From 89a35a108e5c7f56095c87090d38fb0e5b1df2a0 Mon Sep 17 00:00:00 2001
From: Liu Xiao <liuxiaogenius@gmail.com>
Date: Fri, 29 Jun 2018 09:10:47 +0800
Subject: [PATCH 1/3] try to preallocate space after
 RandomAccessFile#setLength()

---
 .../hash/impl/VanillaChronicleHash.java       | 53 +++++++++++++++++--
 1 file changed, 49 insertions(+), 4 deletions(-)

diff --git a/src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java b/src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java
index 2d7daa05a..39111e31f 100644
--- a/src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java
+++ b/src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java
@@ -17,6 +17,8 @@
 
 package net.openhft.chronicle.hash.impl;
 
+import com.sun.jna.Native;
+import com.sun.jna.Platform;
 import net.openhft.chronicle.algo.locks.*;
 import net.openhft.chronicle.bytes.BytesStore;
 import net.openhft.chronicle.bytes.MappedBytesStoreFactory;
@@ -40,12 +42,12 @@ import net.openhft.chronicle.wire.Marshallable;
 import net.openhft.chronicle.wire.WireIn;
 import net.openhft.chronicle.wire.WireOut;
 import org.jetbrains.annotations.NotNull;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
-import java.io.Closeable;
-import java.io.File;
-import java.io.IOException;
-import java.io.RandomAccessFile;
+import java.io.*;
 import java.lang.ref.WeakReference;
+import java.lang.reflect.Field;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 import java.util.ArrayList;
@@ -68,6 +70,9 @@ public abstract class VanillaChronicleHash<K,
         ECQ extends ExternalHashQueryContext<K>>
         implements ChronicleHash<K, C, SC, ECQ>, Marshallable {
 
+    private static final Logger LOG =
+            LoggerFactory.getLogger(VanillaChronicleHash.class.getName());
+
     public static final long TIER_COUNTERS_AREA_SIZE = 64;
     public static final long RESERVED_GLOBAL_MUTABLE_STATE_BYTES = 1024;
 
@@ -944,6 +949,36 @@ public abstract class VanillaChronicleHash<K,
                 firstBulkToMapOffsetWithinMapping);
     }
 
+    private static class PosixFallocateProxy {
+
+        static {
+            Native.register(Platform.C_LIBRARY_NAME);
+        }
+
+        private static native int posix_fallocate(int fd, long offset, long length);
+
+        private static int getNativeFileDescriptor(FileDescriptor descriptor) {
+            try {
+                final Field field = descriptor.getClass().getDeclaredField("fd");
+                field.setAccessible(true);
+                return (int) field.get(descriptor);
+            } catch (final Exception e) {
+                LOG.warn("unsupported FileDescriptor implementation: e={}", e.getLocalizedMessage());
+                return -1;
+            }
+        }
+
+        static void posixFallocate(FileDescriptor descriptor, long offset, long length) {
+            int fd = getNativeFileDescriptor(descriptor);
+            if (fd != -1) {
+                int ret = posix_fallocate(getNativeFileDescriptor(descriptor), offset, length);
+                if (ret != 0) {
+                    LOG.warn("posix_fallocate() returned {}", ret);
+                }
+            }
+        }
+    }
+
     /**
      * @see net.openhft.chronicle.bytes.MappedFile#acquireByteStore(long, MappedBytesStoreFactory)
      */
@@ -958,6 +993,16 @@ public abstract class VanillaChronicleHash<K,
             // globalMutableStateLock), or on map creation, when race condition should be excluded
             // by self-bootstrapping header spec
             raf.setLength(minFileSize);
+
+            // RandomAccessFile#setLength() only calls ftruncate,
+            // which will not preallocate space on XFS filesystem of Linux.
+            // And writing that file will create a sparse file with a large number of extents.
+            // This kind of fragmented file may hang the program and cause dmesg reports
+            // "XFS: ... possible memory allocation deadlock size ... in kmem_alloc (mode:0x250)".
+            // We can fix this by trying calling posix_fallocate to preallocate the space.
+            if (Platform.isLinux()) {
+                PosixFallocateProxy.posixFallocate(raf.getFD(), 0, minFileSize);
+            }
         }
         long address = OS.map(fileChannel, READ_WRITE, mappingOffsetInFile, mapSize);
         resources.addMemoryResource(address, mapSize);

From e78677120b9356b382fa3b5856f537bc981e0996 Mon Sep 17 00:00:00 2001
From: Liu Xiao <liuxiaogenius@gmail.com>
Date: Mon, 2 Jul 2018 09:00:34 +0800
Subject: [PATCH 2/3] code refactoring

---
 .../hash/impl/VanillaChronicleHash.java       | 40 +---------------
 .../hash/impl/util/jna/PosixFallocate.java    | 46 +++++++++++++++++++
 2 files changed, 48 insertions(+), 38 deletions(-)
 create mode 100644 src/main/java/net/openhft/chronicle/hash/impl/util/jna/PosixFallocate.java

diff --git a/src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java b/src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java
index 39111e31f..2c47fc690 100644
--- a/src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java
+++ b/src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java
@@ -17,7 +17,6 @@
 
 package net.openhft.chronicle.hash.impl;
 
-import com.sun.jna.Native;
 import com.sun.jna.Platform;
 import net.openhft.chronicle.algo.locks.*;
 import net.openhft.chronicle.bytes.BytesStore;
@@ -29,6 +28,7 @@ import net.openhft.chronicle.hash.*;
 import net.openhft.chronicle.hash.impl.util.BuildVersion;
 import net.openhft.chronicle.hash.impl.util.Cleaner;
 import net.openhft.chronicle.hash.impl.util.CleanerUtils;
+import net.openhft.chronicle.hash.impl.util.jna.PosixFallocate;
 import net.openhft.chronicle.hash.impl.util.jna.PosixMsync;
 import net.openhft.chronicle.hash.impl.util.jna.WindowsMsync;
 import net.openhft.chronicle.hash.serialization.DataAccess;
@@ -42,12 +42,9 @@ import net.openhft.chronicle.wire.Marshallable;
 import net.openhft.chronicle.wire.WireIn;
 import net.openhft.chronicle.wire.WireOut;
 import org.jetbrains.annotations.NotNull;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.io.*;
 import java.lang.ref.WeakReference;
-import java.lang.reflect.Field;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 import java.util.ArrayList;
@@ -70,9 +67,6 @@ public abstract class VanillaChronicleHash<K,
         ECQ extends ExternalHashQueryContext<K>>
         implements ChronicleHash<K, C, SC, ECQ>, Marshallable {
 
-    private static final Logger LOG =
-            LoggerFactory.getLogger(VanillaChronicleHash.class.getName());
-
     public static final long TIER_COUNTERS_AREA_SIZE = 64;
     public static final long RESERVED_GLOBAL_MUTABLE_STATE_BYTES = 1024;
 
@@ -949,36 +943,6 @@ public abstract class VanillaChronicleHash<K,
                 firstBulkToMapOffsetWithinMapping);
     }
 
-    private static class PosixFallocateProxy {
-
-        static {
-            Native.register(Platform.C_LIBRARY_NAME);
-        }
-
-        private static native int posix_fallocate(int fd, long offset, long length);
-
-        private static int getNativeFileDescriptor(FileDescriptor descriptor) {
-            try {
-                final Field field = descriptor.getClass().getDeclaredField("fd");
-                field.setAccessible(true);
-                return (int) field.get(descriptor);
-            } catch (final Exception e) {
-                LOG.warn("unsupported FileDescriptor implementation: e={}", e.getLocalizedMessage());
-                return -1;
-            }
-        }
-
-        static void posixFallocate(FileDescriptor descriptor, long offset, long length) {
-            int fd = getNativeFileDescriptor(descriptor);
-            if (fd != -1) {
-                int ret = posix_fallocate(getNativeFileDescriptor(descriptor), offset, length);
-                if (ret != 0) {
-                    LOG.warn("posix_fallocate() returned {}", ret);
-                }
-            }
-        }
-    }
-
     /**
      * @see net.openhft.chronicle.bytes.MappedFile#acquireByteStore(long, MappedBytesStoreFactory)
      */
@@ -1001,7 +965,7 @@ public abstract class VanillaChronicleHash<K,
             // "XFS: ... possible memory allocation deadlock size ... in kmem_alloc (mode:0x250)".
             // We can fix this by trying calling posix_fallocate to preallocate the space.
             if (Platform.isLinux()) {
-                PosixFallocateProxy.posixFallocate(raf.getFD(), 0, minFileSize);
+                PosixFallocate.fallocate(raf.getFD(), 0, minFileSize);
             }
         }
         long address = OS.map(fileChannel, READ_WRITE, mappingOffsetInFile, mapSize);
diff --git a/src/main/java/net/openhft/chronicle/hash/impl/util/jna/PosixFallocate.java b/src/main/java/net/openhft/chronicle/hash/impl/util/jna/PosixFallocate.java
new file mode 100644
index 000000000..5aecb5cb0
--- /dev/null
+++ b/src/main/java/net/openhft/chronicle/hash/impl/util/jna/PosixFallocate.java
@@ -0,0 +1,46 @@
+package net.openhft.chronicle.hash.impl.util.jna;
+
+import com.sun.jna.Native;
+import com.sun.jna.Platform;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.FileDescriptor;
+import java.lang.reflect.Field;
+
+public final class PosixFallocate {
+
+    private static final Logger LOG =
+            LoggerFactory.getLogger(PosixFallocate.class.getName());
+
+    static {
+        Native.register(Platform.C_LIBRARY_NAME);
+    }
+
+    private PosixFallocate() {
+    }
+
+    public static void fallocate(FileDescriptor descriptor, long offset, long length) {
+        int fd = getNativeFileDescriptor(descriptor);
+        if (fd != -1) {
+            int ret = posix_fallocate(getNativeFileDescriptor(descriptor), offset, length);
+            if (ret != 0) {
+                LOG.warn("posix_fallocate() returned {}", ret);
+            }
+        }
+    }
+
+    private static native int posix_fallocate(int fd, long offset, long length);
+
+    private static int getNativeFileDescriptor(FileDescriptor descriptor) {
+        try {
+            final Field field = descriptor.getClass().getDeclaredField("fd");
+            field.setAccessible(true);
+            return (int) field.get(descriptor);
+        } catch (final Exception e) {
+            LOG.warn("unsupported FileDescriptor implementation: e={}", e.getLocalizedMessage());
+            return -1;
+        }
+    }
+
+}

From b6432ef7963e8fcb00a619385e9ea742666f14ad Mon Sep 17 00:00:00 2001
From: Liu Xiao <liuxiaogenius@gmail.com>
Date: Mon, 2 Jul 2018 09:12:01 +0800
Subject: [PATCH 3/3] use OS.isLinux() instead of Platform.isLinux() for
 consistency

---
 .../net/openhft/chronicle/hash/impl/VanillaChronicleHash.java  | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java b/src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java
index 2c47fc690..beea4ceef 100644
--- a/src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java
+++ b/src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java
@@ -17,7 +17,6 @@
 
 package net.openhft.chronicle.hash.impl;
 
-import com.sun.jna.Platform;
 import net.openhft.chronicle.algo.locks.*;
 import net.openhft.chronicle.bytes.BytesStore;
 import net.openhft.chronicle.bytes.MappedBytesStoreFactory;
@@ -964,7 +963,7 @@ public abstract class VanillaChronicleHash<K,
             // This kind of fragmented file may hang the program and cause dmesg reports
             // "XFS: ... possible memory allocation deadlock size ... in kmem_alloc (mode:0x250)".
             // We can fix this by trying calling posix_fallocate to preallocate the space.
-            if (Platform.isLinux()) {
+            if (OS.isLinux()) {
                 PosixFallocate.fallocate(raf.getFD(), 0, minFileSize);
             }
         }