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 /* 167 * Kernel address space for mapping pages. 168 * Used by pagers where KVAs are needed for IO. 169 * 170 * XXX needs to be large enough to support the number of pending async 171 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size 172 * (MAXPHYS == 64k) if you want to get the most efficiency. 173 */ 174 vm_offset_t swapbkva; /* swap buffers kva */ 175 176 void 177 vm_pager_init(void) 178 { 179 struct pagerops **pgops; 180 181 /* 182 * Initialize known pagers 183 */ 184 for (pgops = pagertab; pgops < &pagertab[nitems(pagertab)]; pgops++) 185 if ((*pgops)->pgo_init != NULL) 186 (*(*pgops)->pgo_init)(); 187 } 188 189 static int nswbuf_max; 190 191 void 192 vm_pager_bufferinit(void) 193 { 194 195 /* Main zone for paging bufs. */ 196 pbuf_zone = uma_zcreate("pbuf", sizeof(struct buf), 197 pbuf_ctor, pbuf_dtor, pbuf_init, NULL, UMA_ALIGN_CACHE, 198 UMA_ZONE_VM | UMA_ZONE_NOFREE); 199 /* Few systems may still use this zone directly, so it needs a limit. */ 200 nswbuf_max += uma_zone_set_max(pbuf_zone, NSWBUF_MIN); 201 } 202 203 uma_zone_t 204 pbuf_zsecond_create(char *name, int max) 205 { 206 uma_zone_t zone; 207 208 zone = uma_zsecond_create(name, pbuf_ctor, pbuf_dtor, NULL, NULL, 209 pbuf_zone); 210 /* 211 * uma_prealloc() rounds up to items per slab. If we would prealloc 212 * immediately on every pbuf_zsecond_create(), we may accumulate too 213 * much of difference between hard limit and prealloced items, which 214 * means wasted memory. 215 */ 216 if (nswbuf_max > 0) 217 nswbuf_max += uma_zone_set_max(zone, max); 218 else 219 uma_prealloc(pbuf_zone, uma_zone_set_max(zone, max)); 220 221 return (zone); 222 } 223 224 static void 225 pbuf_prealloc(void *arg __unused) 226 { 227 228 uma_prealloc(pbuf_zone, nswbuf_max); 229 nswbuf_max = -1; 230 } 231 232 SYSINIT(pbuf, SI_SUB_KTHREAD_BUF, SI_ORDER_ANY, pbuf_prealloc, NULL); 233 234 /* 235 * Allocate an instance of a pager of the given type. 236 * Size, protection and offset parameters are passed in for pagers that 237 * need to perform page-level validation (e.g. the device pager). 238 */ 239 vm_object_t 240 vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, 241 vm_prot_t prot, vm_ooffset_t off, struct ucred *cred) 242 { 243 vm_object_t ret; 244 struct pagerops *ops; 245 246 ops = pagertab[type]; 247 if (ops) 248 ret = (*ops->pgo_alloc)(handle, size, prot, off, cred); 249 else 250 ret = NULL; 251 return (ret); 252 } 253 254 /* 255 * The object must be locked. 256 */ 257 void 258 vm_pager_deallocate(vm_object_t object) 259 { 260 261 VM_OBJECT_ASSERT_WLOCKED(object); 262 (*pagertab[object->type]->pgo_dealloc) (object); 263 } 264 265 static void 266 vm_pager_assert_in(vm_object_t object, vm_page_t *m, int count) 267 { 268 #ifdef INVARIANTS 269 270 VM_OBJECT_ASSERT_WLOCKED(object); 271 KASSERT(count > 0, ("%s: 0 count", __func__)); 272 /* 273 * All pages must be busied, not mapped, not fully valid, 274 * not dirty and belong to the proper object. 275 */ 276 for (int i = 0 ; i < count; i++) { 277 if (m[i] == bogus_page) 278 continue; 279 vm_page_assert_xbusied(m[i]); 280 KASSERT(!pmap_page_is_mapped(m[i]), 281 ("%s: page %p is mapped", __func__, m[i])); 282 KASSERT(m[i]->valid != VM_PAGE_BITS_ALL, 283 ("%s: request for a valid page %p", __func__, m[i])); 284 KASSERT(m[i]->dirty == 0, 285 ("%s: page %p is dirty", __func__, m[i])); 286 KASSERT(m[i]->object == object, 287 ("%s: wrong object %p/%p", __func__, object, m[i]->object)); 288 } 289 #endif 290 } 291 292 /* 293 * Page in the pages for the object using its associated pager. 294 * The requested page must be fully valid on successful return. 295 */ 296 int 297 vm_pager_get_pages(vm_object_t object, vm_page_t *m, int count, int *rbehind, 298 int *rahead) 299 { 300 #ifdef INVARIANTS 301 vm_pindex_t pindex = m[0]->pindex; 302 #endif 303 int r; 304 305 vm_pager_assert_in(object, m, count); 306 307 r = (*pagertab[object->type]->pgo_getpages)(object, m, count, rbehind, 308 rahead); 309 if (r != VM_PAGER_OK) 310 return (r); 311 312 for (int i = 0; i < count; i++) { 313 /* 314 * If pager has replaced a page, assert that it had 315 * updated the array. 316 */ 317 KASSERT(m[i] == vm_page_lookup(object, pindex++), 318 ("%s: mismatch page %p pindex %ju", __func__, 319 m[i], (uintmax_t )pindex - 1)); 320 /* 321 * Zero out partially filled data. 322 */ 323 if (m[i]->valid != VM_PAGE_BITS_ALL) 324 vm_page_zero_invalid(m[i], TRUE); 325 } 326 return (VM_PAGER_OK); 327 } 328 329 int 330 vm_pager_get_pages_async(vm_object_t object, vm_page_t *m, int count, 331 int *rbehind, int *rahead, pgo_getpages_iodone_t iodone, void *arg) 332 { 333 334 vm_pager_assert_in(object, m, count); 335 336 return ((*pagertab[object->type]->pgo_getpages_async)(object, m, 337 count, rbehind, rahead, iodone, arg)); 338 } 339 340 /* 341 * vm_pager_put_pages() - inline, see vm/vm_pager.h 342 * vm_pager_has_page() - inline, see vm/vm_pager.h 343 */ 344 345 /* 346 * Search the specified pager object list for an object with the 347 * specified handle. If an object with the specified handle is found, 348 * increase its reference count and return it. Otherwise, return NULL. 349 * 350 * The pager object list must be locked. 351 */ 352 vm_object_t 353 vm_pager_object_lookup(struct pagerlst *pg_list, void *handle) 354 { 355 vm_object_t object; 356 357 TAILQ_FOREACH(object, pg_list, pager_object_list) { 358 if (object->handle == handle) { 359 VM_OBJECT_WLOCK(object); 360 if ((object->flags & OBJ_DEAD) == 0) { 361 vm_object_reference_locked(object); 362 VM_OBJECT_WUNLOCK(object); 363 break; 364 } 365 VM_OBJECT_WUNLOCK(object); 366 } 367 } 368 return (object); 369 } 370 371 static int 372 pbuf_ctor(void *mem, int size, void *arg, int flags) 373 { 374 struct buf *bp = mem; 375 376 bp->b_vp = NULL; 377 bp->b_bufobj = NULL; 378 379 /* copied from initpbuf() */ 380 bp->b_rcred = NOCRED; 381 bp->b_wcred = NOCRED; 382 bp->b_qindex = 0; /* On no queue (QUEUE_NONE) */ 383 bp->b_data = bp->b_kvabase; 384 bp->b_xflags = 0; 385 bp->b_flags = 0; 386 bp->b_ioflags = 0; 387 bp->b_iodone = NULL; 388 bp->b_error = 0; 389 BUF_LOCK(bp, LK_EXCLUSIVE, NULL); 390 391 return (0); 392 } 393 394 static void 395 pbuf_dtor(void *mem, int size, void *arg) 396 { 397 struct buf *bp = mem; 398 399 if (bp->b_rcred != NOCRED) { 400 crfree(bp->b_rcred); 401 bp->b_rcred = NOCRED; 402 } 403 if (bp->b_wcred != NOCRED) { 404 crfree(bp->b_wcred); 405 bp->b_wcred = NOCRED; 406 } 407 408 BUF_UNLOCK(bp); 409 } 410 411 static int 412 pbuf_init(void *mem, int size, int flags) 413 { 414 struct buf *bp = mem; 415 416 bp->b_kvabase = (void *)kva_alloc(MAXPHYS); 417 if (bp->b_kvabase == NULL) 418 return (ENOMEM); 419 bp->b_kvasize = MAXPHYS; 420 BUF_LOCKINIT(bp); 421 LIST_INIT(&bp->b_dep); 422 bp->b_rcred = bp->b_wcred = NOCRED; 423 bp->b_xflags = 0; 424 425 return (0); 426 } 427 428 /* 429 * Associate a p-buffer with a vnode. 430 * 431 * Also sets B_PAGING flag to indicate that vnode is not fully associated 432 * with the buffer. i.e. the bp has not been linked into the vnode or 433 * ref-counted. 434 */ 435 void 436 pbgetvp(struct vnode *vp, struct buf *bp) 437 { 438 439 KASSERT(bp->b_vp == NULL, ("pbgetvp: not free")); 440 KASSERT(bp->b_bufobj == NULL, ("pbgetvp: not free (bufobj)")); 441 442 bp->b_vp = vp; 443 bp->b_flags |= B_PAGING; 444 bp->b_bufobj = &vp->v_bufobj; 445 } 446 447 /* 448 * Associate a p-buffer with a vnode. 449 * 450 * Also sets B_PAGING flag to indicate that vnode is not fully associated 451 * with the buffer. i.e. the bp has not been linked into the vnode or 452 * ref-counted. 453 */ 454 void 455 pbgetbo(struct bufobj *bo, struct buf *bp) 456 { 457 458 KASSERT(bp->b_vp == NULL, ("pbgetbo: not free (vnode)")); 459 KASSERT(bp->b_bufobj == NULL, ("pbgetbo: not free (bufobj)")); 460 461 bp->b_flags |= B_PAGING; 462 bp->b_bufobj = bo; 463 } 464 465 /* 466 * Disassociate a p-buffer from a vnode. 467 */ 468 void 469 pbrelvp(struct buf *bp) 470 { 471 472 KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL")); 473 KASSERT(bp->b_bufobj != NULL, ("pbrelvp: NULL bufobj")); 474 KASSERT((bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) == 0, 475 ("pbrelvp: pager buf on vnode list.")); 476 477 bp->b_vp = NULL; 478 bp->b_bufobj = NULL; 479 bp->b_flags &= ~B_PAGING; 480 } 481 482 /* 483 * Disassociate a p-buffer from a bufobj. 484 */ 485 void 486 pbrelbo(struct buf *bp) 487 { 488 489 KASSERT(bp->b_vp == NULL, ("pbrelbo: vnode")); 490 KASSERT(bp->b_bufobj != NULL, ("pbrelbo: NULL bufobj")); 491 KASSERT((bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) == 0, 492 ("pbrelbo: pager buf on vnode list.")); 493 494 bp->b_bufobj = NULL; 495 bp->b_flags &= ~B_PAGING; 496 } 497