Additional Linux VM integration

Added support for Solaris swapfs_minfree, and swapfs_reserve tunables.
In additional availrmem is now available and return a reasonable value
which is reasonably analogous to the Solaris meaning.  On linux we
return the sun of free and inactive pages since these are all easily
reclaimable.

All tunables are available in /proc/sys/kernel/spl/vm/* and they may
need a little adjusting once we observe the real behavior.  Some of
the defaults are mapped to similar linux counterparts, others are
straight from the OpenSolaris defaults.

configure

@@ -20598,6 +20598,45 @@ _ACEOF
 
 
 
+	echo "$as_me:$LINENO: checking whether symbol get_zone_counts is exported" >&5
+echo $ECHO_N "checking whether symbol get_zone_counts is exported... $ECHO_C" >&6
+	grep -q -E '[[:space:]]get_zone_counts[[:space:]]' $LINUX/Module.symvers 2>/dev/null
+	rc=$?
+	if test $rc -ne 0; then
+		export=0
+		for file in ; do
+			grep -q -E "EXPORT_SYMBOL.*(get_zone_counts)" "$LINUX/$file" 2>/dev/null
+			rc=$?
+		        if test $rc -eq 0; then
+		                export=1
+		                break;
+		        fi
+		done
+		if test $export -eq 0; then
+			echo "$as_me:$LINENO: result: no" >&5
+echo "${ECHO_T}no" >&6
+
+		else
+			echo "$as_me:$LINENO: result: yes" >&5
+echo "${ECHO_T}yes" >&6
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_GET_ZONE_COUNTS 1
+_ACEOF
+
+		fi
+	else
+		echo "$as_me:$LINENO: result: yes" >&5
+echo "${ECHO_T}yes" >&6
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_GET_ZONE_COUNTS 1
+_ACEOF
+
+	fi
+
+
+
 TOPDIR=`/bin/pwd`
 
 # Add "V=1" to KERNELMAKE_PARAMS to enable verbose module build