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Annotation of 43BSDReno/sys/kern/vm_drum.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1982, 1986, 1989 Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * Redistribution is only permitted until one year after the first shipment
        !             6:  * of 4.4BSD by the Regents.  Otherwise, redistribution and use in source and
        !             7:  * binary forms are permitted provided that: (1) source distributions retain
        !             8:  * this entire copyright notice and comment, and (2) distributions including
        !             9:  * binaries display the following acknowledgement:  This product includes
        !            10:  * software developed by the University of California, Berkeley and its
        !            11:  * contributors'' in the documentation or other materials provided with the
        !            12:  * distribution and in all advertising materials mentioning features or use
        !            13:  * of this software.  Neither the name of the University nor the names of
        !            14:  * its contributors may be used to endorse or promote products derived from
        !            15:  * this software without specific prior written permission.
        !            16:  * THIS SOFTWARE IS PROVIDED AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
        !            17:  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
        !            18:  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            19:  *
        !            20:  *     @(#)vm_drum.c   7.8 (Berkeley) 6/28/90
        !            21:  */
        !            22: 
        !            23: #include "param.h"
        !            24: #include "systm.h"
        !            25: #include "user.h"
        !            26: #include "proc.h"
        !            27: #include "buf.h"
        !            28: #include "text.h"
        !            29: #include "map.h"
        !            30: #include "vm.h"
        !            31: #include "cmap.h"
        !            32: #include "kernel.h"
        !            33: 
        !            34: #include "machine/pte.h"
        !            35: 
        !            36: /*
        !            37:  * Expand the swap area for both the data and stack segments.
        !            38:  * If space is not available for both, retract and return ENOMEM.
        !            39:  */
        !            40: swpexpand(ds, ss, dmp, smp)
        !            41:        segsz_t ds, ss;
        !            42:        register struct dmap *dmp, *smp;
        !            43: {
        !            44:        register struct dmap *tmp;
        !            45:        register int ts;
        !            46:        segsz_t ods;
        !            47: 
        !            48:        /*
        !            49:         * If dmap isn't growing, do smap first.
        !            50:         * This avoids anomalies if smap will try to grow and
        !            51:         * fail, which otherwise would shrink ds without expanding
        !            52:         * ss, a rather curious side effect!
        !            53:         */
        !            54:        if (dmp->dm_alloc > ctod(ds)) {
        !            55:                tmp = dmp; ts = ds;
        !            56:                dmp = smp; ds = ss;
        !            57:                smp = tmp; ss = ts;
        !            58:        }
        !            59:        ods = dtoc(dmp->dm_size);
        !            60:        if (vsexpand(ds, dmp, 0) == 0)
        !            61:                return (ENOMEM);
        !            62:        if (vsexpand(ss, smp, 0) == 0) {
        !            63:                /* flush text cache and try again */
        !            64:                if (xpurge() && vsexpand(ss, smp, 0))
        !            65:                        return (0);
        !            66:                (void) vsexpand(ods, dmp, 1);
        !            67:                return (ENOMEM);
        !            68:        }
        !            69:        return (0);
        !            70: }
        !            71: 
        !            72: /*
        !            73:  * Expand or contract the virtual swap segment mapped
        !            74:  * by the argument diskmap so as to just allow the given size.
        !            75:  *
        !            76:  * FOR NOW CANT RELEASE UNLESS SHRINKING TO ZERO, SINCE PAGEOUTS MAY
        !            77:  * BE IN PROGRESS... TYPICALLY NEVER SHRINK ANYWAYS, SO DOESNT MATTER MUCH
        !            78:  */
        !            79: vsexpand(vssize, dmp, canshrink)
        !            80:        register segsz_t vssize;
        !            81:        register struct dmap *dmp;
        !            82: {
        !            83:        register long blk = dmmin;
        !            84:        register int vsbase = 0;
        !            85:        register swblk_t *ip = dmp->dm_map;
        !            86:        segsz_t oldsize = dmp->dm_size;
        !            87:        segsz_t oldalloc = dmp->dm_alloc;
        !            88: 
        !            89:        vssize = ctod(vssize);
        !            90:        while (vsbase < oldalloc || vsbase < vssize) {
        !            91:                if (ip - dmp->dm_map >= NDMAP)
        !            92:                        panic("vmdrum NDMAP");
        !            93:                if (vsbase >= oldalloc) {
        !            94:                        *ip = rmalloc(swapmap, blk);
        !            95:                        if (*ip == 0) {
        !            96:                                dmp->dm_size = vsbase;
        !            97:                                if (vsexpand(dtoc(oldsize), dmp, 1) == 0)
        !            98:                                        panic("vsexpand");
        !            99:                                return (0);
        !           100:                        }
        !           101:                        dmp->dm_alloc += blk;
        !           102:                } else if (vssize == 0 ||
        !           103:                    vsbase >= vssize && canshrink) {
        !           104:                        rmfree(swapmap, blk, *ip);
        !           105:                        *ip = 0;
        !           106:                        dmp->dm_alloc -= blk;
        !           107:                }
        !           108:                vsbase += blk;
        !           109:                if (blk < dmmax)
        !           110:                        blk *= 2;
        !           111:                ip++;
        !           112:        }
        !           113:        dmp->dm_size = vssize;
        !           114:        return (1);
        !           115: }
        !           116: 
        !           117: /*
        !           118:  * Allocate swap space for a text segment,
        !           119:  * in chunks of at most dmtext pages.
        !           120:  */
        !           121: vsxalloc(xp)
        !           122:        struct text *xp;
        !           123: {
        !           124:        register long blk;
        !           125:        register swblk_t *dp;
        !           126:        swblk_t vsbase;
        !           127: 
        !           128:        if (ctod(xp->x_size) > NXDAD * dmtext)
        !           129:                return (0);
        !           130:        dp = xp->x_daddr;
        !           131:        for (vsbase = 0; vsbase < ctod(xp->x_size); vsbase += dmtext) {
        !           132:                blk = ctod(xp->x_size) - vsbase;
        !           133:                if (blk > dmtext)
        !           134:                        blk = dmtext;
        !           135:                if ((*dp++ = rmalloc(swapmap, blk)) == 0) {
        !           136:                        vsxfree(xp, dtoc(vsbase));
        !           137:                        return (0);
        !           138:                }
        !           139:        }
        !           140:        if (xp->x_flag & XPAGV) {
        !           141:                xp->x_ptdaddr =
        !           142:                    rmalloc(swapmap, (long)ctod(clrnd(ctopt(xp->x_size))));
        !           143:                if (xp->x_ptdaddr == 0) {
        !           144:                        vsxfree(xp, (long)xp->x_size);
        !           145:                        return (0);
        !           146:                }
        !           147:        }
        !           148:        return (1);
        !           149: }
        !           150: 
        !           151: /*
        !           152:  * Free the swap space of a text segment which
        !           153:  * has been allocated ts pages.
        !           154:  */
        !           155: vsxfree(xp, ts)
        !           156:        struct text *xp;
        !           157:        long ts;
        !           158: {
        !           159:        register long blk;
        !           160:        register swblk_t *dp;
        !           161:        swblk_t vsbase;
        !           162: 
        !           163:        ts = ctod(ts);
        !           164:        dp = xp->x_daddr;
        !           165:        for (vsbase = 0; vsbase < ts; vsbase += dmtext) {
        !           166:                blk = ts - vsbase;
        !           167:                if (blk > dmtext)
        !           168:                        blk = dmtext;
        !           169:                rmfree(swapmap, blk, *dp);
        !           170:                *dp++ = 0;
        !           171:        }
        !           172:        if ((xp->x_flag&XPAGV) && xp->x_ptdaddr) {
        !           173:                rmfree(swapmap, (long)ctod(clrnd(ctopt(xp->x_size))),
        !           174:                    xp->x_ptdaddr);
        !           175:                xp->x_ptdaddr = 0;
        !           176:        }
        !           177: }
        !           178: 
        !           179: /*
        !           180:  * Swap a segment of virtual memory to disk,
        !           181:  * by locating the contiguous dirty pte's
        !           182:  * and calling vschunk with each chunk.
        !           183:  * We ignore swap errors here because swap()
        !           184:  * will panic on an error when writing to disk.
        !           185:  */
        !           186: vsswap(p, pte, type, vsbase, vscount, dmp)
        !           187:        struct proc *p;
        !           188:        register struct pte *pte;
        !           189:        int type;
        !           190:        register int vsbase, vscount;
        !           191:        struct dmap *dmp;
        !           192: {
        !           193:        register int size = 0;
        !           194:        register struct cmap *c;
        !           195: 
        !           196:        if (vscount % CLSIZE)
        !           197:                panic("vsswap");
        !           198:        for (;;) {
        !           199:                if (vscount == 0 || pte->pg_fod || pte->pg_pfnum == 0 ||
        !           200:                    !dirtycl(pte)) {
        !           201:                        if (size) {
        !           202:                                vschunk(p, vsbase, size, type, dmp);
        !           203:                                vsbase += size;
        !           204:                                size = 0;
        !           205:                        }
        !           206:                        if (vscount == 0)
        !           207:                                return;
        !           208:                        vsbase += CLSIZE;
        !           209:                        if (pte->pg_fod == 0 && pte->pg_pfnum)
        !           210:                                if (type == CTEXT)
        !           211:                                        p->p_textp->x_rssize -= vmemfree(pte, CLSIZE);
        !           212:                                else
        !           213:                                        p->p_rssize -= vmemfree(pte, CLSIZE);
        !           214:                } else {
        !           215:                        size += CLSIZE;
        !           216:                        c = &cmap[pgtocm(pte->pg_pfnum)];
        !           217:                        MLOCK(c);
        !           218:                        MUNLOCK(c);
        !           219:                }
        !           220:                vscount -= CLSIZE;
        !           221:                if (type == CSTACK)
        !           222:                        pte -= CLSIZE;
        !           223:                else
        !           224:                        pte += CLSIZE;
        !           225:        }
        !           226: }
        !           227: 
        !           228: vschunk(p, base, size, type, dmp)
        !           229:        register struct proc *p;
        !           230:        register int base, size;
        !           231:        int type;
        !           232:        struct dmap *dmp;
        !           233: {
        !           234:        register struct pte *pte;
        !           235:        struct dblock db;
        !           236:        unsigned v;
        !           237: 
        !           238:        base = ctod(base);
        !           239:        size = ctod(size);
        !           240:        if (type == CTEXT) {
        !           241:                while (size > 0) {
        !           242:                        db.db_size = dmtext - base % dmtext;
        !           243:                        if (db.db_size > size)
        !           244:                                db.db_size = size;
        !           245:                        (void)swap(p,
        !           246:                            p->p_textp->x_daddr[base/dmtext] + base%dmtext,
        !           247:                            ptob(tptov(p, dtoc(base))), (int)dtob(db.db_size),
        !           248:                            B_WRITE, 0, swapdev_vp, 0);
        !           249:                        pte = tptopte(p, dtoc(base));
        !           250:                        p->p_textp->x_rssize -=
        !           251:                            vmemfree(pte, (int)dtoc(db.db_size));
        !           252:                        base += db.db_size;
        !           253:                        size -= db.db_size;
        !           254:                }
        !           255:                return;
        !           256:        }
        !           257:        do {
        !           258:                vstodb(base, size, dmp, &db, type == CSTACK);
        !           259:                v = type==CSTACK ?
        !           260:                    sptov(p, dtoc(base+db.db_size)-1) :
        !           261:                    dptov(p, dtoc(base));
        !           262:                (void)swap(p, db.db_base, ptob(v), (int)dtob(db.db_size),
        !           263:                    B_WRITE, 0, swapdev_vp, 0);
        !           264:                pte = type==CSTACK ?
        !           265:                    sptopte(p, dtoc(base+db.db_size)-1) :
        !           266:                    dptopte(p, dtoc(base));
        !           267:                p->p_rssize -= vmemfree(pte, (int)dtoc(db.db_size));
        !           268:                base += db.db_size;
        !           269:                size -= db.db_size;
        !           270:        } while (size != 0);
        !           271: }
        !           272: 
        !           273: /*
        !           274:  * Given a base/size pair in virtual swap area,
        !           275:  * return a physical base/size pair which is the
        !           276:  * (largest) initial, physically contiguous block.
        !           277:  */
        !           278: vstodb(vsbase, vssize, dmp, dbp, rev)
        !           279:        register int vsbase, vssize;
        !           280:        struct dmap *dmp;
        !           281:        register struct dblock *dbp;
        !           282: {
        !           283:        register int blk = dmmin;
        !           284:        register swblk_t *ip = dmp->dm_map;
        !           285: 
        !           286:        if (vsbase < 0 || vssize < 0 || vsbase + vssize > dmp->dm_size)
        !           287:                panic("vstodb");
        !           288:        while (vsbase >= blk) {
        !           289:                vsbase -= blk;
        !           290:                if (blk < dmmax)
        !           291:                        blk *= 2;
        !           292:                ip++;
        !           293:        }
        !           294:        if (*ip + blk > nswap)
        !           295:                panic("vstodb *ip");
        !           296:        dbp->db_size = imin(vssize, blk - vsbase);
        !           297:        dbp->db_base = *ip + (rev ? blk - (vsbase + dbp->db_size) : vsbase);
        !           298: }
        !           299: 
        !           300: /*
        !           301:  * Convert a virtual page number 
        !           302:  * to its corresponding disk block number.
        !           303:  * Used in pagein/pageout to initiate single page transfers.
        !           304:  * An assumption here is that dmmin >= CLBYTES/DEV_BSIZE
        !           305:  * i.e. a page cluster must be stored contiguously in the swap area.
        !           306:  */
        !           307: swblk_t
        !           308: vtod(p, v, dmap, smap)
        !           309:        register struct proc *p;
        !           310:        unsigned v;
        !           311:        struct dmap *dmap, *smap;
        !           312: {
        !           313:        struct dblock db;
        !           314:        int tp;
        !           315: 
        !           316:        if (isatsv(p, v)) {
        !           317:                tp = ctod(vtotp(p, v));
        !           318:                return (p->p_textp->x_daddr[tp/dmtext] + tp%dmtext);
        !           319:        }
        !           320:        if (isassv(p, v))
        !           321:                vstodb(ctod(vtosp(p, v)), ctod(1), smap, &db, 1);
        !           322:        else
        !           323:                vstodb(ctod(vtodp(p, v)), ctod(1), dmap, &db, 0);
        !           324:        return (db.db_base);
        !           325: }

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