rfjakob/earlyoom
Earlyoom
earlyoom is a Linux OOM killer daemon that monitors system memory and terminates processes to prevent system freezes. It acts as a memory resource monitor and process termination manager, tracking available RAM and swap space to ensure the operating system remains responsive.
The project distinguishes itself by selecting termination targets based on the largest resident set size rather than relying solely on kernel OOM scores. It provides granular control through regular expression-based process filtering to protect specific applications and can terminate entire process groups to ensure complete application cleanup.
The system includes a notification framework that sends d-bus alerts when memory reaches critical thresholds and supports custom termination hooks. These hooks allow for the execution of external scripts and binaries before or after a process is killed. It also integrates with the native Linux kernel OOM killer to defer victim selection to the OS when requested.
The daemon extracts process statistics and memory data by parsing the kernel pseudo-filesystem and records operational events via system event logging.
Features
- Automated Process Termination - Automatically kills memory-hungry processes based on resident set size and user-defined rules to prevent system freezes.
- OOM Prevention Systems - Monitors memory and terminates processes to prevent system freezes and Out-Of-Memory crashes.
- Process Termination Managers - Manages the selection and termination of processes based on resident set size and configuration rules.
- Exemption Rules - Adjusts the likelihood of a process being killed or exempts it based on regular expression matches.
- Memory Management - Manages system responsiveness by reclaiming memory through the termination of memory-intensive processes.
- Memory-Based Victim Selection - Identifies the process to terminate based on the largest resident set size rather than kernel OOM scores.
- Process Targeting by Name - Identifies target processes for termination based on memory usage, user ownership, or name patterns.
- Procfs Extractions - Extracts real-time system memory and process statistics by parsing the Linux /proc pseudo-filesystem.
- Resident Set Size Selection - Identifies the best process to terminate by selecting the one with the largest resident set size.
- Memory-Hogging Process Termination - Kills the largest process by resident set size to reclaim memory and maintain system responsiveness.
- Out-of-Memory Analysis - Integrates with and manages the behavior of the native Linux kernel OOM killer.
- Threshold-Driven Script Execution - Automatically triggers process termination sequences when available RAM and swap fall below configured percentage thresholds.
- Kernel OOM Triggering - Allows the system to defer the selection of a victim process to the native Linux kernel OOM killer.
- Process Resource Statistics - Extracts real-time process statistics, including parent PIDs and resident set sizes, from the system.
- System Resource Monitors - Tracks available RAM and swap space in real-time to trigger alerts or corrective process termination.
- System Memory Monitoring - Parses kernel memory statistics to track available RAM and swap space in real-time.
- System Memory Monitors - Monitors overall system RAM and swap usage by parsing kernel statistics.
- Process Memory Monitors - Analyzes per-process resident set size and OOM scores to identify the best candidates for termination.
- External Script Hooks - Provides architectural hooks to execute external shell scripts before or after a process is terminated.
- Process Group Signaling - Implements process group signaling to ensure all related processes in a multi-process application are terminated together.
- Termination Rule Configurations - Provides configuration for memory and swap thresholds to determine which processes to prefer, avoid, or ignore.
- Process Protection Rules - Excludes specific processes from being killed by matching their names against regular expressions.
- Regex-Based Filters - Uses regular expressions to protect critical applications or prioritize specific processes for termination.
- Kernel OOM Triggering - Integrates with the native Linux kernel OOM killer to defer victim selection to the OS.
- Memory Threshold Alerting - Dispatches system notifications via d-bus when memory usage reaches critical user-defined thresholds.
- Custom OOM Workflows - Executes custom scripts and notifications as part of a structured workflow before and after process termination.
- Process Termination Notifications - Sends system notifications or executes custom scripts to alert administrators after a process is killed.
