1 /* 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)vm_swap.c 8.5 (Berkeley) 2/17/94 34 * $FreeBSD: src/sys/vm/vm_swap.c,v 1.96.2.2 2001/10/14 18:46:47 iedowse Exp $ 35 * $DragonFly: src/sys/vm/vm_swap.c,v 1.35 2007/05/15 22:44:21 dillon Exp $ 36 */ 37 38 #include "opt_swap.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/sysproto.h> 43 #include <sys/buf.h> 44 #include <sys/proc.h> 45 #include <sys/nlookup.h> 46 #include <sys/dmap.h> /* XXX */ 47 #include <sys/vnode.h> 48 #include <sys/fcntl.h> 49 #include <sys/blist.h> 50 #include <sys/kernel.h> 51 #include <sys/lock.h> 52 #include <sys/conf.h> 53 #include <sys/stat.h> 54 #include <sys/thread2.h> 55 #include <vm/vm.h> 56 #include <vm/vm_extern.h> 57 #include <vm/swap_pager.h> 58 #include <vm/vm_zone.h> 59 60 /* 61 * Indirect driver for multi-controller paging. 62 */ 63 64 #ifndef NSWAPDEV 65 #define NSWAPDEV 4 66 #endif 67 static struct swdevt should_be_malloced[NSWAPDEV]; 68 struct swdevt *swdevt = should_be_malloced; /* exported to pstat/systat */ 69 static int nswap; /* first block after the interleaved devs */ 70 int nswdev = NSWAPDEV; /* exported to pstat/systat */ 71 int vm_swap_size; 72 73 static int swapdev_strategy (struct vop_strategy_args *ap); 74 struct vnode *swapdev_vp; 75 76 /* 77 * swapdev_strategy: 78 * 79 * vn_strategy() for swapdev_vp. 80 * Perform swap strategy interleave device selection. 81 * 82 * The bp is expected to be locked and on call. 83 * 84 * (struct vnode *a_vp, struct bio *b_bio) 85 */ 86 87 static int 88 swapdev_strategy(struct vop_strategy_args *ap) 89 { 90 struct bio *bio = ap->a_bio; 91 struct bio *nbio; 92 struct buf *bp = bio->bio_buf; 93 int sz, off, seg, index, blkno, nblkno; 94 struct swdevt *sp; 95 struct vnode *vp; 96 97 vp = ap->a_vp; 98 sz = howmany(bp->b_bcount, PAGE_SIZE); 99 blkno = (int)(bio->bio_offset >> PAGE_SHIFT); 100 101 /* 102 * Convert interleaved swap into per-device swap. Note that 103 * the block size is left in PAGE_SIZE'd chunks (for the newswap) 104 * here. 105 */ 106 nbio = push_bio(bio); 107 if (nswdev > 1) { 108 off = blkno % dmmax; 109 if (off + sz > dmmax) { 110 bp->b_error = EINVAL; 111 bp->b_flags |= B_ERROR; 112 biodone(bio); 113 return 0; 114 } 115 seg = blkno / dmmax; 116 index = seg % nswdev; 117 seg /= nswdev; 118 nbio->bio_offset = (off_t)(seg * dmmax + off) << PAGE_SHIFT; 119 } else { 120 index = 0; 121 nbio->bio_offset = bio->bio_offset; 122 } 123 nblkno = (int)(nbio->bio_offset >> PAGE_SHIFT); 124 sp = &swdevt[index]; 125 if (nblkno + sz > sp->sw_nblks) { 126 bp->b_error = EINVAL; 127 bp->b_flags |= B_ERROR; 128 /* I/O was never started on nbio, must biodone(bio) */ 129 biodone(bio); 130 return 0; 131 } 132 if (sp->sw_vp == NULL) { 133 bp->b_error = ENODEV; 134 bp->b_flags |= B_ERROR; 135 /* I/O was never started on nbio, must biodone(bio) */ 136 biodone(bio); 137 return 0; 138 } 139 140 /* 141 * Issue a strategy call on the appropriate swap vnode. Note that 142 * bp->b_vp is not modified. Strategy code is always supposed to 143 * use the passed vp. 144 * 145 * XXX do a dev_dstrategy() call on sp->sw_device instead of on 146 * sp->sw_vp ? 147 */ 148 vn_strategy(sp->sw_vp, nbio); 149 return 0; 150 } 151 152 /* 153 * Create a special vnode op vector for swapdev_vp - we only use 154 * vn_strategy(), everything else returns an error. 155 */ 156 static struct vop_ops swapdev_vnode_vops = { 157 .vop_default = vop_defaultop, 158 .vop_strategy = swapdev_strategy 159 }; 160 static struct vop_ops *swapdev_vnode_vops_p = &swapdev_vnode_vops; 161 162 VNODEOP_SET(swapdev_vnode_vops); 163 164 /* 165 * swapon_args(char *name) 166 * 167 * System call swapon(name) enables swapping on device name, 168 * which must be in the swdevsw. Return EBUSY 169 * if already swapping on this device. 170 */ 171 /* ARGSUSED */ 172 int 173 sys_swapon(struct swapon_args *uap) 174 { 175 struct thread *td = curthread; 176 struct vattr attr; 177 struct vnode *vp; 178 struct nlookupdata nd; 179 int error; 180 struct ucred *cred; 181 182 KKASSERT(td->td_proc); 183 cred = td->td_proc->p_ucred; 184 185 error = suser(td); 186 if (error) 187 return (error); 188 189 vp = NULL; 190 error = nlookup_init(&nd, uap->name, UIO_USERSPACE, NLC_FOLLOW); 191 if (error == 0) 192 error = nlookup(&nd); 193 if (error == 0) 194 error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp); 195 nlookup_done(&nd); 196 if (error) 197 return (error); 198 199 if (vn_isdisk(vp, &error)) 200 error = swaponvp(td, vp, 0); 201 else if (vp->v_type == VREG && vp->v_tag == VT_NFS && 202 (error = VOP_GETATTR(vp, &attr)) == 0) { 203 /* 204 * Allow direct swapping to NFS regular files in the same 205 * way that nfs_mountroot() sets up diskless swapping. 206 */ 207 error = swaponvp(td, vp, attr.va_size / DEV_BSIZE); 208 } 209 210 if (error) 211 vrele(vp); 212 213 return (error); 214 } 215 216 /* 217 * Swfree(index) frees the index'th portion of the swap map. 218 * Each of the nswdev devices provides 1/nswdev'th of the swap 219 * space, which is laid out with blocks of dmmax pages circularly 220 * among the devices. 221 * 222 * The new swap code uses page-sized blocks. The old swap code used 223 * DEV_BSIZE'd chunks. 224 * 225 * XXX locking when multiple swapon's run in parallel 226 */ 227 int 228 swaponvp(struct thread *td, struct vnode *vp, u_long nblks) 229 { 230 u_long aligned_nblks; 231 int64_t dpsize; 232 struct ucred *cred; 233 struct swdevt *sp; 234 swblk_t vsbase; 235 swblk_t dvbase; 236 cdev_t dev; 237 int index; 238 int error; 239 long blk; 240 241 KKASSERT(td->td_proc); 242 cred = td->td_proc->p_ucred; 243 244 if (!swapdev_vp) { 245 error = getspecialvnode(VT_NON, NULL, &swapdev_vnode_vops_p, 246 &swapdev_vp, 0, 0); 247 if (error) 248 panic("Cannot get vnode for swapdev"); 249 swapdev_vp->v_type = VNON; /* Untyped */ 250 vx_unlock(swapdev_vp); 251 } 252 253 for (sp = swdevt, index = 0 ; index < nswdev; index++, sp++) { 254 if (sp->sw_vp == vp) 255 return EBUSY; 256 if (!sp->sw_vp) 257 goto found; 258 259 } 260 return EINVAL; 261 found: 262 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 263 error = VOP_OPEN(vp, FREAD | FWRITE, cred, NULL); 264 vn_unlock(vp); 265 if (error) 266 return (error); 267 268 /* 269 * v_rdev is not valid until after the VOP_OPEN() call. dev_psize() 270 * must be supported if a character device has been specified. 271 */ 272 if (vp->v_type == VCHR) 273 dev = vp->v_rdev; 274 else 275 dev = NULL; 276 277 if (nblks == 0 && dev != NULL) { 278 dpsize = dev_dpsize(dev); 279 if (dpsize == -1) { 280 VOP_CLOSE(vp, FREAD | FWRITE); 281 return (ENXIO); 282 } 283 if ((u_int64_t)dpsize < 0x100000000ULL) 284 nblks = (u_long)dpsize; 285 else 286 nblks = 0xffffffffU; 287 } 288 if (nblks == 0) { 289 VOP_CLOSE(vp, FREAD | FWRITE); 290 return (ENXIO); 291 } 292 293 /* 294 * If we go beyond this, we get overflows in the radix 295 * tree bitmap code. 296 */ 297 if (nblks > 0x40000000 / BLIST_META_RADIX / nswdev) { 298 kprintf("exceeded maximum of %d blocks per swap unit\n", 299 0x40000000 / BLIST_META_RADIX / nswdev); 300 VOP_CLOSE(vp, FREAD | FWRITE); 301 return (ENXIO); 302 } 303 /* 304 * nblks is in DEV_BSIZE'd chunks, convert to PAGE_SIZE'd chunks. 305 * First chop nblks off to page-align it, then convert. 306 * 307 * sw->sw_nblks is in page-sized chunks now too. 308 */ 309 nblks &= ~(ctodb(1) - 1); 310 nblks = dbtoc(nblks); 311 312 sp->sw_vp = vp; 313 sp->sw_dev = dev2udev(dev); 314 sp->sw_device = dev; 315 sp->sw_flags |= SW_FREED; 316 sp->sw_nblks = nblks; 317 318 /* 319 * nblks, nswap, and dmmax are PAGE_SIZE'd parameters now, not 320 * DEV_BSIZE'd. aligned_nblks is used to calculate the 321 * size of the swap bitmap, taking into account the stripe size. 322 */ 323 aligned_nblks = (nblks + (dmmax - 1)) & ~(u_long)(dmmax - 1); 324 325 if (aligned_nblks * nswdev > nswap) 326 nswap = aligned_nblks * nswdev; 327 328 if (swapblist == NULL) 329 swapblist = blist_create(nswap); 330 else 331 blist_resize(&swapblist, nswap, 0); 332 333 for (dvbase = dmmax; dvbase < nblks; dvbase += dmmax) { 334 blk = min(nblks - dvbase, dmmax); 335 vsbase = index * dmmax + dvbase * nswdev; 336 blist_free(swapblist, vsbase, blk); 337 vm_swap_size += blk; 338 } 339 340 return (0); 341 } 342