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 78 #include <vm/vm.h> 79 #include <vm/vm_param.h> 80 #include <vm/vm_object.h> 81 #include <vm/vm_page.h> 82 #include <vm/vm_pager.h> 83 #include <vm/vm_extern.h> 84 85 MALLOC_DEFINE(M_VMPGDATA, "vm_pgdata", "XXX: VM pager private data"); 86 87 int cluster_pbuf_freecnt = -1; /* unlimited to begin with */ 88 89 static int dead_pager_getpages(vm_object_t, vm_page_t *, int, int); 90 static vm_object_t dead_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 91 vm_ooffset_t, struct ucred *); 92 static void dead_pager_putpages(vm_object_t, vm_page_t *, int, int, int *); 93 static boolean_t dead_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 94 static void dead_pager_dealloc(vm_object_t); 95 96 static int 97 dead_pager_getpages(obj, ma, count, req) 98 vm_object_t obj; 99 vm_page_t *ma; 100 int count; 101 int req; 102 { 103 return VM_PAGER_FAIL; 104 } 105 106 static vm_object_t 107 dead_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 108 vm_ooffset_t off, struct ucred *cred) 109 { 110 return NULL; 111 } 112 113 static void 114 dead_pager_putpages(object, m, count, flags, rtvals) 115 vm_object_t object; 116 vm_page_t *m; 117 int count; 118 int flags; 119 int *rtvals; 120 { 121 int i; 122 123 for (i = 0; i < count; i++) { 124 rtvals[i] = VM_PAGER_AGAIN; 125 } 126 } 127 128 static int 129 dead_pager_haspage(object, pindex, prev, next) 130 vm_object_t object; 131 vm_pindex_t pindex; 132 int *prev; 133 int *next; 134 { 135 if (prev) 136 *prev = 0; 137 if (next) 138 *next = 0; 139 return FALSE; 140 } 141 142 static void 143 dead_pager_dealloc(object) 144 vm_object_t object; 145 { 146 return; 147 } 148 149 static struct pagerops deadpagerops = { 150 .pgo_alloc = dead_pager_alloc, 151 .pgo_dealloc = dead_pager_dealloc, 152 .pgo_getpages = dead_pager_getpages, 153 .pgo_putpages = dead_pager_putpages, 154 .pgo_haspage = dead_pager_haspage, 155 }; 156 157 struct pagerops *pagertab[] = { 158 &defaultpagerops, /* OBJT_DEFAULT */ 159 &swappagerops, /* OBJT_SWAP */ 160 &vnodepagerops, /* OBJT_VNODE */ 161 &devicepagerops, /* OBJT_DEVICE */ 162 &physpagerops, /* OBJT_PHYS */ 163 &deadpagerops, /* OBJT_DEAD */ 164 &sgpagerops /* OBJT_SG */ 165 }; 166 167 static const int npagers = sizeof(pagertab) / sizeof(pagertab[0]); 168 169 /* 170 * Kernel address space for mapping pages. 171 * Used by pagers where KVAs are needed for IO. 172 * 173 * XXX needs to be large enough to support the number of pending async 174 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size 175 * (MAXPHYS == 64k) if you want to get the most efficiency. 176 */ 177 vm_map_t pager_map; 178 static int bswneeded; 179 static vm_offset_t swapbkva; /* swap buffers kva */ 180 struct mtx pbuf_mtx; 181 static TAILQ_HEAD(swqueue, buf) bswlist; 182 183 void 184 vm_pager_init() 185 { 186 struct pagerops **pgops; 187 188 TAILQ_INIT(&bswlist); 189 /* 190 * Initialize known pagers 191 */ 192 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 193 if (pgops && ((*pgops)->pgo_init != NULL)) 194 (*(*pgops)->pgo_init) (); 195 } 196 197 void 198 vm_pager_bufferinit() 199 { 200 struct buf *bp; 201 int i; 202 203 mtx_init(&pbuf_mtx, "pbuf mutex", NULL, MTX_DEF); 204 bp = swbuf; 205 /* 206 * Now set up swap and physical I/O buffer headers. 207 */ 208 for (i = 0; i < nswbuf; i++, bp++) { 209 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 210 BUF_LOCKINIT(bp); 211 LIST_INIT(&bp->b_dep); 212 bp->b_rcred = bp->b_wcred = NOCRED; 213 bp->b_xflags = 0; 214 } 215 216 cluster_pbuf_freecnt = nswbuf / 2; 217 vnode_pbuf_freecnt = nswbuf / 2 + 1; 218 219 swapbkva = kmem_alloc_nofault(pager_map, nswbuf * MAXPHYS); 220 if (!swapbkva) 221 panic("Not enough pager_map VM space for physical buffers"); 222 } 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(object) 249 vm_object_t object; 250 { 251 252 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 253 (*pagertab[object->type]->pgo_dealloc) (object); 254 } 255 256 /* 257 * vm_pager_get_pages() - inline, see vm/vm_pager.h 258 * vm_pager_put_pages() - inline, see vm/vm_pager.h 259 * vm_pager_has_page() - inline, see vm/vm_pager.h 260 */ 261 262 /* 263 * Search the specified pager object list for an object with the 264 * specified handle. If an object with the specified handle is found, 265 * increase its reference count and return it. Otherwise, return NULL. 266 * 267 * The pager object list must be locked. 268 */ 269 vm_object_t 270 vm_pager_object_lookup(struct pagerlst *pg_list, void *handle) 271 { 272 vm_object_t object; 273 274 TAILQ_FOREACH(object, pg_list, pager_object_list) { 275 VM_OBJECT_LOCK(object); 276 if (object->handle == handle && 277 (object->flags & OBJ_DEAD) == 0) { 278 vm_object_reference_locked(object); 279 VM_OBJECT_UNLOCK(object); 280 break; 281 } 282 VM_OBJECT_UNLOCK(object); 283 } 284 return (object); 285 } 286 287 /* 288 * initialize a physical buffer 289 */ 290 291 /* 292 * XXX This probably belongs in vfs_bio.c 293 */ 294 static void 295 initpbuf(struct buf *bp) 296 { 297 KASSERT(bp->b_bufobj == NULL, ("initpbuf with bufobj")); 298 KASSERT(bp->b_vp == NULL, ("initpbuf with vp")); 299 bp->b_rcred = NOCRED; 300 bp->b_wcred = NOCRED; 301 bp->b_qindex = 0; /* On no queue (QUEUE_NONE) */ 302 bp->b_saveaddr = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva; 303 bp->b_data = bp->b_saveaddr; 304 bp->b_kvabase = bp->b_saveaddr; 305 bp->b_kvasize = MAXPHYS; 306 bp->b_xflags = 0; 307 bp->b_flags = 0; 308 bp->b_ioflags = 0; 309 bp->b_iodone = NULL; 310 bp->b_error = 0; 311 BUF_LOCK(bp, LK_EXCLUSIVE, NULL); 312 } 313 314 /* 315 * allocate a physical buffer 316 * 317 * There are a limited number (nswbuf) of physical buffers. We need 318 * to make sure that no single subsystem is able to hog all of them, 319 * so each subsystem implements a counter which is typically initialized 320 * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and 321 * increments it on release, and blocks if the counter hits zero. A 322 * subsystem may initialize the counter to -1 to disable the feature, 323 * but it must still be sure to match up all uses of getpbuf() with 324 * relpbuf() using the same variable. 325 * 326 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 327 * relatively soon when the rest of the subsystems get smart about it. XXX 328 */ 329 struct buf * 330 getpbuf(int *pfreecnt) 331 { 332 struct buf *bp; 333 334 mtx_lock(&pbuf_mtx); 335 336 for (;;) { 337 if (pfreecnt) { 338 while (*pfreecnt == 0) { 339 msleep(pfreecnt, &pbuf_mtx, PVM, "wswbuf0", 0); 340 } 341 } 342 343 /* get a bp from the swap buffer header pool */ 344 if ((bp = TAILQ_FIRST(&bswlist)) != NULL) 345 break; 346 347 bswneeded = 1; 348 msleep(&bswneeded, &pbuf_mtx, PVM, "wswbuf1", 0); 349 /* loop in case someone else grabbed one */ 350 } 351 TAILQ_REMOVE(&bswlist, bp, b_freelist); 352 if (pfreecnt) 353 --*pfreecnt; 354 mtx_unlock(&pbuf_mtx); 355 356 initpbuf(bp); 357 return bp; 358 } 359 360 /* 361 * allocate a physical buffer, if one is available. 362 * 363 * Note that there is no NULL hack here - all subsystems using this 364 * call understand how to use pfreecnt. 365 */ 366 struct buf * 367 trypbuf(int *pfreecnt) 368 { 369 struct buf *bp; 370 371 mtx_lock(&pbuf_mtx); 372 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) { 373 mtx_unlock(&pbuf_mtx); 374 return NULL; 375 } 376 TAILQ_REMOVE(&bswlist, bp, b_freelist); 377 378 --*pfreecnt; 379 380 mtx_unlock(&pbuf_mtx); 381 382 initpbuf(bp); 383 384 return bp; 385 } 386 387 /* 388 * release a physical buffer 389 * 390 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 391 * relatively soon when the rest of the subsystems get smart about it. XXX 392 */ 393 void 394 relpbuf(struct buf *bp, int *pfreecnt) 395 { 396 397 if (bp->b_rcred != NOCRED) { 398 crfree(bp->b_rcred); 399 bp->b_rcred = NOCRED; 400 } 401 if (bp->b_wcred != NOCRED) { 402 crfree(bp->b_wcred); 403 bp->b_wcred = NOCRED; 404 } 405 406 KASSERT(bp->b_vp == NULL, ("relpbuf with vp")); 407 KASSERT(bp->b_bufobj == NULL, ("relpbuf with bufobj")); 408 409 BUF_UNLOCK(bp); 410 411 mtx_lock(&pbuf_mtx); 412 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 413 414 if (bswneeded) { 415 bswneeded = 0; 416 wakeup(&bswneeded); 417 } 418 if (pfreecnt) { 419 if (++*pfreecnt == 1) 420 wakeup(pfreecnt); 421 } 422 mtx_unlock(&pbuf_mtx); 423 } 424 425 /* 426 * Associate a p-buffer with a vnode. 427 * 428 * Also sets B_PAGING flag to indicate that vnode is not fully associated 429 * with the buffer. i.e. the bp has not been linked into the vnode or 430 * ref-counted. 431 */ 432 void 433 pbgetvp(struct vnode *vp, struct buf *bp) 434 { 435 436 KASSERT(bp->b_vp == NULL, ("pbgetvp: not free")); 437 KASSERT(bp->b_bufobj == NULL, ("pbgetvp: not free (bufobj)")); 438 439 bp->b_vp = vp; 440 bp->b_flags |= B_PAGING; 441 bp->b_bufobj = &vp->v_bufobj; 442 } 443 444 /* 445 * Associate a p-buffer with a vnode. 446 * 447 * Also sets B_PAGING flag to indicate that vnode is not fully associated 448 * with the buffer. i.e. the bp has not been linked into the vnode or 449 * ref-counted. 450 */ 451 void 452 pbgetbo(struct bufobj *bo, struct buf *bp) 453 { 454 455 KASSERT(bp->b_vp == NULL, ("pbgetbo: not free (vnode)")); 456 KASSERT(bp->b_bufobj == NULL, ("pbgetbo: not free (bufobj)")); 457 458 bp->b_flags |= B_PAGING; 459 bp->b_bufobj = bo; 460 } 461 462 /* 463 * Disassociate a p-buffer from a vnode. 464 */ 465 void 466 pbrelvp(struct buf *bp) 467 { 468 469 KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL")); 470 KASSERT(bp->b_bufobj != NULL, ("pbrelvp: NULL bufobj")); 471 472 /* XXX REMOVE ME */ 473 BO_LOCK(bp->b_bufobj); 474 if (TAILQ_NEXT(bp, b_bobufs) != NULL) { 475 panic( 476 "relpbuf(): b_vp was probably reassignbuf()d %p %x", 477 bp, 478 (int)bp->b_flags 479 ); 480 } 481 BO_UNLOCK(bp->b_bufobj); 482 bp->b_vp = NULL; 483 bp->b_bufobj = NULL; 484 bp->b_flags &= ~B_PAGING; 485 } 486 487 /* 488 * Disassociate a p-buffer from a bufobj. 489 */ 490 void 491 pbrelbo(struct buf *bp) 492 { 493 494 KASSERT(bp->b_vp == NULL, ("pbrelbo: vnode")); 495 KASSERT(bp->b_bufobj != NULL, ("pbrelbo: NULL bufobj")); 496 497 /* XXX REMOVE ME */ 498 BO_LOCK(bp->b_bufobj); 499 if (TAILQ_NEXT(bp, b_bobufs) != NULL) { 500 panic( 501 "relpbuf(): b_vp was probably reassignbuf()d %p %x", 502 bp, 503 (int)bp->b_flags 504 ); 505 } 506 BO_UNLOCK(bp->b_bufobj); 507 bp->b_bufobj = NULL; 508 bp->b_flags &= ~B_PAGING; 509 } 510