Bug 1214445

Summary:	Change: Increase vm.max_map_count value
Product:	[openSUSE] openSUSE Tumbleweed	Reporter:	B <reiokorn>
Component:	Kernel	Assignee:	openSUSE Kernel Bugs <kernel-bugs>
Status:	RESOLVED FIXED	QA Contact:	E-mail List <qa-bugs>
Severity:	Enhancement
Priority:	P5 - None	CC:	jslaby
Version:	Current
Target Milestone:	---
Hardware:	x86-64
OS:	openSUSE Tumbleweed
Whiteboard:
Found By:	---	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---

Description B 2023-08-21 16:25:30 UTC

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. 
While Tumbleweed defaults to of ~65k for vm.max_map_count and matches that of many other OS defaults, SteamOS for e.g. ships with a value of 2147483642.

Most software doesn't use too many mmaps that the 65k default is suitably for the vast majority of user-space software out there. But in particular for a few and unfortunately increasing number of Windows games running on Linux via Steam Play (Proton), that limit can actually be exceeded. Among the known games needing a higher memory map limit are DayZ, Hogwarts Legacy, Counter Strike 2, and others. 


-Fixes some newer video games, as mentioned in https://www.phoronix.com/news/Fedora-39-Max-Map-Count-Approve

-Without this you will experience crashes on some newer games. (Hogwarts Legacy, Etc..)

The easiest way to "fix" this is to add a drop-in conf file into 
/usr/lib/sysctl.d/ with the desired (higher) value.

Kernel Docs: kernel.org/doc/Documentation/sysctl/vm.txt
SUSE Support: suse.com/support/kb/doc/?id=000016692

Comment 1 Jiri Slaby 2023-09-13 10:47:06 UTC

Fedora went for 1'048'576 in the end. I don't see reasons why we should keep the limit low, unless something breaks.

So raising to 1048576 in master.