use /sys/fs/cgroup/memory.max as maximum memory metric instead of the

output of the free command in case RaspberryMatic is used in a memory
limiting container environment so that HMIPServer won't consume and
overly amount of host memory.

buildroot-external/overlay/base/etc/init.d/S62HMServer

@@ -166,7 +166,11 @@ start() {
 
   # calculate the maximum used heap size (-Xmx) depending on the
   # total amount of RAM we have (use max. 25%) - use multiple of 128MB
-  MAXHEAP=$(free -m | grep Mem: | awk '{print int($2*0.25/128)*128}')
+  if [[ -e /sys/fs/cgroup/memory.max ]]; then
+    MAXHEAP=$(cat /sys/fs/cgroup/memory.max | awk '{print int(($1/1024/1024)*0.25/128)*128}')
+  else
+    MAXHEAP=$(/usr/bin/free -m | grep Mem: | awk '{print int($2*0.25/128)*128}')
+  fi
   if [[ -n "${MAXHEAP}" ]] && [[ "${MAXHEAP}" -gt 128 ]]; then
     JAVAOPT="-Xmx${MAXHEAP}m ${JAVAOPT}"
   else