Re: [yocto] Limiting Yocto Memory Usage

["Ulrich Ölmann" <u.oelmann@pengutronix.de>]

Hi Randy,

On Tue, Jul 21 2026 at 11:22 -0400, Randy MacLeod <randy.macleod@windriver.com> wrote:
> On 2026-07-16 04:22, Ulrich Ölmann via lists.yoctoproject.org wrote:
> >
> > Hey Luis,
> >
> > On Fri, Jul 10 2026 at 15:26 -0600, "Luis Merayo via lists.yoctoproject.org"<luis.merayo=ridgerun.com@lists.yoctoproject.org> wrote:
> >>
> >> Hi,
> >>
> >> I would like to know if there is a way to limit Bitbake's Memory usage
> >> to a specific percentage of the available RAM. For example, can the
> >> Yocto build be limited to use a maximum of 70% of RAM?
> > if you are doing your Bitbake work on a machine running a systemd based
> > Linux distribution you could simply do something like
> >
> >    $ systemd-run \
> >         --user \
> >         --scope \
> >         --property=CPUWeight=<YOUR_CPUWEIGHT> \
> >         --property=IOWeight=<YOUR_IOWEIGHT> \
> >         --property=MemoryHigh=<YOUR_MEMORYHIGH> \
> >         --property=OOMPolicy=kill \
> >         --unit="bitbake-run" \
> >         bitbake [...]
> >
> > to somewhat limit the resources, see systemd.resource-control(5) and
> > systemd.scope(5) for details regarding the used parameters.
> >
> > Best regards,
> > Ulrich
>
>
> Hi Ulrich,
>
> Using systemd-run is something that I've been meaning to try so it's good to
> hear that you're doing it.
>
> Do you have any experiences to share about this approach ?

we currently use the systemd-run approach mainly to make resource
sharing on our build servers a bit fairer between colleagues when
building customer BSPs.

One nice side effect is that every single process of the control group
gets terminated when the systemd-run scope is terminated. No stray
processes are left behind by mistake.

> Do you do world builds?

So far, I am not using it for world builds. Our use case is more about
encapsulating individual build jobs and avoiding that a single build
grabs too much of the machine, rather than stress-testing the setup with
"bitbake world".

> Do you run more than one systemd-run build on a given machine?

Yes, in practice we do end up with multiple builds running in parallel
on the same machine, since (hopefully ;) all colleagues use the same
systemd-run approach.

> Of course it doesn't prevent bitbake from pushing the cgroup contained system
> harder that it can handle and bitbake doesn't have any feedback so that's
> something
> to consider when doing the jobserver or free memory build regulation work.

Right. For our purpose, though, it works reasonably well as a pragmatic
way to improve sharing/fairness on multi-user build machines.

Best regards,
Ulrich


> ../Randy
>
>
> >
> >
> >> Could these three variables achieve this?
> >>
> >>   BB_PRESSURE_MAX_CPU, BB_PRESSURE_MAX_IO , BB_PRESSURE_MAX_MEMORY
> >>
> >> I see the range for these variables is from 1 to 1000000, so I would
> >> like to understand if there is a way to specify their values as a
> >> function of the available RAM.
> >>
> >> Regards,
> >>
> >> Luis
> >>
> >>
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> --
> # Randy MacLeod
> # Wind River Linux
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