Re: About swapaccount=

["Jonas Schäfer" <jonas@wielicki.name>]

Hi Yosry,

On Donnerstag, 2. März 2023 20:12:43 CET Yosry Ahmed wrote:
> 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).

Thank you for the swift reply. Indeed, I am using swapaccount=1, so I assumed 
the deprecation warning was related to =1. If =1 continues to work as default, 
that just means I have one less thing to carry around in the grub config and 
is not a problem at all!

Thanks!

kind regards,
Jonas