[systemd-devel] Memory in systemctl status

[Greg KH]

On Sun, Sep 27, 2020 at 01:41:33PM +0200, Reindl Harald wrote:
> Memory: 8.6G
> 
> looks like there is a large part of os-caching included where i wonmder
> how that's done because a file can be read by muliple processes /
> services and is hopfefully only once cached
> 
> however, that value makes little to no sense and if that's the same
> value as accounted for "MemoryMax" it's plain wrong
> 
> [root at arrakis:~]$ free
>               total        used        free      shared  buff/cache
> available
> Mem:           15Gi       2.2Gi       585Mi       309Mi        12Gi
>    12Gi
> Swap:            0B          0B          0B

The kernel does this, it's nothing to do with systemd or anything else.

You can get "back" that memory for a short while if you really want it
by doing:
	echo 3 > /proc/sys/vm/drop_caches

For more details, see https://www.linuxatemyram.com/

good luck!

greg k-h-