c4e82fbab0
have declined due to code-rot over time. The swap pager rundown code has been clean-up, and unneeded wakeups removed. Lots of splbio's are changed to splvm's. Also, set the dynamic tunables for the pageout daemon to be more sane for larger systems (thereby decreasing the daemon overheadla.)
333 lines
8.1 KiB
C
333 lines
8.1 KiB
C
/*
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)vm_swap.c 8.5 (Berkeley) 2/17/94
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* $Id: vm_swap.c,v 1.52 1998/02/19 12:15:06 msmith Exp $
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*/
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#include "opt_devfs.h"
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#include "opt_swap.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/buf.h>
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#include <sys/conf.h>
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#ifdef DEVFS
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#include <sys/devfsext.h>
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#endif
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#include <sys/proc.h>
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#include <sys/namei.h>
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#include <sys/dmap.h> /* XXX */
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#include <sys/vnode.h>
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#include <sys/fcntl.h>
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#include <sys/rlist.h>
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#include <sys/kernel.h>
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#include <vm/vm.h>
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#include <vm/vm_extern.h>
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#include <vm/swap_pager.h>
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#include <miscfs/specfs/specdev.h>
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/*
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* "sw" is a fake device implemented
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* in vm_swap.c and used only internally to get to swstrategy.
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* It cannot be provided to the users, because the
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* swstrategy routine munches the b_dev and b_blkno entries
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* before calling the appropriate driver. This would horribly
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* confuse, e.g. the hashing routines. Instead, /dev/drum is
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* provided as a character (raw) device.
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*/
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static void swstrategy __P((struct buf *));
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#define CDEV_MAJOR 4
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#define BDEV_MAJOR 26
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extern struct cdevsw sw_cdevsw ;
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static struct bdevsw sw_bdevsw =
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{ noopen, noclose, swstrategy, noioc, /*1*/
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nodump, nopsize, 0, "sw", &sw_cdevsw, -1 };
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static struct cdevsw sw_cdevsw =
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{ nullopen, nullclose, rawread, rawwrite, /*4*/
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noioc, nostop, noreset, nodevtotty,/* swap */
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seltrue, nommap, swstrategy, "sw",
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&sw_bdevsw, -1 };
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static dev_t swapdev = makedev(BDEV_MAJOR, 0);
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/*
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* Indirect driver for multi-controller paging.
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*/
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#ifndef NSWAPDEV
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#define NSWAPDEV 4
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#endif
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static struct swdevt should_be_malloced[NSWAPDEV];
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static struct swdevt *swdevt = should_be_malloced;
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struct vnode *swapdev_vp;
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/* XXX swapinfo(8) needs this one I belive */
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int nswap; /* first block after the interleaved devs */
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static int nswdev = NSWAPDEV;
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int vm_swap_size;
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static void
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swstrategy(bp)
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register struct buf *bp;
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{
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int s, sz, off, seg, index;
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register struct swdevt *sp;
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struct vnode *vp;
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sz = howmany(bp->b_bcount, DEV_BSIZE);
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if (nswdev > 1) {
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off = bp->b_blkno % dmmax;
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if (off + sz > dmmax) {
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bp->b_error = EINVAL;
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bp->b_flags |= B_ERROR;
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biodone(bp);
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return;
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}
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seg = bp->b_blkno / dmmax;
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index = seg % nswdev;
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seg /= nswdev;
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bp->b_blkno = seg * dmmax + off;
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} else
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index = 0;
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sp = &swdevt[index];
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if (bp->b_blkno + sz > sp->sw_nblks) {
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bp->b_error = EINVAL;
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bp->b_flags |= B_ERROR;
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biodone(bp);
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return;
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}
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bp->b_dev = sp->sw_dev;
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if (sp->sw_vp == NULL) {
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bp->b_error = ENODEV;
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bp->b_flags |= B_ERROR;
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biodone(bp);
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return;
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}
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vhold(sp->sw_vp);
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s = splvm();
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if ((bp->b_flags & B_READ) == 0) {
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vp = bp->b_vp;
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if (vp) {
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vp->v_numoutput--;
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if ((vp->v_flag & VBWAIT) && vp->v_numoutput <= 0) {
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vp->v_flag &= ~VBWAIT;
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wakeup(&vp->v_numoutput);
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}
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}
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sp->sw_vp->v_numoutput++;
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}
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if (bp->b_vp != NULL)
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pbrelvp(bp);
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splx(s);
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bp->b_vp = sp->sw_vp;
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VOP_STRATEGY(bp);
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}
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/*
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* System call swapon(name) enables swapping on device name,
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* which must be in the swdevsw. Return EBUSY
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* if already swapping on this device.
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*/
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#ifndef _SYS_SYSPROTO_H_
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struct swapon_args {
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char *name;
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};
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#endif
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/* ARGSUSED */
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int
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swapon(p, uap)
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struct proc *p;
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struct swapon_args *uap;
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{
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register struct vnode *vp;
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dev_t dev;
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struct nameidata nd;
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int error;
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error = suser(p->p_ucred, &p->p_acflag);
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if (error)
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return (error);
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NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, uap->name, p);
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error = namei(&nd);
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if (error)
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return (error);
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vp = nd.ni_vp;
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switch (vp->v_type) {
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case VBLK:
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dev = (dev_t) vp->v_rdev;
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if (major(dev) >= nblkdev) {
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error = ENXIO;
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break;
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}
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error = swaponvp(p, vp, dev, 0);
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break;
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case VCHR:
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/*
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* For now, we disallow swapping to regular files.
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* It requires logical->physcal block translation
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* support in the swap pager before it will work.
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*/
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error = ENOTBLK;
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break;
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#if 0
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error = VOP_GETATTR(vp, &attr, p->p_ucred, p);
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if (!error)
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error = swaponvp(p, vp, NODEV, attr.va_size / DEV_BSIZE);
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break;
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#endif
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default:
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error = EINVAL;
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break;
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}
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if (error)
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vrele(vp);
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return (error);
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}
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/*
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* Swfree(index) frees the index'th portion of the swap map.
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* Each of the nswdev devices provides 1/nswdev'th of the swap
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* space, which is laid out with blocks of dmmax pages circularly
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* among the devices.
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*/
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int
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swaponvp(p, vp, dev, nblks)
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struct proc *p;
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struct vnode *vp;
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dev_t dev;
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u_long nblks;
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{
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int index;
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register struct swdevt *sp;
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register swblk_t vsbase;
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register long blk;
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swblk_t dvbase;
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int error;
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for (sp = swdevt, index = 0 ; index < nswdev; index++, sp++) {
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if (sp->sw_vp == vp)
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return EBUSY;
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if (!sp->sw_vp)
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goto found;
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}
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return EINVAL;
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found:
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if (dev != NODEV && (major(dev) >= nblkdev))
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return (ENXIO);
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error = VOP_OPEN(vp, FREAD | FWRITE, p->p_ucred, p);
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if (error)
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return (error);
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if (nblks == 0 && (bdevsw[major(dev)]->d_psize == 0 ||
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(nblks = (*bdevsw[major(dev)]->d_psize) (dev)) == -1)) {
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(void) VOP_CLOSE(vp, FREAD | FWRITE, p->p_ucred, p);
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return (ENXIO);
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}
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if (nblks == 0) {
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(void) VOP_CLOSE(vp, FREAD | FWRITE, p->p_ucred, p);
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return (ENXIO);
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}
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sp->sw_vp = vp;
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sp->sw_dev = dev;
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sp->sw_flags |= SW_FREED;
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sp->sw_nblks = nblks;
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if (nblks * nswdev > nswap)
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nswap = (nblks+1) * nswdev;
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for (dvbase = dmmax; dvbase < nblks; dvbase += dmmax) {
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blk = min(nblks - dvbase,dmmax);
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vsbase = index * dmmax + dvbase * nswdev;
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rlist_free(&swaplist, vsbase, vsbase + blk - 1);
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vm_swap_size += blk;
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}
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if (!swapdev_vp) {
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struct vnode *vp1;
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struct vnode *nvp;
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error = getnewvnode(VT_NON, (struct mount *) 0,
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spec_vnodeop_p, &nvp);
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if (error)
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panic("Cannot get vnode for swapdev");
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vp1 = nvp;
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vp1->v_type = VBLK;
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if ((nvp = checkalias(vp1, swapdev,
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(struct mount *) 0))) {
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vput(vp1);
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vp1 = nvp;
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}
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swapdev_vp = vp1;
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}
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return (0);
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}
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static sw_devsw_installed = 0;
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#ifdef DEVFS
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static void *drum_devfs_token;
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#endif
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static void sw_drvinit(void *unused)
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{
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dev_t dev;
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if( ! sw_devsw_installed ) {
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dev = makedev(CDEV_MAJOR,0);
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cdevsw_add(&dev,&sw_cdevsw,NULL);
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dev = makedev(BDEV_MAJOR,0);
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bdevsw_add(&dev,&sw_bdevsw,NULL);
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sw_devsw_installed = 1;
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#ifdef DEVFS
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drum_devfs_token = devfs_add_devswf(&sw_cdevsw, 0, DV_CHR,
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UID_ROOT, GID_KMEM, 0640,
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"drum");
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#endif
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}
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}
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SYSINIT(swdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,sw_drvinit,NULL)
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