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_drum.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 "proc.h"
  16: #include "buf.h"
  17: #include "text.h"
  18: #include "map.h"
  19: #include "vm.h"
  20: #include "cmap.h"
  21: #include "kernel.h"
  22: 
  23: /*
  24:  * Expand the swap area for both the data and stack segments.
  25:  * If space is not available for both, retract and return 0.
  26:  */
  27: swpexpand(ds, ss, dmp, smp)
  28:     size_t ds, ss;
  29:     register struct dmap *dmp, *smp;
  30: {
  31:     register struct dmap *tmp;
  32:     register int ts;
  33:     size_t ods;
  34: 
  35:     /*
  36: 	 * If dmap isn't growing, do smap first.
  37: 	 * This avoids anomalies if smap will try to grow and
  38: 	 * fail, which otherwise would shrink ds without expanding
  39: 	 * ss, a rather curious side effect!
  40: 	 */
  41:     if (dmp->dm_alloc > ds) {
  42:         tmp = dmp; ts = ds;
  43:         dmp = smp; ds = ss;
  44:         smp = tmp; ss = ts;
  45:     }
  46:     ods = dmp->dm_size;
  47:     if (vsexpand(ds, dmp, 0) == 0)
  48:         goto bad;
  49:     if (vsexpand(ss, smp, 0) == 0) {
  50:         (void) vsexpand(ods, dmp, 1);
  51:         goto bad;
  52:     }
  53:     return (1);
  54: 
  55: bad:
  56:     u.u_error = ENOMEM;
  57:     return (0);
  58: }
  59: 
  60: /*
  61:  * Expand or contract the virtual swap segment mapped
  62:  * by the argument diskmap so as to just allow the given size.
  63:  *
  64:  * FOR NOW CANT RELEASE UNLESS SHRINKING TO ZERO, SINCE PAGEOUTS MAY
  65:  * BE IN PROGRESS... TYPICALLY NEVER SHRINK ANYWAYS, SO DOESNT MATTER MUCH
  66:  */
  67: vsexpand(vssize, dmp, canshrink)
  68:     register size_t vssize;
  69:     register struct dmap *dmp;
  70: {
  71:     register long blk = dmmin;
  72:     register int vsbase = 0;
  73:     register swblk_t *ip = dmp->dm_map;
  74:     size_t oldsize = dmp->dm_size;
  75:     size_t oldalloc = dmp->dm_alloc;
  76: 
  77:     vssize = ctod(vssize);
  78:     while (vsbase < oldalloc || vsbase < vssize) {
  79:         if (ip - dmp->dm_map >= NDMAP)
  80:             panic("vmdrum NDMAP");
  81:         if (vsbase >= oldalloc) {
  82:             *ip = rmalloc(swapmap, blk);
  83:             if (*ip == 0) {
  84:                 dmp->dm_size = vsbase;
  85:                 if (vsexpand(dtoc(oldsize), dmp, 1) == 0)
  86:                     panic("vsexpand");
  87:                 return (0);
  88:             }
  89:             dmp->dm_alloc += blk;
  90:         } else if (vssize == 0 ||
  91:             vsbase >= vssize && canshrink) {
  92:             rmfree(swapmap, blk, *ip);
  93:             *ip = 0;
  94:             dmp->dm_alloc -= blk;
  95:         }
  96:         vsbase += blk;
  97:         if (blk < dmmax)
  98:             blk *= 2;
  99:         ip++;
 100:     }
 101:     dmp->dm_size = vssize;
 102:     return (1);
 103: }
 104: 
 105: /*
 106:  * Allocate swap space for a text segment,
 107:  * in chunks of at most dmtext pages.
 108:  */
 109: vsxalloc(xp)
 110:     struct text *xp;
 111: {
 112:     register long blk;
 113:     register swblk_t *dp;
 114:     swblk_t vsbase;
 115: 
 116:     if (ctod(xp->x_size) > NXDAD * dmtext)
 117:         return (0);
 118:     dp = xp->x_daddr;
 119:     for (vsbase = 0; vsbase < ctod(xp->x_size); vsbase += dmtext) {
 120:         blk = ctod(xp->x_size) - vsbase;
 121:         if (blk > dmtext)
 122:             blk = dmtext;
 123:         if ((*dp++ = rmalloc(swapmap, blk)) == 0) {
 124:             vsxfree(xp, vsbase);
 125:             return (0);
 126:         }
 127:     }
 128:     if (xp->x_flag & XPAGI) {
 129:         xp->x_ptdaddr =
 130:             rmalloc(swapmap, (long)ctod(clrnd(ctopt(xp->x_size))));
 131:         if (xp->x_ptdaddr == 0) {
 132:             vsxfree(xp, (long)xp->x_size);
 133:             return (0);
 134:         }
 135:     }
 136:     return (1);
 137: }
 138: 
 139: /*
 140:  * Free the swap space of a text segment which
 141:  * has been allocated ts pages.
 142:  */
 143: vsxfree(xp, ts)
 144:     struct text *xp;
 145:     long ts;
 146: {
 147:     register long blk;
 148:     register swblk_t *dp;
 149:     swblk_t vsbase;
 150: 
 151:     ts = ctod(ts);
 152:     dp = xp->x_daddr;
 153:     for (vsbase = 0; vsbase < ts; vsbase += dmtext) {
 154:         blk = ts - vsbase;
 155:         if (blk > dmtext)
 156:             blk = dmtext;
 157:         rmfree(swapmap, blk, *dp);
 158:         *dp++ = 0;
 159:     }
 160:     if ((xp->x_flag&XPAGI) && xp->x_ptdaddr) {
 161:         rmfree(swapmap, (long)ctod(clrnd(ctopt(xp->x_size))),
 162:             xp->x_ptdaddr);
 163:         xp->x_ptdaddr = 0;
 164:     }
 165: }
 166: 
 167: /*
 168:  * Swap a segment of virtual memory to disk,
 169:  * by locating the contiguous dirty pte's
 170:  * and calling vschunk with each chunk.
 171:  * We ignore swap errors here because swap()
 172:  * will panic on an error when writing to disk.
 173:  */
 174: vsswap(p, pte, type, vsbase, vscount, dmp)
 175:     struct proc *p;
 176:     register struct pte *pte;
 177:     int type;
 178:     register int vsbase, vscount;
 179:     struct dmap *dmp;
 180: {
 181:     register int size = 0;
 182:     register struct cmap *c;
 183: 
 184:     if (vscount % CLSIZE)
 185:         panic("vsswap");
 186:     for (;;) {
 187:         if (vscount == 0 || !dirtycl(pte)) {
 188:             if (size) {
 189:                 vschunk(p, vsbase, size, type, dmp);
 190:                 vsbase += size;
 191:                 size = 0;
 192:             }
 193:             if (vscount == 0)
 194:                 return;
 195:             vsbase += CLSIZE;
 196:             if (pte->pg_fod == 0 && pte->pg_pfnum)
 197:                 if (type == CTEXT)
 198:                     p->p_textp->x_rssize -= vmemfree(pte, CLSIZE);
 199:                 else
 200:                     p->p_rssize -= vmemfree(pte, CLSIZE);
 201:         } else {
 202:             size += CLSIZE;
 203:             c = &cmap[pgtocm(pte->pg_pfnum)];
 204:             MLOCK(c);
 205:             MUNLOCK(c);
 206:         }
 207:         vscount -= CLSIZE;
 208:         if (type == CSTACK)
 209:             pte -= CLSIZE;
 210:         else
 211:             pte += CLSIZE;
 212:     }
 213: }
 214: 
 215: vschunk(p, base, size, type, dmp)
 216:     register struct proc *p;
 217:     register int base, size;
 218:     int type;
 219:     struct dmap *dmp;
 220: {
 221:     register struct pte *pte;
 222:     struct dblock db;
 223:     unsigned v;
 224: 
 225:     base = ctod(base);
 226:     size = ctod(size);
 227:     if (type == CTEXT) {
 228:         while (size > 0) {
 229:             db.db_size = dmtext - base % dmtext;
 230:             if (db.db_size > size)
 231:                 db.db_size = size;
 232:             (void)swap(p,
 233:                 p->p_textp->x_daddr[base/dmtext] + base%dmtext,
 234:                 ptob(tptov(p, dtoc(base))), (int)dtob(db.db_size),
 235:                 B_WRITE, 0, swapdev, 0);
 236:             pte = tptopte(p, dtoc(base));
 237:             p->p_textp->x_rssize -=
 238:                 vmemfree(pte, (int)dtoc(db.db_size));
 239:             base += db.db_size;
 240:             size -= db.db_size;
 241:         }
 242:         return;
 243:     }
 244:     do {
 245:         vstodb(base, size, dmp, &db, type == CSTACK);
 246:         v = type==CSTACK ?
 247:             sptov(p, dtoc(base+db.db_size)-1) :
 248:             dptov(p, dtoc(base));
 249:         (void)swap(p, db.db_base, ptob(v), (int)dtob(db.db_size),
 250:             B_WRITE, 0, swapdev, 0);
 251:         pte = type==CSTACK ?
 252:             sptopte(p, dtoc(base+db.db_size)-1) :
 253:             dptopte(p, dtoc(base));
 254:         p->p_rssize -= vmemfree(pte, (int)dtoc(db.db_size));
 255:         base += db.db_size;
 256:         size -= db.db_size;
 257:     } while (size != 0);
 258: }
 259: 
 260: /*
 261:  * Given a base/size pair in virtual swap area,
 262:  * return a physical base/size pair which is the
 263:  * (largest) initial, physically contiguous block.
 264:  */
 265: vstodb(vsbase, vssize, dmp, dbp, rev)
 266:     register int vsbase, vssize;
 267:     struct dmap *dmp;
 268:     register struct dblock *dbp;
 269: {
 270:     register int blk = dmmin;
 271:     register swblk_t *ip = dmp->dm_map;
 272: 
 273:     if (vsbase < 0 || vssize < 0 || vsbase + vssize > dmp->dm_size)
 274:         panic("vstodb");
 275:     while (vsbase >= blk) {
 276:         vsbase -= blk;
 277:         if (blk < dmmax)
 278:             blk *= 2;
 279:         ip++;
 280:     }
 281:     if (*ip + blk > nswap)
 282:         panic("vstodb *ip");
 283:     dbp->db_size = imin(vssize, blk - vsbase);
 284:     dbp->db_base = *ip + (rev ? blk - (vsbase + dbp->db_size) : vsbase);
 285: }
 286: 
 287: /*
 288:  * Convert a virtual page number
 289:  * to its corresponding disk block number.
 290:  * Used in pagein/pageout to initiate single page transfers.
 291:  */
 292: swblk_t
 293: vtod(p, v, dmap, smap)
 294:     register struct proc *p;
 295:     unsigned v;
 296:     struct dmap *dmap, *smap;
 297: {
 298:     struct dblock db;
 299:     int tp;
 300: 
 301:     if (isatsv(p, v)) {
 302:         tp = ctod(vtotp(p, v));
 303:         return (p->p_textp->x_daddr[tp/dmtext] + tp%dmtext);
 304:     }
 305:     if (isassv(p, v))
 306:         vstodb(ctod(vtosp(p, v)), ctod(1), smap, &db, 1);
 307:     else
 308:         vstodb(ctod(vtodp(p, v)), ctod(1), dmap, &db, 0);
 309:     return (db.db_base);
 310: }

Defined functions

vschunk defined in line 215; used 1 times
vsexpand defined in line 67; used 8 times
vsswap defined in line 174; used 3 times
vstodb defined in line 265; used 3 times
vsxalloc defined in line 109; used 1 times
vsxfree defined in line 143; used 3 times
vtod defined in line 292; used 8 times
Last modified: 1986-06-05
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