Kernel
Get OOM score
cat /proc/<pid>/oom_score
Disable
echo 1 > /proc/sys/vm/panic_on_oom
Disable for proccess
echo -17 > /proc/<pid>/oom_adj
Set priority
echo <+-value> > /proc/<pid>/oom_adj
/etc/sysctl.conf
Maximum of objects inotify per user
fs.inotify.max_user_instances=
Maximum of watch files and directories per object inotify
fs.inotify.max_user_watches=
Maximum of events in queued
fs.inotify.max_queued_events=
Maximum of open descriptors
fs.file-max=
Maximum queue size of packet
net.core.netdev_max_backlog =
Maximum number of open sockets waiting to be connected
net.core.somaxconn =
Enable
-
On work
sysctl kernel.sysrq=1 echo "1" > /proc/sys/kernel/sysrq -
On boot
echo "kernel.sysrq = 1" >> /etc/sysctl.d/99-sysctl.conf -
Before mounting and ini
Kernel
sysrq_always_enabled=1
Set dump directory
kernel.core_pattern = <path>/core.%u.%e.$p
Configure
make menuconfig
Make kernel all targets
make -j(<NUMBER_OF_CORES> + 1) all
Make modules
make modules_install
Make headers
make headers_install
Install kernel
make install
Show memory overcommit
cat /proc/sys/vm/overcommit_memory
Unraw
Alt+SysRq+r
Terminate
Alt+SysRq+e
Kill
Alt+SysRq+i
Sync
Alt+SysRq+s
Unmount
Alt+SysRq+u
Reboot
Alt+SysRq+b
Write cache to persistent storage
sync
PageCache
sync; echo 1 > /proc/sys/vm/drop_caches
Inode and dentrie
sync; echo 2 > /proc/sys/vm/drop_caches
sysctl -w vm.drop_caches=3
Inode, dentrie and PageCache
sync; echo 3 > /proc/sys/vm/drop_caches
Swap
swapoff -a && swapon -a
Percentage value controls the tendency of the kernel to reclaim the memory which is used for caching of directory and inode objects
echo 1000 > /proc/sys/vm/vfs_cache_pressure
View the size of the entropy pool
cat /proc/sys/kernel/random/poolsize
View status of server’s entropy
cat /proc/sys/kernel/random/entropy_avail