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NetBSD/sys/vm/vm_swap.c

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/* $NetBSD: vm_swap.c,v 1.35 1996/10/21 01:32:38 perry 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 <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/dmap.h> /* XXX */
#include <sys/vnode.h>
#include <sys/map.h>
#include <sys/file.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <vm/vm.h>
#include <vm/vm_conf.h>
#include <miscfs/specfs/specdev.h>
/*
* 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
int swfree __P((struct proc *, int));
/*
* 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;
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) != NULL) {
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);
}
/*ARGSUSED*/
int
swread(dev, uio, ioflag)
dev_t dev;
struct uio *uio;
int ioflag;
{
return (physio(swstrategy, NULL, dev, B_READ, minphys, uio));
}
/*ARGSUSED*/
int
swwrite(dev, uio, ioflag)
dev_t dev;
struct uio *uio;
int ioflag;
{
return (physio(swstrategy, NULL, dev, B_WRITE, minphys, uio));
}
/*
* 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
sys_swapon(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
struct sys_swapon_args /* {
syscallarg(char *) name;
} */ *uap = v;
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)) != 0)
return (error);
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, name), p);
if ((error = namei(&nd)) != 0)
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)) != 0) {
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 root on swap, then the skip open/close operations. */
if (vp != rootvp) {
if ((error = VOP_OPEN(vp, FREAD|FWRITE, p->p_ucred, p)) != 0)
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) {
if (vp != rootvp)
(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) {
if (vp != rootvp)
(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);
}
/*
* Preserve the mini-root if appropriate:
* Note: this requires !SEQSWAP && nswdev==1
*
* 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).
*/
if (vp == rootvp) {
#ifndef MINIROOTSIZE
struct mount *mp;
struct statfs *sp;
#endif
long firstblk;
int rootblks;
#ifdef MINIROOTSIZE
rootblks = MINIROOTSIZE;
#else
/* Get size from root FS (mountroot did statfs) */
mp = rootvnode->v_mount;
sp = &mp->mnt_stat;
rootblks = sp->f_blocks * (sp->f_bsize / DEV_BSIZE);
#endif
if (rootblks > nblks)
panic("swfree miniroot size");
/* First ctod(CLSIZE) blocks are not in the map. */
firstblk = rmalloc(swapmap, rootblks - ctod(CLSIZE));
if (firstblk != ctod(CLSIZE))
panic("swfree miniroot save");
printf("Preserved %d blocks of miniroot leaving %d pages of swap\n",
rootblks, dtoc(nblks - rootblks));
}
return (0);
}
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