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Add vm.conf with sysctl parameters optimized for embedded network devices 512MB-8GB of memory. Focus on fast recovery and determinism. - Panic on OOM - Aggressive dirty page writeback - Increased watermark scale factor for proactive reclaim Includes tuning guide documentation for alternative scenarios. Signed-off-by: Richard Alpe <richard@bit42.se>
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Pull request overview
This PR adds kernel memory tuning configuration optimized for embedded network devices with limited memory (512MB-4GB RAM). The configuration focuses on aggressive dirty page writeback and OOM panic behavior to ensure deterministic recovery on memory-constrained systems.
Changes:
- Add sysctl configuration for memory management with aggressive dirty page limits and OOM panic behavior
- Add comprehensive tuning guide documentation with alternative configurations for different system profiles
- Update ChangeLog and documentation index
Reviewed changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
| board/common/rootfs/etc/sysctl.d/vm.conf | New sysctl configuration file with memory tuning parameters for embedded devices |
| doc/system-tuning.md | New documentation guide with memory tuning recommendations for different system profiles |
| doc/ChangeLog.md | Added entry documenting the new memory tuning feature |
| mkdocs.yml | Added system tuning guide to Developer's Corner navigation |
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| # Memory and OOM tuning for embedded network devices | |||
| # Optimized for systems with 512MB-4GB RAM | |||
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The PR description states the configuration is "optimized for embedded network devices 512MB-8GB of memory" but this file states "512MB-4GB RAM". This inconsistency should be resolved. Based on the documentation file which also mentions "512MB-4GB RAM" and provides separate guidance for "4GB+ Memory", the configuration file appears correct and the PR description may need updating.
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| ## Memory | ||
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| Default memory tuning is defined in `/etc/sysctl.d/vm.conf`, optimized for embedded network devices with 512MB-4GB RAM. |
There was a problem hiding this comment.
The PR description states the configuration is "optimized for embedded network devices 512MB-8GB of memory" but this documentation states "512MB-4GB RAM". This inconsistency should be resolved. Based on the configuration file comments and the fact that this documentation provides separate guidance for "4GB+ Memory", the documentation appears correct and the PR description may need updating.
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| # OOM Behavior | ||
| # Panic on OOM for fast system reset and recovery | ||
| vm.panic_on_oom=1 |
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Setting vm.panic_on_oom=1 will cause a kernel panic on OOM, but without also setting kernel.panic to a non-zero value (e.g., kernel.panic=10), the system will hang at the panic screen rather than automatically rebooting. For "fast system reset and recovery" as stated in the comments and PR description, consider adding kernel.panic=10 (or similar value) to enable automatic reboot after a panic. This would complete the "deterministic recovery" behavior.
| vm.panic_on_oom=1 | |
| vm.panic_on_oom=1 | |
| # Automatically reboot 10 seconds after a kernel panic for deterministic recovery | |
| kernel.panic=10 |
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Description
Add vm.conf with sysctl parameters optimized for embedded network devices 512MB-8GB of memory.
Focus on fast recovery and determinism.
Includes tuning guide documentation for alternative scenarios.
Checklist
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