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 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#)vm_pager.c 8.6 (Berkeley) 1/12/94 37 * 38 * 39 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 40 * All rights reserved. 41 * 42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 43 * 44 * Permission to use, copy, modify and distribute this software and 45 * its documentation is hereby granted, provided that both the copyright 46 * notice and this permission notice appear in all copies of the 47 * software, derivative works or modified versions, and any portions 48 * thereof, and that both notices appear in supporting documentation. 49 * 50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 53 * 54 * Carnegie Mellon requests users of this software to return to 55 * 56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 57 * School of Computer Science 58 * Carnegie Mellon University 59 * Pittsburgh PA 15213-3890 60 * 61 * any improvements or extensions that they make and grant Carnegie the 62 * rights to redistribute these changes. 63 */ 64 65 /* 66 * Paging space routine stubs. Emulates a matchmaker-like interface 67 * for builtin pagers. 68 */ 69 70 #include <sys/cdefs.h> 71 __FBSDID("$FreeBSD$"); 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 82 #include <vm/vm.h> 83 #include <vm/vm_param.h> 84 #include <vm/vm_object.h> 85 #include <vm/vm_page.h> 86 #include <vm/vm_pager.h> 87 #include <vm/vm_extern.h> 88 89 MALLOC_DEFINE(M_VMPGDATA, "VM pgdata", "XXX: VM pager private data"); 90 91 int cluster_pbuf_freecnt = -1; /* unlimited to begin with */ 92 93 static int dead_pager_getpages(vm_object_t, vm_page_t *, int, int); 94 static vm_object_t dead_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 95 vm_ooffset_t); 96 static void dead_pager_putpages(vm_object_t, vm_page_t *, int, int, int *); 97 static boolean_t dead_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 98 static void dead_pager_dealloc(vm_object_t); 99 100 static int 101 dead_pager_getpages(obj, ma, count, req) 102 vm_object_t obj; 103 vm_page_t *ma; 104 int count; 105 int req; 106 { 107 return VM_PAGER_FAIL; 108 } 109 110 static vm_object_t 111 dead_pager_alloc(handle, size, prot, off) 112 void *handle; 113 vm_ooffset_t size; 114 vm_prot_t prot; 115 vm_ooffset_t off; 116 { 117 return NULL; 118 } 119 120 static void 121 dead_pager_putpages(object, m, count, flags, rtvals) 122 vm_object_t object; 123 vm_page_t *m; 124 int count; 125 int flags; 126 int *rtvals; 127 { 128 int i; 129 130 for (i = 0; i < count; i++) { 131 rtvals[i] = VM_PAGER_AGAIN; 132 } 133 } 134 135 static int 136 dead_pager_haspage(object, pindex, prev, next) 137 vm_object_t object; 138 vm_pindex_t pindex; 139 int *prev; 140 int *next; 141 { 142 if (prev) 143 *prev = 0; 144 if (next) 145 *next = 0; 146 return FALSE; 147 } 148 149 static void 150 dead_pager_dealloc(object) 151 vm_object_t object; 152 { 153 return; 154 } 155 156 static struct pagerops deadpagerops = { 157 .pgo_alloc = dead_pager_alloc, 158 .pgo_dealloc = dead_pager_dealloc, 159 .pgo_getpages = dead_pager_getpages, 160 .pgo_putpages = dead_pager_putpages, 161 .pgo_haspage = dead_pager_haspage, 162 }; 163 164 struct pagerops *pagertab[] = { 165 &defaultpagerops, /* OBJT_DEFAULT */ 166 &swappagerops, /* OBJT_SWAP */ 167 &vnodepagerops, /* OBJT_VNODE */ 168 &devicepagerops, /* OBJT_DEVICE */ 169 &physpagerops, /* OBJT_PHYS */ 170 &deadpagerops /* OBJT_DEAD */ 171 }; 172 173 int npagers = sizeof(pagertab) / sizeof(pagertab[0]); 174 175 /* 176 * Kernel address space for mapping pages. 177 * Used by pagers where KVAs are needed for IO. 178 * 179 * XXX needs to be large enough to support the number of pending async 180 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size 181 * (MAXPHYS == 64k) if you want to get the most efficiency. 182 */ 183 #define PAGER_MAP_SIZE (8 * 1024 * 1024) 184 185 int pager_map_size = PAGER_MAP_SIZE; 186 vm_map_t pager_map; 187 static int bswneeded; 188 static vm_offset_t swapbkva; /* swap buffers kva */ 189 struct mtx pbuf_mtx; 190 static TAILQ_HEAD(swqueue, buf) bswlist; 191 192 void 193 vm_pager_init() 194 { 195 struct pagerops **pgops; 196 197 TAILQ_INIT(&bswlist); 198 /* 199 * Initialize known pagers 200 */ 201 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 202 if (pgops && ((*pgops)->pgo_init != NULL)) 203 (*(*pgops)->pgo_init) (); 204 } 205 206 void 207 vm_pager_bufferinit() 208 { 209 struct buf *bp; 210 int i; 211 212 mtx_init(&pbuf_mtx, "pbuf mutex", NULL, MTX_DEF); 213 bp = swbuf; 214 /* 215 * Now set up swap and physical I/O buffer headers. 216 */ 217 for (i = 0; i < nswbuf; i++, bp++) { 218 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 219 BUF_LOCKINIT(bp); 220 LIST_INIT(&bp->b_dep); 221 bp->b_rcred = bp->b_wcred = NOCRED; 222 bp->b_xflags = 0; 223 } 224 225 cluster_pbuf_freecnt = nswbuf / 2; 226 227 swapbkva = kmem_alloc_nofault(pager_map, nswbuf * MAXPHYS); 228 if (!swapbkva) 229 panic("Not enough pager_map VM space for physical buffers"); 230 } 231 232 /* 233 * Allocate an instance of a pager of the given type. 234 * Size, protection and offset parameters are passed in for pagers that 235 * need to perform page-level validation (e.g. the device pager). 236 */ 237 vm_object_t 238 vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, 239 vm_prot_t prot, vm_ooffset_t off) 240 { 241 vm_object_t ret; 242 struct pagerops *ops; 243 244 ops = pagertab[type]; 245 if (ops) 246 ret = (*ops->pgo_alloc) (handle, size, prot, off); 247 else 248 ret = NULL; 249 return (ret); 250 } 251 252 /* 253 * The object must be locked. 254 */ 255 void 256 vm_pager_deallocate(object) 257 vm_object_t object; 258 { 259 260 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 261 (*pagertab[object->type]->pgo_dealloc) (object); 262 } 263 264 /* 265 * vm_pager_get_pages() - inline, see vm/vm_pager.h 266 * vm_pager_put_pages() - inline, see vm/vm_pager.h 267 * vm_pager_has_page() - inline, see vm/vm_pager.h 268 */ 269 270 vm_offset_t 271 vm_pager_map_page(m) 272 vm_page_t m; 273 { 274 vm_offset_t kva; 275 276 kva = kmem_alloc_wait(pager_map, PAGE_SIZE); 277 pmap_qenter(kva, &m, 1); 278 return (kva); 279 } 280 281 void 282 vm_pager_unmap_page(kva) 283 vm_offset_t kva; 284 { 285 286 pmap_qremove(kva, 1); 287 kmem_free_wakeup(pager_map, kva, PAGE_SIZE); 288 } 289 290 vm_object_t 291 vm_pager_object_lookup(pg_list, handle) 292 struct pagerlst *pg_list; 293 void *handle; 294 { 295 vm_object_t object; 296 297 TAILQ_FOREACH(object, pg_list, pager_object_list) 298 if (object->handle == handle) 299 return (object); 300 return (NULL); 301 } 302 303 /* 304 * initialize a physical buffer 305 */ 306 307 /* 308 * XXX This probably belongs in vfs_bio.c 309 */ 310 static void 311 initpbuf(struct buf *bp) 312 { 313 bp->b_rcred = NOCRED; 314 bp->b_wcred = NOCRED; 315 bp->b_qindex = 0; /* On no queue (QUEUE_NONE) */ 316 bp->b_saveaddr = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva; 317 bp->b_data = bp->b_saveaddr; 318 bp->b_kvabase = bp->b_saveaddr; 319 bp->b_kvasize = MAXPHYS; 320 bp->b_xflags = 0; 321 bp->b_flags = 0; 322 bp->b_ioflags = 0; 323 bp->b_iodone = NULL; 324 bp->b_error = 0; 325 bp->b_magic = B_MAGIC_BIO; 326 bp->b_op = &buf_ops_bio; 327 BUF_LOCK(bp, LK_EXCLUSIVE, NULL); 328 } 329 330 /* 331 * allocate a physical buffer 332 * 333 * There are a limited number (nswbuf) of physical buffers. We need 334 * to make sure that no single subsystem is able to hog all of them, 335 * so each subsystem implements a counter which is typically initialized 336 * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and 337 * increments it on release, and blocks if the counter hits zero. A 338 * subsystem may initialize the counter to -1 to disable the feature, 339 * but it must still be sure to match up all uses of getpbuf() with 340 * relpbuf() using the same variable. 341 * 342 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 343 * relatively soon when the rest of the subsystems get smart about it. XXX 344 */ 345 struct buf * 346 getpbuf(pfreecnt) 347 int *pfreecnt; 348 { 349 int s; 350 struct buf *bp; 351 352 s = splvm(); 353 mtx_lock(&pbuf_mtx); 354 355 for (;;) { 356 if (pfreecnt) { 357 while (*pfreecnt == 0) { 358 msleep(pfreecnt, &pbuf_mtx, PVM, "wswbuf0", 0); 359 } 360 } 361 362 /* get a bp from the swap buffer header pool */ 363 if ((bp = TAILQ_FIRST(&bswlist)) != NULL) 364 break; 365 366 bswneeded = 1; 367 msleep(&bswneeded, &pbuf_mtx, PVM, "wswbuf1", 0); 368 /* loop in case someone else grabbed one */ 369 } 370 TAILQ_REMOVE(&bswlist, bp, b_freelist); 371 if (pfreecnt) 372 --*pfreecnt; 373 mtx_unlock(&pbuf_mtx); 374 splx(s); 375 376 initpbuf(bp); 377 return bp; 378 } 379 380 /* 381 * allocate a physical buffer, if one is available. 382 * 383 * Note that there is no NULL hack here - all subsystems using this 384 * call understand how to use pfreecnt. 385 */ 386 struct buf * 387 trypbuf(pfreecnt) 388 int *pfreecnt; 389 { 390 int s; 391 struct buf *bp; 392 393 s = splvm(); 394 mtx_lock(&pbuf_mtx); 395 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) { 396 mtx_unlock(&pbuf_mtx); 397 splx(s); 398 return NULL; 399 } 400 TAILQ_REMOVE(&bswlist, bp, b_freelist); 401 402 --*pfreecnt; 403 404 mtx_unlock(&pbuf_mtx); 405 splx(s); 406 407 initpbuf(bp); 408 409 return bp; 410 } 411 412 /* 413 * release a physical buffer 414 * 415 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 416 * relatively soon when the rest of the subsystems get smart about it. XXX 417 */ 418 void 419 relpbuf(bp, pfreecnt) 420 struct buf *bp; 421 int *pfreecnt; 422 { 423 int s; 424 425 s = splvm(); 426 427 if (bp->b_rcred != NOCRED) { 428 crfree(bp->b_rcred); 429 bp->b_rcred = NOCRED; 430 } 431 if (bp->b_wcred != NOCRED) { 432 crfree(bp->b_wcred); 433 bp->b_wcred = NOCRED; 434 } 435 436 if (bp->b_vp) 437 pbrelvp(bp); 438 439 BUF_UNLOCK(bp); 440 441 mtx_lock(&pbuf_mtx); 442 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 443 444 if (bswneeded) { 445 bswneeded = 0; 446 wakeup(&bswneeded); 447 } 448 if (pfreecnt) { 449 if (++*pfreecnt == 1) 450 wakeup(pfreecnt); 451 } 452 mtx_unlock(&pbuf_mtx); 453 splx(s); 454 } 455