Discover why Linus Torvalds reverted DAMON's default enablement in Linux 6.16. Learn about DAMON’s benefits, kernel configuration policies, and what this means for sysadmins and developers. Stay updated on Linux kernel optimization trends.
The Controversy Around DAMON’s Default Status
The Linux kernel is renowned for its meticulous approach to feature integration, ensuring stability and performance. Recently, a debate emerged around DAMON (Data Access Monitoring), a system monitoring and optimization tool developed by Amazon and collaborators.
Initially set to be enabled by default in Linux 6.16, the decision was swiftly reverted by Linus Torvalds, sparking discussions on kernel configuration policies.
This article explores:
What DAMON is and its role in Linux performance tuning
Why it was proposed for default enablement
Linus Torvalds’ rationale for rejecting the change
The broader implications for Linux kernel development
What Is DAMON? A Deep Dive into Linux’s Data Access Monitor
DAMON (Data Access MONitor) is an advanced kernel subsystem designed for:
Efficiency optimization (memory, CPU, I/O)
System performance monitoring
Proactive resource management
Key Benefits of DAMON
✔ Lightweight profiling – Minimal runtime overhead
✔ Distro adoption – Already enabled in AlmaLinux, Amazon Linux, Android, CentOS, Debian, Fedora, and Oracle Linux
✔ No runtime impact unless explicitly activated – Safe for production environments
Despite its advantages, enabling DAMON by default was deemed unnecessary by Torvalds.
Why Was DAMON Almost Enabled by Default?
The original patch submission argued:
Widespread distro adoption – Major Linux distributions already enable it.
Negligible footprint – Only 0.1% increase in kernel size.
User convenience – Saves manual configuration for sysadmins and developers.
However, Torvalds disagreed, emphasizing:
"No, we don't make random features default to being on."
His stance aligns with Linux’s long-standing policy:
New features require strong justification for default activation
Avoid unnecessary bloat – Even minor size increases add up
Prevent confusion – Users should opt into advanced tools
Linus Torvalds’ Decision: A Lesson in Kernel Governance
Torvalds’ reversion of the DAMON patch highlights key principles in Linux kernel development:
1. Minimalism Over Convenience
Default configurations must be justified
"Odd-ball" features stay opt-in
2. Avoiding Unnecessary Kernel Bloat
Even a 0.1% size increase is scrutinized
Production systems prioritize stability over experimental tools
3. User Choice Matters
Experts can enable DAMON manually
Default settings should cater to the broadest use case
This decision reinforces why Linux remains the gold standard for system stability.
Current Status: DAMON Remains Disabled by Default
Following Torvalds’ intervention:
Linux 6.16-rc2 and later kernels disable DAMON by default
Users must manually enable
CONFIG_DAMON
Distros may still pre-enable it in their builds
Should You Use DAMON?
✅ Yes, if:
You need fine-grained system monitoring
Your workload benefits from memory/CPU optimizations
❌ No, if:
You run ultra-minimalist kernels
You don’t require advanced profiling
Conclusion: Balancing Innovation and Stability in Linux
The DAMON debate underscores the challenge of modern kernel development—weighing cutting-edge features against core stability. While DAMON offers valuable insights, Torvalds’ decision ensures Linux remains lean and predictable.
For sysadmins and developers, the takeaway is clear:
Evaluate new kernel features before adoption
Customize builds based on workload needs
Stay informed on kernel policy changes
Frequently Asked Questions (FAQ)
Q: Does DAMON impact performance when disabled?
A: No—DAMON only activates when explicitly configured.
Q: Which Linux distros enable DAMON by default?
A: Amazon Linux, Android, Fedora, and others enable it in their kernel builds.
Q: Can I still use DAMON in the latest kernel?
A: Yes, but you must manually enable CONFIG_DAMON.
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