I want to limit the CPU usage of the process through CGroup.After searching for some information on the Internet, I learned that it needed to be revised "cpu.cfs_period_us" and "cpu.cfs_quota_us",but now I can`t find these two files in cgroup.
My steps are as follows
The path "/sys/fs/cgroup" already exists in my Linux system, but there are no files in it.So I mount the cgroup/cpu/ file according to the reference standard steps:
cd /sys/fs/
mount -t tmpfs cgroup_root ./cgroup
mkdir cgroup/cpu
mount -t cgroup -ocpu cpu ./cgroup/cpu/
What puzzles me is that my ./cgroup/cpu/ directory doesn't have "cpu.cfs_period_us" and "cpu.cfs_quota_us"... What's the reason? Is it a kernel configuration problem?
I have these files in my ./cgroup/cpu path:
/sys/fs # ls ./cgroup/cpu/
cgroup.clone_children cpu.rt_period_us release_agent
cgroup.procs cpu.rt_runtime_us tasks
cgroup.sane_behavior haoel
cpu.notify_on_migrate notify_on_release
Other information
1)my linux system info
/ # cat /proc/version
Linux version 3.18.20 (gcc version 4.9.2 (GCC) ) #1 PREEMPT Tue Mar 9 03:52:45 CST 2021
/ # uname -a
Linux mdm9607-perf 3.18.20 #1 PREEMPT Tue Mar 9 03:52:45 CST 2021 armv7l GNU/Linux
2)Related kernel configuration
CONFIG_CGROUPS=y
CONFIG_CGROUP_DEBUG=y
CONFIG_CGROUP_FREEZER=y
# CONFIG_CGROUP_DEVICE is not set
# CONFIG_CPUSETS is not set
CONFIG_CGROUP_CPUACCT=y
CONFIG_RESOURCE_COUNTERS=y
# CONFIG_MEMCG is not set
# CONFIG_CGROUP_PERF is not set
CONFIG_CGROUP_SCHED=y
# CONFIG_FAIR_GROUP_SCHED is not set
CONFIG_RT_GROUP_SCHED=y
# CONFIG_BLK_CGROUP is not set
Related
# cat /etc/oracle-release
Oracle Linux Server release 7.8
uname -a
Linux 3.10.0-957.el7.x86_64 #1 SMP Thu Oct 4 20:48:51 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
cat 99-custom.rules
ACTION!="add|change", GOTO="rule_end"
ENV{ID_VENDOR}=="NETAPP*", RUN+="/bin/sh -c 'echo 4096 > /sys%p/queue/max_sectors_kb'"
LABEL="rule_end"
----2nd option using KERNEL option just for dm-* devices
ACTION!="add|change", GOTO="rule_end"
KERNEL=="dm-[0-9]*",ENV{ID_VENDOR}=="NETAPP*", RUN+="/bin/sh -c 'echo 4096 > /sys%p/queue/max_sectors_kb'"
LABEL="rule_end"
udevadm control --reload-rules && udevadm trigger
/sbin/udevadm trigger --type=devices --action=change
Issue : We don't see udev rule applied to all dm-* device
/sys/block/dm-19/queue/max_sectors_kb:512
/sys/block/dm-9/queue/max_sectors_kb:512
We even tried to remove ENV{ID_VENDOR}=="NETAPP*" from rule
What we need to apply max_sectors_kb to 4096 to all dm-* ( multipath devices )
and all sd* devices can be left default of 512
Any idea what could be wrong ?
I want to know the creation time for the filesystem in linux .
You can use tune2fs tool to get creation time:
sudo tune2fs -l /dev/sda1
In result one of the lines is:
Filesystem created: Mon Apr 4 15:07:44 2016
Last mount time: Mon Dec 12 14:48:51 2016
Last write time: Mon Dec 12 14:48:50 2016
This command works on ext2 -ext 4 filesystem. The command is not supported on XFS filesystem. Refer the below link :man tune2fs
I've just tried Bash on my Windows 10 PC, and it works fine. However, I found that there is no such thing as loop devices by ls /dev/, and modprobe loop gives an error output.
Does it mean this Bash doesn't support loop devices at all or is there a solution for mounting an image as a loop device?
Windows Subsystem for Linux 1 (WSL, formerly known as Bash on Ubuntu on Windows) did not support loop devices. There was a feature request and an issue about it on Microsoft's Git repo.
WSL 2, however, does support loop devices.
$ uname -a
Linux Blade 5.10.102.1-microsoft-standard-WSL2 #1 SMP Wed Mar 2 00:30:59 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
$ fallocate -l 1G test.img
$ mkfs.ext3 test.img
mke2fs 1.45.5 (07-Jan-2020)
Discarding device blocks: done
Creating filesystem with 262144 4k blocks and 65536 inodes
Filesystem UUID: 549cca4d-a65f-4f4f-8428-e324feaed3d0
Superblock backups stored on blocks:
32768, 98304, 163840, 229376
Allocating group tables: done
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done
$ sudo mount -o loop test.img /media/
$ ls /media/
lost+found
Do you know that Bash is just a shell (something that reads your commands, executes them, pipes between them and permits you to write scripts) and is not an operating system?
Loop devices are part of the Linux kernel, and they simply don't exist in the Windows kernel.
I have been given a server with OS installed. I want to check which Operating system is installed in it. I have used uname -a with ouput of
Linux ctl 2.6.32-573.3.1.el6.x86_64 #1 SMP Mon Aug 10 09:44:54 EDT 2015 x86_64 x86_64 x86_64 GNU/Linux
Any suggestions ?
You could use the /etc/os-release file, which contains information on the os using the freedesktop spec.
Printing out just the OS name and version:
awk -F '=' '/PRETTY_NAME/ { print $2 }' /etc/os-release
Using os-release file available in Linux:
cat /etc/os-release
on many OS's, you can get the os via:
lsb_release -d
The el6 in the kernel version could indicate a RedHat (thus Fedora as well), Oracle, Centos, Scientific Linux. Potentially others as well.
At least on some of these systems (others as well) the distribution can be identified from the /etc/issue* files. For example:
> ls -la /etc/issue*
-rw-r--r-- 1 root root 57 Oct 22 2014 /etc/issue
-rw-r--r-- 1 root root 55 Oct 22 2014 /etc/issue.net
> cat /etc/issue
Welcome to openSUSE 13.2 "Harlequin" - Kernel \r (\l).
you can try this command to check all detail related to operating system version:
cat /etc/*elease
When I am trying to set kernel.softlockup_panic value to 30 instead of 0. I am getting Invalid argument error
# sysctl -w kernel.softlockup_panic=30
Error message
# sysctl: setting key "kernel.softlockup_panic": Invalid argument
kernel.softlockup_panic = 30
Can anyone please guide?
I am using SLES12 64bit OS
# uname -a
Linux linux-r1qg 3.12.28-4-default #1 SMP Thu Sep 25 17:02:34 UTC 2014 (9879bd4) x86_64 x86_64 x86_64 GNU/Linux
I Have used syctl for other purposes. Guess this params is not supported by kernel .
you can check this thru either of the commands
sudo sysctl -a | grep softlockup
cat /proc/sys /etc/sysctl.conf