From 2bb3c290cb28f29053e8610c26a22ebdc687bad7 Mon Sep 17 00:00:00 2001
From: Stefan Johansson <stefan.johansson@oracle.com>
Date: Tue, 24 Feb 2026 15:52:59 +0000
Subject: [PATCH] 8380773: Extend ContainerMemoryUsageEvent to include host
 memory usage

---
 src/hotspot/share/jfr/jni/jfrJniMethod.cpp                 | 7 +++++++
 src/hotspot/share/jfr/jni/jfrJniMethod.hpp                 | 2 ++
 src/hotspot/share/jfr/jni/jfrJniMethodRegistration.cpp     | 1 +
 .../classes/jdk/jfr/events/ContainerMemoryUsageEvent.java  | 5 +++++
 src/jdk.jfr/share/classes/jdk/jfr/internal/JDKEvents.java  | 1 +
 src/jdk.jfr/share/classes/jdk/jfr/internal/JVM.java        | 6 ++++++
 6 files changed, 22 insertions(+)

diff --git a/src/hotspot/share/jfr/jni/jfrJniMethod.cpp b/src/hotspot/share/jfr/jni/jfrJniMethod.cpp
index 885484020bd..915d59d00a7 100644
--- a/src/hotspot/share/jfr/jni/jfrJniMethod.cpp
+++ b/src/hotspot/share/jfr/jni/jfrJniMethod.cpp
@@ -410,6 +410,13 @@ JVM_ENTRY_NO_ENV(jlong, jfr_host_total_swap_memory(JNIEnv* env, jclass jvm))
   return static_cast<jlong>(total_swap_space);
 JVM_END
 
+JVM_ENTRY_NO_ENV(jlong, jfr_host_memory_usage(JNIEnv* env, jclass jvm))
+  physical_memory_size_type memory_usage = 0;
+  // Return value ignored - defaulting to 0 on failure.
+  (void)os::Machine::used_memory(memory_usage);
+  return static_cast<jlong>(memory_usage);
+JVM_END
+
 JVM_ENTRY_NO_ENV(void, jfr_emit_data_loss(JNIEnv* env, jclass jvm, jlong bytes))
   EventDataLoss::commit(bytes, min_jlong);
 JVM_END
diff --git a/src/hotspot/share/jfr/jni/jfrJniMethod.hpp b/src/hotspot/share/jfr/jni/jfrJniMethod.hpp
index 9769df57bd3..bcdaf7a99b7 100644
--- a/src/hotspot/share/jfr/jni/jfrJniMethod.hpp
+++ b/src/hotspot/share/jfr/jni/jfrJniMethod.hpp
@@ -163,6 +163,8 @@ jlong JNICALL jfr_host_total_memory(JNIEnv* env, jclass jvm);
 
 jlong JNICALL jfr_host_total_swap_memory(JNIEnv* env, jclass jvm);
 
+jlong JNICALL jfr_host_memory_usage(JNIEnv* env, jclass jvm);
+
 void JNICALL jfr_emit_data_loss(JNIEnv* env, jclass jvm, jlong bytes);
 
 jlong JNICALL jfr_register_stack_filter(JNIEnv* env, jclass jvm, jobjectArray classes, jobjectArray methods);
diff --git a/src/hotspot/share/jfr/jni/jfrJniMethodRegistration.cpp b/src/hotspot/share/jfr/jni/jfrJniMethodRegistration.cpp
index 2979f5c5c2d..0813289e840 100644
--- a/src/hotspot/share/jfr/jni/jfrJniMethodRegistration.cpp
+++ b/src/hotspot/share/jfr/jni/jfrJniMethodRegistration.cpp
@@ -101,6 +101,7 @@ JfrJniMethodRegistration::JfrJniMethodRegistration(JNIEnv* env) {
       (char*)"isContainerized", (char*)"()Z", (void*) jfr_is_containerized,
       (char*)"hostTotalMemory", (char*)"()J", (void*) jfr_host_total_memory,
       (char*)"hostTotalSwapMemory", (char*)"()J", (void*) jfr_host_total_swap_memory,
+      (char*)"hostMemoryUsage", (char*)"()J", (void*) jfr_host_memory_usage,
       (char*)"emitDataLoss", (char*)"(J)V", (void*)jfr_emit_data_loss,
       (char*)"registerStackFilter", (char*)"([Ljava/lang/String;[Ljava/lang/String;)J", (void*)jfr_register_stack_filter,
       (char*)"unregisterStackFilter", (char*)"(J)V", (void*)jfr_unregister_stack_filter,
diff --git a/src/jdk.jfr/share/classes/jdk/jfr/events/ContainerMemoryUsageEvent.java b/src/jdk.jfr/share/classes/jdk/jfr/events/ContainerMemoryUsageEvent.java
index 285952d0c66..9a83877a967 100644
--- a/src/jdk.jfr/share/classes/jdk/jfr/events/ContainerMemoryUsageEvent.java
+++ b/src/jdk.jfr/share/classes/jdk/jfr/events/ContainerMemoryUsageEvent.java
@@ -50,4 +50,9 @@ public final class ContainerMemoryUsageEvent extends AbstractPeriodicEvent {
     @Description("Amount of physical memory and swap space, in bytes, that is currently allocated in the current container")
     @DataAmount
     public long swapMemoryUsage;
+
+    @Label("Host Memory Usage")
+    @Description("Amount of physical memory, in bytes, that is currently allocated in the host system")
+    @DataAmount
+    public long hostMemoryUsage;
 }
diff --git a/src/jdk.jfr/share/classes/jdk/jfr/internal/JDKEvents.java b/src/jdk.jfr/share/classes/jdk/jfr/internal/JDKEvents.java
index 53d40c1e5e1..79bc614545e 100644
--- a/src/jdk.jfr/share/classes/jdk/jfr/internal/JDKEvents.java
+++ b/src/jdk.jfr/share/classes/jdk/jfr/internal/JDKEvents.java
@@ -181,6 +181,7 @@ public final class JDKEvents {
             event.memoryFailCount = containerMetrics.getMemoryFailCount();
             event.memoryUsage = containerMetrics.getMemoryUsage();
             event.swapMemoryUsage = containerMetrics.getMemoryAndSwapUsage();
+            event.hostMemoryUsage = JVM.hostMemoryUsage();
             event.commit();
         }
     }
diff --git a/src/jdk.jfr/share/classes/jdk/jfr/internal/JVM.java b/src/jdk.jfr/share/classes/jdk/jfr/internal/JVM.java
index 24c92e81a4c..2aa7dfd6e97 100644
--- a/src/jdk.jfr/share/classes/jdk/jfr/internal/JVM.java
+++ b/src/jdk.jfr/share/classes/jdk/jfr/internal/JVM.java
@@ -657,6 +657,12 @@ public final class JVM {
      */
     public static native long hostTotalSwapMemory();
 
+    /**
+     * Returns the amount of memory used in the host system whether or not this
+     * JVM runs in a container.
+     */
+    public static native long hostMemoryUsage();
+
     /**
      * Emit a jdk.DataLoss event for the specified amount of bytes.
      *