Re: [yocto] Limiting Yocto Memory Usage

["Nate Kent" <yocto@nkent.net>]

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On Tue, Jul 21, 2026 at 05:22 PM, Randy MacLeod 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 ?
> Do you do world builds?
> Do you run more than one systemd-run build on a given machine?

I do this as a regular part of my development, though I tend to use '-S' ('-shell', essentially interactive mode) rather than spawning a unit just for a single build. I'll also often modify the resource constraints while BitBake is running if I need to reserve additional resources for non-BitBake tasks while a build is running. That being said, I generally do not do more than a single build at a time simply because reasoning about how to get two competing processes to maximize the usage of the system is a much more difficult challenge.

For theor the most my experience shows that it will work as you expect. If you give the slice three cores and it will act like building on a machine with just three cores, give it a low CPU weight and you'll get a build that's low priority to the scheduler, etc.

If you have other questions I can try to answer them but, for the most part, it's so painless and unsurprising that I don't really have much in the way of advice.

- Nate

PS: I'm sending this from the Yocto Mailing list website and I can't tell if it's going to send as "Github Flavored Markdown" + HTML or the plaintext that I'm typing. Apologies if this comes through mangled. 

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