Swap free for used in HeapUsage

Author: nicktindall

server/src/internalClusterTest/java/org/elasticsearch/index/shard/IndexShardIT.java

@@ -830,8 +830,8 @@ public void getClusterHeapUsage(ActionListener<Map<String, HeapUsage>> listener)
  listener,
  () -> clusterService.state().nodes().stream().collect(Collectors.toUnmodifiableMap(DiscoveryNode::getId, node -> {
  final long maxHeap = randomNonNegativeLong();
- final long freeHeap = (long) (randomFloat() * maxHeap);
- return new HeapUsage(node.getId(), node.getName(), maxHeap, freeHeap);
+ final long usedHeap = (long) (randomFloat() * maxHeap);
+ return new HeapUsage(node.getId(), node.getName(), maxHeap, usedHeap);
  }))
  );
  }

server/src/main/java/org/elasticsearch/cluster/HeapUsage.java

@@ -21,7 +21,11 @@
 /**
  * Record representing the heap usage for a single cluster node
  */
-public record HeapUsage(String nodeId, String nodeName, long totalBytes, long freeBytes) implements ToXContentFragment, Writeable {
+public record HeapUsage(String nodeId, String nodeName, long totalBytes, long usedBytes) implements ToXContentFragment, Writeable {
+
+ public HeapUsage {
+ assert usedBytes <= totalBytes;
+ }
 
  public HeapUsage(StreamInput in) throws IOException {
  this(in.readString(), in.readString(), in.readVLong(), in.readVLong());
@@ -32,14 +36,14 @@ public void writeTo(StreamOutput out) throws IOException {
  out.writeString(this.nodeId);
  out.writeString(this.nodeName);
  out.writeVLong(this.totalBytes);
- out.writeVLong(this.freeBytes);
+ out.writeVLong(this.usedBytes);
  }
 
  public XContentBuilder toShortXContent(XContentBuilder builder) throws IOException {
  builder.field("node_name", this.nodeName);
  builder.humanReadableField("total_heap_bytes", "total", ByteSizeValue.ofBytes(this.totalBytes));
- builder.humanReadableField("used_heap_bytes", "used", ByteSizeValue.ofBytes(this.usedBytes()));
- builder.humanReadableField("free_heap_bytes", "free", ByteSizeValue.ofBytes(this.freeBytes));
+ builder.humanReadableField("used_heap_bytes", "used", ByteSizeValue.ofBytes(this.usedBytes));
+ builder.humanReadableField("free_heap_bytes", "free", ByteSizeValue.ofBytes(this.freeBytes()));
  builder.field("free_heap_percent", truncatePercent(this.freeHeapAsPercentage()));
  builder.field("used_heap_percent", truncatePercent(this.usedHeapAsPercentage()));
  return builder;
@@ -53,15 +57,15 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
  }
 
  public double freeHeapAsPercentage() {
- return 100.0 * freeBytes / (double) totalBytes;
+ return 100.0 - usedHeapAsPercentage();
  }
 
  public double usedHeapAsPercentage() {
- return 100.0 - freeHeapAsPercentage();
+ return 100.0 * usedBytes / (double) totalBytes;
  }
 
- public long usedBytes() {
- return totalBytes - freeBytes;
+ public long freeBytes() {
+ return totalBytes - usedBytes;
  }
 
  private static double truncatePercent(double pct) {