https://bugs.kde.org/show_bug.cgi?id=476972
Bug ID: 476972
Summary: Plasma shell freezes for a few seconds when adding or
removing icons
Classification: Plasma
Product: plasmashell
Version: 5.27.9
Platform: Archlinux
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: Icon
Assignee: plasma-b...@kde.org
Reporter: s.r...@outlook.com
Target Milestone: 1.0
SUMMARY
When an arbitrary number of icons exist in the user's icon paths, a several
second stall will occur when adding or removing even a single (empty) file from
/usr/share/icons or the user's .local icon directory. The mouse remains
functional but the display is frozen. The system recovers shortly, but the
disruption to one's work is complete.
My investigation has led me to ~/.cache/icon-cache.kcache as a culprit
STEPS TO REPRODUCE
1. Have a good number of icons in /usr/share/icons. I.e. the tela-icon-theme
aur package has a lot
2. Install or remove this package
alternatively, with tela-icon-theme installed (also able to reproduce at times
with just breeze, oxygen and adwaita):
touch /usr/share/icons/foo
rm /usr/share/icons/foo
OBSERVED RESULT
When critical mass is observed, adding or changing even a single file in the
icon directory results in a several second hang. It appears the
~/.cache/icon-cache.kcache file is being updated in this time and this update
is the cause of the hangs.
This makes sense as to why even removing files from the system results in
hangs, it's less the IO of the icon adding process but the resulting cache
update done by plasma.
EXPECTED RESULT
The icon cache to be updated without disrupting the user's experience
SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch Linux 6.6.1
KDE Plasma Version: 5.27.9
KDE Frameworks Version: 5.112.0
Qt Version: 5.15.11
ADDITIONAL INFORMATION
NVMe m.2 1TB disk is on the FS, AMD 5900x processor
I can only reproduce the hangs in plasma desktop. I cannot replicate a hang if
doing the same action on a different tty without plasma loaded or over ssh. In
fact, I can easily continue to watch things like htop, iotop etc over ssh all
while my desktop is frozen.
I originally suspected some feature of btrfs to blame, but I cannot mitigate
the issue with the use of any:
- disabling zstd compression
- disabling cow (and therefore compression)
- symlinking ~/.cache/icon-cache.kcache to a file on an ext4 SSD (bypassing
btrfs completely)
However, I did discover the following mitigations to the freezes:
- symlink the icon-cache.kcache file to /dev/shm
- change the ownership of icon-cache.kcache to root: to prevent the system from
updating the cache file during changes to this directory.
Hence, I'm quite certain the issue lies in some process that could be made a
bit nicer during the cache update process. It seems the update is happening on
the same thread as UI functions and ends up blocking updates to the graphical
session.
--
You are receiving this mail because:
You are watching all bug changes.
