Index: sys/uvm/uvm_fault.c
===================================================================
RCS file: /home/netbsd/src/sys/uvm/uvm_fault.c,v
retrieving revision 1.227
diff -p -u -r1.227 uvm_fault.c
--- sys/uvm/uvm_fault.c	17 May 2020 19:38:17 -0000	1.227
+++ sys/uvm/uvm_fault.c	30 Jun 2020 06:29:50 -0000
@@ -152,17 +152,7 @@ struct uvm_advice {
 	int nforw;
 };
 
-/*
- * page range array:
- * note: index in array must match "advice" value
- * XXX: borrowed numbers from freebsd.   do they work well for us?
- */
-
-static const struct uvm_advice uvmadvice[] = {
-	{ UVM_ADV_NORMAL, 3, 4 },
-	{ UVM_ADV_RANDOM, 0, 0 },
-	{ UVM_ADV_SEQUENTIAL, 8, 7},
-};
+static struct uvm_advice uvmadvice[3];
 
 #define UVM_MAXRANGE 16	/* must be MAX() of nback+nforw+1 */
 
@@ -206,9 +196,63 @@ uvmfault_anonflush(struct vm_anon **anon
 }
 
 /*
+ * uvmfault_rescale_advice: rescale # of pages around fault address to be
+ * resolved on fault.
+ */
+
+static int
+uvmfault_rescale_advice(int n)
+{
+
+	/*
+	 * n is # of pages for 4k pages. If page size is smaller than 4k,
+	 * i.e., mc68010, do not increase pages for safety.
+	 */
+	if (uvmexp.pagesize <= 4096)
+		return n;
+
+	/*
+	 * Rescale # of pages so that amount of memory resolved is
+	 * approximately same as that for 4k pages.
+	 */
+	n = (n + 1) * 4096 / uvmexp.pagesize;
+	return n == 0 ? 0 : (n - 1);
+}
+
+/*
  * normal functions
  */
 
+void
+uvmfault_init(void)
+{
+
+	/*
+	 * page range array:
+	 * note: index in array must match "advice" value
+	 * XXX: borrowed numbers from freebsd.   do they work well for us?
+	 */
+
+	CTASSERT(__arraycount(uvmadvice) == UVM_ADV_SEQUENTIAL + 1);
+
+#define	INIT_ADVICE(a, b, f)						\
+	do {								\
+		uvmadvice[a].advice = a;				\
+		uvmadvice[a].nback  = uvmfault_rescale_advice(b);	\
+		uvmadvice[a].nforw  = uvmfault_rescale_advice(f);	\
+		printf("%s: advice %d nback %d nforw %d\n", __func__,	\
+			uvmadvice[a].advice,				\
+			uvmadvice[a].nback,				\
+			uvmadvice[a].nforw);				\
+	} while (0 /* CONSTCOND */)
+
+	INIT_ADVICE(UVM_ADV_NORMAL,	3, 4);
+	INIT_ADVICE(UVM_ADV_RANDOM,	0, 0);
+	INIT_ADVICE(UVM_ADV_SEQUENTIAL, 8, 7);
+
+#undef	INIT_ADVICE
+}
+
 /*
  * uvmfault_amapcopy: clear "needs_copy" in a map.
  *
Index: sys/uvm/uvm_fault.h
===================================================================
RCS file: /home/netbsd/src/sys/uvm/uvm_fault.h,v
retrieving revision 1.20
diff -p -u -r1.20 uvm_fault.h
--- sys/uvm/uvm_fault.h	2 Feb 2011 15:13:34 -0000	1.20
+++ sys/uvm/uvm_fault.h	28 Jun 2020 12:38:23 -0000
@@ -52,6 +52,8 @@ struct uvm_faultinfo {
 
 #ifdef _KERNEL
 
+void uvmfault_init(void);
+
 /*
  * fault prototypes
  */
Index: sys/uvm/uvm_init.c
===================================================================
RCS file: /home/netbsd/src/sys/uvm/uvm_init.c,v
retrieving revision 1.53
diff -p -u -r1.53 uvm_init.c
--- sys/uvm/uvm_init.c	6 Mar 2020 20:46:12 -0000	1.53
+++ sys/uvm/uvm_init.c	28 Jun 2020 12:38:23 -0000
@@ -185,4 +185,6 @@ uvm_init(void)
 	 */
 
 	uvm_ra_init();
+
+	uvmfault_init();
 }