5 files changed, 52 insertions(+), 9 deletions(-)

M port/error.h
M port/fault.c
M port/portfns.h
M port/segment.c
M port/swap.c

@@ 46,6 46,7 @@ extern char Enetunreach[];	/* network unreachable */
 extern char Eintr[];		/* interrupted */
 extern char Eneedservice[];	/* service required for tcp/udp/il calls */
 extern char Enomem[];		/* kernel allocate failed */
+extern char Enoswap[];		/* swap space full */
 extern char Esfnotcached[];	/* subfont not cached */
 extern char Esoverlap[];	/* segments overlap */
 extern char Emouseset[];	/* mouse type already set */

@@ 38,13 38,13 @@ fault(ulong addr, int read)
 }
 
 static void
-faulterror(char *s)
+faulterror(char *s, int freemem)
 {
 	if(up->nerrlab) {
 		postnote(up, 1, s, NDebug);
 		error(s);
 	}
-	pexit(s, 0);
+	pexit(s, freemem);
 }
 
 int


@@ 125,6 125,13 @@ fixfault(Segment *s, ulong addr, int read, int doputmmu)
 			ref = lkp->ref;
 		if(ref > 1) {
 			unlock(lkp);
+
+			if(swapfull()){
+				qunlock(&s->lk);
+				pprint("swap space full\n");
+				faulterror(Enoswap, 1);
+			}
+
 			new = newpage(0, &s, addr);
 			if(s == 0)
 				return -1;


@@ 134,7 141,7 @@ fixfault(Segment *s, ulong addr, int read, int doputmmu)
 		}
 		else {
 			/* save a copy of the original for the image cache */
-			if(lkp->image)
+			if(lkp->image && !swapfull())
 				duppage(lkp);
 
 			unlock(lkp);


@@ 214,7 221,7 @@ retry:
 				continue;
 			kunmap(k);
 			putpage(new);
-			faulterror("sys: demand load I/O error");
+			faulterror("sys: demand load I/O error", 0);
 		}
 
 		ask = s->flen-soff;


@@ 223,7 230,7 @@ retry:
 
 		n = devtab[c->type]->read(c, kaddr, ask, daddr);
 		if(n != ask)
-			faulterror(Eioload);
+			faulterror(Eioload, 0);
 		if(ask < BY2PG)
 			memset(kaddr+ask, 0, BY2PG-ask);
 


@@ 250,12 257,12 @@ retry:
 			putpage(new);
 			qlock(&s->lk);
 			qunlock(&s->lk);
-			faulterror("sys: page in I/O error");
+			faulterror("sys: page in I/O error", 0);
 		}
 
 		n = devtab[c->type]->read(c, kaddr, BY2PG, daddr);
 		if(n != BY2PG)
-			faulterror(Eioload);
+			faulterror(Eioload, 0);
 
 		poperror();
 		kunmap(k);

@@ 295,6 295,7 @@ void		splx(int);
 void		splxpc(int);
 void		srvrecover(Chan*, Chan*);
 int		swapcount(ulong);
+int		swapfull(void);
 void		swapinit(void);
 Block*		trimblock(Block*, int, int);
 void		tsleep(Rendez*, int (*)(void*), void*, int);

@@ 53,6 53,9 @@ newseg(int type, ulong base, ulong size)
 	if(size > (SEGMAPSIZE*PTEPERTAB))
 		error(Enovmem);
 
+	if(swapfull())
+		error(Enoswap);
+
 	s = smalloc(sizeof(Segment));
 	s->ref = 1;
 	s->type = type;


@@ 157,7 160,12 @@ dupseg(Segment **seg, int segno, int share)
 
 	case SG_STACK:
 		qlock(&s->lk);
+		if(waserror()){
+			qunlock(&s->lk);
+			nexterror();
+		}
 		n = newseg(s->type, s->base, s->size);
+		poperror();
 		break;
 
 	case SG_BSS:		/* Just copy on write */


@@ 169,7 177,12 @@ dupseg(Segment **seg, int segno, int share)
 			qunlock(&s->lk);
 			return s;
 		}
+		if(waserror()){
+			qunlock(&s->lk);
+			nexterror();
+		}
 		n = newseg(s->type, s->base, s->size);
+		poperror();
 		break;
 
 	case SG_DATA:		/* Copy on write plus demand load info */


@@ 183,7 196,12 @@ dupseg(Segment **seg, int segno, int share)
 			qunlock(&s->lk);
 			return s;
 		}
+		if(waserror()){
+			qunlock(&s->lk);
+			nexterror();
+		}
 		n = newseg(s->type, s->base, s->size);
+		poperror();
 
 		incref(s->image);
 		n->image = s->image;


@@ 438,6 456,11 @@ ibrk(ulong addr, int seg)
 		return 0;
 	}
 
+	if(swapfull()){
+		qunlock(&s->lk);
+		error(Enoswap);
+	}
+
 	for(i = 0; i < NSEG; i++) {
 		ns = up->seg[i];
 		if(ns == 0 || ns == s)

@@ 38,8 38,11 @@ newswap(void)
 	uchar *look;
 
 	lock(&swapalloc);
-	if(swapalloc.free == 0)
-		panic("out of swap space");
+
+	if(swapalloc.free == 0){
+		unlock(&swapalloc);
+		return ~0;
+	}
 
 	look = memchr(swapalloc.last, 0, swapalloc.top-swapalloc.last);
 	if(look == 0)


@@ 285,6 288,8 @@ pagepte(int type, Page **pg)
 		 *  referring to it from the cache
 		 */
 		daddr = newswap();
+		if(daddr == ~0)
+			break;
 		cachedel(&swapimage, daddr);
 
 		lock(outp);


@@ 396,3 401,9 @@ setswapchan(Chan *c)
 
 	swapimage.c = c;
 }
+
+int
+swapfull(void)
+{
+	return swapalloc.free < conf.nswap/10;
+}