1 /* 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)vm_swap.c 8.5 (Berkeley) 02/17/94 8 */ 9 10 #include <sys/param.h> 11 #include <sys/systm.h> 12 #include <sys/buf.h> 13 #include <sys/conf.h> 14 #include <sys/proc.h> 15 #include <sys/namei.h> 16 #include <sys/dmap.h> /* XXX */ 17 #include <sys/vnode.h> 18 #include <sys/map.h> 19 #include <sys/file.h> 20 21 #include <miscfs/specfs/specdev.h> 22 23 /* 24 * Indirect driver for multi-controller paging. 25 */ 26 27 int nswap, nswdev; 28 #ifdef SEQSWAP 29 int niswdev; /* number of interleaved swap devices */ 30 int niswap; /* size of interleaved swap area */ 31 #endif 32 33 /* 34 * Set up swap devices. 35 * Initialize linked list of free swap 36 * headers. These do not actually point 37 * to buffers, but rather to pages that 38 * are being swapped in and out. 39 */ 40 void 41 swapinit() 42 { 43 register int i; 44 register struct buf *sp = swbuf; 45 register struct proc *p = &proc0; /* XXX */ 46 struct swdevt *swp; 47 int error; 48 49 /* 50 * Count swap devices, and adjust total swap space available. 51 * Some of the space will not be countable until later (dynamically 52 * configurable devices) and some of the counted space will not be 53 * available until a swapon() system call is issued, both usually 54 * happen when the system goes multi-user. 55 * 56 * If using NFS for swap, swdevt[0] will already be bdevvp'd. XXX 57 */ 58 #ifdef SEQSWAP 59 nswdev = niswdev = 0; 60 nswap = niswap = 0; 61 /* 62 * All interleaved devices must come first 63 */ 64 for (swp = swdevt; swp->sw_dev != NODEV || swp->sw_vp != NULL; swp++) { 65 if (swp->sw_flags & SW_SEQUENTIAL) 66 break; 67 niswdev++; 68 if (swp->sw_nblks > niswap) 69 niswap = swp->sw_nblks; 70 } 71 niswap = roundup(niswap, dmmax); 72 niswap *= niswdev; 73 if (swdevt[0].sw_vp == NULL && 74 bdevvp(swdevt[0].sw_dev, &swdevt[0].sw_vp)) 75 panic("swapvp"); 76 /* 77 * The remainder must be sequential 78 */ 79 for ( ; swp->sw_dev != NODEV; swp++) { 80 if ((swp->sw_flags & SW_SEQUENTIAL) == 0) 81 panic("binit: mis-ordered swap devices"); 82 nswdev++; 83 if (swp->sw_nblks > 0) { 84 if (swp->sw_nblks % dmmax) 85 swp->sw_nblks -= (swp->sw_nblks % dmmax); 86 nswap += swp->sw_nblks; 87 } 88 } 89 nswdev += niswdev; 90 if (nswdev == 0) 91 panic("swapinit"); 92 nswap += niswap; 93 #else 94 nswdev = 0; 95 nswap = 0; 96 for (swp = swdevt; swp->sw_dev != NODEV || swp->sw_vp != NULL; swp++) { 97 nswdev++; 98 if (swp->sw_nblks > nswap) 99 nswap = swp->sw_nblks; 100 } 101 if (nswdev == 0) 102 panic("swapinit"); 103 if (nswdev > 1) 104 nswap = ((nswap + dmmax - 1) / dmmax) * dmmax; 105 nswap *= nswdev; 106 if (swdevt[0].sw_vp == NULL && 107 bdevvp(swdevt[0].sw_dev, &swdevt[0].sw_vp)) 108 panic("swapvp"); 109 #endif 110 if (nswap == 0) 111 printf("WARNING: no swap space found\n"); 112 else if (error = swfree(p, 0)) { 113 printf("swfree errno %d\n", error); /* XXX */ 114 panic("swapinit swfree 0"); 115 } 116 117 /* 118 * Now set up swap buffer headers. 119 */ 120 bswlist.b_actf = sp; 121 for (i = 0; i < nswbuf - 1; i++, sp++) { 122 sp->b_actf = sp + 1; 123 sp->b_rcred = sp->b_wcred = p->p_ucred; 124 sp->b_vnbufs.le_next = NOLIST; 125 } 126 sp->b_rcred = sp->b_wcred = p->p_ucred; 127 sp->b_vnbufs.le_next = NOLIST; 128 sp->b_actf = NULL; 129 } 130 131 void 132 swstrategy(bp) 133 register struct buf *bp; 134 { 135 int sz, off, seg, index; 136 register struct swdevt *sp; 137 struct vnode *vp; 138 139 #ifdef GENERIC 140 /* 141 * A mini-root gets copied into the front of the swap 142 * and we run over top of the swap area just long 143 * enough for us to do a mkfs and restor of the real 144 * root (sure beats rewriting standalone restor). 145 */ 146 #define MINIROOTSIZE 4096 147 if (rootdev == dumpdev) 148 bp->b_blkno += MINIROOTSIZE; 149 #endif 150 sz = howmany(bp->b_bcount, DEV_BSIZE); 151 if (bp->b_blkno + sz > nswap) { 152 bp->b_error = EINVAL; 153 bp->b_flags |= B_ERROR; 154 biodone(bp); 155 return; 156 } 157 if (nswdev > 1) { 158 #ifdef SEQSWAP 159 if (bp->b_blkno < niswap) { 160 if (niswdev > 1) { 161 off = bp->b_blkno % dmmax; 162 if (off+sz > dmmax) { 163 bp->b_error = EINVAL; 164 bp->b_flags |= B_ERROR; 165 biodone(bp); 166 return; 167 } 168 seg = bp->b_blkno / dmmax; 169 index = seg % niswdev; 170 seg /= niswdev; 171 bp->b_blkno = seg*dmmax + off; 172 } else 173 index = 0; 174 } else { 175 register struct swdevt *swp; 176 177 bp->b_blkno -= niswap; 178 for (index = niswdev, swp = &swdevt[niswdev]; 179 swp->sw_dev != NODEV; 180 swp++, index++) { 181 if (bp->b_blkno < swp->sw_nblks) 182 break; 183 bp->b_blkno -= swp->sw_nblks; 184 } 185 if (swp->sw_dev == NODEV || 186 bp->b_blkno+sz > swp->sw_nblks) { 187 bp->b_error = swp->sw_dev == NODEV ? 188 ENODEV : EINVAL; 189 bp->b_flags |= B_ERROR; 190 biodone(bp); 191 return; 192 } 193 } 194 #else 195 off = bp->b_blkno % dmmax; 196 if (off+sz > dmmax) { 197 bp->b_error = EINVAL; 198 bp->b_flags |= B_ERROR; 199 biodone(bp); 200 return; 201 } 202 seg = bp->b_blkno / dmmax; 203 index = seg % nswdev; 204 seg /= nswdev; 205 bp->b_blkno = seg*dmmax + off; 206 #endif 207 } else 208 index = 0; 209 sp = &swdevt[index]; 210 if ((bp->b_dev = sp->sw_dev) == NODEV) 211 panic("swstrategy"); 212 if (sp->sw_vp == NULL) { 213 bp->b_error = ENODEV; 214 bp->b_flags |= B_ERROR; 215 biodone(bp); 216 return; 217 } 218 VHOLD(sp->sw_vp); 219 if ((bp->b_flags & B_READ) == 0) { 220 if (vp = bp->b_vp) { 221 vp->v_numoutput--; 222 if ((vp->v_flag & VBWAIT) && vp->v_numoutput <= 0) { 223 vp->v_flag &= ~VBWAIT; 224 wakeup((caddr_t)&vp->v_numoutput); 225 } 226 } 227 sp->sw_vp->v_numoutput++; 228 } 229 if (bp->b_vp != NULL) 230 brelvp(bp); 231 bp->b_vp = sp->sw_vp; 232 VOP_STRATEGY(bp); 233 } 234 235 /* 236 * System call swapon(name) enables swapping on device name, 237 * which must be in the swdevsw. Return EBUSY 238 * if already swapping on this device. 239 */ 240 struct swapon_args { 241 char *name; 242 }; 243 /* ARGSUSED */ 244 int 245 swapon(p, uap, retval) 246 struct proc *p; 247 struct swapon_args *uap; 248 int *retval; 249 { 250 register struct vnode *vp; 251 register struct swdevt *sp; 252 dev_t dev; 253 int error; 254 struct nameidata nd; 255 256 if (error = suser(p->p_ucred, &p->p_acflag)) 257 return (error); 258 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, uap->name, p); 259 if (error = namei(&nd)) 260 return (error); 261 vp = nd.ni_vp; 262 if (vp->v_type != VBLK) { 263 vrele(vp); 264 return (ENOTBLK); 265 } 266 dev = (dev_t)vp->v_rdev; 267 if (major(dev) >= nblkdev) { 268 vrele(vp); 269 return (ENXIO); 270 } 271 for (sp = &swdevt[0]; sp->sw_dev != NODEV; sp++) { 272 if (sp->sw_dev == dev) { 273 if (sp->sw_flags & SW_FREED) { 274 vrele(vp); 275 return (EBUSY); 276 } 277 sp->sw_vp = vp; 278 if (error = swfree(p, sp - swdevt)) { 279 vrele(vp); 280 return (error); 281 } 282 return (0); 283 } 284 #ifdef SEQSWAP 285 /* 286 * If we have reached a non-freed sequential device without 287 * finding what we are looking for, it is an error. 288 * That is because all interleaved devices must come first 289 * and sequential devices must be freed in order. 290 */ 291 if ((sp->sw_flags & (SW_SEQUENTIAL|SW_FREED)) == SW_SEQUENTIAL) 292 break; 293 #endif 294 } 295 vrele(vp); 296 return (EINVAL); 297 } 298 299 /* 300 * Swfree(index) frees the index'th portion of the swap map. 301 * Each of the nswdev devices provides 1/nswdev'th of the swap 302 * space, which is laid out with blocks of dmmax pages circularly 303 * among the devices. 304 */ 305 int 306 swfree(p, index) 307 struct proc *p; 308 int index; 309 { 310 register struct swdevt *sp; 311 register swblk_t vsbase; 312 register long blk; 313 struct vnode *vp; 314 register swblk_t dvbase; 315 register int nblks; 316 int error; 317 318 sp = &swdevt[index]; 319 vp = sp->sw_vp; 320 if (error = VOP_OPEN(vp, FREAD|FWRITE, p->p_ucred, p)) 321 return (error); 322 sp->sw_flags |= SW_FREED; 323 nblks = sp->sw_nblks; 324 /* 325 * Some devices may not exist til after boot time. 326 * If so, their nblk count will be 0. 327 */ 328 if (nblks <= 0) { 329 int perdev; 330 dev_t dev = sp->sw_dev; 331 332 if (bdevsw[major(dev)].d_psize == 0 || 333 (nblks = (*bdevsw[major(dev)].d_psize)(dev)) == -1) { 334 (void) VOP_CLOSE(vp, FREAD|FWRITE, p->p_ucred, p); 335 sp->sw_flags &= ~SW_FREED; 336 return (ENXIO); 337 } 338 #ifdef SEQSWAP 339 if (index < niswdev) { 340 perdev = niswap / niswdev; 341 if (nblks > perdev) 342 nblks = perdev; 343 } else { 344 if (nblks % dmmax) 345 nblks -= (nblks % dmmax); 346 nswap += nblks; 347 } 348 #else 349 perdev = nswap / nswdev; 350 if (nblks > perdev) 351 nblks = perdev; 352 #endif 353 sp->sw_nblks = nblks; 354 } 355 if (nblks == 0) { 356 (void) VOP_CLOSE(vp, FREAD|FWRITE, p->p_ucred, p); 357 sp->sw_flags &= ~SW_FREED; 358 return (0); /* XXX error? */ 359 } 360 #ifdef SEQSWAP 361 if (sp->sw_flags & SW_SEQUENTIAL) { 362 register struct swdevt *swp; 363 364 blk = niswap; 365 for (swp = &swdevt[niswdev]; swp != sp; swp++) 366 blk += swp->sw_nblks; 367 rmfree(swapmap, nblks, blk); 368 return (0); 369 } 370 #endif 371 for (dvbase = 0; dvbase < nblks; dvbase += dmmax) { 372 blk = nblks - dvbase; 373 #ifdef SEQSWAP 374 if ((vsbase = index*dmmax + dvbase*niswdev) >= niswap) 375 panic("swfree"); 376 #else 377 if ((vsbase = index*dmmax + dvbase*nswdev) >= nswap) 378 panic("swfree"); 379 #endif 380 if (blk > dmmax) 381 blk = dmmax; 382 if (vsbase == 0) { 383 /* 384 * First of all chunks... initialize the swapmap. 385 * Don't use the first cluster of the device 386 * in case it starts with a label or boot block. 387 */ 388 rminit(swapmap, blk - ctod(CLSIZE), 389 vsbase + ctod(CLSIZE), "swap", nswapmap); 390 } else if (dvbase == 0) { 391 /* 392 * Don't use the first cluster of the device 393 * in case it starts with a label or boot block. 394 */ 395 rmfree(swapmap, blk - ctod(CLSIZE), 396 vsbase + ctod(CLSIZE)); 397 } else 398 rmfree(swapmap, blk, vsbase); 399 } 400 return (0); 401 } 402