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 1.12 2004/05/19 22:53:06 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/namei.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 <vm/vm.h> 55 #include <vm/vm_extern.h> 56 #include <vm/swap_pager.h> 57 #include <vm/vm_zone.h> 58 59 /* 60 * Indirect driver for multi-controller paging. 61 */ 62 63 #ifndef NSWAPDEV 64 #define NSWAPDEV 4 65 #endif 66 static struct swdevt should_be_malloced[NSWAPDEV]; 67 static struct swdevt *swdevt = should_be_malloced; 68 static int nswap; /* first block after the interleaved devs */ 69 static int nswdev = NSWAPDEV; 70 int vm_swap_size; 71 72 static int swapdev_strategy (struct vop_strategy_args *ap); 73 struct vnode *swapdev_vp; 74 75 /* 76 * swapdev_strategy: 77 * 78 * VOP_STRATEGY() for swapdev_vp. 79 * Perform swap strategy interleave device selection. 80 * 81 * The bp is expected to be locked and *not* B_DONE on call. 82 */ 83 84 static int 85 swapdev_strategy(struct vop_strategy_args /* { 86 struct vnode *a_vp; 87 struct buf *a_bp; 88 } */ *ap) 89 { 90 int s, sz, off, seg, index; 91 struct swdevt *sp; 92 struct vnode *vp; 93 struct buf *bp; 94 95 bp = ap->a_bp; 96 sz = howmany(bp->b_bcount, PAGE_SIZE); 97 98 /* 99 * Convert interleaved swap into per-device swap. Note that 100 * the block size is left in PAGE_SIZE'd chunks (for the newswap) 101 * here. 102 */ 103 if (nswdev > 1) { 104 off = bp->b_blkno % dmmax; 105 if (off + sz > dmmax) { 106 bp->b_error = EINVAL; 107 bp->b_flags |= B_ERROR; 108 biodone(bp); 109 return 0; 110 } 111 seg = bp->b_blkno / dmmax; 112 index = seg % nswdev; 113 seg /= nswdev; 114 bp->b_blkno = seg * dmmax + off; 115 } else { 116 index = 0; 117 } 118 sp = &swdevt[index]; 119 if (bp->b_blkno + sz > sp->sw_nblks) { 120 bp->b_error = EINVAL; 121 bp->b_flags |= B_ERROR; 122 biodone(bp); 123 return 0; 124 } 125 bp->b_dev = sp->sw_device; 126 if (sp->sw_vp == NULL) { 127 bp->b_error = ENODEV; 128 bp->b_flags |= B_ERROR; 129 biodone(bp); 130 return 0; 131 } 132 133 /* 134 * Convert from PAGE_SIZE'd to DEV_BSIZE'd chunks for the actual I/O 135 */ 136 bp->b_blkno = ctodb(bp->b_blkno); 137 138 vhold(sp->sw_vp); 139 s = splvm(); 140 if ((bp->b_flags & B_READ) == 0) { 141 vp = bp->b_vp; 142 if (vp) { 143 vp->v_numoutput--; 144 if ((vp->v_flag & VBWAIT) && vp->v_numoutput <= 0) { 145 vp->v_flag &= ~VBWAIT; 146 wakeup(&vp->v_numoutput); 147 } 148 } 149 sp->sw_vp->v_numoutput++; 150 } 151 pbreassignbuf(bp, sp->sw_vp); 152 splx(s); 153 VOP_STRATEGY(bp->b_vp, bp); 154 return 0; 155 } 156 157 /* 158 * Create a special vnode op vector for swapdev_vp - we only use 159 * VOP_STRATEGY(), everything else returns an error. 160 */ 161 vop_t **swapdev_vnodeop_p; 162 static struct vnodeopv_entry_desc swapdev_vnodeop_entries[] = { 163 { &vop_default_desc, (vop_t *) vop_defaultop }, 164 { &vop_strategy_desc, (vop_t *) swapdev_strategy }, 165 { NULL, NULL } 166 }; 167 static struct vnodeopv_desc swapdev_vnodeop_opv_desc = 168 { &swapdev_vnodeop_p, swapdev_vnodeop_entries }; 169 170 VNODEOP_SET(swapdev_vnodeop_opv_desc); 171 172 /* 173 * swapon_args(char *name) 174 * 175 * System call swapon(name) enables swapping on device name, 176 * which must be in the swdevsw. Return EBUSY 177 * if already swapping on this device. 178 */ 179 /* ARGSUSED */ 180 int 181 swapon(struct swapon_args *uap) 182 { 183 struct thread *td = curthread; 184 struct vattr attr; 185 struct vnode *vp; 186 struct nameidata nd; 187 int error; 188 struct ucred *cred; 189 190 KKASSERT(td->td_proc); 191 cred = td->td_proc->p_ucred; 192 193 error = suser(td); 194 if (error) 195 return (error); 196 197 NDINIT(&nd, NAMEI_LOOKUP, CNP_FOLLOW, UIO_USERSPACE, uap->name, td); 198 error = namei(&nd); 199 if (error) 200 return (error); 201 202 NDFREE(&nd, NDF_ONLY_PNBUF); 203 vp = nd.ni_vp; 204 205 if (vn_isdisk(vp, &error)) 206 error = swaponvp(td, vp, 0); 207 else if (vp->v_type == VREG && vp->v_tag == VT_NFS && 208 (error = VOP_GETATTR(vp, &attr, td)) == 0) { 209 /* 210 * Allow direct swapping to NFS regular files in the same 211 * way that nfs_mountroot() sets up diskless swapping. 212 */ 213 error = swaponvp(td, vp, attr.va_size / DEV_BSIZE); 214 } 215 216 if (error) 217 vrele(vp); 218 219 return (error); 220 } 221 222 /* 223 * Swfree(index) frees the index'th portion of the swap map. 224 * Each of the nswdev devices provides 1/nswdev'th of the swap 225 * space, which is laid out with blocks of dmmax pages circularly 226 * among the devices. 227 * 228 * The new swap code uses page-sized blocks. The old swap code used 229 * DEV_BSIZE'd chunks. 230 * 231 * XXX locking when multiple swapon's run in parallel 232 */ 233 int 234 swaponvp(struct thread *td, struct vnode *vp, u_long nblks) 235 { 236 u_long aligned_nblks; 237 struct ucred *cred; 238 struct swdevt *sp; 239 swblk_t vsbase; 240 swblk_t dvbase; 241 dev_t dev; 242 int index; 243 int error; 244 long blk; 245 246 KKASSERT(td->td_proc); 247 cred = td->td_proc->p_ucred; 248 249 if (!swapdev_vp) { 250 error = getnewvnode(VT_NON, NULL, swapdev_vnodeop_p, 251 &swapdev_vp); 252 if (error) 253 panic("Cannot get vnode for swapdev"); 254 swapdev_vp->v_type = VNON; /* Untyped */ 255 } 256 257 ASSERT_VOP_UNLOCKED(vp, "swaponvp"); 258 for (sp = swdevt, index = 0 ; index < nswdev; index++, sp++) { 259 if (sp->sw_vp == vp) 260 return EBUSY; 261 if (!sp->sw_vp) 262 goto found; 263 264 } 265 return EINVAL; 266 found: 267 vn_lock(vp, NULL, LK_EXCLUSIVE | LK_RETRY, td); 268 error = VOP_OPEN(vp, FREAD | FWRITE, cred, td); 269 VOP_UNLOCK(vp, NULL, 0, td); 270 if (error) 271 return (error); 272 273 /* 274 * v_rdev is not valid until after the VOP_OPEN() call. dev_psize() 275 * must be supported if a character device has been specified. 276 */ 277 if (vp->v_type == VCHR) 278 dev = vp->v_rdev; 279 else 280 dev = NODEV; 281 282 if (nblks == 0 && dev != NODEV && ((nblks = dev_dpsize(dev)) == -1)) { 283 (void) VOP_CLOSE(vp, FREAD | FWRITE, td); 284 return (ENXIO); 285 } 286 if (nblks == 0) { 287 (void) VOP_CLOSE(vp, FREAD | FWRITE, td); 288 return (ENXIO); 289 } 290 291 /* 292 * If we go beyond this, we get overflows in the radix 293 * tree bitmap code. 294 */ 295 if (nblks > 0x40000000 / BLIST_META_RADIX / nswdev) { 296 printf("exceeded maximum of %d blocks per swap unit\n", 297 0x40000000 / BLIST_META_RADIX / nswdev); 298 (void) VOP_CLOSE(vp, FREAD | FWRITE, td); 299 return (ENXIO); 300 } 301 /* 302 * nblks is in DEV_BSIZE'd chunks, convert to PAGE_SIZE'd chunks. 303 * First chop nblks off to page-align it, then convert. 304 * 305 * sw->sw_nblks is in page-sized chunks now too. 306 */ 307 nblks &= ~(ctodb(1) - 1); 308 nblks = dbtoc(nblks); 309 310 sp->sw_vp = vp; 311 sp->sw_dev = dev2udev(dev); 312 sp->sw_device = dev; 313 sp->sw_flags |= SW_FREED; 314 sp->sw_nblks = nblks; 315 316 /* 317 * nblks, nswap, and dmmax are PAGE_SIZE'd parameters now, not 318 * DEV_BSIZE'd. aligned_nblks is used to calculate the 319 * size of the swap bitmap, taking into account the stripe size. 320 */ 321 aligned_nblks = (nblks + (dmmax - 1)) & ~(u_long)(dmmax - 1); 322 323 if (aligned_nblks * nswdev > nswap) 324 nswap = aligned_nblks * nswdev; 325 326 if (swapblist == NULL) 327 swapblist = blist_create(nswap); 328 else 329 blist_resize(&swapblist, nswap, 0); 330 331 for (dvbase = dmmax; dvbase < nblks; dvbase += dmmax) { 332 blk = min(nblks - dvbase, dmmax); 333 vsbase = index * dmmax + dvbase * nswdev; 334 blist_free(swapblist, vsbase, blk); 335 vm_swap_size += blk; 336 } 337 338 return (0); 339 } 340