These comments are not helping.  uvm_mapanon() does the right thing, ok?

Index: uvm/uvm_mmap.c
===================================================================
RCS file: /cvs/src/sys/uvm/uvm_mmap.c,v
diff -u -p -r1.201 uvm_mmap.c
--- uvm/uvm_mmap.c	20 May 2025 07:02:20 -0000	1.201
+++ uvm/uvm_mmap.c	11 Jun 2025 14:14:05 -0000
@@ -1013,10 +1013,8 @@ uvm_mmapanon(vm_map_t map, vaddr_t *addr
 	if ((flags & MAP_FIXED) == 0 && size >= __LDPGSZ)
 		align = __LDPGSZ;
 	if ((flags & MAP_SHARED) == 0)
-		/* XXX: defer amap create */
 		uvmflag |= UVM_FLAG_COPYONW;
 	else
-		/* shared: create amap now */
 		uvmflag |= UVM_FLAG_OVERLAY;
 	if (flags & MAP_STACK)
 		uvmflag |= UVM_FLAG_STACK;