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The cgroup available memory calculation used memory.current (total cgroup usage) directly, which includes page cache (file-backed memory). Since page cache is reclaimable by the kernel under memory pressure, it should not count as unavailable. This caused GetCurrentMemAvailableMiB() to significantly underestimate available memory, making QEMU instance scheduling overly conservative. Read the "file" field from /sys/fs/cgroup/memory.stat, which reports the page cache size in bytes, and subtract it from current usage before computing available memory. The effective formula becomes: available = limit - (current - page_cache) This mirrors how /proc/meminfo computes MemAvailable by considering reclaimable caches. A new helper getCgroupMemoryStatField() is added for parsing individual fields from memory.stat, returning 0 gracefully if the file or field is absent. Written-by: <anthropic/claude-opus-4.6>
Let's pass in a boolean and also warn on the first wait and then periodically after that.
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This pull request refactors memory reservation logging in mantle/kola/harness.go to provide earlier warnings, and improves the accuracy of available memory calculation in cgroup environments in mantle/system/nproc.go by accounting for reclaimable page cache. The changes are well-implemented and improve both logging behavior and correctness. I have one minor suggestion to simplify an error handling block to follow a more common Go idiom.
mantle/system/nproc.go
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| if os.IsNotExist(err) { | ||
| return 0, nil | ||
| } else if err != nil { | ||
| return 0, fmt.Errorf("reading memory.stat: %w", err) | ||
| } |
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This error handling block can be simplified to a more common Go idiom by checking for err != nil first, and then handling the specific os.IsNotExist case within that block. This can improve readability.
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| if os.IsNotExist(err) { | |
| return 0, nil | |
| } else if err != nil { | |
| return 0, fmt.Errorf("reading memory.stat: %w", err) | |
| } | |
| if err != nil { | |
| if os.IsNotExist(err) { | |
| return 0, nil | |
| } | |
| return 0, fmt.Errorf("reading memory.stat: %w", err) | |
| } |
…le memory" This reverts commit 662d9f1.
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