Kernel with zswap support

[bjmi]

Is your feature request related to a problem? Please describe.
Zswap support is currently not availble.

$ cat /sys/module/zswap/parameters/enabled
cat: /sys/module/zswap/parameters/enabled: No such file or directory

Describe the solution you'd like
I'd like to use zswap in WSL2 to use memory more efficiently or run more apps / services when e.g. the host machine itself owns only little memory.

Additional context
WSL2 with Ubuntu is currently in use.

> wsl --version
WSL version: 1.2.5.0
Kernel version: 5.15.90.1
WSLg version: 1.0.51
MSRDC version: 1.2.3770
Direct3D version: 1.608.2-61064218
DXCore version: 10.0.25131.1002-220531-1700.rs-onecore-base2-hyp
Windows version: 10.0.22621.1702

[anton0k]

Sounds like a good idea. Maybe include zram as well.

[javier-garcia-tilburg]

+1 particularly for zram #9417. This could alleviate the constraints of splitting limited resources between windows and linux.

[vware]

enabling it in the default config shouldn't hurt anyone, should it?

[theoparis]

I tried to enable zswap via a custom kernel with the following:

CONFIG_ZSWAP=y
CONFIG_ZSWAP_DEFAULT_ON=y
CONFIG_ZSWAP_COMPRESSOR_DEFAULT_ZSTD=y
CONFIG_ZSWAP_COMPRESSOR_DEFAULT="zstd"

and I got a page fault error:

0.387401] hv_balloon: Cold memory discard hint enabled with order 9       
[    0.387896] BUG: unable to handle page fault for address: fffffffffffffff1
[    0.388107] #PF: supervisor read access in kernel mode
[    0.388255] #PF: error_code(0x0000) - not-present page 

[4-FLOSS-Free-Libre-Open-Source-Software]

enabling it in the default config shouldn't hurt anyone, should it?

Yes, ZRAM works very well inside WSL2. In the meantime, you could use the zRAM enabled wsl2 kernel https://github.com/Locietta/xanmod-kernel-WSL2?tab=readme-ov-file#usage