Manual: choom

CHOOM(1)						User Commands						    CHOOM(1)

NAME
       choom - display and adjust OOM-killer score.

       choom -p PID

       choom -p PID -n number

       choom -n number [--] command [argument ...]

DESCRIPTION
       The choom command displays and adjusts Out-Of-Memory killer score setting.

OPTIONS
       -p, --pid pid
	   Specifies process ID.

       -n, --adjust value
	   Specify the adjust score value.

       -h, --help
	   Display help text and exit.

       -V, --version
	   Display version and exit.

NOTES
       Linux kernel uses the badness heuristic to select which process gets killed in out of memory conditions.

       The badness heuristic assigns a value to each candidate task ranging from 0 (never kill) to 1000 (always kill) to
       determine which process is targeted. The units are roughly a proportion along that range of allowed memory the
       process may allocate from based on an estimation of its current memory and swap use. For example, if a task is using
       all allowed memory, its badness score will be 1000. If it is using half of its allowed memory, its score will be 500.

       There is an additional factor included in the badness score: the current memory and swap usage is discounted by 3%
       for root processes.

       The amount of "allowed" memory depends on the context in which the oom killer was called. If it is due to the memory
       assigned to the allocating task’s cpuset being exhausted, the allowed memory represents the set of mems assigned to
       that cpuset. If it is due to a mempolicy’s node(s) being exhausted, the allowed memory represents the set of
       mempolicy nodes. If it is due to a memory limit (or swap limit) being reached, the allowed memory is that configured
       limit. Finally, if it is due to the entire system being out of memory, the allowed memory represents all allocatable
       resources.

       The adjust score value is added to the badness score before it is used to determine which task to kill. Acceptable
       values range from -1000 to +1000. This allows userspace to polarize the preference for oom killing either by always
       preferring a certain task or completely disabling it. The lowest possible value, -1000, is equivalent to disabling
       oom killing entirely for that task since it will always report a badness score of 0.

       Setting an adjust score value of +500, for example, is roughly equivalent to allowing the remainder of tasks sharing
       the same system, cpuset, mempolicy, or memory controller resources to use at least 50% more memory. A value of -500,
       on the other hand, would be roughly equivalent to discounting 50% of the task’s allowed memory from being considered
       as scoring against the task.

AUTHORS
       Karel Zak 

SEE ALSO
       proc(5)

REPORTING BUGS
       For bug reports, use the issue tracker .

AVAILABILITY
       The choom command is part of the util-linux package which can be downloaded from Linux Kernel Archive
       .

util-linux 2.41.3					 2025-12-15						    CHOOM(1)