Re: About swapaccount=

[Yosry Ahmed <yosryahmed@google.com>]

On Thu, Mar 2, 2023 at 11:01 AM Jonas Schäfer <jonas@wielicki.name> wrote:
>
> Hi there,
>
> By coincidence, I found this log message in my kernel logs:
>
> Mär 02 17:23:19 sinistra kernel: The swapaccount= commandline option is
> deprecated. Please report your usecase to linux-mm@kvack.org if you depend on
> this functionality.
>
> My usecase does depend on this in the following way:
>
> I use LXC extensively to isolate workloads from one another. Kind of like
> docker, but with full operating systems inside.
>
> Before I found out about swapaccount, I often ran into the issue that one
> misbehaving workload from one of those containers would bring the entire
> machine to a halt because it occupied lots of swap, and thus triggered
> significant slowdown.
>
> With swapaccount, I limit swap to about 10% of the RAM assigned to the
> containers. This allows them to swap out unused stuff, but invokes the OOM
> killer before any significant slowdown happens.
>
> The alternative would be to turn off swap for the system entirely, but it is
> running fairly efficiently thanks to swapping stuff out.
>
> I'd be interested to hear about alternatives.
>
> Thanks for hearing me, anyway.

If I understand correctly you were setting swapaccount=1, right?

IIRC, swapaccount= was deprecated in the sense that it is always on
now (i.e you cannot set swapaccount=0).

>
> kind regards,
> Jonas Schäfer