https://bugs.kde.org/show_bug.cgi?id=506863
Bug ID: 506863
Summary: On a 15.6GiB RAM system, kwin will crash with out of
memory even when more than 8GiB is free when
overcomitting is disabled
Classification: Plasma
Product: kwin
Version First 6.4.2
Reported In:
Platform: Other
OS: Linux
Status: REPORTED
Severity: wishlist
Priority: NOR
Component: general
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
SUMMARY
On a 15.6GiB RAM system, kwin will crash with out of memory even when more than
8GiB is free when overcommitting is disabled, with kernel log messages like
these:
[ 6219.447523] __vm_enough_memory: pid: 5777, comm: kwin_wayland, bytes:
3739648 not enough memory for the allocation
I understand that disabling overcommitting memory has inherent limitations in
particular when it comes to using fork() instead of vfork(). However, I wanted
to leave this here in case there is some obvious low hanging fruit on how to
improve this. Disabling overcommitting can be useful as a protective measure
for some processes from others and to enable programs capable of recovering
from failed allocations to do so, I recognize almost nobody uses this but it
would still be neat if it worked. Also, I distinctly remember not having this
issue quite a while ago when testing out this kernel mode, so this might be a
regression of some sort.
Perhaps kwin is mmap()ing some huge files or should be using vfork() in an
obvious place?
My apologies if this ticket isn't useful.
STEPS TO REPRODUCE
1. Disable overcommitting RAM on a ~16GB RAM system
2. Do light usage with roughly 3GiB RAM taken.
3. It seems like kwin_wayland will eventually crash.
OBSERVED RESULT
Even with plenty of memory free, kwin seems to do something that requires a
relatively giant allocation (even if not actually written into and therefore
not actually reserved with overcommitting disabled) when perhaps that might be
avoidable.
EXPECTED RESULT
It would be nice if kwin somewhat worked with overcommitting disabled, at least
under such low RAM usage.
SOFTWARE/OS VERSIONS
Windows:
macOS:
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: postmarketOS EDge
KDE Plasma Version: 6.4.2
KDE Frameworks Version: 6.15.0
Qt Version: 6.8.3
ADDITIONAL INFORMATION
--
You are receiving this mail because:
You are watching all bug changes.
