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 1.18 2005/06/02 20:57:21 swildner 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 static struct swdevt *swdevt = should_be_malloced; 69 static int nswap; /* first block after the interleaved devs */ 70 static int nswdev = NSWAPDEV; 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 * VOP_STRATEGY() for swapdev_vp. 80 * Perform swap strategy interleave device selection. 81 * 82 * The bp is expected to be locked and *not* B_DONE on call. 83 */ 84 85 static int 86 swapdev_strategy(struct vop_strategy_args /* { 87 struct vnode *a_vp; 88 struct buf *a_bp; 89 } */ *ap) 90 { 91 int sz, off, seg, index; 92 struct swdevt *sp; 93 struct vnode *vp; 94 struct buf *bp; 95 96 bp = ap->a_bp; 97 sz = howmany(bp->b_bcount, PAGE_SIZE); 98 99 /* 100 * Convert interleaved swap into per-device swap. Note that 101 * the block size is left in PAGE_SIZE'd chunks (for the newswap) 102 * here. 103 */ 104 if (nswdev > 1) { 105 off = bp->b_blkno % dmmax; 106 if (off + sz > dmmax) { 107 bp->b_error = EINVAL; 108 bp->b_flags |= B_ERROR; 109 biodone(bp); 110 return 0; 111 } 112 seg = bp->b_blkno / dmmax; 113 index = seg % nswdev; 114 seg /= nswdev; 115 bp->b_blkno = seg * dmmax + off; 116 } else { 117 index = 0; 118 } 119 sp = &swdevt[index]; 120 if (bp->b_blkno + sz > sp->sw_nblks) { 121 bp->b_error = EINVAL; 122 bp->b_flags |= B_ERROR; 123 biodone(bp); 124 return 0; 125 } 126 bp->b_dev = sp->sw_device; 127 if (sp->sw_vp == NULL) { 128 bp->b_error = ENODEV; 129 bp->b_flags |= B_ERROR; 130 biodone(bp); 131 return 0; 132 } 133 134 /* 135 * Convert from PAGE_SIZE'd to DEV_BSIZE'd chunks for the actual I/O 136 */ 137 bp->b_blkno = ctodb(bp->b_blkno); 138 139 vhold(sp->sw_vp); 140 crit_enter(); 141 if ((bp->b_flags & B_READ) == 0) { 142 vp = bp->b_vp; 143 if (vp) { 144 vp->v_numoutput--; 145 if ((vp->v_flag & VBWAIT) && vp->v_numoutput <= 0) { 146 vp->v_flag &= ~VBWAIT; 147 wakeup(&vp->v_numoutput); 148 } 149 } 150 sp->sw_vp->v_numoutput++; 151 } 152 pbreassignbuf(bp, sp->sw_vp); 153 crit_exit(); 154 VOP_STRATEGY(bp->b_vp, bp); 155 return 0; 156 } 157 158 /* 159 * Create a special vnode op vector for swapdev_vp - we only use 160 * VOP_STRATEGY(), everything else returns an error. 161 */ 162 struct vop_ops *swapdev_vnode_vops; 163 static struct vnodeopv_entry_desc swapdev_vnodeop_entries[] = { 164 { &vop_default_desc, vop_defaultop }, 165 { &vop_strategy_desc, (void *) swapdev_strategy }, 166 { NULL, NULL } 167 }; 168 static struct vnodeopv_desc swapdev_vnodeop_opv_desc = 169 { &swapdev_vnode_vops, swapdev_vnodeop_entries }; 170 171 VNODEOP_SET(swapdev_vnodeop_opv_desc); 172 173 /* 174 * swapon_args(char *name) 175 * 176 * System call swapon(name) enables swapping on device name, 177 * which must be in the swdevsw. Return EBUSY 178 * if already swapping on this device. 179 */ 180 /* ARGSUSED */ 181 int 182 swapon(struct swapon_args *uap) 183 { 184 struct thread *td = curthread; 185 struct vattr attr; 186 struct vnode *vp; 187 struct nlookupdata nd; 188 int error; 189 struct ucred *cred; 190 191 KKASSERT(td->td_proc); 192 cred = td->td_proc->p_ucred; 193 194 error = suser(td); 195 if (error) 196 return (error); 197 198 vp = NULL; 199 error = nlookup_init(&nd, uap->name, UIO_USERSPACE, NLC_FOLLOW); 200 if (error == 0) 201 error = nlookup(&nd); 202 if (error == 0) 203 error = cache_vref(nd.nl_ncp, nd.nl_cred, &vp); 204 nlookup_done(&nd); 205 if (error) 206 return (error); 207 208 if (vn_isdisk(vp, &error)) 209 error = swaponvp(td, vp, 0); 210 else if (vp->v_type == VREG && vp->v_tag == VT_NFS && 211 (error = VOP_GETATTR(vp, &attr, td)) == 0) { 212 /* 213 * Allow direct swapping to NFS regular files in the same 214 * way that nfs_mountroot() sets up diskless swapping. 215 */ 216 error = swaponvp(td, vp, attr.va_size / DEV_BSIZE); 217 } 218 219 if (error) 220 vrele(vp); 221 222 return (error); 223 } 224 225 /* 226 * Swfree(index) frees the index'th portion of the swap map. 227 * Each of the nswdev devices provides 1/nswdev'th of the swap 228 * space, which is laid out with blocks of dmmax pages circularly 229 * among the devices. 230 * 231 * The new swap code uses page-sized blocks. The old swap code used 232 * DEV_BSIZE'd chunks. 233 * 234 * XXX locking when multiple swapon's run in parallel 235 */ 236 int 237 swaponvp(struct thread *td, struct vnode *vp, u_long nblks) 238 { 239 u_long aligned_nblks; 240 struct ucred *cred; 241 struct swdevt *sp; 242 swblk_t vsbase; 243 swblk_t dvbase; 244 dev_t dev; 245 int index; 246 int error; 247 long blk; 248 249 KKASSERT(td->td_proc); 250 cred = td->td_proc->p_ucred; 251 252 if (!swapdev_vp) { 253 error = getspecialvnode(VT_NON, NULL, &swapdev_vnode_vops, 254 &swapdev_vp, 0, 0); 255 if (error) 256 panic("Cannot get vnode for swapdev"); 257 swapdev_vp->v_type = VNON; /* Untyped */ 258 vx_unlock(swapdev_vp); 259 } 260 261 ASSERT_VOP_UNLOCKED(vp, "swaponvp"); 262 for (sp = swdevt, index = 0 ; index < nswdev; index++, sp++) { 263 if (sp->sw_vp == vp) 264 return EBUSY; 265 if (!sp->sw_vp) 266 goto found; 267 268 } 269 return EINVAL; 270 found: 271 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 272 error = VOP_OPEN(vp, FREAD | FWRITE, cred, NULL, td); 273 VOP_UNLOCK(vp, 0, td); 274 if (error) 275 return (error); 276 277 /* 278 * v_rdev is not valid until after the VOP_OPEN() call. dev_psize() 279 * must be supported if a character device has been specified. 280 */ 281 if (vp->v_type == VCHR) 282 dev = vp->v_rdev; 283 else 284 dev = NODEV; 285 286 if (nblks == 0 && dev != NODEV && ((nblks = dev_dpsize(dev)) == -1)) { 287 (void) VOP_CLOSE(vp, FREAD | FWRITE, td); 288 return (ENXIO); 289 } 290 if (nblks == 0) { 291 (void) VOP_CLOSE(vp, FREAD | FWRITE, td); 292 return (ENXIO); 293 } 294 295 /* 296 * If we go beyond this, we get overflows in the radix 297 * tree bitmap code. 298 */ 299 if (nblks > 0x40000000 / BLIST_META_RADIX / nswdev) { 300 printf("exceeded maximum of %d blocks per swap unit\n", 301 0x40000000 / BLIST_META_RADIX / nswdev); 302 (void) VOP_CLOSE(vp, FREAD | FWRITE, td); 303 return (ENXIO); 304 } 305 /* 306 * nblks is in DEV_BSIZE'd chunks, convert to PAGE_SIZE'd chunks. 307 * First chop nblks off to page-align it, then convert. 308 * 309 * sw->sw_nblks is in page-sized chunks now too. 310 */ 311 nblks &= ~(ctodb(1) - 1); 312 nblks = dbtoc(nblks); 313 314 sp->sw_vp = vp; 315 sp->sw_dev = dev2udev(dev); 316 sp->sw_device = dev; 317 sp->sw_flags |= SW_FREED; 318 sp->sw_nblks = nblks; 319 320 /* 321 * nblks, nswap, and dmmax are PAGE_SIZE'd parameters now, not 322 * DEV_BSIZE'd. aligned_nblks is used to calculate the 323 * size of the swap bitmap, taking into account the stripe size. 324 */ 325 aligned_nblks = (nblks + (dmmax - 1)) & ~(u_long)(dmmax - 1); 326 327 if (aligned_nblks * nswdev > nswap) 328 nswap = aligned_nblks * nswdev; 329 330 if (swapblist == NULL) 331 swapblist = blist_create(nswap); 332 else 333 blist_resize(&swapblist, nswap, 0); 334 335 for (dvbase = dmmax; dvbase < nblks; dvbase += dmmax) { 336 blk = min(nblks - dvbase, dmmax); 337 vsbase = index * dmmax + dvbase * nswdev; 338 blist_free(swapblist, vsbase, blk); 339 vm_swap_size += blk; 340 } 341 342 return (0); 343 } 344