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 __FBSDID("$FreeBSD$"); 70 71 #include "opt_param.h" 72 73 #include <sys/param.h> 74 #include <sys/systm.h> 75 #include <sys/kernel.h> 76 #include <sys/vnode.h> 77 #include <sys/bio.h> 78 #include <sys/buf.h> 79 #include <sys/ucred.h> 80 #include <sys/malloc.h> 81 #include <sys/rwlock.h> 82 83 #include <vm/vm.h> 84 #include <vm/vm_param.h> 85 #include <vm/vm_kern.h> 86 #include <vm/vm_object.h> 87 #include <vm/vm_page.h> 88 #include <vm/vm_pager.h> 89 #include <vm/vm_extern.h> 90 #include <vm/uma.h> 91 92 uma_zone_t pbuf_zone; 93 static int pbuf_init(void *, int, int); 94 static int pbuf_ctor(void *, int, void *, int); 95 static void pbuf_dtor(void *, int, void *); 96 97 static int dead_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *); 98 static vm_object_t dead_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 99 vm_ooffset_t, struct ucred *); 100 static void dead_pager_putpages(vm_object_t, vm_page_t *, int, int, int *); 101 static boolean_t dead_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 102 static void dead_pager_dealloc(vm_object_t); 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 int 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 struct pagerops deadpagerops = { 148 .pgo_alloc = dead_pager_alloc, 149 .pgo_dealloc = dead_pager_dealloc, 150 .pgo_getpages = dead_pager_getpages, 151 .pgo_putpages = dead_pager_putpages, 152 .pgo_haspage = dead_pager_haspage, 153 }; 154 155 struct pagerops *pagertab[] = { 156 &defaultpagerops, /* OBJT_DEFAULT */ 157 &swappagerops, /* OBJT_SWAP */ 158 &vnodepagerops, /* OBJT_VNODE */ 159 &devicepagerops, /* OBJT_DEVICE */ 160 &physpagerops, /* OBJT_PHYS */ 161 &deadpagerops, /* OBJT_DEAD */ 162 &sgpagerops, /* OBJT_SG */ 163 &mgtdevicepagerops, /* OBJT_MGTDEVICE */ 164 }; 165 166 void 167 vm_pager_init(void) 168 { 169 struct pagerops **pgops; 170 171 /* 172 * Initialize known pagers 173 */ 174 for (pgops = pagertab; pgops < &pagertab[nitems(pagertab)]; pgops++) 175 if ((*pgops)->pgo_init != NULL) 176 (*(*pgops)->pgo_init)(); 177 } 178 179 static int nswbuf_max; 180 181 void 182 vm_pager_bufferinit(void) 183 { 184 185 /* Main zone for paging bufs. */ 186 pbuf_zone = uma_zcreate("pbuf", sizeof(struct buf), 187 pbuf_ctor, pbuf_dtor, pbuf_init, NULL, UMA_ALIGN_CACHE, 188 UMA_ZONE_VM | UMA_ZONE_NOFREE); 189 /* Few systems may still use this zone directly, so it needs a limit. */ 190 nswbuf_max += uma_zone_set_max(pbuf_zone, NSWBUF_MIN); 191 } 192 193 uma_zone_t 194 pbuf_zsecond_create(char *name, int max) 195 { 196 uma_zone_t zone; 197 198 zone = uma_zsecond_create(name, pbuf_ctor, pbuf_dtor, NULL, NULL, 199 pbuf_zone); 200 /* 201 * uma_prealloc() rounds up to items per slab. If we would prealloc 202 * immediately on every pbuf_zsecond_create(), we may accumulate too 203 * much of difference between hard limit and prealloced items, which 204 * means wasted memory. 205 */ 206 if (nswbuf_max > 0) 207 nswbuf_max += uma_zone_set_max(zone, max); 208 else 209 uma_prealloc(pbuf_zone, uma_zone_set_max(zone, max)); 210 211 return (zone); 212 } 213 214 static void 215 pbuf_prealloc(void *arg __unused) 216 { 217 218 uma_prealloc(pbuf_zone, nswbuf_max); 219 nswbuf_max = -1; 220 } 221 222 SYSINIT(pbuf, SI_SUB_KTHREAD_BUF, SI_ORDER_ANY, pbuf_prealloc, NULL); 223 224 /* 225 * Allocate an instance of a pager of the given type. 226 * Size, protection and offset parameters are passed in for pagers that 227 * need to perform page-level validation (e.g. the device pager). 228 */ 229 vm_object_t 230 vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, 231 vm_prot_t prot, vm_ooffset_t off, struct ucred *cred) 232 { 233 vm_object_t ret; 234 struct pagerops *ops; 235 236 ops = pagertab[type]; 237 if (ops) 238 ret = (*ops->pgo_alloc)(handle, size, prot, off, cred); 239 else 240 ret = NULL; 241 return (ret); 242 } 243 244 /* 245 * The object must be locked. 246 */ 247 void 248 vm_pager_deallocate(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 if (m[i] == bogus_page) 268 continue; 269 vm_page_assert_xbusied(m[i]); 270 KASSERT(!pmap_page_is_mapped(m[i]), 271 ("%s: page %p is mapped", __func__, m[i])); 272 KASSERT(m[i]->valid != VM_PAGE_BITS_ALL, 273 ("%s: request for a valid page %p", __func__, m[i])); 274 KASSERT(m[i]->dirty == 0, 275 ("%s: page %p is dirty", __func__, m[i])); 276 KASSERT(m[i]->object == object, 277 ("%s: wrong object %p/%p", __func__, object, m[i]->object)); 278 } 279 #endif 280 } 281 282 /* 283 * Page in the pages for the object using its associated pager. 284 * The requested page must be fully valid on successful return. 285 */ 286 int 287 vm_pager_get_pages(vm_object_t object, vm_page_t *m, int count, int *rbehind, 288 int *rahead) 289 { 290 #ifdef INVARIANTS 291 vm_pindex_t pindex = m[0]->pindex; 292 #endif 293 int r; 294 295 vm_pager_assert_in(object, m, count); 296 297 r = (*pagertab[object->type]->pgo_getpages)(object, m, count, rbehind, 298 rahead); 299 if (r != VM_PAGER_OK) 300 return (r); 301 302 for (int i = 0; i < count; i++) { 303 /* 304 * If pager has replaced a page, assert that it had 305 * updated the array. 306 */ 307 KASSERT(m[i] == vm_page_lookup(object, pindex++), 308 ("%s: mismatch page %p pindex %ju", __func__, 309 m[i], (uintmax_t )pindex - 1)); 310 /* 311 * Zero out partially filled data. 312 */ 313 if (m[i]->valid != VM_PAGE_BITS_ALL) 314 vm_page_zero_invalid(m[i], TRUE); 315 } 316 return (VM_PAGER_OK); 317 } 318 319 int 320 vm_pager_get_pages_async(vm_object_t object, vm_page_t *m, int count, 321 int *rbehind, int *rahead, pgo_getpages_iodone_t iodone, void *arg) 322 { 323 324 vm_pager_assert_in(object, m, count); 325 326 return ((*pagertab[object->type]->pgo_getpages_async)(object, m, 327 count, rbehind, rahead, iodone, arg)); 328 } 329 330 /* 331 * vm_pager_put_pages() - inline, see vm/vm_pager.h 332 * vm_pager_has_page() - inline, see vm/vm_pager.h 333 */ 334 335 /* 336 * Search the specified pager object list for an object with the 337 * specified handle. If an object with the specified handle is found, 338 * increase its reference count and return it. Otherwise, return NULL. 339 * 340 * The pager object list must be locked. 341 */ 342 vm_object_t 343 vm_pager_object_lookup(struct pagerlst *pg_list, void *handle) 344 { 345 vm_object_t object; 346 347 TAILQ_FOREACH(object, pg_list, pager_object_list) { 348 if (object->handle == handle) { 349 VM_OBJECT_WLOCK(object); 350 if ((object->flags & OBJ_DEAD) == 0) { 351 vm_object_reference_locked(object); 352 VM_OBJECT_WUNLOCK(object); 353 break; 354 } 355 VM_OBJECT_WUNLOCK(object); 356 } 357 } 358 return (object); 359 } 360 361 static int 362 pbuf_ctor(void *mem, int size, void *arg, int flags) 363 { 364 struct buf *bp = mem; 365 366 bp->b_vp = NULL; 367 bp->b_bufobj = NULL; 368 369 /* copied from initpbuf() */ 370 bp->b_rcred = NOCRED; 371 bp->b_wcred = NOCRED; 372 bp->b_qindex = 0; /* On no queue (QUEUE_NONE) */ 373 bp->b_data = bp->b_kvabase; 374 bp->b_xflags = 0; 375 bp->b_flags = 0; 376 bp->b_ioflags = 0; 377 bp->b_iodone = NULL; 378 bp->b_error = 0; 379 BUF_LOCK(bp, LK_EXCLUSIVE, NULL); 380 381 return (0); 382 } 383 384 static void 385 pbuf_dtor(void *mem, int size, void *arg) 386 { 387 struct buf *bp = mem; 388 389 if (bp->b_rcred != NOCRED) { 390 crfree(bp->b_rcred); 391 bp->b_rcred = NOCRED; 392 } 393 if (bp->b_wcred != NOCRED) { 394 crfree(bp->b_wcred); 395 bp->b_wcred = NOCRED; 396 } 397 398 BUF_UNLOCK(bp); 399 } 400 401 static int 402 pbuf_init(void *mem, int size, int flags) 403 { 404 struct buf *bp = mem; 405 406 bp->b_kvabase = (void *)kva_alloc(MAXPHYS); 407 if (bp->b_kvabase == NULL) 408 return (ENOMEM); 409 bp->b_kvasize = MAXPHYS; 410 BUF_LOCKINIT(bp); 411 LIST_INIT(&bp->b_dep); 412 bp->b_rcred = bp->b_wcred = NOCRED; 413 bp->b_xflags = 0; 414 415 return (0); 416 } 417 418 /* 419 * Associate a p-buffer with a vnode. 420 * 421 * Also sets B_PAGING flag to indicate that vnode is not fully associated 422 * with the buffer. i.e. the bp has not been linked into the vnode or 423 * ref-counted. 424 */ 425 void 426 pbgetvp(struct vnode *vp, struct buf *bp) 427 { 428 429 KASSERT(bp->b_vp == NULL, ("pbgetvp: not free")); 430 KASSERT(bp->b_bufobj == NULL, ("pbgetvp: not free (bufobj)")); 431 432 bp->b_vp = vp; 433 bp->b_flags |= B_PAGING; 434 bp->b_bufobj = &vp->v_bufobj; 435 } 436 437 /* 438 * Associate a p-buffer with a vnode. 439 * 440 * Also sets B_PAGING flag to indicate that vnode is not fully associated 441 * with the buffer. i.e. the bp has not been linked into the vnode or 442 * ref-counted. 443 */ 444 void 445 pbgetbo(struct bufobj *bo, struct buf *bp) 446 { 447 448 KASSERT(bp->b_vp == NULL, ("pbgetbo: not free (vnode)")); 449 KASSERT(bp->b_bufobj == NULL, ("pbgetbo: not free (bufobj)")); 450 451 bp->b_flags |= B_PAGING; 452 bp->b_bufobj = bo; 453 } 454 455 /* 456 * Disassociate a p-buffer from a vnode. 457 */ 458 void 459 pbrelvp(struct buf *bp) 460 { 461 462 KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL")); 463 KASSERT(bp->b_bufobj != NULL, ("pbrelvp: NULL bufobj")); 464 KASSERT((bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) == 0, 465 ("pbrelvp: pager buf on vnode list.")); 466 467 bp->b_vp = NULL; 468 bp->b_bufobj = NULL; 469 bp->b_flags &= ~B_PAGING; 470 } 471 472 /* 473 * Disassociate a p-buffer from a bufobj. 474 */ 475 void 476 pbrelbo(struct buf *bp) 477 { 478 479 KASSERT(bp->b_vp == NULL, ("pbrelbo: vnode")); 480 KASSERT(bp->b_bufobj != NULL, ("pbrelbo: NULL bufobj")); 481 KASSERT((bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) == 0, 482 ("pbrelbo: pager buf on vnode list.")); 483 484 bp->b_bufobj = NULL; 485 bp->b_flags &= ~B_PAGING; 486 } 487