Mmap() failed: Cannot allocate memory

Hello, when I run “ionic emulate android”, I got “mmap() failed: Cannot allocate memory” problem.
How to solve it? thanks.

litingjun@litingjun-All-Series:~/myApp$ ionic emulate android
Running command: /home/litingjun/myApp/hooks/after_prepare/010_add_platform_class.js /home/litingjun/myApp
add to body class: platform-android
Running command: /home/litingjun/myApp/platforms/android/cordova/run --emulator
WARNING : no emulator specified, defaulting to Nexus_5_API_22_x86
Waiting for emulator…
emulator: emulator window was out of view and was recentered

mmap() failed: Cannot allocate memory
mmap() failed: Cannot allocate memory

set a min-ram of 512mb in your emulated device settings for Nexus_5_API_22_x86

thanks, I’ve installed my ubuntu to x86_64, and problem is solved.