amap_extend is never called, remove it.

In the code, this function is called when vm_map_entries are merged.
However, only kernel map entries are merged, and these do not use amaps.
Therefore amap_extend() is never called at runtime.

ok millert@, KASSERT suggestion and ok mpi@

3 files changed, 8 insertions, 178 deletions

diff --git a/sys/uvm/uvm_amap.c b/sys/uvm/uvm_amap.c
index dc1506e74d3..6472c0f4bee 100644
--- a/sys/uvm/uvm_amap.c
+++ b/sys/uvm/uvm_amap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_amap.c,v 1.62 2016/03/16 16:53:43 stefan Exp $	*/
+/*	$OpenBSD: uvm_amap.c,v 1.63 2016/03/27 09:51:37 stefan Exp $	*/
 /*	$NetBSD: uvm_amap.c,v 1.27 2000/11/25 06:27:59 chs Exp $	*/
 
 /*
@@ -279,174 +279,6 @@ amap_free(struct vm_amap *amap)
 }
 
 /*
- * amap_extend: extend the size of an amap (if needed)
- *
- * => called from uvm_map when we want to extend an amap to cover
- *    a new mapping (rather than allocate a new one)
- * => to safely extend an amap it should have a reference count of
- *    one (thus it can't be shared)
- * => XXXCDC: support padding at this level?
- */
-int
-amap_extend(struct vm_map_entry *entry, vsize_t addsize)
-{
-	struct vm_amap *amap = entry->aref.ar_amap;
-	int slotoff = entry->aref.ar_pageoff;
-	int slotmapped, slotadd, slotneed, slotalloc;
-#ifdef UVM_AMAP_PPREF
-	int *newppref, *oldppref;
-#endif
-	u_int *newsl, *newbck, *oldsl, *oldbck;
-	struct vm_anon **newover, **oldover;
-	int slotadded;
-
-	/*
-	 * first, determine how many slots we need in the amap.  don't
-	 * forget that ar_pageoff could be non-zero: this means that
-	 * there are some unused slots before us in the amap.
-	 */
-	AMAP_B2SLOT(slotmapped, entry->end - entry->start); /* slots mapped */
-	AMAP_B2SLOT(slotadd, addsize);			/* slots to add */
-	slotneed = slotoff + slotmapped + slotadd;
-
-	/*
-	 * case 1: we already have enough slots in the map and thus
-	 * only need to bump the reference counts on the slots we are
-	 * adding.
-	 */
-	if (amap->am_nslot >= slotneed) {
-#ifdef UVM_AMAP_PPREF
-		if (amap->am_ppref && amap->am_ppref != PPREF_NONE) {
-			amap_pp_adjref(amap, slotoff + slotmapped, slotadd, 1);
-		}
-#endif
-		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) {
-			if ((slotoff + slotmapped) < amap->am_nslot)
-				amap_pp_adjref(amap, slotoff + slotmapped, 
-				    (amap->am_nslot - (slotoff + slotmapped)),
-				    1);
-			pp_setreflen(amap->am_ppref, amap->am_nslot, 1, 
-			   slotneed - amap->am_nslot);
-		}
-#endif
-		amap->am_nslot = slotneed;
-		/*
-		 * no need to zero am_anon since that was done at
-		 * alloc time and we never shrink an allocation.
-		 */
-		return (0);
-	}
-
-	/*
-	 * case 3: we need to malloc a new amap and copy all the amap
-	 * data over from old amap to the new one.
-	 *
-	 * XXXCDC: could we take advantage of a kernel realloc()?  
-	 */
-	if (slotneed >= UVM_AMAP_LARGE)
-		return E2BIG;
-
-	if (slotneed > UVM_AMAP_CHUNK)
-		slotalloc = malloc_roundup(slotneed * MALLOC_SLOT_UNIT) /
-		    MALLOC_SLOT_UNIT;
-	else
-		slotalloc = slotneed;
-
-#ifdef UVM_AMAP_PPREF
-	newppref = NULL;
-	if (amap->am_ppref && amap->am_ppref != PPREF_NONE) {
-		newppref = mallocarray(slotalloc, sizeof(int), M_UVMAMAP,
-		    M_WAITOK | M_CANFAIL);
-		if (newppref == NULL) {
-			/* give up if malloc fails */
-			free(amap->am_ppref, M_UVMAMAP, 0);
-			amap->am_ppref = PPREF_NONE;
-		}
-	}
-#endif
-	if (slotneed > UVM_AMAP_CHUNK)
-		newsl = malloc(slotalloc * MALLOC_SLOT_UNIT, M_UVMAMAP,
-		    M_WAITOK | M_CANFAIL);
-	else
-		newsl = pool_get(&uvm_amap_slot_pools[slotalloc - 1],
-		    PR_WAITOK | PR_LIMITFAIL);
-	if (newsl == NULL) {
-#ifdef UVM_AMAP_PPREF
-		if (newppref != NULL) {
-			free(newppref, M_UVMAMAP, 0);
-		}
-#endif
-		return (ENOMEM);
-	}
-	newbck = (int *)(((char *)newsl) + slotalloc * sizeof(int));
-	newover = (struct vm_anon **)(((char *)newbck) + slotalloc *
-	    sizeof(int));
-	KASSERT(amap->am_maxslot < slotneed);
-
-	/* now copy everything over to new malloc'd areas... */
-	slotadded = slotalloc - amap->am_nslot;
-
-	/* do am_slots */
-	oldsl = amap->am_slots;
-	memcpy(newsl, oldsl, sizeof(int) * amap->am_nused);
-	amap->am_slots = newsl;
-
-	/* 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);
-	amap->am_anon = newover;
-
-	/* do am_bckptr */
-	oldbck = amap->am_bckptr;
-	memcpy(newbck, oldbck, sizeof(int) * amap->am_nslot);
-	memset(newbck + amap->am_nslot, 0, sizeof(int) * slotadded); /* XXX: needed? */
-	amap->am_bckptr = newbck;
-
-#ifdef UVM_AMAP_PPREF
-	/* do ppref */
-	oldppref = amap->am_ppref;
-	if (newppref) {
-		memcpy(newppref, oldppref, sizeof(int) * amap->am_nslot);
-		memset(newppref + amap->am_nslot, 0, sizeof(int) * slotadded);
-		amap->am_ppref = newppref;
-		if ((slotoff + slotmapped) < amap->am_nslot)
-			amap_pp_adjref(amap, slotoff + slotmapped, 
-			    (amap->am_nslot - (slotoff + slotmapped)), 1);
-		pp_setreflen(newppref, amap->am_nslot, 1,
-		    slotneed - amap->am_nslot);
-	}
-#endif
-
-	/* free */
-	if (amap->am_maxslot > UVM_AMAP_CHUNK)
-		free(oldsl, M_UVMAMAP, 0);
-	else
-		pool_put(&uvm_amap_slot_pools[amap->am_maxslot - 1],
-		    oldsl);
-
-	/* and update master values */
-	amap->am_nslot = slotneed;
-	amap->am_maxslot = slotalloc;
-
-#ifdef UVM_AMAP_PPREF
-	if (oldppref && oldppref != PPREF_NONE)
-		free(oldppref, M_UVMAMAP, 0);
-#endif
-	return (0);
-}
-
-/*
  * amap_wipeout: wipeout all anon's in an amap; then free the amap!
  *
  * => called from amap_unref when the final reference to an amap is
diff --git a/sys/uvm/uvm_amap.h b/sys/uvm/uvm_amap.h
index 333aa49eb35..a98b44073ad 100644
--- a/sys/uvm/uvm_amap.h
+++ b/sys/uvm/uvm_amap.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_amap.h,v 1.21 2016/03/06 14:47:07 stefan Exp $	*/
+/*	$OpenBSD: uvm_amap.h,v 1.22 2016/03/27 09:51:37 stefan Exp $	*/
 /*	$NetBSD: uvm_amap.h,v 1.14 2001/02/18 21:19:08 chs Exp $	*/
 
 /*
@@ -72,8 +72,6 @@ void		amap_copy(vm_map_t, vm_map_entry_t, int, boolean_t, vaddr_t,
 		    vaddr_t);
 					/* resolve all COW faults now */
 void		amap_cow_now(vm_map_t, vm_map_entry_t);
-					/* make amap larger */
-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_map.c b/sys/uvm/uvm_map.c
index f6569d64b14..ff7c5e407c6 100644
--- a/sys/uvm/uvm_map.c
+++ b/sys/uvm/uvm_map.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_map.c,v 1.209 2016/03/15 20:50:23 krw Exp $	*/
+/*	$OpenBSD: uvm_map.c,v 1.210 2016/03/27 09:51:37 stefan Exp $	*/
 /*	$NetBSD: uvm_map.c,v 1.86 2000/11/27 08:40:03 chs Exp $	*/
 
 /*
@@ -1448,14 +1448,14 @@ uvm_mapent_merge(struct vm_map *map, struct vm_map_entry *e1,
 	struct uvm_addr_state *free;
 
 	/*
-	 * Amap of e1 must be extended to include e2.
+	 * Merging is not supported for map entries that
+	 * contain an amap in e1. This should never happen
+	 * anyway, because only kernel entries are merged.
+	 * These do not contain amaps.
 	 * e2 contains no real information in its amap,
 	 * so it can be erased immediately.
 	 */
-	if (e1->aref.ar_amap) {
-		if (amap_extend(e1, e2->end - e2->start))
-			return NULL;
-	}
+	KASSERT(e1->aref.ar_amap == NULL);
 
 	/*
 	 * Don't drop obj reference: