Merge pull request #23582 from vespa-engine/hakonhall/memory-overhead-metricv8.30.50

Memory overhead metric

1 files changed, 42 insertions, 0 deletions

diff --git a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeadmin/ProcMeminfoReader.java b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeadmin/ProcMeminfoReader.java
new file mode 100644
index 00000000000..17abe6c7b46
--- /dev/null
+++ b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeadmin/ProcMeminfoReader.java
@@ -0,0 +1,42 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.node.admin.nodeadmin;
+
+import com.yahoo.yolean.Exceptions;
+
+import java.nio.file.FileSystem;
+import java.nio.file.Files;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Reads /proc/meminfo, see proc(5).
+ *
+ * @author hakon
+ */
+public class ProcMeminfoReader {
+    private static final String PROC_MEMINFO = "/proc/meminfo";
+    private static final Pattern MEM_TOTAL_PATTERN = Pattern.compile("MemTotal: *([0-9]+) kB");
+    private static final Pattern MEM_AVAILABLE_PATTERN = Pattern.compile("MemAvailable: *([0-9]+) kB");
+
+    private final FileSystem fileSystem;
+
+    public ProcMeminfoReader(FileSystem fileSystem) {
+        this.fileSystem = fileSystem;
+    }
+
+    public ProcMeminfo read() {
+        return read(Exceptions.uncheck(() -> Files.readString(fileSystem.getPath(PROC_MEMINFO))));
+    }
+
+    static ProcMeminfo read(String meminfoContent) {
+        return new ProcMeminfo(readKbGroup(meminfoContent, MEM_TOTAL_PATTERN),
+                               readKbGroup(meminfoContent, MEM_AVAILABLE_PATTERN));
+    }
+
+    private static long readKbGroup(String string, Pattern pattern) {
+        Matcher matcher = pattern.matcher(string);
+        if (!matcher.find())
+            throw new IllegalArgumentException(pattern + " did not match anything in " + PROC_MEMINFO);
+        return Long.parseLong(matcher.group(1)) * 1024;
+    }
+}