Application to fully Fill Android RAM

Need to write Android application which is capable to consume all the RAM. Did app which creates multiple MemoryFile-s in infinitive loop inside worker thread. When run application I see that Android restricts RAM allocation till some magic threshold simultaneously trying to free RAM by closing some other apps. Finally, either OS kills my application or continues to keep RAM close to magic threshold. Slightly less then half of free RAM stays available. How to consume all?

What I tried:

1. Tried to use sudo mount -t tmpfs tmpfs /sdcard/tmp on rooted device. However, in my particular case LG Nexus with Oreo 8.1 just starts to reboot with no effect after.
2. Tried to turn off lmkd by echo 1,1,1,1,1,1 > /sys/module/lowmemorykiller/parameters/minfree. As result the magic threshold I was talking about above changes to allow me to consume more RAM, but still almost 1/3 of RAM stays free.

Please, help me to consume all of it!

I'm not sure why you'd want to intentionally shoot yourself in the foot like this, so to speak, but I digress...

Android apps use a java-like runtime (art or dalvik, see https://source.android.com/devices/tech/dalvik). Each app runs in it own process space, and each has it's own max heap setting - just like any java app. You can tweak the size of that heap space by enabling largeheap mode (https://developer.android.com/guide/topics/manifest/application-element#largeHeap). However you will still hit this limit before you exhaust device memory.

You can bypass the heap and garbage collection and by allocating memory directly from native code (but you have to write and integrate the native code into your application using the NDK, which is not exactly trivial).

However the linux kernel will still likely shutdown your application before you can actually consume all the memory on the device - not sure if you'd have much luck tuning the OOM killer (https://www.percona.com/blog/2019/08/02/out-of-memory-killer-or-savior/) further.