/* vm_swp.c 4.39 83/01/20 */ #include "../machine/pte.h" #include "../h/param.h" #include "../h/systm.h" #include "../h/dir.h" #include "../h/user.h" #include "../h/buf.h" #include "../h/conf.h" #include "../h/proc.h" #include "../h/seg.h" #include "../h/vm.h" #include "../h/trace.h" #include "../h/uio.h" /* * Swap IO headers - * They contain the necessary information for the swap I/O. * At any given time, a swap header can be in three * different lists. When free it is in the free list, * when allocated and the I/O queued, it is on the swap * device list, and finally, if the operation was a dirty * page push, when the I/O completes, it is inserted * in a list of cleaned pages to be processed by the pageout daemon. */ struct buf *swbuf; short *swsize; /* CAN WE JUST USE B_BCOUNT? */ int *swpf; /* * swap I/O - * * If the flag indicates a dirty page push initiated * by the pageout daemon, we map the page into the i th * virtual page of process 2 (the daemon itself) where i is * the index of the swap header that has been allocated. * We simply initialize the header and queue the I/O but * do not wait for completion. When the I/O completes, * iodone() will link the header to a list of cleaned * pages to be processed by the pageout daemon. */ swap(p, dblkno, addr, nbytes, rdflg, flag, dev, pfcent) struct proc *p; swblk_t dblkno; caddr_t addr; int nbytes, rdflg, flag; dev_t dev; u_int pfcent; { register struct buf *bp; register u_int c; int p2dp; register struct pte *dpte, *vpte; int s; s = spl6(); while (bswlist.av_forw == NULL) { bswlist.b_flags |= B_WANTED; sleep((caddr_t)&bswlist, PSWP+1); } bp = bswlist.av_forw; bswlist.av_forw = bp->av_forw; splx(s); bp->b_flags = B_BUSY | B_PHYS | rdflg | flag; if ((bp->b_flags & (B_DIRTY|B_PGIN)) == 0) if (rdflg == B_READ) sum.v_pswpin += btoc(nbytes); else sum.v_pswpout += btoc(nbytes); bp->b_proc = p; if (flag & B_DIRTY) { p2dp = ((bp - swbuf) * CLSIZE) * KLMAX; dpte = dptopte(&proc[2], p2dp); vpte = vtopte(p, btop(addr)); for (c = 0; c < nbytes; c += NBPG) { if (vpte->pg_pfnum == 0 || vpte->pg_fod) panic("swap bad pte"); *dpte++ = *vpte++; } bp->b_un.b_addr = (caddr_t)ctob(p2dp); } else bp->b_un.b_addr = addr; while (nbytes > 0) { bp->b_bcount = nbytes; minphys(bp); c = bp->b_bcount; bp->b_blkno = dblkno; bp->b_dev = dev; if (flag & B_DIRTY) { swpf[bp - swbuf] = pfcent; swsize[bp - swbuf] = nbytes; } #ifdef TRACE trace(TR_SWAPIO, dev, bp->b_blkno); #endif physstrat(bp, bdevsw[major(dev)].d_strategy, PSWP); if (flag & B_DIRTY) { if (c < nbytes) panic("big push"); return; } bp->b_un.b_addr += c; bp->b_flags &= ~B_DONE; if (bp->b_flags & B_ERROR) { if ((flag & (B_UAREA|B_PAGET)) || rdflg == B_WRITE) panic("hard IO err in swap"); swkill(p, (char *)0); } nbytes -= c; dblkno += c / DEV_BSIZE; } s = spl6(); bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY); bp->av_forw = bswlist.av_forw; bswlist.av_forw = bp; if (bswlist.b_flags & B_WANTED) { bswlist.b_flags &= ~B_WANTED; wakeup((caddr_t)&bswlist); wakeup((caddr_t)&proc[2]); } splx(s); } /* * If rout == 0 then killed on swap error, else * rout is the name of the routine where we ran out of * swap space. */ swkill(p, rout) struct proc *p; char *rout; { char *mesg; printf("pid %d: ", p->p_pid); if (rout) printf(mesg = "killed due to no swap space\n"); else printf(mesg = "killed on swap error\n"); uprintf("sorry, pid %d was %s", p->p_pid, mesg); /* * To be sure no looping (e.g. in vmsched trying to * swap out) mark process locked in core (as though * done by user) after killing it so noone will try * to swap it out. */ psignal(p, SIGKILL); p->p_flag |= SULOCK; } /* * Raw I/O. The arguments are * The strategy routine for the device * A buffer, which will always be a special buffer * header owned exclusively by the device for this purpose * The device number * Read/write flag * Essentially all the work is computing physical addresses and * validating them. * If the user has the proper access privilidges, the process is * marked 'delayed unlock' and the pages involved in the I/O are * faulted and locked. After the completion of the I/O, the above pages * are unlocked. */ physio(strat, bp, dev, rw, mincnt, uio) int (*strat)(); register struct buf *bp; dev_t dev; int rw; unsigned (*mincnt)(); struct uio *uio; { register struct iovec *iov = uio->uio_iov; register int c; char *a; int s, error = 0; nextiov: if (uio->uio_iovcnt == 0) return (0); if (useracc(iov->iov_base,(u_int)iov->iov_len,rw==B_READ?B_WRITE:B_READ) == NULL) return (EFAULT); s = spl6(); while (bp->b_flags&B_BUSY) { bp->b_flags |= B_WANTED; sleep((caddr_t)bp, PRIBIO+1); } splx(s); bp->b_error = 0; bp->b_proc = u.u_procp; bp->b_un.b_addr = iov->iov_base; while (iov->iov_len > 0) { bp->b_flags = B_BUSY | B_PHYS | rw; bp->b_dev = dev; bp->b_blkno = uio->uio_offset / DEV_BSIZE; bp->b_bcount = iov->iov_len; (*mincnt)(bp); c = bp->b_bcount; u.u_procp->p_flag |= SPHYSIO; vslock(a = bp->b_un.b_addr, c); physstrat(bp, strat, PRIBIO); (void) spl6(); vsunlock(a, c, rw); u.u_procp->p_flag &= ~SPHYSIO; if (bp->b_flags&B_WANTED) wakeup((caddr_t)bp); splx(s); c -= bp->b_resid; bp->b_un.b_addr += c; iov->iov_len -= c; uio->uio_resid -= c; uio->uio_offset += c; /* temp kludge for tape drives */ if (bp->b_resid || (bp->b_flags&B_ERROR)) break; } bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS); error = geterror(bp); /* temp kludge for tape drives */ if (bp->b_resid || error) return (error); uio->uio_iov++; uio->uio_iovcnt--; goto nextiov; } #define MAXPHYS (63 * 1024) /* network disk brain damage */ #include "nd.h" #if NND > 0 #undef MAXPHYS #define MAXPHYS (32 * 1024) #endif unsigned minphys(bp) struct buf *bp; { if (bp->b_bcount > MAXPHYS) bp->b_bcount = MAXPHYS; }