Nathan Roberts created YARN-4768:
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Summary: getAvailablePhysicalMemorySize can be inaccurate on linux
Key: YARN-4768
URL: https://issues.apache.org/jira/browse/YARN-4768
Project: Hadoop YARN
Issue Type: Bug
Components: nodemanager
Affects Versions: 2.7.2, 3.0.0
Environment: Linux
Reporter: Nathan Roberts
Assignee: Nathan Roberts
Algorithm currently uses "MemFree" + "Inactive" from /proc/meminfo
"Inactive" may not be a very good indication of how much memory can be readily
freed because it contains both:
- Pages mapped with MAP_SHARED|MAP_ANONYMOUS (regardless of whether they're
being actively accessed or not. Unclear to me why this is the case...)
- Pages mapped MAP_PRIVATE|MAP_ANONYMOUS that have not been accessed recently
Both of these types of pages probably shouldn't be considered "Available".
"Inactive(file)" would seem more accurate but it's not available in all kernel
versions. To keep things simple, maybe just use "Inactive(file)" if available,
otherwise fallback to "Inactive".
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