dbafb3660f
Make the alias list a SLIST.
Drop the "fast recycling" optimization of vnodes (including
the returning of a prexisting but stale vnode from checkalias).
It doesn't buy us anything now that we don't hardlimit
vnodes anymore.
Rename checkalias2() and checkalias() to addalias() and
addaliasu() - which takes dev_t and udev_t arg respectively.
Make the revoke syscalls use vcount() instead of VALIASED.
Remove VALIASED flag, we don't need it now and it is faster
to traverse the much shorter lists than to maintain the
flag.
vfs_mountedon() can check the dev_t directly, all the vnodes
point to the same one.
Print the devicename in specfs/vprint().
Remove a couple of stale LFS vnode flags.
Remove unimplemented/unused LK_DRAINED;
357 lines
8.5 KiB
C
357 lines
8.5 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 1.83 1999/08/24 05:58:35 green Exp $
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*/
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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/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/blist.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/conf.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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/*
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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 d_strategy_t swstrategy;
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#define CDEV_MAJOR 4
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#define BDEV_MAJOR 26
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static struct cdevsw sw_cdevsw = {
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/* open */ nullopen,
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/* close */ nullclose,
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/* read */ physread,
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/* write */ physwrite,
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/* ioctl */ noioctl,
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/* stop */ nostop,
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/* reset */ noreset,
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/* devtotty */ nodevtotty,
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/* poll */ nopoll,
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/* mmap */ nommap,
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/* strategy */ swstrategy,
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/* name */ "sw",
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/* parms */ noparms,
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/* maj */ CDEV_MAJOR,
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/* dump */ nodump,
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/* psize */ nopsize,
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/* flags */ 0,
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/* maxio */ 0,
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/* bmaj */ BDEV_MAJOR
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};
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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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static 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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/*
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* swstrategy:
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*
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* Perform swap strategy interleave device selection
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*
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* The bp is expected to be locked and *not* B_DONE on call.
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*/
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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, PAGE_SIZE);
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/*
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* Convert interleaved swap into per-device swap. Note that
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* the block size is left in PAGE_SIZE'd chunks (for the newswap)
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* here.
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*/
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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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}
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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_device;
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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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/*
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* Convert from PAGE_SIZE'd to DEV_BSIZE'd chunks for the actual I/O
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*/
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bp->b_blkno = ctodb(bp->b_blkno);
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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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pbreassignbuf(bp, sp->sw_vp);
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splx(s);
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VOP_STRATEGY(bp->b_vp, 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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static int once;
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if (!once) {
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cdevsw_add(&sw_cdevsw);
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make_dev(&sw_cdevsw, 0, UID_ROOT, GID_KMEM, 0640, "drum");
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once++;
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}
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error = suser(p);
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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 = vp->v_rdev;
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if (devsw(dev) == NULL) {
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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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* The new swap code uses page-sized blocks. The old swap code used
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* DEV_BSIZE'd chunks.
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*
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* XXX locking when multiple swapon's run in parallel
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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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ASSERT_VOP_UNLOCKED(vp, "swaponvp");
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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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(void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
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error = VOP_OPEN(vp, FREAD | FWRITE, p->p_ucred, p);
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(void) VOP_UNLOCK(vp, 0, p);
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if (error)
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return (error);
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if (nblks == 0 && dev != NODEV && (devsw(dev)->d_psize == 0 ||
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(nblks = (*devsw(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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/*
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* nblks is in DEV_BSIZE'd chunks, convert to PAGE_SIZE'd chunks.
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* First chop nblks off to page-align it, then convert.
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*
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* sw->sw_nblks is in page-sized chunks now too.
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*/
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nblks &= ~(ctodb(1) - 1);
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nblks = dbtoc(nblks);
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sp->sw_vp = vp;
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sp->sw_dev = dev2budev(dev);
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sp->sw_device = dev;
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sp->sw_flags |= SW_FREED;
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sp->sw_nblks = nblks;
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/*
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* nblks, nswap, and dmmax are PAGE_SIZE'd parameters now, not
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* DEV_BSIZE'd.
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*/
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if (nblks * nswdev > nswap)
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nswap = (nblks+1) * nswdev;
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if (swapblist == NULL)
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swapblist = blist_create(nswap);
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else
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blist_resize(&swapblist, nswap, 0);
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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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blist_free(swapblist, vsbase, blk);
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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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addaliasu(vp1, makeudev(BDEV_MAJOR, 0));
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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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