Use metric-schema to report JVM Buffer Pool metrics (#2018)

Use metric-schema to report JVM Buffer Pool metrics

changelog/@unreleased/pr-2018.v2.yml

@@ -0,0 +1,5 @@
+type: improvement
+improvement:
+  description: Use metric-schema to report JVM Buffer Pool metrics
+  links:
+  - https://github.com/palantir/tritium/pull/2018

tritium-metrics-jvm/src/main/java/com/palantir/tritium/metrics/jvm/JvmMetrics.java

@@ -18,7 +18,6 @@
 
 import com.codahale.metrics.Gauge;
 import com.codahale.metrics.RatioGauge;
-import com.codahale.metrics.jvm.BufferPoolMetricSet;
 import com.codahale.metrics.jvm.ThreadDeadlockDetector;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Suppliers;
@@ -31,6 +30,7 @@
 import com.palantir.tritium.metrics.jvm.InternalJvmMetrics.AttributeUptime_EnablePreview;
 import com.palantir.tritium.metrics.jvm.InternalJvmMetrics.DnsCacheTtlSeconds_Cache;
 import com.palantir.tritium.metrics.registry.TaggedMetricRegistry;
+import java.lang.management.BufferPoolMXBean;
 import java.lang.management.ClassLoadingMXBean;
 import java.lang.management.ManagementFactory;
 import java.lang.management.MemoryMXBean;
@@ -69,8 +69,7 @@ public static void register(TaggedMetricRegistry registry) {
         OperatingSystemMetrics.register(registry);
         SafepointMetrics.register(registry);
         registerAttributes(metrics);
-        MetricRegistries.registerAll(
-                registry, "jvm.buffers", new BufferPoolMetricSet(ManagementFactory.getPlatformMBeanServer()));
+        registerJvmBufferPools(registry);
         registerClassLoading(metrics);
         registerJvmMemory(registry);
         registerThreads(metrics);
@@ -216,6 +215,22 @@ protected RatioGauge.Ratio getRatio() {
         });
     }
 
+    private static void registerJvmBufferPools(TaggedMetricRegistry registry) {
+        JvmBuffersMetrics jvmBuffersMetrics = JvmBuffersMetrics.of(registry);
+        for (BufferPoolMXBean pool : ManagementFactory.getPlatformMXBeans(BufferPoolMXBean.class)) {
+            String poolName = pool.getName();
+            if ("direct".equals(poolName)) {
+                jvmBuffersMetrics.directCount(nonNegative(pool::getCount));
+                jvmBuffersMetrics.directUsed(nonNegative(pool::getMemoryUsed));
+                jvmBuffersMetrics.directCapacity(nonNegative(pool::getTotalCapacity));
+            } else if ("mapped".equals(poolName)) {
+                jvmBuffersMetrics.mappedCount(nonNegative(pool::getCount));
+                jvmBuffersMetrics.mappedUsed(nonNegative(pool::getMemoryUsed));
+                jvmBuffersMetrics.mappedCapacity(nonNegative(pool::getTotalCapacity));
+            }
+        }
+    }
+
     /**
      * Computes the total heap + non-heap result of applying the specified function.
      * If either value is negative, returns null to avoid misleading metric data.

tritium-metrics-jvm/src/main/metrics/metrics.yml

@@ -147,4 +147,25 @@ namespaces:
         docs: Amount of committed memory in bytes for the JVM non-heap (e.g. direct memory).
       non-heap.usage:
         type: gauge
-        docs: Ratio of `jvm.memory.non-heap.used` to `jvm.memory.non-heap.max`.
+        docs: Ratio of `jvm.memory.non-heap.used` to `jvm.memory.non-heap.max`.
+  jvm.buffers:
+    docs: Java virtual machine buffer pool metrics.
+    metrics:
+      direct.count:
+        type: gauge
+        docs: Number of buffers in the direct buffer pool.
+      direct.used:
+        type: gauge
+        docs: Total memory used by the direct buffer pool.
+      direct.capacity:
+        type: gauge
+        docs: Total capacity of the direct buffer pool.
+      mapped.count:
+        type: gauge
+        docs: Number of buffers in the mapped buffer pool.
+      mapped.used:
+        type: gauge
+        docs: Total memory used by the mapped buffer pool.
+      mapped.capacity:
+        type: gauge
+        docs: Total capacity of the mapped buffer pool.