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 * $FreeBSD: src/sys/vm/vm_pager.c,v 1.54.2.2 2001/11/18 07:11:00 dillon Exp $ 65 * $DragonFly: src/sys/vm/vm_pager.c,v 1.24 2007/11/06 03:50:01 dillon Exp $ 66 */ 67 68 /* 69 * Paging space routine stubs. Emulates a matchmaker-like interface 70 * for builtin pagers. 71 */ 72 73 #include <sys/param.h> 74 #include <sys/systm.h> 75 #include <sys/kernel.h> 76 #include <sys/vnode.h> 77 #include <sys/buf.h> 78 #include <sys/ucred.h> 79 #include <sys/malloc.h> 80 #include <sys/proc.h> 81 #include <sys/thread2.h> 82 83 #include <vm/vm.h> 84 #include <vm/vm_param.h> 85 #include <vm/vm_object.h> 86 #include <vm/vm_page.h> 87 #include <vm/vm_pager.h> 88 #include <vm/vm_extern.h> 89 90 #include <sys/buf2.h> 91 92 MALLOC_DEFINE(M_VMPGDATA, "VM pgdata", "XXX: VM pager private data"); 93 94 extern struct pagerops defaultpagerops; 95 extern struct pagerops swappagerops; 96 extern struct pagerops vnodepagerops; 97 extern struct pagerops devicepagerops; 98 extern struct pagerops physpagerops; 99 100 int cluster_pbuf_freecnt = -1; /* unlimited to begin with */ 101 102 static int dead_pager_getpage (vm_object_t, vm_page_t *, int); 103 static void dead_pager_putpages (vm_object_t, vm_page_t *, int, int, int *); 104 static boolean_t dead_pager_haspage (vm_object_t, vm_pindex_t); 105 static void dead_pager_dealloc (vm_object_t); 106 107 static int 108 dead_pager_getpage(vm_object_t obj, vm_page_t *mpp, int seqaccess) 109 { 110 return VM_PAGER_FAIL; 111 } 112 113 static void 114 dead_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags, 115 int *rtvals) 116 { 117 int i; 118 119 for (i = 0; i < count; i++) { 120 rtvals[i] = VM_PAGER_AGAIN; 121 } 122 } 123 124 static int 125 dead_pager_haspage(vm_object_t object, vm_pindex_t pindex) 126 { 127 return FALSE; 128 } 129 130 static void 131 dead_pager_dealloc(vm_object_t object) 132 { 133 KKASSERT(object->swblock_count == 0); 134 return; 135 } 136 137 static struct pagerops deadpagerops = { 138 dead_pager_dealloc, 139 dead_pager_getpage, 140 dead_pager_putpages, 141 dead_pager_haspage 142 }; 143 144 struct pagerops *pagertab[] = { 145 &defaultpagerops, /* OBJT_DEFAULT */ 146 &swappagerops, /* OBJT_SWAP */ 147 &vnodepagerops, /* OBJT_VNODE */ 148 &devicepagerops, /* OBJT_DEVICE */ 149 &physpagerops, /* OBJT_PHYS */ 150 &deadpagerops /* OBJT_DEAD */ 151 }; 152 153 int npagers = sizeof(pagertab) / sizeof(pagertab[0]); 154 155 /* 156 * Kernel address space for mapping pages. 157 * Used by pagers where KVAs are needed for IO. 158 * 159 * XXX needs to be large enough to support the number of pending async 160 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size 161 * (MAXPHYS == 64k) if you want to get the most efficiency. 162 */ 163 #define PAGER_MAP_SIZE (8 * 1024 * 1024) 164 165 int pager_map_size = PAGER_MAP_SIZE; 166 struct vm_map pager_map; 167 168 static int bswneeded; 169 static vm_offset_t swapbkva; /* swap buffers kva */ 170 static TAILQ_HEAD(swqueue, buf) bswlist; 171 static struct spinlock bswspin = SPINLOCK_INITIALIZER(&bswspin); 172 173 static void 174 vm_pager_init(void *arg __unused) 175 { 176 /* 177 * Initialize the swap buffer list. 178 */ 179 TAILQ_INIT(&bswlist); 180 } 181 SYSINIT(vm_mem, SI_BOOT1_VM, SI_ORDER_SECOND, vm_pager_init, NULL) 182 183 void 184 vm_pager_bufferinit(void) 185 { 186 struct buf *bp; 187 int i; 188 189 /* 190 * Reserve KVM space for pbuf data. 191 */ 192 swapbkva = kmem_alloc_pageable(&pager_map, nswbuf * MAXPHYS); 193 if (!swapbkva) 194 panic("Not enough pager_map VM space for physical buffers"); 195 196 /* 197 * Initial pbuf setup. 198 */ 199 bp = swbuf; 200 for (i = 0; i < nswbuf; ++i, ++bp) { 201 bp->b_kvabase = (caddr_t)((intptr_t)i * MAXPHYS) + swapbkva; 202 bp->b_kvasize = MAXPHYS; 203 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 204 BUF_LOCKINIT(bp); 205 buf_dep_init(bp); 206 } 207 208 /* 209 * Allow the clustering code to use half of our pbufs. 210 */ 211 cluster_pbuf_freecnt = nswbuf / 2; 212 } 213 214 void 215 vm_pager_deallocate(vm_object_t object) 216 { 217 (*pagertab[object->type]->pgo_dealloc) (object); 218 } 219 220 /* 221 * vm_pager_get_pages() - inline, see vm/vm_pager.h 222 * vm_pager_put_pages() - inline, see vm/vm_pager.h 223 * vm_pager_has_page() - inline, see vm/vm_pager.h 224 * vm_pager_page_inserted() - inline, see vm/vm_pager.h 225 * vm_pager_page_removed() - inline, see vm/vm_pager.h 226 */ 227 228 #if 0 229 /* 230 * vm_pager_sync: 231 * 232 * Called by pageout daemon before going back to sleep. 233 * Gives pagers a chance to clean up any completed async pageing 234 * operations. 235 */ 236 void 237 vm_pager_sync(void) 238 { 239 struct pagerops **pgops; 240 241 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 242 if (pgops && ((*pgops)->pgo_sync != NULL)) 243 (*(*pgops)->pgo_sync) (); 244 } 245 246 #endif 247 248 /* 249 * Initialize a physical buffer. 250 */ 251 static void 252 initpbuf(struct buf *bp) 253 { 254 bp->b_qindex = 0; /* BQUEUE_NONE */ 255 bp->b_data = bp->b_kvabase; 256 bp->b_flags = B_PAGING; 257 bp->b_cmd = BUF_CMD_DONE; 258 bp->b_error = 0; 259 bp->b_bcount = 0; 260 bp->b_bufsize = MAXPHYS; 261 initbufbio(bp); 262 xio_init(&bp->b_xio); 263 BUF_LOCK(bp, LK_EXCLUSIVE); 264 } 265 266 /* 267 * Allocate a physical buffer 268 * 269 * There are a limited number (nswbuf) of physical buffers. We need 270 * to make sure that no single subsystem is able to hog all of them, 271 * so each subsystem implements a counter which is typically initialized 272 * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and 273 * increments it on release, and blocks if the counter hits zero. A 274 * subsystem may initialize the counter to -1 to disable the feature, 275 * but it must still be sure to match up all uses of getpbuf() with 276 * relpbuf() using the same variable. 277 * 278 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 279 * relatively soon when the rest of the subsystems get smart about it. XXX 280 * 281 * MPSAFE 282 */ 283 struct buf * 284 getpbuf(int *pfreecnt) 285 { 286 struct buf *bp; 287 288 spin_lock_wr(&bswspin); 289 290 for (;;) { 291 if (pfreecnt) { 292 while (*pfreecnt == 0) 293 ssleep(pfreecnt, &bswspin, 0, "wswbuf0", 0); 294 } 295 296 /* get a bp from the swap buffer header pool */ 297 if ((bp = TAILQ_FIRST(&bswlist)) != NULL) 298 break; 299 bswneeded = 1; 300 ssleep(&bswneeded, &bswspin, 0, "wswbuf1", 0); 301 /* loop in case someone else grabbed one */ 302 } 303 TAILQ_REMOVE(&bswlist, bp, b_freelist); 304 if (pfreecnt) 305 --*pfreecnt; 306 307 spin_unlock_wr(&bswspin); 308 309 initpbuf(bp); 310 return bp; 311 } 312 313 /* 314 * Allocate a physical buffer, if one is available. 315 * 316 * Note that there is no NULL hack here - all subsystems using this 317 * call understand how to use pfreecnt. 318 * 319 * MPSAFE 320 */ 321 struct buf * 322 trypbuf(int *pfreecnt) 323 { 324 struct buf *bp; 325 326 spin_lock_wr(&bswspin); 327 328 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) { 329 spin_unlock_wr(&bswspin); 330 return NULL; 331 } 332 TAILQ_REMOVE(&bswlist, bp, b_freelist); 333 --*pfreecnt; 334 335 spin_unlock_wr(&bswspin); 336 337 initpbuf(bp); 338 339 return bp; 340 } 341 342 /* 343 * Release a physical buffer 344 * 345 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 346 * relatively soon when the rest of the subsystems get smart about it. XXX 347 * 348 * MPSAFE 349 */ 350 void 351 relpbuf(struct buf *bp, int *pfreecnt) 352 { 353 int wake_bsw = 0; 354 int wake_freecnt = 0; 355 356 KKASSERT(bp->b_flags & B_PAGING); 357 358 spin_lock_wr(&bswspin); 359 360 BUF_UNLOCK(bp); 361 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 362 if (bswneeded) { 363 bswneeded = 0; 364 wake_bsw = 1; 365 } 366 if (pfreecnt) { 367 if (++*pfreecnt == 1) 368 wake_freecnt = 1; 369 } 370 371 spin_unlock_wr(&bswspin); 372 373 if (wake_bsw) 374 wakeup(&bswneeded); 375 if (wake_freecnt) 376 wakeup(pfreecnt); 377 } 378 379