Hi all,
Apologies if this is not the most appropriate list, in which case
please direct me where to go.
I've noticed a surprising result from the
com.sun.management.OperatingSystemMXBean implementation when running in
a containerized (specifically, using Docker on Linux) environment. The
bean appears to be container-aware for processors, in that running with
Docker option `--cpus 1.0` for example, on a multicore system, will
cause both java.lang.Runtime#availableProcessors and
java.lang.management.OperatingSystemMXBean#getAvailableProcessors /
com.sun.management.OperatingSystemMXBean#getAvailableProcessors to
return 1. However, the Docker option `--memory 100M` (or any other
limit value) is not reflected in the value returned by
com.sun.management.OperatingSystemMXBeam#getTotalPhysicalMemorySize,
and instead the returned value is still the total physical memory of
the host machine - of which only a small portion may actually be
available to the "Operating System" of the JVM. Similarly for the
methods regarding free physical memory, total swap, and free swap.
I have attached a patch which adds a small reproducer to the existing
MemoryAwareness test.
This seems like a bug to me, since if the imposed container limit on
processors as a resource is included as part of the "Operating System"
resource reporting, then surely memory resources should be reported the
same way. As I said, I found the current behaviour quite surprising.
--
Andrew Azores
Software Engineer, OpenJDK Team
Red Hat
# HG changeset patch
# User Andrew Azores <aazo...@redhat.com>
# Date 1561037890 14400
# Thu Jun 20 09:38:10 2019 -0400
# Node ID 25d8a60c172afc57902e8655889dd47ef26b9ca2
# Parent 8d50ff464ae56ad62679b44afa705276c7aece50
[mq]: test
diff --git a/test/hotspot/jtreg/containers/docker/CheckOperatingSystemMXBean.java b/test/hotspot/jtreg/containers/docker/CheckOperatingSystemMXBean.java
new file mode 100644
--- /dev/null
+++ b/test/hotspot/jtreg/containers/docker/CheckOperatingSystemMXBean.java
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import com.sun.management.OperatingSystemMXBean;
+import java.lang.management.ManagementFactory;
+
+public class CheckOperatingSystemMXBean {
+
+ public static void main(String[] args) {
+ System.out.println("Checking OperatingSystemMXBean");
+
+ OperatingSystemMXBean osBean = (OperatingSystemMXBean) ManagementFactory.getOperatingSystemMXBean();
+ System.out.println(String.format("Runtime.availableProcessors: %d", Runtime.getRuntime().availableProcessors()));
+ System.out.println(String.format("OperatingSystemMXBean.getAvailableProcessors: %d", osBean.getAvailableProcessors()));
+ System.out.println(String.format("OperatingSystemMXBean.getTotalPhysicalMemorySize: %d", osBean.getTotalPhysicalMemorySize()));
+ System.out.println(String.format("OperatingSystemMXBean.getTotalSwapSpaceSize: %d", osBean.getTotalSwapSpaceSize()));
+ }
+
+}
diff --git a/test/hotspot/jtreg/containers/docker/TestMemoryAwareness.java b/test/hotspot/jtreg/containers/docker/TestMemoryAwareness.java
--- a/test/hotspot/jtreg/containers/docker/TestMemoryAwareness.java
+++ b/test/hotspot/jtreg/containers/docker/TestMemoryAwareness.java
@@ -30,7 +30,7 @@
* @modules java.base/jdk.internal.misc
* java.management
* jdk.jartool/sun.tools.jar
- * @build AttemptOOM sun.hotspot.WhiteBox PrintContainerInfo
+ * @build AttemptOOM sun.hotspot.WhiteBox PrintContainerInfo CheckOperatingSystemMXBean
* @run driver ClassFileInstaller -jar whitebox.jar sun.hotspot.WhiteBox sun.hotspot.WhiteBox$WhiteBoxPermission
* @run driver TestMemoryAwareness
*/
@@ -62,8 +62,25 @@
// Add extra 10 Mb to allocator limit, to be sure to cause OOM
testOOM("256m", 256 + 10);
+ testMXBeanAwareness(
+ "1.0", "1",
+ "100M", Integer.toString(((int) Math.pow(2, 20)) * 100),
+ "150M", Integer.toString(((int) Math.pow(2, 20)) * 150)
+ );
+ testMXBeanAwareness(
+ "1.0", "1",
+ "128M", Integer.toString(((int) Math.pow(2, 20)) * 128),
+ "256M", Integer.toString(((int) Math.pow(2, 20)) * 256)
+ );
+ testMXBeanAwareness(
+ "1.0", "1",
+ "1G", Integer.toString(((int) Math.pow(2, 20)) * 1024),
+ "1500M", Integer.toString(((int) Math.pow(2, 20)) * 1500)
+ );
} finally {
- DockerTestUtils.removeDockerImage(imageName);
+ if (!DockerTestUtils.RETAIN_IMAGE_AFTER_TEST) {
+ DockerTestUtils.removeDockerImage(imageName);
+ }
}
}
@@ -109,4 +126,24 @@
.shouldContain("java.lang.OutOfMemoryError");
}
+ private static void testMXBeanAwareness(String cpuAllocation, String expectedCpus, String memoryAllocation,
+ String expectedMemory, String swapAllocation, String expectedSwap) throws Exception {
+ Common.logNewTestCase("Check OperatingSystemMXBean");
+
+ DockerRunOptions opts = Common.newOpts(imageName, "CheckOperatingSystemMXBean")
+ .addDockerOpts(
+ "--cpus", cpuAllocation,
+ "--memory", memoryAllocation,
+ "--memory-swap", swapAllocation
+ );
+
+ DockerTestUtils.dockerRunJava(opts)
+ .shouldHaveExitValue(0)
+ .shouldContain("Checking OperatingSystemMXBean")
+ .shouldContain("Runtime.availableProcessors: " + expectedCpus)
+ .shouldContain("OperatingSystemMXBean.getAvailableProcessors: " + expectedCpus)
+ .shouldContain("OperatingSystemMXBean.getTotalPhysicalMemorySize: " + expectedMemory)
+ .shouldContain("OperatingSystemMXBean.getTotalSwapSpaceSize: " + expectedSwap);
+ }
+
}
