1 files changed, 121 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/util/ProcMeminfoParser.java b/src/main/java/com/google/devtools/build/lib/util/ProcMeminfoParser.java
new file mode 100644
index 0000000000..44c1112d61
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+++ b/src/main/java/com/google/devtools/build/lib/util/ProcMeminfoParser.java
@@ -0,0 +1,121 @@
+// Copyright 2014 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.util;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.CharMatcher;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.io.Files;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Parse and return information from /proc/meminfo.
+ */
+public class ProcMeminfoParser {
+
+  public static final String FILE = "/proc/meminfo";
+
+  private final Map<String, Long> memInfo;
+
+  /**
+   * Populates memory information by reading /proc/meminfo.
+   * @throws IOException if reading the file failed.
+   */
+  public ProcMeminfoParser() throws IOException {
+    this(FILE);
+  }
+
+  @VisibleForTesting
+  public ProcMeminfoParser(String fileName) throws IOException {
+    List<String> lines = Files.readLines(new File(fileName), Charset.defaultCharset());
+    ImmutableMap.Builder<String, Long> builder = ImmutableMap.builder();
+    for (String line : lines) {
+      int colon = line.indexOf(":");
+      String keyword = line.substring(0, colon);
+      String valString = line.substring(colon + 1);
+      try {
+        long val =  Long.parseLong(CharMatcher.inRange('0', '9').retainFrom(valString));
+        builder.put(keyword, val);
+      } catch (NumberFormatException e) {
+        // Ignore: we'll fail later if somebody tries to capture this value.
+      }
+    }
+    memInfo = builder.build();
+  }
+
+  /**
+   * Gets a named field in KB.
+   */
+  public long getRamKb(String keyword) {
+    Long val = memInfo.get(keyword);
+    if (val == null) {
+      throw new IllegalArgumentException("Can't locate " + keyword + " in the /proc/meminfo");
+    }
+    return val;
+  }
+
+  /**
+   * Return the total physical memory.
+   */
+  public long getTotalKb() {
+    return getRamKb("MemTotal");
+  }
+
+  /**
+   * Return the inactive memory.
+   */
+  public long getInactiveKb() {
+    return getRamKb("Inactive");
+  }
+
+  /**
+   * Return the active memory.
+   */
+  public long getActiveKb() {
+    return getRamKb("Active");
+  }
+
+  /**
+   * Return the slab memory.
+   */
+  public long getSlabKb() {
+    return getRamKb("Slab");
+  }
+
+  /**
+   * Convert KB to MB.
+   */
+  public static double kbToMb(long kb) {
+    return kb / 1E3;
+  }
+
+  /**
+   * Calculates amount of free RAM from /proc/meminfo content by using
+   * MemTotal - (Active + 0.3*InActive + 0.8*Slab) formula.
+   * Assumption here is that we allow Blaze to use all memory except when
+   * used by active pages, 30% of the inactive pages (since they may become
+   * active at any time) and 80% of memory used by kernel slab heap (since we
+   * want to keep most of the slab heap in the memory but do not want it to
+   * consume all available free memory).
+   */
+  public long getFreeRamKb() {
+    return getTotalKb() - getActiveKb() - (long)(getInactiveKb() * 0.3) - (long)(getSlabKb() * 0.8);
+  }
+}