Bug 494200 - Increase vm.max_map_count
Summary: Increase vm.max_map_count
Status: CONFIRMED
Alias: None
Product: neon
Classification: KDE Neon
Component: general (show other bugs)
Version: unspecified
Platform: Neon Linux
: NOR normal
Target Milestone: ---
Assignee: Neon Bugs
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2024-10-06 09:06 UTC by Thomas-Luke Duffin
Modified: 2024-10-17 10:32 UTC (History)
3 users (show)

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Description Thomas-Luke Duffin 2024-10-06 09:06:05 UTC
SUMMARY
To improve compatibility with certain memory-intensive applications, we should increase the default map_map_count value to a higher value (eg. 2147483642),

This fixes a number of crashes in user applications such as Valve's game Deadlock, which otherwise crashes on startup once enough memory is allocated.

Other distros such as Fedora are also increasing this default value, so updating this will keep Neon in line with other Linux systems and reduce potential incompatibility reports later.

STEPS TO REPRODUCE
Another example: https://bugs.kde.org/show_bug.cgi?id=396142

1. Launch an application known to crash due to vm max count limitation (eg. Deadlock)
2. Wait

OBSERVED RESULT
Application will crash

EXPECTED RESULT
Application is stable

SOFTWARE/OS VERSIONS
KDE Plasma Version: 6.1.5
KDE Frameworks Version: 6.6.0
Qt Version: 6.7.2
Kernel Version: 6.8.0-45-generic (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 7840HS with Radeon 780M Graphics
Memory: 27.1 GiB of RAM
Graphics Processor: AMD Radeon Graphics

ADDITIONAL INFORMATION
I know KDE Neon is a "testing" distro and "not meant for daily driving" but I think this is a win-win for everyone - Daily drivers will get better app compatibiility and a more stable system, and devs will have a more "standard" Linux system that will represent the platforms that KDE is running on.
Comment 1 Jonathan Riddell 2024-10-17 10:32:17 UTC
/etc/sysctl.d/10-map-count.conf from procps already changes this to be over a million
vm.max_map_count=1048576

I can't say I know any better than what Ubuntu picks for it but looking at
https://fedoraproject.org/wiki/Changes/IncreaseVmMaxMapCount
Fedora have picked the same