4.3BSD - /usr/src/sys/sys/vm_swp.c

   1: /*
   2:  * Copyright (c) 1982, 1986 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  *
   6:  *	@(#)vm_swp.c	7.1 (Berkeley) 6/5/86
   7:  */
   8: 
   9: #include "../machine/pte.h"
  10: 
  11: #include "param.h"
  12: #include "systm.h"
  13: #include "dir.h"
  14: #include "user.h"
  15: #include "buf.h"
  16: #include "conf.h"
  17: #include "proc.h"
  18: #include "seg.h"
  19: #include "vm.h"
  20: #include "trace.h"
  21: #include "map.h"
  22: #include "uio.h"
  23: 
  24: /*
  25:  * Swap IO headers -
  26:  * They contain the necessary information for the swap I/O.
  27:  * At any given time, a swap header can be in three
  28:  * different lists. When free it is in the free list,
  29:  * when allocated and the I/O queued, it is on the swap
  30:  * device list, and finally, if the operation was a dirty
  31:  * page push, when the I/O completes, it is inserted
  32:  * in a list of cleaned pages to be processed by the pageout daemon.
  33:  */
  34: struct  buf *swbuf;
  35: 
  36: /*
  37:  * swap I/O -
  38:  *
  39:  * If the flag indicates a dirty page push initiated
  40:  * by the pageout daemon, we map the page into the i th
  41:  * virtual page of process 2 (the daemon itself) where i is
  42:  * the index of the swap header that has been allocated.
  43:  * We simply initialize the header and queue the I/O but
  44:  * do not wait for completion. When the I/O completes,
  45:  * iodone() will link the header to a list of cleaned
  46:  * pages to be processed by the pageout daemon.
  47:  */
  48: swap(p, dblkno, addr, nbytes, rdflg, flag, dev, pfcent)
  49:     struct proc *p;
  50:     swblk_t dblkno;
  51:     caddr_t addr;
  52:     int nbytes, rdflg, flag;
  53:     dev_t dev;
  54:     u_int pfcent;
  55: {
  56:     register struct buf *bp;
  57:     register u_int c;
  58:     int p2dp;
  59:     register struct pte *dpte, *vpte;
  60:     int s;
  61:     extern swdone();
  62:     int error = 0;
  63: 
  64:     s = splbio();
  65:     while (bswlist.av_forw == NULL) {
  66:         bswlist.b_flags |= B_WANTED;
  67:         sleep((caddr_t)&bswlist, PSWP+1);
  68:     }
  69:     bp = bswlist.av_forw;
  70:     bswlist.av_forw = bp->av_forw;
  71:     splx(s);
  72: 
  73:     bp->b_flags = B_BUSY | B_PHYS | rdflg | flag;
  74:     if ((bp->b_flags & (B_DIRTY|B_PGIN)) == 0)
  75:         if (rdflg == B_READ)
  76:             sum.v_pswpin += btoc(nbytes);
  77:         else
  78:             sum.v_pswpout += btoc(nbytes);
  79:     bp->b_proc = p;
  80:     if (flag & B_DIRTY) {
  81:         p2dp = ((bp - swbuf) * CLSIZE) * KLMAX;
  82:         dpte = dptopte(&proc[2], p2dp);
  83:         vpte = vtopte(p, btop(addr));
  84:         for (c = 0; c < nbytes; c += NBPG) {
  85:             if (vpte->pg_pfnum == 0 || vpte->pg_fod)
  86:                 panic("swap bad pte");
  87:             *dpte++ = *vpte++;
  88:         }
  89:         bp->b_un.b_addr = (caddr_t)ctob(dptov(&proc[2], p2dp));
  90:         bp->b_flags |= B_CALL;
  91:         bp->b_iodone = swdone;
  92:         bp->b_pfcent = pfcent;
  93:     } else
  94:         bp->b_un.b_addr = addr;
  95:     while (nbytes > 0) {
  96:         bp->b_bcount = nbytes;
  97:         minphys(bp);
  98:         c = bp->b_bcount;
  99:         bp->b_blkno = dblkno;
 100:         bp->b_dev = dev;
 101: #ifdef TRACE
 102:         trace(TR_SWAPIO, dev, bp->b_blkno);
 103: #endif
 104:         physstrat(bp, bdevsw[major(dev)].d_strategy, PSWP);
 105:         if (flag & B_DIRTY) {
 106:             if (c < nbytes)
 107:                 panic("big push");
 108:             return (error);
 109:         }
 110:         bp->b_un.b_addr += c;
 111:         bp->b_flags &= ~B_DONE;
 112:         if (bp->b_flags & B_ERROR) {
 113:             if ((flag & (B_UAREA|B_PAGET)) || rdflg == B_WRITE)
 114:                 panic("hard IO err in swap");
 115:             swkill(p, "swap: read error from swap device");
 116:             error = EIO;
 117:         }
 118:         nbytes -= c;
 119:         dblkno += btodb(c);
 120:     }
 121:     s = splbio();
 122:     bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY);
 123:     bp->av_forw = bswlist.av_forw;
 124:     bswlist.av_forw = bp;
 125:     if (bswlist.b_flags & B_WANTED) {
 126:         bswlist.b_flags &= ~B_WANTED;
 127:         wakeup((caddr_t)&bswlist);
 128:         wakeup((caddr_t)&proc[2]);
 129:     }
 130:     splx(s);
 131:     return (error);
 132: }
 133: 
 134: /*
 135:  * Put a buffer on the clean list after I/O is done.
 136:  * Called from biodone.
 137:  */
 138: swdone(bp)
 139:     register struct buf *bp;
 140: {
 141:     register int s;
 142: 
 143:     if (bp->b_flags & B_ERROR)
 144:         panic("IO err in push");
 145:     s = splbio();
 146:     bp->av_forw = bclnlist;
 147:     cnt.v_pgout++;
 148:     cnt.v_pgpgout += bp->b_bcount / NBPG;
 149:     bclnlist = bp;
 150:     if (bswlist.b_flags & B_WANTED)
 151:         wakeup((caddr_t)&proc[2]);
 152:     splx(s);
 153: }
 154: 
 155: /*
 156:  * If rout == 0 then killed on swap error, else
 157:  * rout is the name of the routine where we ran out of
 158:  * swap space.
 159:  */
 160: swkill(p, rout)
 161:     struct proc *p;
 162:     char *rout;
 163: {
 164: 
 165:     printf("pid %d: %s\n", p->p_pid, rout);
 166:     uprintf("sorry, pid %d was killed in %s\n", p->p_pid, rout);
 167:     /*
 168: 	 * To be sure no looping (e.g. in vmsched trying to
 169: 	 * swap out) mark process locked in core (as though
 170: 	 * done by user) after killing it so noone will try
 171: 	 * to swap it out.
 172: 	 */
 173:     psignal(p, SIGKILL);
 174:     p->p_flag |= SULOCK;
 175: }
 176: 
 177: /*
 178:  * Raw I/O. The arguments are
 179:  *	The strategy routine for the device
 180:  *	A buffer, which will always be a special buffer
 181:  *	  header owned exclusively by the device for this purpose
 182:  *	The device number
 183:  *	Read/write flag
 184:  * Essentially all the work is computing physical addresses and
 185:  * validating them.
 186:  * If the user has the proper access privilidges, the process is
 187:  * marked 'delayed unlock' and the pages involved in the I/O are
 188:  * faulted and locked. After the completion of the I/O, the above pages
 189:  * are unlocked.
 190:  */
 191: physio(strat, bp, dev, rw, mincnt, uio)
 192:     int (*strat)();
 193:     register struct buf *bp;
 194:     dev_t dev;
 195:     int rw;
 196:     unsigned (*mincnt)();
 197:     struct uio *uio;
 198: {
 199:     register struct iovec *iov;
 200:     register int c;
 201:     char *a;
 202:     int s, error = 0;
 203: 
 204: nextiov:
 205:     if (uio->uio_iovcnt == 0)
 206:         return (0);
 207:     iov = uio->uio_iov;
 208:     if (useracc(iov->iov_base,(u_int)iov->iov_len,rw==B_READ?B_WRITE:B_READ) == NULL)
 209:         return (EFAULT);
 210:     s = splbio();
 211:     while (bp->b_flags&B_BUSY) {
 212:         bp->b_flags |= B_WANTED;
 213:         sleep((caddr_t)bp, PRIBIO+1);
 214:     }
 215:     splx(s);
 216:     bp->b_error = 0;
 217:     bp->b_proc = u.u_procp;
 218:     bp->b_un.b_addr = iov->iov_base;
 219:     while (iov->iov_len > 0) {
 220:         bp->b_flags = B_BUSY | B_PHYS | rw;
 221:         bp->b_dev = dev;
 222:         bp->b_blkno = btodb(uio->uio_offset);
 223:         bp->b_bcount = iov->iov_len;
 224:         (*mincnt)(bp);
 225:         c = bp->b_bcount;
 226:         u.u_procp->p_flag |= SPHYSIO;
 227:         vslock(a = bp->b_un.b_addr, c);
 228:         physstrat(bp, strat, PRIBIO);
 229:         (void) splbio();
 230:         vsunlock(a, c, rw);
 231:         u.u_procp->p_flag &= ~SPHYSIO;
 232:         if (bp->b_flags&B_WANTED)
 233:             wakeup((caddr_t)bp);
 234:         splx(s);
 235:         c -= bp->b_resid;
 236:         bp->b_un.b_addr += c;
 237:         iov->iov_len -= c;
 238:         uio->uio_resid -= c;
 239:         uio->uio_offset += c;
 240:         /* temp kludge for tape drives */
 241:         if (bp->b_resid || (bp->b_flags&B_ERROR))
 242:             break;
 243:     }
 244:     bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS);
 245:     error = geterror(bp);
 246:     /* temp kludge for tape drives */
 247:     if (bp->b_resid || error)
 248:         return (error);
 249:     uio->uio_iov++;
 250:     uio->uio_iovcnt--;
 251:     goto nextiov;
 252: }
 253: 
 254: #define MAXPHYS (63 * 1024)
 255: 
 256: unsigned
 257: minphys(bp)
 258:     struct buf *bp;
 259: {
 260: 
 261:     if (bp->b_bcount > MAXPHYS)
 262:         bp->b_bcount = MAXPHYS;
 263: }

Defined functions

Defined variables

Defined macros