Questions tagged [cgroups]
Linux cgroups (control groups) allow limiting and accounting for resources on a system, including CPU, memory, and block I/O.
356 questions
1 vote
1 answer
44 views
rsyslog holds on to dirty pages and does not flush pages to disk
We have kernel dirty bytes settings configured as below. vm.dirty_background_bytes = 262144000 vm.dirty_background_ratio = 0 vm.dirty_bytes = 0 vm.dirty_expire_centisecs = 0 vm.dirty_ratio = 10 vm....
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1 vote
0 answers
178 views
How does memory.max.swap work in linux's cgroup v2?
I can't figure out how swap limitation should work based on the documentation. https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html memory.swap.max A read-write single value file which ...
- 11
14 votes
1 answer
1k views
How does the Linux kernel decide whether to deny memory allocation or invoke the OOM killer when a cgroup exceeds its memory limit?
This question comes from my curiosity about how Kubernetes handles resource requests and limits, especially memory constraints defined for pods. I understand that Kubernetes uses cgroups under the ...
- 143
2 votes
1 answer
292 views
Getting `cgroupfs-mount lacks a native systemd unit file, automatically generating a unit file for compatibility.`
I'm getting this error after a system upgrade to trixie. SysV service '/etc/init.d/cgroupfs-mount' lacks a native systemd unit file, automatically generating a unit file for compatibility. What is ...
- 35.2k
2 votes
0 answers
99 views
cgroup / cpu scheduler tuning questions, cpu pressure & uclamp behavior
I've been working on this for a few days and I'm scratching my head. The kernel docs for cgroups, pressure stall information, and the scheduler have not helped me shed any light on this so far, so I ...
- 21
0 votes
0 answers
123 views
I'm trying to resolve "Failed to open cgroup2 by ID" from my socket statistics "ss"
I'm learning to investigate my socket statistics so I do.. sudo ss -tulerp I get the following in the output.. Failed to open cgroup2 by ID Failed to open cgroup2 by ID Failed to open cgroup2 by ID ...
- 71
1 vote
0 answers
114 views
Too slow Tiered Memory Demotion and CPU Lock-up(maybe) with cgroup v2 memory.high
We are currently testing tiered memory demotion on a machine equipped with a CXL device. To facilitate this, we created a specific script (https://github.com/hyun-sa/comem) and are using the memory....
- 11
2 votes
1 answer
219 views
How does a cgroup namespace work?
I’m trying to understand how cgroup namespaces work, but I’m stuck on something that doesn’t make sense to me. My understanding is that a cgroup namespace should virtualize the cgroup hierarchy for a ...
- 95
0 votes
0 answers
68 views
cgoups: how safe is changing cpuset of a process?
I've recently started to observe unexpected output (and later stty -a outputs terminal settings different from new shell tab) from my shell scripts project. As of now, I'm very close to be sure the ...
- 1,319
0 votes
0 answers
38 views
KDE Desktop file to open a URL: Errors about cgroups no such process
I'm trying to get mailto URLs to open in gmail on KDE. Viagee used to be the accepted approach, but this seems to have been killed by Google revoking the app from its application tore and ignoring ...
- 1,432
1 vote
1 answer
268 views
Cgroups permission denied on Ubuntu 22.04.5 but works on Ubuntu 22.04.03
I'm trying to learn about cgroups. I ran these two commands: root@localhost:~# mkdir /sys/fs/cgroup/container_cpu root@localhost:~# echo '50000 100000' | sudo tee /sys/fs/cgroup/container_cpu/cpu.max ...
- 631
3 votes
0 answers
85 views
Implement a recovery virtual console for a hanged system
This might be a duplicate of "reserve memory for a set of processes", but I think my question is a little broader. I have a system that likes to hang a lot. I tend to use a lot of browser ...
- 273
1 vote
1 answer
302 views
isolcpus kernel option appears to break taskset
I have a laptop with an Intel Core i7-12700H CPU, running Ubuntu 24.04 LTS. This CPU has 6 “performance“ cores, each one running 2 threads, and 8 “efficient” cores. Most of the time, the “efficient” ...
- 1,729
0 votes
1 answer
112 views
Can you use `inotify` with `/sys/fs/cgroup/pids.peak`?
I am trying to implement a program that would run as PID1 in a Podman container and would wait for the the user to podman exec into the container at least once before exiting. /sys/fs/cgroup/pids.peak ...
1 vote
1 answer
75 views
Performance Degradation with rsync in container or cgroupv2 with MEM limit
I'm experiencing a significant performance degradation when using "rsync" to copy files over the network from within a container or cgroup with memory limits on Oracle Linux 9.2. The issue ...
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