/* $NetBSD: vm_swap.c,v 1.25 1994/10/20 04:27:32 cgd Exp $ */ /* * Copyright (c) 1982, 1986, 1989, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)vm_swap.c 8.5 (Berkeley) 2/17/94 */ #include #include #include #include #include #include #include /* XXX */ #include #include #include #include #include #include /* * Indirect driver for multi-controller paging. */ int nswap, nswdev; #ifdef SEQSWAP int niswdev; /* number of interleaved swap devices */ int niswap; /* size of interleaved swap area */ #endif /* * Set up swap devices. * Initialize linked list of free swap * headers. These do not actually point * to buffers, but rather to pages that * are being swapped in and out. */ void swapinit() { register int i; register struct buf *sp = swbuf; register struct proc *p = &proc0; /* XXX */ struct swdevt *swp; int error; /* * Count swap devices, and adjust total swap space available. * Some of the space will not be countable until later (dynamically * configurable devices) and some of the counted space will not be * available until a swapon() system call is issued, both usually * happen when the system goes multi-user. * * If using NFS for swap, swdevt[0] will already be bdevvp'd. XXX */ #ifdef SEQSWAP nswdev = niswdev = 0; nswap = niswap = 0; /* * All interleaved devices must come first */ for (swp = swdevt; swp->sw_dev != NODEV || swp->sw_vp != NULL; swp++) { if (swp->sw_flags & SW_SEQUENTIAL) break; niswdev++; if (swp->sw_nblks > niswap) niswap = swp->sw_nblks; } niswap = roundup(niswap, dmmax); niswap *= niswdev; if (swdevt[0].sw_vp == NULL && bdevvp(swdevt[0].sw_dev, &swdevt[0].sw_vp)) panic("swapvp"); /* * The remainder must be sequential */ for ( ; swp->sw_dev != NODEV; swp++) { if ((swp->sw_flags & SW_SEQUENTIAL) == 0) panic("binit: mis-ordered swap devices"); nswdev++; if (swp->sw_nblks > 0) { if (swp->sw_nblks % dmmax) swp->sw_nblks -= (swp->sw_nblks % dmmax); nswap += swp->sw_nblks; } } nswdev += niswdev; if (nswdev == 0) panic("swapinit"); nswap += niswap; #else nswdev = 0; nswap = 0; for (swp = swdevt; swp->sw_dev != NODEV || swp->sw_vp != NULL; swp++) { nswdev++; if (swp->sw_nblks > nswap) nswap = swp->sw_nblks; } if (nswdev == 0) panic("swapinit"); if (nswdev > 1) nswap = ((nswap + dmmax - 1) / dmmax) * dmmax; nswap *= nswdev; if (swdevt[0].sw_vp == NULL && bdevvp(swdevt[0].sw_dev, &swdevt[0].sw_vp)) panic("swapvp"); #endif if (nswap == 0) printf("WARNING: no swap space found\n"); else if ((error = swfree(p, 0)) == ENXIO) printf("WARNING: primary swap device not configured\n"); else if (error) { printf("swfree errno %d\n", error); /* XXX */ panic("swapinit swfree 0"); } /* * Now set up swap buffer headers. */ bswlist.b_actf = sp; for (i = 0; i < nswbuf - 1; i++, sp++) { sp->b_actf = sp + 1; sp->b_rcred = sp->b_wcred = p->p_ucred; sp->b_vnbufs.le_next = NOLIST; } sp->b_rcred = sp->b_wcred = p->p_ucred; sp->b_vnbufs.le_next = NOLIST; sp->b_actf = NULL; } void swstrategy(bp) register struct buf *bp; { int sz, off, seg, index; register struct swdevt *sp; struct vnode *vp; #ifdef GENERIC /* * A mini-root gets copied into the front of the swap * and we run over top of the swap area just long * enough for us to do a mkfs and restor of the real * root (sure beats rewriting standalone restor). */ #define MINIROOTSIZE 4096 if (rootdev == dumpdev) bp->b_blkno += MINIROOTSIZE; #endif sz = howmany(bp->b_bcount, DEV_BSIZE); if (bp->b_blkno + sz > nswap) { bp->b_error = EINVAL; bp->b_flags |= B_ERROR; biodone(bp); return; } if (nswdev > 1) { #ifdef SEQSWAP if (bp->b_blkno < niswap) { if (niswdev > 1) { off = bp->b_blkno % dmmax; if (off+sz > dmmax) { bp->b_error = EINVAL; bp->b_flags |= B_ERROR; biodone(bp); return; } seg = bp->b_blkno / dmmax; index = seg % niswdev; seg /= niswdev; bp->b_blkno = seg*dmmax + off; } else index = 0; } else { register struct swdevt *swp; bp->b_blkno -= niswap; for (index = niswdev, swp = &swdevt[niswdev]; swp->sw_dev != NODEV; swp++, index++) { if (bp->b_blkno < swp->sw_nblks) break; bp->b_blkno -= swp->sw_nblks; } if (swp->sw_dev == NODEV || bp->b_blkno+sz > swp->sw_nblks) { bp->b_error = swp->sw_dev == NODEV ? ENODEV : EINVAL; bp->b_flags |= B_ERROR; biodone(bp); return; } } #else off = bp->b_blkno % dmmax; if (off+sz > dmmax) { bp->b_error = EINVAL; bp->b_flags |= B_ERROR; biodone(bp); return; } seg = bp->b_blkno / dmmax; index = seg % nswdev; seg /= nswdev; bp->b_blkno = seg*dmmax + off; #endif } else index = 0; sp = &swdevt[index]; if (sp->sw_vp == NULL) { bp->b_error = ENODEV; bp->b_flags |= B_ERROR; biodone(bp); return; } if ((bp->b_dev = sp->sw_dev) == NODEV && sp->sw_vp->v_type != VREG) panic("swstrategy"); VHOLD(sp->sw_vp); if ((bp->b_flags & B_READ) == 0) { if (vp = bp->b_vp) { vp->v_numoutput--; if ((vp->v_flag & VBWAIT) && vp->v_numoutput <= 0) { vp->v_flag &= ~VBWAIT; wakeup((caddr_t)&vp->v_numoutput); } } sp->sw_vp->v_numoutput++; } if (bp->b_vp != NULL) brelvp(bp); bp->b_vp = sp->sw_vp; VOP_STRATEGY(bp); } /* * System call swapon(name) enables swapping on device name, * which must be in the swdevsw. Return EBUSY * if already swapping on this device. */ /* ARGSUSED */ int swapon(p, uap, retval) struct proc *p; struct swapon_args /* { syscallarg(char *) name; } */ *uap; register_t *retval; { register struct vnode *vp; register struct swdevt *sp; dev_t dev; int error; struct nameidata nd; if (error = suser(p->p_ucred, &p->p_acflag)) return (error); NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, name), p); if (error = namei(&nd)) return (error); vp = nd.ni_vp; if (vp->v_type != VBLK) { vrele(vp); return (ENOTBLK); } dev = (dev_t)vp->v_rdev; if (major(dev) >= nblkdev) { vrele(vp); return (ENXIO); } for (sp = &swdevt[0]; sp->sw_dev != NODEV; sp++) { if (sp->sw_dev == dev) { if (sp->sw_flags & SW_FREED) { vrele(vp); return (EBUSY); } sp->sw_vp = vp; if (error = swfree(p, sp - swdevt)) { vrele(vp); return (error); } return (0); } #ifdef SEQSWAP /* * If we have reached a non-freed sequential device without * finding what we are looking for, it is an error. * That is because all interleaved devices must come first * and sequential devices must be freed in order. */ if ((sp->sw_flags & (SW_SEQUENTIAL|SW_FREED)) == SW_SEQUENTIAL) break; #endif } vrele(vp); return (EINVAL); } /* * Swfree(index) frees the index'th portion of the swap map. * Each of the nswdev devices provides 1/nswdev'th of the swap * space, which is laid out with blocks of dmmax pages circularly * among the devices. */ int swfree(p, index) struct proc *p; int index; { register struct swdevt *sp; register swblk_t vsbase; register long blk; struct vnode *vp; register swblk_t dvbase; register int nblks; int error; sp = &swdevt[index]; vp = sp->sw_vp; if (error = VOP_OPEN(vp, FREAD|FWRITE, p->p_ucred, p)) return (error); sp->sw_flags |= SW_FREED; nblks = sp->sw_nblks; /* * Some devices may not exist til after boot time. * If so, their nblk count will be 0. */ if (nblks <= 0) { int perdev; dev_t dev = sp->sw_dev; if (bdevsw[major(dev)].d_psize == 0 || (nblks = (*bdevsw[major(dev)].d_psize)(dev)) == -1) { (void) VOP_CLOSE(vp, FREAD|FWRITE, p->p_ucred, p); sp->sw_flags &= ~SW_FREED; return (ENXIO); } #ifdef SEQSWAP if (index < niswdev) { perdev = niswap / niswdev; if (nblks > perdev) nblks = perdev; } else { if (nblks % dmmax) nblks -= (nblks % dmmax); nswap += nblks; } #else perdev = nswap / nswdev; if (nblks > perdev) nblks = perdev; #endif sp->sw_nblks = nblks; } if (nblks == 0) { (void) VOP_CLOSE(vp, FREAD|FWRITE, p->p_ucred, p); sp->sw_flags &= ~SW_FREED; return (0); /* XXX error? */ } #ifdef SEQSWAP if (sp->sw_flags & SW_SEQUENTIAL) { register struct swdevt *swp; blk = niswap; for (swp = &swdevt[niswdev]; swp != sp; swp++) blk += swp->sw_nblks; rmfree(swapmap, nblks, blk); return (0); } #endif for (dvbase = 0; dvbase < nblks; dvbase += dmmax) { blk = nblks - dvbase; #ifdef SEQSWAP if ((vsbase = index*dmmax + dvbase*niswdev) >= niswap) panic("swfree"); #else if ((vsbase = index*dmmax + dvbase*nswdev) >= nswap) panic("swfree"); #endif if (blk > dmmax) blk = dmmax; if (vsbase == 0) { /* * First of all chunks... initialize the swapmap. * Don't use the first cluster of the device * in case it starts with a label or boot block. */ rminit(swapmap, blk - ctod(CLSIZE), vsbase + ctod(CLSIZE), "swap", nswapmap); } else if (dvbase == 0) { /* * Don't use the first cluster of the device * in case it starts with a label or boot block. */ rmfree(swapmap, blk - ctod(CLSIZE), vsbase + ctod(CLSIZE)); } else rmfree(swapmap, blk, vsbase); } return (0); }