273 lines
6.6 KiB
C
273 lines
6.6 KiB
C
/* @(#)vm_swp.c 1.1 94/10/31 SMI; from UCB 4.41 83/05/21 */
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#include <machine/pte.h>
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/user.h>
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#include <sys/buf.h>
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#include <sys/conf.h>
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#include <sys/proc.h>
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#include <sys/seg.h>
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#include <sys/vm.h>
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#include <sys/trace.h>
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#include <sys/map.h>
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#include <sys/uio.h>
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#include <sys/vnode.h>
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/*
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* Swap IO headers -
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* They contain the necessary information for the swap I/O.
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* At any given time, a swap header can be in three
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* different lists. When free it is in the free list,
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* when allocated and the I/O queued, it is on the swap
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* device list, and finally, if the operation was a dirty
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* page push, when the I/O completes, it is inserted
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* in a list of cleaned pages to be processed by the pageout daemon.
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*/
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struct buf *swbuf;
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/*
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* swap I/O -
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*
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* If the flag indicates a dirty page push initiated
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* by the pageout daemon, we map the page into the i th
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* virtual page of process 2 (the daemon itself) where i is
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* the index of the swap header that has been allocated.
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* We simply initialize the header and queue the I/O but
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* do not wait for completion. When the I/O completes,
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* iodone() will link the header to a list of cleaned
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* pages to be processed by the pageout daemon.
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*/
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swap(p, dblkno, addr, nbytes, rdflg, flag, vp, pfcent)
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struct proc *p;
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swblk_t dblkno;
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caddr_t addr;
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int nbytes, rdflg, flag;
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struct vnode *vp;
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u_int pfcent;
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{
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register struct buf *bp;
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register u_int c;
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int p2dp;
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register struct pte *dpte, *vpte;
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int s;
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extern swdone();
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int error = 0;
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s = spl6();
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while (bswlist.av_forw == NULL) {
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bswlist.b_flags |= B_WANTED;
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(void) sleep((caddr_t)&bswlist, PSWP+1);
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}
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bp = bswlist.av_forw;
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bswlist.av_forw = bp->av_forw;
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(void) splx(s);
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bp->b_flags = B_BUSY | B_PHYS | rdflg | flag;
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if ((bp->b_flags & (B_DIRTY|B_PGIN)) == 0)
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if (rdflg == B_READ)
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sum.v_pswpin += btoc(nbytes);
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else
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sum.v_pswpout += btoc(nbytes);
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bp->b_proc = p;
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if (flag & B_DIRTY) {
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p2dp = ((bp - swbuf) * CLSIZE) * KLMAX;
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dpte = dptopte(&proc[2], p2dp);
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vpte = vtopte(p, btop(addr));
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for (c = 0; c < nbytes; c += NBPG) {
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if (vpte->pg_pfnum == 0 || vpte->pg_fod)
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panic("swap bad pte");
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/*
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* Mapping of addr+c is replaced by dpte.
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* Since we have flushed these pages in pageout,
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* no flush is needed here.
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*/
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*dpte++ = *vpte++;
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}
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bp->b_un.b_addr = (caddr_t)ctob(dptov(&proc[2], p2dp));
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bp->b_flags |= B_CALL;
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bp->b_iodone = swdone;
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bp->b_pfcent = pfcent;
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} else
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bp->b_un.b_addr = addr;
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while (nbytes > 0) {
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bp->b_bcount = nbytes;
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bp->b_blkno = dblkno;
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bp->b_dev = vp->v_rdev;
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bsetvp(bp, vp);
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minphys(bp);
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c = bp->b_bcount;
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#ifdef TRACE
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trace(TR_SWAPIO, vp, bp->b_blkno);
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#endif
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physstrat(bp, vp->v_op->vn_strategy, PSWP);
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if (flag & B_DIRTY) {
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if (c < nbytes)
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panic("big push");
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return (0);
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}
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bp->b_un.b_addr += c;
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bp->b_flags &= ~B_DONE;
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if (bp->b_flags & B_ERROR) {
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if ((flag & (B_UAREA|B_PAGET)) || rdflg == B_WRITE)
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panic("hard IO err in swap");
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swkill(p, "swap: i/o error");
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error = 1;
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}
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nbytes -= c;
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dblkno += btodb(c);
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}
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if (flag & B_DIRTY) {
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/*
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* Mapping from i-th virtual page of process 2 to physical
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* page is not valid anymore.
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*/
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register caddr_t vaddr = (caddr_t)dptov(&proc[2], p2dp);
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caddr_t evaddr;
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for (evaddr = vaddr + nbytes; vaddr < evaddr; vaddr += NBPG)
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vac_pageflush(vaddr);
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}
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s = spl6();
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bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY);
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bp->av_forw = bswlist.av_forw;
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bswlist.av_forw = bp;
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if (bswlist.b_flags & B_WANTED) {
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bswlist.b_flags &= ~B_WANTED;
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wakeup((caddr_t)&bswlist);
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wakeup((caddr_t)&proc[2]);
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}
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(void) splx(s);
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return (error);
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}
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/*
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* Put a buffer on the clean list after I/O is done.
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* Called from biodone.
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*/
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swdone(bp)
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register struct buf *bp;
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{
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register int s;
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if (bp->b_flags & B_ERROR)
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panic("IO err in push");
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s = spl6();
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bp->av_forw = bclnlist;
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cnt.v_pgout++;
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cnt.v_pgpgout += bp->b_bcount / NBPG;
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bclnlist = bp;
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if (bswlist.b_flags & B_WANTED)
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wakeup((caddr_t)&proc[2]);
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(void) splx(s);
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}
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/*
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* rout is the name of the routine where we ran into problems.
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*/
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swkill(p, rout)
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struct proc *p;
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char *rout;
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{
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printf("pid %d: killed due to swap problems in %s\n",
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p->p_pid, rout);
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uprintf("sorry, pid %d was killed due to swap problems in %s\n",
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p->p_pid, rout);
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/*
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* To be sure no looping (e.g. in vmsched trying to
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* swap out) mark process locked in core (as though
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* done by user) after killing it so noone will try
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* to swap it out.
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*/
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psignal(p, SIGKILL);
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p->p_flag |= SULOCK;
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}
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/*
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* Raw I/O. The arguments are
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* The strategy routine for the device
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* A buffer, which will always be a special buffer
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* header owned exclusively by the device for this purpose
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* The device number
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* Read/write flag
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* Essentially all the work is computing physical addresses and
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* validating them.
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* If the user has the proper access privilidges, the process is
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* marked 'delayed unlock' and the pages involved in the I/O are
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* faulted and locked. After the completion of the I/O, the above pages
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* are unlocked.
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*/
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physio(strat, bp, dev, rw, mincnt, uio)
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int (*strat)();
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register struct buf *bp;
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dev_t dev;
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int rw;
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void (*mincnt)();
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struct uio *uio;
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{
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register struct iovec *iov = uio->uio_iov;
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register int c;
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char *a;
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int s, error = 0;
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nextiov:
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if (uio->uio_iovcnt == 0)
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return (0);
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if (useracc(iov->iov_base, (u_int)iov->iov_len,
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rw==B_READ?B_WRITE:B_READ) == NULL)
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return (EFAULT);
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s = spl6();
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while (bp->b_flags&B_BUSY) {
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bp->b_flags |= B_WANTED;
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(void) sleep((caddr_t)bp, PRIBIO+1);
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}
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(void) splx(s);
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bp->b_error = 0;
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bp->b_proc = u.u_procp;
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bp->b_un.b_addr = iov->iov_base;
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while (iov->iov_len > 0) {
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bp->b_flags = B_BUSY | B_PHYS | rw;
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bp->b_dev = dev;
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bp->b_blkno = btodb(uio->uio_offset);
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bp->b_bcount = iov->iov_len;
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(*mincnt)(bp);
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c = bp->b_bcount;
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u.u_procp->p_flag |= SPHYSIO;
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vslock(a = bp->b_un.b_addr, c);
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physstrat(bp, strat, PRIBIO);
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(void) spl6();
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vsunlock(a, c, rw);
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u.u_procp->p_flag &= ~SPHYSIO;
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if (bp->b_flags&B_WANTED)
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wakeup((caddr_t)bp);
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(void) splx(s);
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c -= bp->b_resid;
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bp->b_un.b_addr += c;
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iov->iov_len -= c;
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uio->uio_resid -= c;
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uio->uio_offset += c;
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/* temp kludge for tape drives */
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if (bp->b_resid || (bp->b_flags&B_ERROR))
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break;
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}
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bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS);
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error = geterror(bp);
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/* temp kludge for tape drives */
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if (bp->b_resid || error)
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return (error);
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uio->uio_iov++;
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uio->uio_iovcnt--;
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goto nextiov;
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}
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#define MAXPHYS (63 * 1024) /* don't increase beyond NDMAXIO */
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void
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minphys(bp)
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struct buf *bp;
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{
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if (bp->b_bcount > MAXPHYS)
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bp->b_bcount = MAXPHYS;
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}
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