Debian 13 High CPU From kswapd and Memory Reclaim 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 slow or unresponsive under sustained memory pressure.

Environment & Reproduction

Observed on memory-constrained hosts running bursty workloads.

Root Cause Analysis

Aggressive reclaim and swap activity cause CPU spikes and latency.

Quick Triage

Inspect memory, swap, and page fault activity.

Step-by-Step Diagnosis

Profile top memory consumers and reclaim pressure metrics.

Solution – Primary Fix

Reduce memory pressure by tuning swappiness and scaling memory allocation.

Solution – Alternative Approaches

Add RAM or enforce cgroup memory limits for noisy workloads.

Verification & Acceptance Criteria

CPU usage stabilizes and latency remains within service SLO targets.

Rollback Plan

Revert kernel memory tuning if workload behavior worsens.

Prevention & Hardening

Track memory pressure indicators and right-size workloads proactively.

Related Errors & Cross-Refs

Related to OOM kills and swap saturation incidents.

Related tutorial: View the step-by-step tutorial for Debian 13.

View all Debian 13 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Linux memory management and performance tuning references.