547 lines
13 KiB
C
547 lines
13 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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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_mac.h"
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#include "opt_swap.h"
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#include "opt_vm.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/bio.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/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 <sys/disk.h>
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#include <sys/stat.h>
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#include <sys/sysctl.h>
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#include <sys/mac.h>
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#include <sys/mount.h>
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#include <vm/vm.h>
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#include <vm/vm_extern.h>
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#include <vm/vm_param.h>
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#include <vm/vm_pageout.h>
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#include <vm/swap_pager.h>
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#include <vm/uma.h>
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/*
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* Indirect driver for multi-controller paging.
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*/
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typedef int32_t swblk_t; /* swap offset */
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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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struct swdevt *swdevt = should_be_malloced;
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static int nswap; /* first block after the interleaved devs */
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int nswdev = NSWAPDEV;
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int vm_swap_size;
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static int swdev_syscall_active = 0; /* serialize swap(on|off) */
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static int swapdev_strategy(struct vop_strategy_args *ap);
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struct vnode *swapdev_vp;
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/*
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* swapdev_strategy:
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*
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* VOP_STRATEGY() for swapdev_vp.
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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 int
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swapdev_strategy(ap)
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struct vop_strategy_args /* {
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struct vnode *a_vp;
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struct buf *a_bp;
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} */ *ap;
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{
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int s, sz, off, seg, index;
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struct swdevt *sp;
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struct vnode *vp;
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struct buf *bp;
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KASSERT(ap->a_vp == ap->a_bp->b_vp, ("%s(%p != %p)",
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__func__, ap->a_vp, ap->a_bp->b_vp));
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bp = ap->a_bp;
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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_ioflags |= BIO_ERROR;
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bufdone(bp);
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return 0;
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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_ioflags |= BIO_ERROR;
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bufdone(bp);
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return 0;
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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_ioflags |= BIO_ERROR;
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bufdone(bp);
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return 0;
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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_iocmd == BIO_WRITE) {
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vp = bp->b_vp;
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if (vp) {
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VI_LOCK(vp);
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vp->v_numoutput--;
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if ((vp->v_iflag & VI_BWAIT) && vp->v_numoutput <= 0) {
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vp->v_iflag &= ~VI_BWAIT;
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wakeup(&vp->v_numoutput);
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}
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VI_UNLOCK(vp);
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}
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VI_LOCK(sp->sw_vp);
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sp->sw_vp->v_numoutput++;
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VI_UNLOCK(sp->sw_vp);
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}
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bp->b_vp = sp->sw_vp;
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splx(s);
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if (bp->b_vp->v_type == VCHR)
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VOP_SPECSTRATEGY(bp->b_vp, bp);
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else
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VOP_STRATEGY(bp->b_vp, bp);
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return 0;
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}
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/*
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* Create a special vnode op vector for swapdev_vp - we only use
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* VOP_STRATEGY() and reclaim; everything else returns an error.
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*/
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vop_t **swapdev_vnodeop_p;
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static struct vnodeopv_entry_desc swapdev_vnodeop_entries[] = {
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{ &vop_default_desc, (vop_t *) vop_defaultop },
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{ &vop_reclaim_desc, (vop_t *) vop_null },
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{ &vop_strategy_desc, (vop_t *) swapdev_strategy },
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{ NULL, NULL }
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};
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static struct vnodeopv_desc swapdev_vnodeop_opv_desc =
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{ &swapdev_vnodeop_p, swapdev_vnodeop_entries };
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VNODEOP_SET(swapdev_vnodeop_opv_desc);
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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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/*
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* MPSAFE
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*/
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/* ARGSUSED */
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int
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swapon(td, uap)
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struct thread *td;
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struct swapon_args *uap;
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{
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struct vattr attr;
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struct vnode *vp;
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struct nameidata nd;
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int error;
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mtx_lock(&Giant);
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error = suser(td);
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if (error)
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goto done2;
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while (swdev_syscall_active)
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tsleep(&swdev_syscall_active, PUSER - 1, "swpon", 0);
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swdev_syscall_active = 1;
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/*
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* Swap metadata may not fit in the KVM if we have physical
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* memory of >1GB.
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*/
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if (swap_zone == NULL) {
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error = ENOMEM;
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goto done;
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}
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NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, uap->name, td);
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error = namei(&nd);
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if (error)
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goto done;
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NDFREE(&nd, NDF_ONLY_PNBUF);
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vp = nd.ni_vp;
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if (vn_isdisk(vp, &error))
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error = swaponvp(td, vp, vp->v_rdev, 0);
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else if (vp->v_type == VREG &&
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(vp->v_mount->mnt_vfc->vfc_flags & VFCF_NETWORK) != 0 &&
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(error = VOP_GETATTR(vp, &attr, td->td_ucred, td)) == 0) {
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/*
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* Allow direct swapping to NFS regular files in the same
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* way that nfs_mountroot() sets up diskless swapping.
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*/
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error = swaponvp(td, vp, NODEV, attr.va_size / DEV_BSIZE);
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}
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if (error)
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vrele(vp);
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done:
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swdev_syscall_active = 0;
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wakeup_one(&swdev_syscall_active);
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done2:
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mtx_unlock(&Giant);
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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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int
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swaponvp(td, vp, dev, nblks)
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struct thread *td;
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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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struct swdevt *sp;
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swblk_t vsbase;
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long blk;
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swblk_t dvbase;
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int error;
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u_long aligned_nblks;
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off_t mediasize;
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if (!swapdev_vp) {
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error = getnewvnode("none", NULL, swapdev_vnodeop_p,
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&swapdev_vp);
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if (error)
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panic("Cannot get vnode for swapdev");
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swapdev_vp->v_type = VNON; /* Untyped */
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}
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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, td);
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#ifdef MAC
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error = mac_check_system_swapon(td->td_ucred, vp);
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if (error == 0)
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#endif
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error = VOP_OPEN(vp, FREAD | FWRITE, td->td_ucred, td);
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(void) VOP_UNLOCK(vp, 0, td);
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if (error)
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return (error);
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if (nblks == 0) {
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error = VOP_IOCTL(vp, DIOCGMEDIASIZE, (caddr_t)&mediasize,
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FREAD, td->td_ucred, td);
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if (error == 0)
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nblks = mediasize / DEV_BSIZE;
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}
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/*
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* XXX: We should also check that the sectorsize makes sense
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* XXX: it should be a power of two, no larger than the page size.
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*/
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if (nblks == 0) {
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(void) VOP_CLOSE(vp, FREAD | FWRITE, td->td_ucred, td);
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return (ENXIO);
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}
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/*
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* If we go beyond this, we get overflows in the radix
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* tree bitmap code.
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*/
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if (nblks > 0x40000000 / BLIST_META_RADIX / nswdev) {
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printf("exceeded maximum of %d blocks per swap unit\n",
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0x40000000 / BLIST_META_RADIX / nswdev);
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(void) VOP_CLOSE(vp, FREAD | FWRITE, td->td_ucred, td);
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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 = dev2udev(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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sp->sw_used = 0;
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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. aligned_nblks is used to calculate the
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* size of the swap bitmap, taking into account the stripe size.
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*/
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aligned_nblks = (nblks + (dmmax -1)) & ~(u_long)(dmmax -1);
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if (aligned_nblks * nswdev > nswap)
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nswap = aligned_nblks * 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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swap_pager_full = 0;
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return (0);
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}
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/*
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* SYSCALL: swapoff(devname)
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*
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* Disable swapping on the given device.
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*/
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#ifndef _SYS_SYSPROTO_H_
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struct swapoff_args {
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char *name;
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};
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#endif
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/*
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* MPSAFE
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*/
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/* ARGSUSED */
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int
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swapoff(td, uap)
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struct thread *td;
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struct swapoff_args *uap;
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{
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struct vnode *vp;
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struct nameidata nd;
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struct swdevt *sp;
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swblk_t dvbase, vsbase;
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u_long nblks, aligned_nblks, blk;
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int error, index;
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mtx_lock(&Giant);
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error = suser(td);
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if (error)
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goto done2;
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while (swdev_syscall_active)
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tsleep(&swdev_syscall_active, PUSER - 1, "swpoff", 0);
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swdev_syscall_active = 1;
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NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, uap->name, td);
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error = namei(&nd);
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if (error)
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goto done;
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NDFREE(&nd, NDF_ONLY_PNBUF);
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vp = nd.ni_vp;
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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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goto found;
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}
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error = EINVAL;
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goto done;
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found:
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#ifdef MAC
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(void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
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error = mac_check_system_swapoff(td->td_ucred, vp);
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(void) VOP_UNLOCK(vp, 0, td);
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if (error != 0)
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goto done;
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#endif
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nblks = sp->sw_nblks;
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/*
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* We can turn off this swap device safely only if the
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* available virtual memory in the system will fit the amount
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* of data we will have to page back in, plus an epsilon so
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* the system doesn't become critically low on swap space.
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*/
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if (cnt.v_free_count + cnt.v_cache_count + vm_swap_size <
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nblks + nswap_lowat) {
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error = ENOMEM;
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goto done;
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}
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/*
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* Prevent further allocations on this device.
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*/
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sp->sw_flags |= SW_CLOSING;
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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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vm_swap_size -= blist_fill(swapblist, vsbase, blk);
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}
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/*
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* Page in the contents of the device and close it.
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*/
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#ifndef NO_SWAPPING
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vm_proc_swapin_all(index);
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#endif /* !NO_SWAPPING */
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swap_pager_swapoff(index, &sp->sw_used);
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VOP_CLOSE(vp, FREAD | FWRITE, td->td_ucred, td);
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vrele(vp);
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sp->sw_vp = NULL;
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/*
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* Resize the bitmap based on the new largest swap device,
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* or free the bitmap if there are no more devices.
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*/
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for (sp = swdevt, nblks = 0; sp < swdevt + nswdev; sp++) {
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if (sp->sw_vp == NULL)
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continue;
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nblks = max(nblks, sp->sw_nblks);
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}
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aligned_nblks = (nblks + (dmmax -1)) & ~(u_long)(dmmax -1);
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nswap = aligned_nblks * nswdev;
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if (nswap == 0) {
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blist_destroy(swapblist);
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swapblist = NULL;
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vrele(swapdev_vp);
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swapdev_vp = NULL;
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} else
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blist_resize(&swapblist, nswap, 0);
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done:
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swdev_syscall_active = 0;
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wakeup_one(&swdev_syscall_active);
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done2:
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mtx_unlock(&Giant);
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return (error);
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}
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static int
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sysctl_vm_swap_info(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int *name = (int *)arg1;
|
|
int error, i, n;
|
|
struct xswdev xs;
|
|
struct swdevt *sp;
|
|
|
|
if (arg2 != 1) /* name length */
|
|
return (EINVAL);
|
|
|
|
for (sp = swdevt, i = 0, n = 0 ; i < nswdev; i++, sp++) {
|
|
if (sp->sw_vp) {
|
|
if (n == *name) {
|
|
xs.xsw_version = XSWDEV_VERSION;
|
|
xs.xsw_dev = sp->sw_dev;
|
|
xs.xsw_flags = sp->sw_flags;
|
|
xs.xsw_nblks = sp->sw_nblks;
|
|
xs.xsw_used = sp->sw_used;
|
|
|
|
error = SYSCTL_OUT(req, &xs, sizeof(xs));
|
|
return (error);
|
|
}
|
|
n++;
|
|
}
|
|
|
|
}
|
|
return (ENOENT);
|
|
}
|
|
|
|
SYSCTL_INT(_vm, OID_AUTO, nswapdev, CTLFLAG_RD, &nswdev, 0,
|
|
"Number of swap devices");
|
|
SYSCTL_NODE(_vm, OID_AUTO, swap_info, CTLFLAG_RD, sysctl_vm_swap_info,
|
|
"Swap statistics by device");
|