On Tue, Jul 27, 2021 at 08:33:12AM +0300, Vasily Averin wrote:

The kernel allocates ~400 bytes of 'strcut mount' for any new mount.
Creating a new mount namespace clones most of the parent mounts,
and this can be repeated many times. Additionally, each mount allocates
up to PATH_MAX=4096 bytes for mnt->mnt_devname.

It makes sense to account for these allocations to restrict the host's
memory consumption from inside the memcg-limited container.

Signed-off-by: Vasily Averin <redacted>
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Looks good. Thank you!
Acked-by: Christian Brauner <christian.brauner-GeWIH/nMZzLQT0dZR+AlfA@public.gmane.org>

I wonder how much this increases reported memory consumption when you
boot full system containers that run systemd and a bunch of systemd
services that each use a separate mount namespace.