allocate swap size for containers based on system ratio

src/addons.js

@@ -59,6 +59,7 @@ var appdb = require('./appdb.js'),
     spawn = require('child_process').spawn,
     split = require('split'),
     request = require('request'),
+    system = require('./system.js'),
     util = require('util');
 
 const NOOP = function (app, options, callback) { return callback(); };
@@ -811,7 +812,7 @@ function updateServiceConfig(platformConfig, callback) {
         const containerConfig = platformConfig[serviceName];
         let memory, memorySwap;
         if (containerConfig && containerConfig.memoryLimit) {
-            memory = containerConfig.memoryLimit / 2;
+            memory = system.getMemoryAllocation(containerConfig.memoryLimit);
             memorySwap = containerConfig.memoryLimit;
         } else {
             memory = SERVICES[serviceName].defaultMemoryLimit;
@@ -838,7 +839,7 @@ function updateAppServiceConfig(name, instance, servicesConfig, callback) {
     const serviceConfig = servicesConfig[name];
     let memory, memorySwap;
     if (serviceConfig && serviceConfig.memoryLimit) {
-        memory = serviceConfig.memoryLimit / 2;
+        memory = system.getMemoryAllocation(serviceConfig.memoryLimit);
         memorySwap = serviceConfig.memoryLimit;
     } else {
         memory = APP_SERVICES[name].defaultMemoryLimit;