Import M_CANFAIL support from NetBSD, removes a nasty panic during low-mem scenarios, instead generating an ENOMEM backfeed, ok tedu@, prodded by many

7 files changed, 61 insertions, 32 deletions

diff --git a/sys/kern/kern_malloc.c b/sys/kern/kern_malloc.c
index 65a4d81848b..c4825e43e88 100644
--- a/sys/kern/kern_malloc.c
+++ b/sys/kern/kern_malloc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_malloc.c,v 1.58 2004/05/23 19:41:23 tedu Exp $	*/
+/*	$OpenBSD: kern_malloc.c,v 1.59 2004/12/30 08:28:39 niklas Exp $	*/
 /*	$NetBSD: kern_malloc.c,v 1.15.4.2 1996/06/13 17:10:56 cgd Exp $	*/
 
 /*
@@ -179,8 +179,9 @@ malloc(size, type, flags)
 			allocsize = 1 << indx;
 		npg = btoc(allocsize);
 		va = (caddr_t) uvm_km_kmemalloc(kmem_map, uvmexp.kmem_object,
-				(vsize_t)ctob(npg), 
-				(flags & M_NOWAIT) ? UVM_KMF_NOWAIT : 0);
+		    (vsize_t)ctob(npg), 
+		    ((flags & M_NOWAIT) ? UVM_KMF_NOWAIT : 0) |
+		    ((flags & M_CANFAIL) ? UVM_KMF_CANFAIL : 0));
 		if (va == NULL) {
 			/*
 			 * Kmem_malloc() can return NULL, even if it can
@@ -190,10 +191,10 @@ malloc(size, type, flags)
 			 * are completely free and which are in buckets
 			 * with too many free elements.)
 			 */
-			if ((flags & M_NOWAIT) == 0)
+			if ((flags & (M_NOWAIT|M_CANFAIL)) == 0)
 				panic("malloc: out of space in kmem_map");
 			splx(s);
-			return ((void *) NULL);
+			return (NULL);
 		}
 #ifdef KMEMSTATS
 		kbp->kb_total += kbp->kb_elmpercl;
diff --git a/sys/sys/malloc.h b/sys/sys/malloc.h
index 89faaec8189..81f7e64c65f 100644
--- a/sys/sys/malloc.h
+++ b/sys/sys/malloc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: malloc.h,v 1.73 2004/07/21 17:30:56 marius Exp $	*/
+/*	$OpenBSD: malloc.h,v 1.74 2004/12/30 08:28:39 niklas Exp $	*/
 /*	$NetBSD: malloc.h,v 1.39 1998/07/12 19:52:01 augustss Exp $	*/
 
 /*
@@ -54,6 +54,7 @@
  */
 #define	M_WAITOK	0x0000
 #define	M_NOWAIT	0x0001
+#define M_CANFAIL	0x0002
 
 /*
  * Types of memory to be allocated
diff --git a/sys/uvm/uvm_amap.c b/sys/uvm/uvm_amap.c
index 967d984823e..5fb4a2bade1 100644
--- a/sys/uvm/uvm_amap.c
+++ b/sys/uvm/uvm_amap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_amap.c,v 1.27 2002/05/09 14:14:18 provos Exp $	*/
+/*	$OpenBSD: uvm_amap.c,v 1.28 2004/12/30 08:28:39 niklas Exp $	*/
 /*	$NetBSD: uvm_amap.c,v 1.27 2000/11/25 06:27:59 chs Exp $	*/
 
 /*
@@ -279,10 +279,9 @@ amap_free(amap)
  * => amap should be unlocked (we will lock it)
  * => to safely extend an amap it should have a reference count of
  *    one (thus it can't be shared)
- * => XXXCDC: needs a waitflag or failure return value?
  * => XXXCDC: support padding at this level?
  */
-void
+int
 amap_extend(entry, addsize)
 	vm_map_entry_t entry;
 	vsize_t addsize;
@@ -307,7 +306,6 @@ amap_extend(entry, addsize)
 	 */
 
 	amap_lock(amap);					/* lock! */
-
 	AMAP_B2SLOT(slotmapped, entry->end - entry->start); /* slots mapped */
 	AMAP_B2SLOT(slotadd, addsize);			/* slots to add */
 	slotneed = slotoff + slotmapped + slotadd;
@@ -327,13 +325,14 @@ amap_extend(entry, addsize)
 		amap_unlock(amap);
 		UVMHIST_LOG(maphist,"<- done (case 1), amap = 0x%x, sltneed=%d", 
 		    amap, slotneed, 0, 0);
-		return;				/* done! */
+		return (0);
 	}
 
 	/*
 	 * case 2: we pre-allocated slots for use and we just need to
 	 * bump nslot up to take account for these slots.
 	 */
+
 	if (amap->am_maxslot >= slotneed) {
 #ifdef UVM_AMAP_PPREF
 		if (amap->am_ppref && amap->am_ppref != PPREF_NONE) {
@@ -347,13 +346,14 @@ amap_extend(entry, addsize)
 #endif
 		amap->am_nslot = slotneed;
 		amap_unlock(amap);
+
 		/*
 		 * no need to zero am_anon since that was done at
 		 * alloc time and we never shrink an allocation.
 		 */
-		UVMHIST_LOG(maphist,"<- done (case 2), amap = 0x%x, slotneed=%d", 
-		    amap, slotneed, 0, 0);
-		return;
+		UVMHIST_LOG(maphist,"<- done (case 2), amap = 0x%x, "
+		    "slotneed=%d", amap, slotneed, 0, 0);
+		return (0);
 	}
 
 	/*
@@ -368,7 +368,8 @@ amap_extend(entry, addsize)
 #ifdef UVM_AMAP_PPREF
 	newppref = NULL;
 	if (amap->am_ppref && amap->am_ppref != PPREF_NONE) {
-		newppref = malloc(slotalloc *sizeof(int), M_UVMAMAP, M_NOWAIT);
+		newppref = malloc(slotalloc *sizeof(int), M_UVMAMAP,
+		    M_WAITOK | M_CANFAIL);
 		if (newppref == NULL) {
 			/* give up if malloc fails */
 			free(amap->am_ppref, M_UVMAMAP);
@@ -376,10 +377,24 @@ amap_extend(entry, addsize)
 		}
 	}
 #endif
-	newsl = malloc(slotalloc * sizeof(int), M_UVMAMAP, M_WAITOK);
-	newbck = malloc(slotalloc * sizeof(int), M_UVMAMAP, M_WAITOK);
-	newover = malloc(slotalloc * sizeof(struct vm_anon *),
-	    M_UVMAMAP, M_WAITOK);
+	newsl = malloc(slotalloc * sizeof(int), M_UVMAMAP,
+	    M_WAITOK | M_CANFAIL);
+	newbck = malloc(slotalloc * sizeof(int), M_UVMAMAP,
+	    M_WAITOK | M_CANFAIL);
+	newover = malloc(slotalloc * sizeof(struct vm_anon *), M_UVMAMAP,
+	    M_WAITOK | M_CANFAIL);
+	if (newsl == NULL || newbck == NULL || newover == NULL) {
+		if (newsl != NULL) {
+			free(newsl, M_UVMAMAP);
+		}
+		if (newbck != NULL) {
+			free(newbck, M_UVMAMAP);
+		}
+		if (newover != NULL) {
+			free(newover, M_UVMAMAP);
+		}
+		return (ENOMEM);
+	}
 	amap_lock(amap);			/* re-lock! */
 	KASSERT(amap->am_maxslot < slotneed);
 
@@ -397,7 +412,8 @@ amap_extend(entry, addsize)
 	/* do am_anon */
 	oldover = amap->am_anon;
 	memcpy(newover, oldover, sizeof(struct vm_anon *) * amap->am_nslot);
-	memset(newover + amap->am_nslot, 0, sizeof(struct vm_anon *) * slotadded);
+	memset(newover + amap->am_nslot, 0, sizeof(struct vm_anon *) *
+	    slotadded);
 	amap->am_anon = newover;
 
 	/* do am_bckptr */
@@ -438,6 +454,7 @@ amap_extend(entry, addsize)
 #endif
 	UVMHIST_LOG(maphist,"<- done (case 3), amap = 0x%x, slotneed=%d", 
 	    amap, slotneed, 0, 0);
+	return (0);
 }
 
 /*
diff --git a/sys/uvm/uvm_amap.h b/sys/uvm/uvm_amap.h
index 1c7c2193b4a..79acf9c4ccb 100644
--- a/sys/uvm/uvm_amap.h
+++ b/sys/uvm/uvm_amap.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_amap.h,v 1.12 2002/03/15 01:20:04 millert Exp $	*/
+/*	$OpenBSD: uvm_amap.h,v 1.13 2004/12/30 08:28:39 niklas Exp $	*/
 /*	$NetBSD: uvm_amap.h,v 1.14 2001/02/18 21:19:08 chs Exp $	*/
 
 /*
@@ -91,7 +91,7 @@ void		amap_copy(vm_map_t, vm_map_entry_t, int, boolean_t, vaddr_t,
 					/* resolve all COW faults now */
 void		amap_cow_now(vm_map_t, vm_map_entry_t);
 					/* make amap larger */
-void		amap_extend(vm_map_entry_t, vsize_t);
+int		amap_extend(vm_map_entry_t, vsize_t);
 					/* get amap's flags */
 int		amap_flags(struct vm_amap *);
 					/* free amap */
diff --git a/sys/uvm/uvm_extern.h b/sys/uvm/uvm_extern.h
index 3efb087c537..91431f49141 100644
--- a/sys/uvm/uvm_extern.h
+++ b/sys/uvm/uvm_extern.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_extern.h,v 1.53 2004/05/27 04:55:28 tedu Exp $	*/
+/*	$OpenBSD: uvm_extern.h,v 1.54 2004/12/30 08:28:39 niklas Exp $	*/
 /*	$NetBSD: uvm_extern.h,v 1.57 2001/03/09 01:02:12 chs Exp $	*/
 
 /*
@@ -203,6 +203,7 @@ typedef int		vm_prot_t;
  */
 #define UVM_KMF_NOWAIT	0x1			/* matches M_NOWAIT */
 #define UVM_KMF_VALLOC	0x2			/* allocate VA only */
+#define UVM_KMF_CANFAIL	0x4			/* caller handles failure */
 #define UVM_KMF_TRYLOCK	UVM_FLAG_TRYLOCK	/* try locking only */
 
 /*
diff --git a/sys/uvm/uvm_km.c b/sys/uvm/uvm_km.c
index 69d36e16eae..e34f1b4161c 100644
--- a/sys/uvm/uvm_km.c
+++ b/sys/uvm/uvm_km.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_km.c,v 1.44 2004/08/24 07:16:12 tedu Exp $	*/
+/*	$OpenBSD: uvm_km.c,v 1.45 2004/12/30 08:28:39 niklas Exp $	*/
 /*	$NetBSD: uvm_km.c,v 1.42 2001/01/14 02:10:01 thorpej Exp $	*/
 
 /* 
@@ -537,10 +537,12 @@ uvm_km_kmemalloc(map, obj, size, flags)
 		 */
 
 		if (__predict_false(pg == NULL)) {
-			if (flags & UVM_KMF_NOWAIT) {
+			if ((flags & UVM_KMF_NOWAIT) ||
+			    ((flags & UVM_KMF_CANFAIL) &&
+			    uvmexp.swpgonly == uvmexp.swpages)) {
 				/* free everything! */
 				uvm_unmap(map, kva, kva + size);
-				return(0);
+				return (0);
 			} else {
 				uvm_wait("km_getwait2");	/* sleep here */
 				continue;
diff --git a/sys/uvm/uvm_map.c b/sys/uvm/uvm_map.c
index 4fbaa4dee79..94e8b0918a2 100644
--- a/sys/uvm/uvm_map.c
+++ b/sys/uvm/uvm_map.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_map.c,v 1.69 2004/08/06 22:39:14 deraadt Exp $	*/
+/*	$OpenBSD: uvm_map.c,v 1.70 2004/12/30 08:28:39 niklas Exp $	*/
 /*	$NetBSD: uvm_map.c,v 1.86 2000/11/27 08:40:03 chs Exp $	*/
 
 /* 
@@ -709,6 +709,7 @@ uvm_map(map, startp, size, uobj, uoffset, align, flags)
 	    UVM_MAXPROTECTION(flags);
 	vm_inherit_t inherit = UVM_INHERIT(flags);
 	int advice = UVM_ADVICE(flags);
+	int error;
 	UVMHIST_FUNC("uvm_map");
 	UVMHIST_CALLED(maphist);
 
@@ -823,7 +824,16 @@ uvm_map(map, startp, size, uobj, uoffset, align, flags)
 			goto step3;
 		}
 
-		/* got it! */
+		if (prev_entry->aref.ar_amap) {
+			error = amap_extend(prev_entry, size);
+			if (error) {
+				vm_map_unlock(map);
+				if (new_entry) {
+					uvm_mapent_free(new_entry);
+				}
+				return (error);
+			}
+		}
 
 		UVMCNT_INCR(map_backmerge);
 		UVMHIST_LOG(maphist,"  starting back merge", 0, 0, 0, 0);
@@ -832,13 +842,10 @@ uvm_map(map, startp, size, uobj, uoffset, align, flags)
 		 * drop our reference to uobj since we are extending a reference
 		 * that we already have (the ref count can not drop to zero).
 		 */
+
 		if (uobj && uobj->pgops->pgo_detach)
 			uobj->pgops->pgo_detach(uobj);
 
-		if (prev_entry->aref.ar_amap) {
-			amap_extend(prev_entry, size);
-		}
-
 		prev_entry->end += size;
 		uvm_rb_fixup(map, prev_entry);
 		map->size += size;