Try smaller sizes if creating an area failed.

Depending on the use case the grow size may be too large to fit into
address space holes. Instead of failing try with smaller sizes until
it either worked or doesn't make sense anymore (< 1MB).

src/system/kernel/guarded_heap.cpp

@@ -364,15 +364,25 @@ guarded_heap_area_init(guarded_heap& heap, area_id id, void* baseAddress,
 static bool
 guarded_heap_area_create(guarded_heap& heap, uint32 flags)
 {
-	void* baseAddress = NULL;
-	area_id id = create_area("guarded_heap_area", &baseAddress,
-		B_ANY_KERNEL_ADDRESS, HEAP_GROW_SIZE, B_FULL_LOCK,
-		B_KERNEL_READ_AREA | B_KERNEL_WRITE_AREA);
+	for (size_t trySize = HEAP_GROW_SIZE; trySize >= 1 * 1024 * 1024;
+		trySize /= 2) {
 
-	if (id < 0)
-		return false;
+		void* baseAddress = NULL;
+		area_id id = create_area("guarded_heap_area", &baseAddress,
+			B_ANY_KERNEL_ADDRESS, trySize, B_FULL_LOCK,
+			B_KERNEL_READ_AREA | B_KERNEL_WRITE_AREA);
 
-	return guarded_heap_area_init(heap, id, baseAddress, HEAP_GROW_SIZE, flags);
+		if (id < 0)
+			continue;
+
+		if (guarded_heap_area_init(heap, id, baseAddress, trySize, flags))
+			return true;
+
+		delete_area(id);
+	}
+
+	panic("failed to allocate a new heap area");
+	return false;
 }