Increase Default vm_max_map_count to Improve Compatibility with Modern Games

[vincentdelor@free.fr]

Hello,

I am writing to highlight an issue impacting many Linux users, especially those who enjoy modern gaming. The current default setting of `vm_max_map_count` at 65530 has been linked to crashes or launch failures in several contemporary games.

To address this, I have opened a detailed bug report (218616 – Increase Default vm_max_map_count to Improve Gaming Experience on Linux) available at: 218616 – Increase Default vm_max_map_count to Improve Gaming Experience on Linux (kernel.org) .


We have identified that several modern games such as Hogwarts Legacy, Star Citizen, and others experience crashes or fail to start on Linux due to the default `vm_max_map_count` being set to 65530. These issues can be mitigated by increasing the `vm_max_map_count` value to over 1048576, which has been confirmed to resolve the crashes without introducing additional bugs related to map handling.

This issue affects a wide range of users and has been noted in distributions like Fedora and Pop!_OS, which have already adjusted this value to accommodate modern gaming requirements.

For reference, here is the change for Fedora:
https://fedoraproject.org/wiki/Changes/IncreaseVmMaxMapCount

Here is a list of games affected by this low value in vm_max_map_count as reported to Valve:

THE FINALS
https://github.com/ValveSoftware/Proton/issues/7317#issuecomment-1974837850

Hogwarts Legacy
https://github.com/ValveSoftware/Proton/issues/6510#issuecomment-1422781100

DayZ
https://github.com/ValveSoftware/Proton/issues/3899#issuecomment-1304397069

Counter-Strike 2
https://github.com/ValveSoftware/Proton/issues/2704#issuecomment-1705199788


**Steps to Reproduce:**
1. Install Ubuntu or other distribution with `vm_max_map_count` being set to 65530 and attempt to run affected games such as Hogwarts Legacy or Star Citizen.
2. Observe that the games crash or fail to start with the default `vm_max_map_count` setting.
3. Modify `/etc/sysctl.conf` to include `vm.max_map_count=1048576` (or another sufficiently high value).
4. Reboot the system and observe that the games now run without issue.

**Expected Result:**
Games should run without crashing or failing to start due to `vm_max_map_count` limitations.

**Actual Result:**
Games crash or fail to start unless `vm_max_map_count` is manually increased.

**Suggested Fix:**
Increase the default `vm_max_map_count` value in Linux to a value greater than 1048576 to accommodate modern gaming software requirements.

**Affected Games:**
- Hogwarts Legacy
- Star Citizen
- THE FINALS
- DayZ
- Counter-Strike 2
- Payday 2
- (and potentially others)

**References:**
- Fedora's change documentation: https://fedoraproject.org/wiki/Changes/IncreaseVmMaxMapCount
- Various user reports and confirmations on gaming performance improvement with increased `vm_max_map_count`.

I appreciate your time and consideration and welcome any feedback or suggestions on this matter.

Best regards,

Vincent DELOR