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Similar to Ubuntu 24.04 LTS, Fedora 39, and other recent Linux distributions increasing its vm.max_map_count default in order to satisfy some Windows games running under Valve’s Steam Play (Proton) and other memory-intensive software, Arch Linux is also increasing its default value.
As explained previously on Phoronix, the vm.max_map_count sysctl value controls the operating system limits on the maximum number of memory map (mmap) areas that a process can have. Most software doesn’t use too many mmaps that the 65k default is plenty suitable for the vast majority of user-space software out there. But there are a few Windows games running on Linux via Steam Play (Proton), that limit can actually be exceeded — DayZ, Hogwarts Legacy, Counter Strike 2, and other games.
To enhance the out-of-the-box experience for Linux gaming and other software, various Linux distributions have been increasing their default vm.max_map_count threshold. In the case of Arch Linux they are now going ahead and bumping the value from 65,530 to 1,048,576. As announced today on the Arch Linux mailing list:
The vm.max_map_count parameter will be increased from the default `65530` value to `1048576`.
This change should help address performance, crash or start-up issues for a number of memory intensive applications, particularly for (but not limited to) some Windows games played through Wine/Steam Proton. Overall, end users should have a smoother experience out of the box with no expressed concerns about potential downsides in the related proposal on arch-dev-public mailing list.
This `vm.max_map_count` increase is introduced in the `2024.04.07-1` release of the filesystem package and will be effective right after the upgrade.
The sysctl vm.max_map_count threshold can still be overrode by the user if so desired.
