Ubuntu 14.04 LTS High CPU by kswapd0 and Severe Memory Thrashing

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

System becomes sluggish with high CPU usage from memory reclaim activity.

Environment & Reproduction

Seen on low-RAM hosts running bursty workloads with insufficient swap headroom.

Root Cause Analysis

Aggressive reclaim loops occur when active memory exceeds available physical and swap limits.

Quick Triage

Check vmstat, free output, and top consumers for runaway memory processes.

Step-by-Step Diagnosis

Correlate page faults, swap in/out rates, and workload spikes to identify root pressure source.

Solution – Primary Fix

Reduce memory pressure, tune swappiness, and resize swap to stabilize reclaim behavior.

Solution – Alternative Approaches

Add RAM, isolate workloads, or cap memory with cgroups where feasible.

Verification & Acceptance Criteria

kswapd CPU drops to normal baseline and response latency returns to acceptable range.

Rollback Plan

Revert vm tunables and workload limits if side effects impact throughput.

Prevention & Hardening

Establish memory SLO alerts and right-size hosts to workload demand patterns.

Related Errors & Cross-Refs

Related to swap activation failures, OOM kills, and disk I/O saturation.

Related tutorial: View the step-by-step tutorial for Ubuntu 14.04 LTS.

View all Ubuntu 14.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Linux VM docs, kernel memory reclaim references, and Ubuntu performance guides.