Can't get ZRAM to work on Cyanogenmod 11 (4.4.4)

I'm using Cyanogenmod 11 (4.4.4) on my GT-i9500 (Samsung Galaxy S4) and I'm trying to get ZRAM working. I could set the swap on and it even shows on /proc/swaps:

Filename                Type        Size    Used    Priority
 /dev/block/zram0                        partition  524284  0   2

As far as I can tell it should be fine but when I run my benchmark (which consists of running a series of apps including one app that makes sure to allocate a lot of memory) and cat /sys/block/zram0/mem_used_total or any other metric zram has, it shows that used only 4KB of memory. I can even get the cellphone to crash allocating memory but no zram usage occurs.

The same benchmark shows zram usage with the stock Samsung kitkat (4.4.2). I even tried to flash the stock kernel and it boots fine but still no zram usage. Any settings I should be looking at? What am I missing?