } 477 478 static void 479 pbuf_dtor(void *mem, int size, void *arg) 480 { 481 struct buf *bp = mem; 482 483 if (bp->b_rcred != NOCRED) { 484 crfree(bp->b_rcred); 485 bp->b_rcred = NOCRED; 486 } 487 if (bp->b_wcred != NOCRED) { 488 crfree(bp->b_wcred); 489 bp->b_wcred = NOCRED; 490 } 491 492 BUF_UNLOCK(bp); 493 } 494 495 static const char pbuf_wmesg[] = "pbufwait"; 496 497 static int 498 pbuf_init(void *mem, int size, int flags) 499 { 500 struct buf *bp = mem; 501 502 TSENTER(); 503 504 bp->b_kvabase = (void *)kva_alloc(ptoa(PBUF_PAGES)); 505 if (bp->b_kvabase == NULL) 506 return (ENOMEM); 507 bp->b_kvasize = ptoa(PBUF_PAGES); 508 BUF_LOCKINIT(bp, pbuf_wmesg); 509 LIST_INIT(&bp->b_dep); 510 bp->b_rcred = bp->b_wcred = NOCRED; 511 bp->b_xflags = 0; 512 513 TSEXIT(); 514 515 return (0); 516 } 517 518 /* 519 * Associate a p-buffer with a vnode. 520 * 521 * Also sets B_PAGING flag to indicate that vnode is not fully associated 522 * with the buffer. i.e. the bp has not been linked into the vnode or 523 * ref-counted. 524 */ 525 void 526 pbgetvp(struct vnode *vp, struct buf *bp) 527 { 528 529 KASSERT(bp->b_vp == NULL, ("pbgetvp: not free")); 530 KASSERT(bp->b_bufobj == NULL, ("pbgetvp: not free (bufobj)")); 531 532 bp->b_vp = vp; 533 bp->b_flags |= B_PAGING; 534 bp->b_bufobj = &vp->v_bufobj; 535 } 536 537 /* 538 * Associate a p-buffer with a vnode. 539 * 540 * Also sets B_PAGING flag to indicate that vnode is not fully associated 541 * with the buffer. i.e. the bp has not been linked into the vnode or 542 * ref-counted. 543 */ 544 void 545 pbgetbo(struct bufobj *bo, struct buf *bp) 546 { 547 548 KASSERT(bp->b_vp == NULL, ("pbgetbo: not free (vnode)")); 549 KASSERT(bp->b_bufobj == NULL, ("pbgetbo: not free (bufobj)")); 550 551 bp->b_flags |= B_PAGING; 552 bp->b_bufobj = bo; 553 } 554 555 /* 556 * Disassociate a p-buffer from a vnode. 557 */ 558 void 559 pbrelvp(struct buf *bp) 560 { 561 562 KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL")); 563 KASSERT(bp->b_bufobj != NULL, ("pbrelvp: NULL bufobj")); 564 KASSERT((bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) == 0, 565 ("pbrelvp: pager buf on vnode list.")); 566 567 bp->b_vp = NULL; 568 bp->b_bufobj = NULL; 569 bp->b_flags &= ~B_PAGING; 570 } 571 572 /* 573 * Disassociate a p-buffer from a bufobj. 574 */ 575 void 576 pbrelbo(struct buf *bp) 577 { 578 579 KASSERT(bp->b_vp == NULL, ("pbrelbo: vnode")); 580 KASSERT(bp->b_bufobj != NULL, ("pbrelbo: NULL bufobj")); 581 KASSERT((bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) == 0, 582 ("pbrelbo: pager buf on vnode list.")); 583 584 bp->b_bufobj = NULL; 585 bp->b_flags &= ~B_PAGING; 586 } 587 588 void 589 vm_object_set_writeable_dirty(vm_object_t object) 590 { 591 pgo_set_writeable_dirty_t *method; 592 593 MPASS(object->type < nitems(pagertab)); 594 595 method = pagertab[object->type]->pgo_set_writeable_dirty; 596 if (method != NULL) 597 method(object); 598 } 599 600 bool 601 vm_object_mightbedirty(vm_object_t object) 602 { 603 pgo_mightbedirty_t *method; 604 605 MPASS(object->type < nitems(pagertab)); 606 607 method = pagertab[object->type]->pgo_mightbedirty; 608 if (method == NULL) 609 return (false); 610 return (method(object)); 611 } 612 613 /* 614 * Return the kvme type of the given object. 615 * If vpp is not NULL, set it to the object's vm_object_vnode() or NULL. 616 */ 617 int 618 vm_object_kvme_type(vm_object_t object, struct vnode **vpp) 619 { 620 VM_OBJECT_ASSERT_LOCKED(object); 621 MPASS(object->type < nitems(pagertab)); 622 623 if (vpp != NULL) 624 *vpp = vm_object_vnode(object); 625 return (pagertab[object->type]->pgo_kvme_type); 626 } 627