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); 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(handle, size, prot, off) 108 void *handle; 109 vm_ooffset_t size; 110 vm_prot_t prot; 111 vm_ooffset_t off; 112 { 113 return NULL; 114 } 115 116 static void 117 dead_pager_putpages(object, m, count, flags, rtvals) 118 vm_object_t object; 119 vm_page_t *m; 120 int count; 121 int flags; 122 int *rtvals; 123 { 124 int i; 125 126 for (i = 0; i < count; i++) { 127 rtvals[i] = VM_PAGER_AGAIN; 128 } 129 } 130 131 static int 132 dead_pager_haspage(object, pindex, prev, next) 133 vm_object_t object; 134 vm_pindex_t pindex; 135 int *prev; 136 int *next; 137 { 138 if (prev) 139 *prev = 0; 140 if (next) 141 *next = 0; 142 return FALSE; 143 } 144 145 static void 146 dead_pager_dealloc(object) 147 vm_object_t object; 148 { 149 return; 150 } 151 152 static struct pagerops deadpagerops = { 153 .pgo_alloc = dead_pager_alloc, 154 .pgo_dealloc = dead_pager_dealloc, 155 .pgo_getpages = dead_pager_getpages, 156 .pgo_putpages = dead_pager_putpages, 157 .pgo_haspage = dead_pager_haspage, 158 }; 159 160 struct pagerops *pagertab[] = { 161 &defaultpagerops, /* OBJT_DEFAULT */ 162 &swappagerops, /* OBJT_SWAP */ 163 &vnodepagerops, /* OBJT_VNODE */ 164 &devicepagerops, /* OBJT_DEVICE */ 165 &physpagerops, /* OBJT_PHYS */ 166 &deadpagerops /* OBJT_DEAD */ 167 }; 168 169 int npagers = sizeof(pagertab) / sizeof(pagertab[0]); 170 171 /* 172 * Kernel address space for mapping pages. 173 * Used by pagers where KVAs are needed for IO. 174 * 175 * XXX needs to be large enough to support the number of pending async 176 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size 177 * (MAXPHYS == 64k) if you want to get the most efficiency. 178 */ 179 vm_map_t pager_map; 180 static int bswneeded; 181 static vm_offset_t swapbkva; /* swap buffers kva */ 182 struct mtx pbuf_mtx; 183 static TAILQ_HEAD(swqueue, buf) bswlist; 184 185 void 186 vm_pager_init() 187 { 188 struct pagerops **pgops; 189 190 TAILQ_INIT(&bswlist); 191 /* 192 * Initialize known pagers 193 */ 194 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 195 if (pgops && ((*pgops)->pgo_init != NULL)) 196 (*(*pgops)->pgo_init) (); 197 } 198 199 void 200 vm_pager_bufferinit() 201 { 202 struct buf *bp; 203 int i; 204 205 mtx_init(&pbuf_mtx, "pbuf mutex", NULL, MTX_DEF); 206 bp = swbuf; 207 /* 208 * Now set up swap and physical I/O buffer headers. 209 */ 210 for (i = 0; i < nswbuf; i++, bp++) { 211 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 212 BUF_LOCKINIT(bp); 213 LIST_INIT(&bp->b_dep); 214 bp->b_rcred = bp->b_wcred = NOCRED; 215 bp->b_xflags = 0; 216 } 217 218 cluster_pbuf_freecnt = nswbuf / 2; 219 220 swapbkva = kmem_alloc_nofault(pager_map, nswbuf * MAXPHYS); 221 if (!swapbkva) 222 panic("Not enough pager_map VM space for physical buffers"); 223 } 224 225 /* 226 * Allocate an instance of a pager of the given type. 227 * Size, protection and offset parameters are passed in for pagers that 228 * need to perform page-level validation (e.g. the device pager). 229 */ 230 vm_object_t 231 vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, 232 vm_prot_t prot, vm_ooffset_t off) 233 { 234 vm_object_t ret; 235 struct pagerops *ops; 236 237 ops = pagertab[type]; 238 if (ops) 239 ret = (*ops->pgo_alloc) (handle, size, prot, off); 240 else 241 ret = NULL; 242 return (ret); 243 } 244 245 /* 246 * The object must be locked. 247 */ 248 void 249 vm_pager_deallocate(object) 250 vm_object_t object; 251 { 252 253 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 254 (*pagertab[object->type]->pgo_dealloc) (object); 255 } 256 257 /* 258 * vm_pager_get_pages() - inline, see vm/vm_pager.h 259 * vm_pager_put_pages() - inline, see vm/vm_pager.h 260 * vm_pager_has_page() - inline, see vm/vm_pager.h 261 */ 262 263 vm_object_t 264 vm_pager_object_lookup(pg_list, handle) 265 struct pagerlst *pg_list; 266 void *handle; 267 { 268 vm_object_t object; 269 270 TAILQ_FOREACH(object, pg_list, pager_object_list) 271 if (object->handle == handle) 272 return (object); 273 return (NULL); 274 } 275 276 /* 277 * initialize a physical buffer 278 */ 279 280 /* 281 * XXX This probably belongs in vfs_bio.c 282 */ 283 static void 284 initpbuf(struct buf *bp) 285 { 286 KASSERT(bp->b_bufobj == NULL, ("initpbuf with bufobj")); 287 KASSERT(bp->b_vp == NULL, ("initpbuf with vp")); 288 bp->b_rcred = NOCRED; 289 bp->b_wcred = NOCRED; 290 bp->b_qindex = 0; /* On no queue (QUEUE_NONE) */ 291 bp->b_saveaddr = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva; 292 bp->b_data = bp->b_saveaddr; 293 bp->b_kvabase = bp->b_saveaddr; 294 bp->b_kvasize = MAXPHYS; 295 bp->b_xflags = 0; 296 bp->b_flags = 0; 297 bp->b_ioflags = 0; 298 bp->b_iodone = NULL; 299 bp->b_error = 0; 300 BUF_LOCK(bp, LK_EXCLUSIVE, NULL); 301 } 302 303 /* 304 * allocate a physical buffer 305 * 306 * There are a limited number (nswbuf) of physical buffers. We need 307 * to make sure that no single subsystem is able to hog all of them, 308 * so each subsystem implements a counter which is typically initialized 309 * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and 310 * increments it on release, and blocks if the counter hits zero. A 311 * subsystem may initialize the counter to -1 to disable the feature, 312 * but it must still be sure to match up all uses of getpbuf() with 313 * relpbuf() using the same variable. 314 * 315 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 316 * relatively soon when the rest of the subsystems get smart about it. XXX 317 */ 318 struct buf * 319 getpbuf(int *pfreecnt) 320 { 321 int s; 322 struct buf *bp; 323 324 s = splvm(); 325 mtx_lock(&pbuf_mtx); 326 327 for (;;) { 328 if (pfreecnt) { 329 while (*pfreecnt == 0) { 330 msleep(pfreecnt, &pbuf_mtx, PVM, "wswbuf0", 0); 331 } 332 } 333 334 /* get a bp from the swap buffer header pool */ 335 if ((bp = TAILQ_FIRST(&bswlist)) != NULL) 336 break; 337 338 bswneeded = 1; 339 msleep(&bswneeded, &pbuf_mtx, PVM, "wswbuf1", 0); 340 /* loop in case someone else grabbed one */ 341 } 342 TAILQ_REMOVE(&bswlist, bp, b_freelist); 343 if (pfreecnt) 344 --*pfreecnt; 345 mtx_unlock(&pbuf_mtx); 346 splx(s); 347 348 initpbuf(bp); 349 return bp; 350 } 351 352 /* 353 * allocate a physical buffer, if one is available. 354 * 355 * Note that there is no NULL hack here - all subsystems using this 356 * call understand how to use pfreecnt. 357 */ 358 struct buf * 359 trypbuf(int *pfreecnt) 360 { 361 int s; 362 struct buf *bp; 363 364 s = splvm(); 365 mtx_lock(&pbuf_mtx); 366 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) { 367 mtx_unlock(&pbuf_mtx); 368 splx(s); 369 return NULL; 370 } 371 TAILQ_REMOVE(&bswlist, bp, b_freelist); 372 373 --*pfreecnt; 374 375 mtx_unlock(&pbuf_mtx); 376 splx(s); 377 378 initpbuf(bp); 379 380 return bp; 381 } 382 383 /* 384 * release a physical buffer 385 * 386 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 387 * relatively soon when the rest of the subsystems get smart about it. XXX 388 */ 389 void 390 relpbuf(struct buf *bp, int *pfreecnt) 391 { 392 int s; 393 394 s = splvm(); 395 396 if (bp->b_rcred != NOCRED) { 397 crfree(bp->b_rcred); 398 bp->b_rcred = NOCRED; 399 } 400 if (bp->b_wcred != NOCRED) { 401 crfree(bp->b_wcred); 402 bp->b_wcred = NOCRED; 403 } 404 405 KASSERT(bp->b_vp == NULL, ("relpbuf with vp")); 406 KASSERT(bp->b_bufobj == NULL, ("relpbuf with bufobj")); 407 408 BUF_UNLOCK(bp); 409 410 mtx_lock(&pbuf_mtx); 411 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 412 413 if (bswneeded) { 414 bswneeded = 0; 415 wakeup(&bswneeded); 416 } 417 if (pfreecnt) { 418 if (++*pfreecnt == 1) 419 wakeup(pfreecnt); 420 } 421 mtx_unlock(&pbuf_mtx); 422 splx(s); 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