Function findMemoryUsagePathByIdentifier

pkg/agent/memoryguard/memoryguard.go:657–708

(layout cgroupLayout, identifiers []string)

}

func findMemoryUsagePathByIdentifier(layout cgroupLayout, identifiers []string) (string, error) {
	const maxWalkDepth = 8 // bound the search to avoid slow walks over large cgroup trees

	type match struct {
		path  string
		idLen int
		depth int
	}

	mountDepth := strings.Count(filepath.Clean(layout.mountPoint), string(os.PathSeparator))
	best := match{}

	err := filepath.WalkDir(layout.mountPoint, func(path string, d os.DirEntry, walkErr error) error {
		if walkErr != nil {
			return walkErr
		}
		currentDepth := strings.Count(path, string(os.PathSeparator)) - mountDepth
		if d.IsDir() && currentDepth > maxWalkDepth {
			return filepath.SkipDir
		}
		if d.IsDir() || d.Name() != layout.usageFile {
			return nil
		}
		dir := filepath.Dir(path)
		if dir == layout.mountPoint {
			return nil
		}
		dirLower := strings.ToLower(dir)
		for _, identifier := range identifiers {
			if !strings.Contains(dirLower, identifier) {
				continue
			}
			depth := strings.Count(dirLower, string(os.PathSeparator))
			if len(identifier) > best.idLen || (len(identifier) == best.idLen && depth > best.depth) {
				best = match{
					path:  path,
					idLen: len(identifier),
					depth: depth,
				}
			}
			break
		}
		return nil
	})
	if err != nil {
		return "", err
	}
	if best.path == "" {
		return "", fmt.Errorf("failed to find container-specific %s under %s", layout.usageFile, layout.mountPoint)
	}
	return best.path, nil
}

// getRootNSPID returns this process's PID in the root (initial) PID namespace
// by reading the NSpid field from /proc/self/status.  NSpid lists namespaces