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Date: Wed, 20 Mar 2024 22:05:34 +0100 (CET)
From: vincentdelor@free.fr
To: linux-kernel@vger.kernel.org
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Subject: Increase Default vm_max_map_count to Improve Compatibility with
 Modern Games
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Hello,

I am writing to highlight an issue impacting many Linux users, especially t=
hose who enjoy modern gaming. The current default setting of `vm_max_map_co=
unt` at 65530 has been linked to crashes or launch failures in several cont=
emporary games.

To address this, I have opened a detailed bug report (218616 =E2=80=93 Incr=
ease Default vm_max_map_count to Improve Gaming Experience on Linux) availa=
ble at: 218616 =E2=80=93 Increase Default vm_max_map_count to Improve Gamin=
g 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 mitigat=
ed by increasing the `vm_max_map_count` value to over 1048576, which has be=
en confirmed to resolve the crashes without introducing additional bugs rel=
ated to map handling.

This issue affects a wide range of users and has been noted in distribution=
s like Fedora and Pop!_OS, which have already adjusted this value to accomm=
odate 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 r=
eported 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 t=
o 65530 and attempt to run affected games such as Hogwarts Legacy or Star C=
itizen.
2. Observe that the games crash or fail to start with the default `vm_max_m=
ap_count` setting.
3. Modify `/etc/sysctl.conf` to include `vm.max_map_count=3D1048576` (or an=
other 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_co=
unt` limitations.

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

**Suggested Fix:**
Increase the default `vm_max_map_count` value in Linux to a value greater t=
han 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/Inc=
reaseVmMaxMapCount
- 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 sugges=
tions on this matter.

Best regards,

Vincent DELOR