Questions tagged [sysfs]
12 questions
54
votes
7 answers
How do I modify "/sys/kernel/mm/transparent_hugepage/enabled"
I use mongodb 3.0 and I find a warning:
MongoDB shell version: 3.0.0
connecting to: test
Server has startup warnings:
2015-03-13T16:28:29.405+0800 I CONTROL [initandlisten]
2015-03-13T16:28:29.406+0800 I CONTROL [initandlisten] ** WARNING:…
Feng Yu
- 857
32
votes
1 answer
What's the "/sys" directory for?
A while ago I noticed this directory that I had not ever seen before, /sys. I researched a bit and read that "modern Linux systems" often have this directory, and that it manages devices. I thought that was what /dev was for. I can't seem to find a…
Chev_603
- 1,728
4
votes
2 answers
No `rc.local` in 16.10, so how can I add a command to set brightness on boot?
I previously solved the problem by adding a command:
echo X > /sys/class/backlight/intel_backlight/brightness
to /etc/rc.local on Ubuntu 14.04 . But there is no /etc/rc.local on Ubuntu 16.10 . I don't know how to solve it now. Is there a new…
Ims Joe
- 43
3
votes
2 answers
'cat': can't open file: Permission denied
I am trying to copy the whole / directory to some other location. When doing cp recursively, it fails on some files like:-
/ # ls -lrt /sys/module/nf_conntrack_ipv4/uevent
--w------- 1 root root 4096 Mar 7 06:29…
Rahul
- 279
2
votes
1 answer
Ubuntu 16.04 Complicated Interface Names
I'm trying to figure out how to restore the simple interface names in Ubuntu 16.04. I.e. enp3s0 renamed to eth0.
I have tried to modify the GRUB configuration. I have tried editing /etc/udev/rules.d/10-network.rules, but both methods did nothing…
Faith Skater
- 63
2
votes
2 answers
how do I make "/sys/kernel/mm/transparent_hugepage/defrag" never status to close the THP warning
reboot the linux (ubuntu 16.04 redis 4.011)
/var/log/redis.log
shows
# WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command…
robspin
- 133
1
vote
1 answer
How to change permission for Sysfs file using udev rules
I am writing a custom module kernel that boots at startup. I can write in the sysFS file using this :
echo -e "(0,0,255,750)\n" | sudo tee /sys/fs/led_sysfs/led_value
But I will have another software that will need to write to the sysFs file. This…
Tamanar
- 11
0
votes
2 answers
How to delete debug files in /sys/kernel/debug?
sudo find / -size +5G -ls
listed debug files with more than 8GB size at /sys/kernel/debug/dri/n/amdgpu_vram
(n is the number of GPUs)
These might be useless debug files.
Cannot delete them (error "Operation not permited").
How to delete these…
cjclm7
- 305
- 1
- 3
- 12
0
votes
0 answers
When running the dvb-fe-tool --femon command, a large number of error logs are recorded in the syslog
Every time I run the command dvb-fe-tool --femon, the following error logs are recorded in the syslog. Since the CPU load is also high, I would like to reduce it. If you know of any methods, please let me know.
PRETTY_NAME="Ubuntu 24.04.1…
tagawa
- 1
0
votes
1 answer
What is the point of creating a symlink in /dev direcory?
I understand that you can write custom udev rules to create a symlink in /dev directory.
Wondering what having a symlink in /dev accomplishes?
What is the symlink linking to?
ACTION=="add", SUBSYSTEM=="usb", ATTRS{idVendor}=="0461",…
Dr. Chocolate
- 111
- 3
0
votes
0 answers
/etc setting to ping as non-root freely
Since some not long time ping stopped working as non-root (I'm not sure if it distro-wide or maybe it is my custom kernel). The ping is fixed by this command:
sysctl -w net.ipv4.ping_group_range="0 1000"
But the problem is I cannot add it to…
midenok
- 848
- 1
- 10
- 15
0
votes
1 answer
16.04 How do I stop Mongo 3.x.x and 4.x.x from complaining about WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'?
A default installation of MongoDB on Ubuntu 18.04 gives the following warning about transparent hugepage defrag. How to deal with it?
init0
- 101
- 6