Make the vm_pmap field of struct vmspace the last field in the

structure. This allows per-CPU variations of struct pmap on a
single architecture without affecting the machine-independent
fields. As such, the PMAP variations don't affect the ABI. They
become part of it.

UPDATING

@@ -22,6 +22,14 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 8.x IS SLOW:
 	to maximize performance.  (To disable malloc debugging, run
 	ln -s aj /etc/malloc.conf.)
 
+20080301:
+	The layout of struct vmspace has changed. This affects libkvm
+	and any executables that link against libkvm and use the
+	kvm_getprocs() function. In particular, but not exclusively,
+	it affects ps(1), fstat(1), pkill(1), systat(1), top(1) and w(1).
+	The effects are minimal, but it's advisable to upgrade world
+	nonetheless.
+
 20080229:
 	The latest em driver no longer has support in it for the
 	82575 adapter, this is now moved to the igb driver. The

sys/vm/vm_map.h

@@ -233,7 +233,6 @@ vm_map_modflags(vm_map_t map, vm_flags_t set, vm_flags_t clear)
  */
 struct vmspace {
 	struct vm_map vm_map;	/* VM address map */
-	struct pmap vm_pmap;	/* private physical map */
 	struct shmmap_state *vm_shm;	/* SYS5 shared memory private data XXX */
 	segsz_t vm_swrss;	/* resident set size before last swap */
 	segsz_t vm_tsize;	/* text size (pages) XXX */
@@ -243,6 +242,12 @@ struct vmspace {
 	caddr_t vm_daddr;	/* (c) user virtual address of data */
 	caddr_t vm_maxsaddr;	/* user VA at max stack growth */
 	int	vm_refcnt;	/* number of references */
+	/*
+	 * Keep the PMAP last, so that CPU-specific variations of that
+	 * structure on a single architecture don't result in offset
+	 * variations of the machine-independent fields in the vmspace.
+	 */
+	struct pmap vm_pmap;	/* private physical map */
 };
 
 #ifdef	_KERNEL