I've been trying to observe zswap's statistics. grep -R . /sys/kernel/debug/zswap/ is frequently recommended, but /sys/kernel/debug/zswap does not exist. I've made /etc/boot.d/user-zswap, it looks like this:

#!/bin/sh
zswap=/sys/module/zswap/parameters
echo 75 > $zswap/max_pool_percent
echo 95 > $zswap/accept_threshold_percent
echo zstd > $zswap/compressor
echo zsmalloc > $zswap/zpool
echo 1 > $zswap/enabled

I checked if zswap was compiled into my kernel based on some older post when zswap was new: cat /boot/config-$(uname -r) | grep CONFIG_ZSWAP= gives me CONFIG_ZSWAP=y.

I also checked if zswap itself is enabled: cat /sys/module/zswap/parameters/enabled is Y.

My kernel version is 5.10.0-20-amd64.

What am I missing?