Remove duplicate code for cgroup/grub instruction

(cherry picked from commit f6f5736)

Author: vmcj

judge/create_cgroups.in

@@ -9,34 +9,31 @@
 JUDGEHOSTUSER=@DOMJUDGE_USER@
 CGROUPBASE=@judgehost_cgroupdir@
 
+print_cgroup_instruction () {
+    echo ""
+    echo "To fix this, please make the following changes:
+    1. In /etc/default/grub, add 'cgroup_enable=memory swapaccount=1' to GRUB_CMDLINE_LINUX_DEFAULT.
+       On modern distros (e.g. Debian bullseye and Ubuntu Jammy Jellyfish) which have cgroup v2 enabled by default,
+       you need to add 'systemd.unified_cgroup_hierarchy=0' as well.
+    2. Run update-grub
+    3. Reboot" >&2
+    exit 1
+}
+
 for i in cpuset memory; do
     mkdir -p $CGROUPBASE/$i
     if [ ! -d $CGROUPBASE/$i/ ]; then
         if ! mount -t cgroup -o$i $i $CGROUPBASE/$i/; then
-            echo "Error: Can not mount $i cgroup. Probably cgroup support is missing from running kernel. Unable to continue.
-
-            To fix this, please make the following changes:
-            1. In /etc/default/grub, add 'cgroup_enable=memory swapaccount=1' to GRUB_CMDLINE_LINUX_DEFAULT
-	       On modern distros (e.g. Debian bullseye and Ubuntu Jammy Jellyfish) which have cgroup v2 enabled by default,
-	       you need to add 'systemd.unified_cgroup_hierarchy=0' as well.
-            2. Run update-grub
-            3. Reboot" >&2
-            exit 1
+            echo "Error: Can not mount $i cgroup. Probably cgroup support is missing from running kernel. Unable to continue."
+            print_cgroup_instruction
         fi
     fi
     mkdir -p $CGROUPBASE/$i/domjudge
 done
 
 if [ ! -f $CGROUPBASE/memory/memory.limit_in_bytes ] || [ ! -f $CGROUPBASE/memory/memory.memsw.limit_in_bytes ]; then
-    echo "Error: cgroup support missing memory features in running kernel. Unable to continue.
-
-    To fix this, please make the following changes:
-    1. In /etc/default/grub, add 'cgroup_enable=memory swapaccount=1' to GRUB_CMDLINE_LINUX_DEFAULT.
-       On modern distros (e.g. Debian bullseye and Ubuntu Jammy Jellyfish) which have cgroup v2 enabled by default,
-       you need to add 'systemd.unified_cgroup_hierarchy=0' as well.
-    2. Run update-grub
-    3. Reboot" >&2
-    exit 1
+    echo "Error: cgroup support missing memory features in running kernel. Unable to continue."
+    print_cgroup_instruction
 fi
 
 chown -R $JUDGEHOSTUSER $CGROUPBASE/*/domjudge