On Mon, 14 Feb 2022 15:27:36 +0100, Joe Salmeri wrote:
If I run cat /boot/config-5.16.1-1-default | grep -i swap
It returns CONFIG_ZSWAP=Y
cat /sys/module/zswap/parameters/enabled returns N
So the kernel supports zswap but it is currently NOT enabled.
When system is booted the following journal message appears
kernel: zswap: loaded using pool lzo/zbud
ps aux | grep -i zswap
returns
root 135 0.0 0.0 0 0 ? I< Feb09 0:00 [zswap-shrink]
If zswap is NOT enabled, why is zswap loaded with a pool at boot time and why is the zswap-shrink process running?
I find that the same situation on a TW test machine I have that is running the 5.16.5.2 kernel so it is not an isolated case.
Is this a bug?
The zswap's enabled sysfs can be toggled dynamically even after the boot, which enables/disables the zswp on the fly. Meanwhile the kconfig specifies whether zswap is supported or not at all. So this is expected behavior. zswap-shrink is a kernel workqueue, and it's idle unless a work is queued there. It consumes some memory, but that's all. Takashi