Add heap size bootstrap check

This commit adds a bootstrap check to ensure that the initial heap size
and max heap size are set equal to each other.

core/src/main/java/org/elasticsearch/bootstrap/BootstrapCheck.java

@@ -26,6 +26,7 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.transport.BoundTransportAddress;
 import org.elasticsearch.common.transport.TransportAddress;
 import org.elasticsearch.discovery.zen.elect.ElectMasterService;
+import org.elasticsearch.monitor.jvm.JvmInfo;
 import org.elasticsearch.monitor.process.ProcessProbe;
 import org.elasticsearch.node.Node;
 
@@ -108,6 +109,7 @@ final class BootstrapCheck {
     // the list of checks to execute
     static List<Check> checks(final Settings settings) {
         final List<Check> checks = new ArrayList<>();
+        checks.add(new HeapSizeCheck());
         final FileDescriptorCheck fileDescriptorCheck
             = Constants.MAC_OS_X ? new OsXFileDescriptorCheck() : new FileDescriptorCheck();
         checks.add(fileDescriptorCheck);
@@ -143,6 +145,38 @@ final class BootstrapCheck {
 
     }
 
+    static class HeapSizeCheck implements BootstrapCheck.Check {
+
+        @Override
+        public boolean check() {
+            final long initialHeapSize = getInitialHeapSize();
+            final long maxHeapSize = getMaxHeapSize();
+            return initialHeapSize != 0 && maxHeapSize != 0 && initialHeapSize != maxHeapSize;
+        }
+
+        @Override
+        public String errorMessage() {
+            return String.format(
+                    Locale.ROOT,
+                    "initial heap size [%d] not equal to maximum heap size [%d]; " +
+                            "this can cause resize pauses and prevents mlockall from locking the entire heap",
+                    getInitialHeapSize(),
+                    getMaxHeapSize()
+            );
+        }
+
+        // visible for testing
+        long getInitialHeapSize() {
+            return JvmInfo.jvmInfo().getConfiguredInitialHeapSize();
+        }
+
+        // visible for testing
+        long getMaxHeapSize() {
+            return JvmInfo.jvmInfo().getConfiguredMaxHeapSize();
+        }
+
+    }
+
     static class OsXFileDescriptorCheck extends FileDescriptorCheck {
 
         public OsXFileDescriptorCheck() {

core/src/main/java/org/elasticsearch/monitor/jvm/JvmInfo.java

@@ -114,15 +114,33 @@ public class JvmInfo implements Streamable, ToXContent {
             Class<?> vmOptionClazz = Class.forName("com.sun.management.VMOption");
             PlatformManagedObject hotSpotDiagnosticMXBean = ManagementFactory.getPlatformMXBean(clazz);
             Method vmOptionMethod = clazz.getMethod("getVMOption", String.class);
-            Object useCompressedOopsVmOption = vmOptionMethod.invoke(hotSpotDiagnosticMXBean, "UseCompressedOops");
             Method valueMethod = vmOptionClazz.getMethod("getValue");
-            info.useCompressedOops = (String)valueMethod.invoke(useCompressedOopsVmOption);
-            Object useG1GCVmOption = vmOptionMethod.invoke(hotSpotDiagnosticMXBean, "UseG1GC");
-            info.useG1GC = (String)valueMethod.invoke(useG1GCVmOption);
-        } catch (Throwable t) {
-            // unable to deduce the state of compressed oops
-            info.useCompressedOops = "unknown";
-            info.useG1GC = "unknown";
+
+            try {
+                Object useCompressedOopsVmOption = vmOptionMethod.invoke(hotSpotDiagnosticMXBean, "UseCompressedOops");
+                info.useCompressedOops = (String) valueMethod.invoke(useCompressedOopsVmOption);
+            } catch (Exception ignored) {
+            }
+
+            try {
+                Object useG1GCVmOption = vmOptionMethod.invoke(hotSpotDiagnosticMXBean, "UseG1GC");
+                info.useG1GC = (String) valueMethod.invoke(useG1GCVmOption);
+            } catch (Exception ignored) {
+            }
+
+            try {
+                Object initialHeapSizeVmOption = vmOptionMethod.invoke(hotSpotDiagnosticMXBean, "InitialHeapSize");
+                info.configuredInitialHeapSize = Long.parseLong((String) valueMethod.invoke(initialHeapSizeVmOption));
+            } catch (Exception ignored) {
+            }
+
+            try {
+                Object maxHeapSizeVmOption = vmOptionMethod.invoke(hotSpotDiagnosticMXBean, "MaxHeapSize");
+                info.configuredMaxHeapSize = Long.parseLong((String) valueMethod.invoke(maxHeapSizeVmOption));
+            } catch (Exception ignored) {
+            }
+        } catch (Exception ignored) {
+
         }
 
         INSTANCE = info;
@@ -146,6 +164,9 @@ public class JvmInfo implements Streamable, ToXContent {
 
     long startTime = -1;
 
+    private long configuredInitialHeapSize;
+    private long configuredMaxHeapSize;
+
     Mem mem;
 
     String[] inputArguments;
@@ -159,9 +180,9 @@ public class JvmInfo implements Streamable, ToXContent {
     String[] gcCollectors = Strings.EMPTY_ARRAY;
     String[] memoryPools = Strings.EMPTY_ARRAY;
 
-    private String useCompressedOops;
+    private String useCompressedOops = "unknown";
 
-    private String useG1GC;
+    private String useG1GC = "unknown";
 
     private JvmInfo() {
     }
@@ -286,6 +307,14 @@ public class JvmInfo implements Streamable, ToXContent {
         return this.systemProperties;
     }
 
+    public long getConfiguredInitialHeapSize() {
+        return configuredInitialHeapSize;
+    }
+
+    public long getConfiguredMaxHeapSize() {
+        return configuredMaxHeapSize;
+    }
+
     /**
      * The value of the JVM flag UseCompressedOops, if available otherwise
      * "unknown". The value "unknown" indicates that an attempt was

core/src/test/java/org/elasticsearch/bootstrap/BootstrapCheckTests.java

@@ -137,6 +137,49 @@ public class BootstrapCheckTests extends ESTestCase {
         assertThat(suppressed[1], hasToString(containsString("second")));
     }
 
+    public void testHeapSizeCheck() {
+        final int initial = randomIntBetween(0, Integer.MAX_VALUE - 1);
+        final int max = randomIntBetween(initial + 1, Integer.MAX_VALUE);
+        final AtomicLong initialHeapSize = new AtomicLong(initial);
+        final AtomicLong maxHeapSize = new AtomicLong(max);
+
+        final BootstrapCheck.HeapSizeCheck check = new BootstrapCheck.HeapSizeCheck() {
+            @Override
+            long getInitialHeapSize() {
+                return initialHeapSize.get();
+            }
+
+            @Override
+            long getMaxHeapSize() {
+                return maxHeapSize.get();
+            }
+        };
+
+        try {
+            BootstrapCheck.check(true, Collections.singletonList(check), "testHeapSizeCheck");
+            fail("should have failed to initial heap size not equal to max heap size");
+        } catch (final RuntimeException e) {
+            assertThat(
+                    e.getMessage(),
+                    containsString("initial heap size [" + initialHeapSize.get() + "] " +
+                            "not equal to maximum heap size [" + maxHeapSize.get() + "]")
+            );
+        }
+
+        initialHeapSize.set(maxHeapSize.get());
+
+        BootstrapCheck.check(true, Collections.singletonList(check), "testHeapSizeCheck");
+
+        // nothing should happen if the initial heap size or the max
+        // heap size is not available
+        if (randomBoolean()) {
+            initialHeapSize.set(0);
+        } else {
+            maxHeapSize.set(0);
+        }
+        BootstrapCheck.check(true, Collections.singletonList(check), "testHeapSizeCheck");
+    }
+
     public void testFileDescriptorLimits() {
         final boolean osX = randomBoolean(); // simulates OS X versus non-OS X
         final int limit = osX ? 10240 : 1 << 16;