Seeing as other distributions have already adopted this change and
gaming is a popular usecase for ArchLinux I do think this is a good
thing to have. The default value will only be more of a bottleneck in
the future.
There's a balance in sticking to defaults. It'd be a shame if users need
to alter multiple kernel parameters just to play modern games or run
other applications with a high memory footprint.
As I understand it there's no real downside to increasing this. Could
someone with more knowledge of the kernel shed some light on any
possible adverse effects that might come from increasing the default?
I am also curious how the upstream discussed will go but I do not expect
them to change it.
Cheers,
Levitating
On 2024-03-25 09:10, Robin Candau wrote:
Hi everyone,
I'm writing this mail as proposal to increase the default
`vm.max_map_count` [1] value in Arch Linux.
The default `vm.max_map_count` 65530 value is making some Windows games
crash (or even prevent them to start at all) while being played through
Wine or Steam Play (Proton).
Examples are (but not limited to) Star Citizen, THE FINALS, Hogwarts
Legacy, DayZ or Counter-Strike 2 (see [2] for a list of bug reported to
Valve for these games on that matter).
In that regard, SteamOS is shipping an increased `vm.max_map_count`
default value to address the above issue and numerous distributions
have since then decided to implement that change on their side as well,
such as Fedora [3], NixOS [4] and, more recently, Ubuntu [5].
While I'm aware that Arch is a user centric/DIY distro and everyone can
set their own `vm.max_map_count` value fairly easily, shipping an
increased value on our side would be a beneficial change to make in my
opinion as it would result in a smoother gaming experience out of the
box for our users without representing any downside/side effect (as far
as I'm aware).
In terms of implementation, the change basically consists of shipping
the following sysctl file:
```
# Increase the number of virtual memory areas that one process may
request
vm.max_map_count=1048576
```
For reference, Fedora added it to their systemd package [6], while
Ubuntu handled it at the procps level [7].
I personally don't have a strong opinion on the implementation
way/place.
To sum up, I think this would be a reasonable and positive change to
make to our distro.
I'd be happy to read your thoughts (or eventual objection)! 😊
[1] https://docs.kernel.org/admin-guide/sysctl/vm.html#max-map-count
[2]
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2057792/comments/5
[3] https://fedoraproject.org/wiki/Changes/IncreaseVmMaxMapCount
[4] https://github.com/NixOS/nixpkgs/pull/238459
[5] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2057792
[6]
https://src.fedoraproject.org/rpms/systemd/blob/f39/f/10-map-count.conf
[7]
https://git.launchpad.net/ubuntu/+source/procps/commit/?h=applied/2%254.0.4-4ubuntu2&id=b4a4a046cf018a942598e55f3fbc7b5ef474f676
