I'd like to move forward with parallel fault handling.  This has been
properly tested on amd64, i386 and arm64.  sparc64 pmap needs some love
and enabling this will expose the existing bugs.

My plan is to enable parallel faults on amd64 and arm64 as a first step
then i386 because it is where swapping is properly exercised. 

Does that sound sane, do you agree with this approach?

Index: uvm/uvm_fault.c
===================================================================
RCS file: /cvs/src/sys/uvm/uvm_fault.c,v
diff -u -p -r1.171 uvm_fault.c
--- uvm/uvm_fault.c	11 Sep 2025 17:04:35 -0000	1.171
+++ uvm/uvm_fault.c	12 Nov 2025 14:09:52 -0000
@@ -618,7 +618,7 @@ uvm_fault(vm_map_t orig_map, vaddr_t vad
 	flt.access_type = access_type;
 	flt.narrow = FALSE;		/* assume normal fault for now */
 	flt.wired = FALSE;		/* assume non-wired fault for now */
-#if notyet
+#if defined(__amd64__) || defined(__arm64__)
 	flt.upper_lock_type = RW_READ;
 	flt.lower_lock_type = RW_READ;	/* shared lock for now */
 #else