Intellij only using 750m, configured to use a lot more

I've modified the Intellij Custom VM options to this:

# custom IntelliJ IDEA VM options

-Xms16g
-Xmx17g
-XX:ReservedCodeCacheSize=4g
-XX:+UseConcMarkSweepGC
-XX:SoftRefLRUPolicyMSPerMB=50
-ea
-Dsun.io.useCanonCaches=false
-Djava.net.preferIPv4Stack=true
-XX:+HeapDumpOnOutOfMemoryError
-XX:-OmitStackTraceInFastThrow
-Dawt.useSystemAAFontSettings=lcd
-Dsun.java2d.renderer=sun.java2d.marlin.MarlinRenderingEngine

If I'm not mistaken, that means it should be using about 16~17g, with 4g reserved.

However, I enabled the memory monitor in the status bar at the bottom, and it only shows 750M available (which it is regularly using up).

I'm running 64-bit Ubuntu with a 64-bit JRE and JVM. Running Intellij IDEA Ultimate 2017.3.1. My machine has 64G of memory.

I've restarted since making the VM option changes. Am I missing something?

Solution

Check the desktop entry for IDE (should be located in ~/.local/share/applications/jetbrains-idea.desktop or in /usr/share/applications/jetbrains-idea*.desktop). Could be that the option is overriden in desktop entry.