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/dsched.h> 81 #include <sys/proc.h> 82 #include <sys/thread2.h> 83 84 #include <vm/vm.h> 85 #include <vm/vm_param.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 91 #include <sys/buf2.h> 92 93 MALLOC_DEFINE(M_VMPGDATA, "VM pgdata", "XXX: VM pager private data"); 94 95 extern struct pagerops defaultpagerops; 96 extern struct pagerops swappagerops; 97 extern struct pagerops vnodepagerops; 98 extern struct pagerops devicepagerops; 99 extern struct pagerops physpagerops; 100 101 int cluster_pbuf_freecnt = -1; /* unlimited to begin with */ 102 103 static int dead_pager_getpage (vm_object_t, vm_page_t *, int); 104 static void dead_pager_putpages (vm_object_t, vm_page_t *, int, int, int *); 105 static boolean_t dead_pager_haspage (vm_object_t, vm_pindex_t); 106 static void dead_pager_dealloc (vm_object_t); 107 108 static int 109 dead_pager_getpage(vm_object_t obj, vm_page_t *mpp, int seqaccess) 110 { 111 return VM_PAGER_FAIL; 112 } 113 114 static void 115 dead_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags, 116 int *rtvals) 117 { 118 int i; 119 120 for (i = 0; i < count; i++) { 121 rtvals[i] = VM_PAGER_AGAIN; 122 } 123 } 124 125 static int 126 dead_pager_haspage(vm_object_t object, vm_pindex_t pindex) 127 { 128 return FALSE; 129 } 130 131 static void 132 dead_pager_dealloc(vm_object_t object) 133 { 134 KKASSERT(object->swblock_count == 0); 135 return; 136 } 137 138 static struct pagerops deadpagerops = { 139 dead_pager_dealloc, 140 dead_pager_getpage, 141 dead_pager_putpages, 142 dead_pager_haspage 143 }; 144 145 struct pagerops *pagertab[] = { 146 &defaultpagerops, /* OBJT_DEFAULT */ 147 &swappagerops, /* OBJT_SWAP */ 148 &vnodepagerops, /* OBJT_VNODE */ 149 &devicepagerops, /* OBJT_DEVICE */ 150 &physpagerops, /* OBJT_PHYS */ 151 &deadpagerops /* OBJT_DEAD */ 152 }; 153 154 int npagers = sizeof(pagertab) / sizeof(pagertab[0]); 155 156 /* 157 * Kernel address space for mapping pages. 158 * Used by pagers where KVAs are needed for IO. 159 * 160 * XXX needs to be large enough to support the number of pending async 161 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size 162 * (MAXPHYS == 64k) if you want to get the most efficiency. 163 */ 164 #define PAGER_MAP_SIZE (8 * 1024 * 1024) 165 166 int pager_map_size = PAGER_MAP_SIZE; 167 struct vm_map pager_map; 168 169 static int bswneeded; 170 static vm_offset_t swapbkva; /* swap buffers kva */ 171 static TAILQ_HEAD(swqueue, buf) bswlist; 172 static struct spinlock bswspin = SPINLOCK_INITIALIZER(&bswspin); 173 174 static void 175 vm_pager_init(void *arg __unused) 176 { 177 /* 178 * Initialize the swap buffer list. 179 */ 180 TAILQ_INIT(&bswlist); 181 } 182 SYSINIT(vm_mem, SI_BOOT1_VM, SI_ORDER_SECOND, vm_pager_init, NULL) 183 184 void 185 vm_pager_bufferinit(void) 186 { 187 struct buf *bp; 188 int i; 189 190 /* 191 * Reserve KVM space for pbuf data. 192 */ 193 swapbkva = kmem_alloc_pageable(&pager_map, nswbuf * MAXPHYS); 194 if (!swapbkva) 195 panic("Not enough pager_map VM space for physical buffers"); 196 197 /* 198 * Initial pbuf setup. 199 */ 200 bp = swbuf; 201 for (i = 0; i < nswbuf; ++i, ++bp) { 202 bp->b_kvabase = (caddr_t)((intptr_t)i * MAXPHYS) + swapbkva; 203 bp->b_kvasize = MAXPHYS; 204 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 205 BUF_LOCKINIT(bp); 206 buf_dep_init(bp); 207 } 208 209 /* 210 * Allow the clustering code to use half of our pbufs. 211 */ 212 cluster_pbuf_freecnt = nswbuf / 2; 213 } 214 215 void 216 vm_pager_deallocate(vm_object_t object) 217 { 218 (*pagertab[object->type]->pgo_dealloc) (object); 219 } 220 221 /* 222 * vm_pager_get_pages() - inline, see vm/vm_pager.h 223 * vm_pager_put_pages() - inline, see vm/vm_pager.h 224 * vm_pager_has_page() - inline, see vm/vm_pager.h 225 * vm_pager_page_inserted() - inline, see vm/vm_pager.h 226 * vm_pager_page_removed() - inline, see vm/vm_pager.h 227 */ 228 229 #if 0 230 /* 231 * vm_pager_sync: 232 * 233 * Called by pageout daemon before going back to sleep. 234 * Gives pagers a chance to clean up any completed async pageing 235 * operations. 236 */ 237 void 238 vm_pager_sync(void) 239 { 240 struct pagerops **pgops; 241 242 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 243 if (pgops && ((*pgops)->pgo_sync != NULL)) 244 (*(*pgops)->pgo_sync) (); 245 } 246 247 #endif 248 249 /* 250 * Initialize a physical buffer. 251 */ 252 static void 253 initpbuf(struct buf *bp) 254 { 255 bp->b_qindex = 0; /* BQUEUE_NONE */ 256 bp->b_data = bp->b_kvabase; 257 bp->b_flags = B_PAGING; 258 bp->b_cmd = BUF_CMD_DONE; 259 bp->b_error = 0; 260 bp->b_bcount = 0; 261 bp->b_bufsize = MAXPHYS; 262 initbufbio(bp); 263 xio_init(&bp->b_xio); 264 BUF_LOCK(bp, LK_EXCLUSIVE); 265 } 266 267 /* 268 * Allocate a physical buffer 269 * 270 * There are a limited number (nswbuf) of physical buffers. We need 271 * to make sure that no single subsystem is able to hog all of them, 272 * so each subsystem implements a counter which is typically initialized 273 * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and 274 * increments it on release, and blocks if the counter hits zero. A 275 * subsystem may initialize the counter to -1 to disable the feature, 276 * but it must still be sure to match up all uses of getpbuf() with 277 * relpbuf() using the same variable. 278 * 279 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 280 * relatively soon when the rest of the subsystems get smart about it. XXX 281 * 282 * MPSAFE 283 */ 284 struct buf * 285 getpbuf(int *pfreecnt) 286 { 287 struct buf *bp; 288 289 spin_lock_wr(&bswspin); 290 291 for (;;) { 292 if (pfreecnt) { 293 while (*pfreecnt == 0) 294 ssleep(pfreecnt, &bswspin, 0, "wswbuf0", 0); 295 } 296 297 /* get a bp from the swap buffer header pool */ 298 if ((bp = TAILQ_FIRST(&bswlist)) != NULL) 299 break; 300 bswneeded = 1; 301 ssleep(&bswneeded, &bswspin, 0, "wswbuf1", 0); 302 /* loop in case someone else grabbed one */ 303 } 304 TAILQ_REMOVE(&bswlist, bp, b_freelist); 305 if (pfreecnt) 306 --*pfreecnt; 307 308 spin_unlock_wr(&bswspin); 309 310 initpbuf(bp); 311 KKASSERT(dsched_is_clear_buf_priv(bp)); 312 return bp; 313 } 314 315 /* 316 * Allocate a physical buffer, if one is available. 317 * 318 * Note that there is no NULL hack here - all subsystems using this 319 * call understand how to use pfreecnt. 320 * 321 * MPSAFE 322 */ 323 struct buf * 324 trypbuf(int *pfreecnt) 325 { 326 struct buf *bp; 327 328 spin_lock_wr(&bswspin); 329 330 if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) { 331 spin_unlock_wr(&bswspin); 332 return NULL; 333 } 334 TAILQ_REMOVE(&bswlist, bp, b_freelist); 335 --*pfreecnt; 336 337 spin_unlock_wr(&bswspin); 338 339 initpbuf(bp); 340 341 return bp; 342 } 343 344 /* 345 * Release a physical buffer 346 * 347 * NOTE: pfreecnt can be NULL, but this 'feature' will be removed 348 * relatively soon when the rest of the subsystems get smart about it. XXX 349 * 350 * MPSAFE 351 */ 352 void 353 relpbuf(struct buf *bp, int *pfreecnt) 354 { 355 int wake_bsw = 0; 356 int wake_freecnt = 0; 357 358 KKASSERT(bp->b_flags & B_PAGING); 359 dsched_exit_buf(bp); 360 361 spin_lock_wr(&bswspin); 362 363 BUF_UNLOCK(bp); 364 TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); 365 if (bswneeded) { 366 bswneeded = 0; 367 wake_bsw = 1; 368 } 369 if (pfreecnt) { 370 if (++*pfreecnt == 1) 371 wake_freecnt = 1; 372 } 373 374 spin_unlock_wr(&bswspin); 375 376 if (wake_bsw) 377 wakeup(&bswneeded); 378 if (wake_freecnt) 379 wakeup(pfreecnt); 380 } 381 382