Add support for posix_madvise to Java 21 MMapDirectory (backport)

gradle/testing/defaults-tests.gradle

@@ -132,6 +132,10 @@ allprojects {
       if (rootProject.vectorIncubatorJavaVersions.contains(rootProject.runtimeJavaVersion)) {
         jvmArgs '--add-modules', 'jdk.incubator.vector'
       }
+
+      if (rootProject.runtimeJavaVersion >= JavaVersion.VERSION_21) {
+        jvmArgs '--enable-native-access=' + (project.path == ':lucene:core' ? 'ALL-UNNAMED' : 'org.apache.lucene.core')
+      }
 
       def loggingConfigFile = layout.projectDirectory.file("${resources}/logging.properties")
       def tempDir = layout.projectDirectory.dir(testsTmpDir.toString())

lucene/CHANGES.txt

@@ -19,6 +19,11 @@ New Features
 * GITHUB#12915: Add new token filters for Japanese sutegana (捨て仮名). This introduces JapaneseHiraganaUppercaseFilter
   and JapaneseKatakanaUppercaseFilter. (Dai Sugimori)
 
+* GITHUB#13196: Add support for posix_madvise to MMapDirectory: If running on Linux/macOS and Java 21
+  or later, MMapDirectory uses IOContext to pass suitable MADV flags to kernel of operating system.
+  This may improve paging logic especially when large segments are merged under memory pressure.
+  (Uwe Schindler, Chris Hegarty, Robert Muir, Adrien Grand)
+
 Improvements
 ---------------------
 

lucene/core/src/java/org/apache/lucene/store/IOContext.java

@@ -46,24 +46,32 @@ public enum Context {
   /** This flag indicates that the file will be opened, then fully read sequentially then closed. */
   public final boolean readOnce;
 
+  /**
+   * This flag indicates that the file will be accessed randomly. If this flag is set, then readOnce
+   * will be false.
+   */
+  public final boolean randomAccess;
+
   /**
    * This flag is used for files that are a small fraction of the total index size and are expected
    * to be heavily accessed in random-access fashion. Some {@link Directory} implementations may
    * choose to load such files into physical memory (e.g. Java heap) as a way to provide stronger
-   * guarantees on query latency.
+   * guarantees on query latency. If this flag is set, then {@link #randomAccess} will be true.
    */
   public final boolean load;
 
   public static final IOContext DEFAULT = new IOContext(Context.DEFAULT);
 
-  public static final IOContext READONCE = new IOContext(true, false);
+  public static final IOContext READONCE = new IOContext(true, false, false);
+
+  public static final IOContext READ = new IOContext(false, false, false);
 
-  public static final IOContext READ = new IOContext(false, false);
+  public static final IOContext LOAD = new IOContext(false, true, true);
 
-  public static final IOContext LOAD = new IOContext(false, true);
+  public static final IOContext RANDOM = new IOContext(false, false, true);
 
   public IOContext() {
-    this(false, false);
+    this(false, false, false);
   }
 
   public IOContext(FlushInfo flushInfo) {
@@ -72,18 +80,26 @@ public IOContext(FlushInfo flushInfo) {
     this.mergeInfo = null;
     this.readOnce = false;
     this.load = false;
+    this.randomAccess = false;
     this.flushInfo = flushInfo;
   }
 
   public IOContext(Context context) {
     this(context, null);
   }
 
-  private IOContext(boolean readOnce, boolean load) {
+  private IOContext(boolean readOnce, boolean load, boolean randomAccess) {
+    if (readOnce && randomAccess) {
+      throw new IllegalArgumentException("cannot be both readOnce and randomAccess");
+    }
+    if (load && randomAccess == false) {
+      throw new IllegalArgumentException("cannot be load but not randomAccess");
+    }
     this.context = Context.READ;
     this.mergeInfo = null;
     this.readOnce = readOnce;
     this.load = load;
+    this.randomAccess = randomAccess;
     this.flushInfo = null;
   }
 
@@ -98,6 +114,7 @@ private IOContext(Context context, MergeInfo mergeInfo) {
     this.context = context;
     this.readOnce = false;
     this.load = false;
+    this.randomAccess = false;
     this.mergeInfo = mergeInfo;
     this.flushInfo = null;
   }
@@ -115,12 +132,13 @@ public IOContext(IOContext ctxt, boolean readOnce) {
     this.mergeInfo = ctxt.mergeInfo;
     this.flushInfo = ctxt.flushInfo;
     this.readOnce = readOnce;
+    this.randomAccess = ctxt.randomAccess;
     this.load = false;
   }
 
   @Override
   public int hashCode() {
-    return Objects.hash(context, flushInfo, mergeInfo, readOnce, load);
+    return Objects.hash(context, flushInfo, mergeInfo, readOnce, load, randomAccess);
   }
 
   @Override
@@ -134,6 +152,7 @@ public boolean equals(Object obj) {
     if (!Objects.equals(mergeInfo, other.mergeInfo)) return false;
     if (readOnce != other.readOnce) return false;
     if (load != other.load) return false;
+    if (randomAccess != other.randomAccess) return false;
     return true;
   }
 
@@ -147,6 +166,10 @@ public String toString() {
         + flushInfo
         + ", readOnce="
         + readOnce
+        + ", load="
+        + load
+        + ", randomAccess="
+        + randomAccess
         + "]";
   }
 }

lucene/core/src/java/org/apache/lucene/store/MMapDirectory.java

@@ -76,9 +76,16 @@
  *   <li>{@code permission java.lang.RuntimePermission "accessClassInPackage.sun.misc";}
  * </ul>
  *
- * <p>On exactly <b>Java 19 / 20 / 21</b> this class will use the modern {@code MemorySegment} API
- * which allows to safely unmap (if you discover any problems with this preview API, you can disable
- * it by using system property {@link #ENABLE_MEMORY_SEGMENTS_SYSPROP}).
+ * <p>Starting with <b>Java 19</b> this class will use the modern {@code MemorySegment} API which
+ * allows to safely unmap (if you discover any problems with this preview API, you can disable it by
+ * using system property {@link #ENABLE_MEMORY_SEGMENTS_SYSPROP}).
+ *
+ * <p>Starting with <b>Java 21</b> on some platforms like Linux and MacOS X, this class will invoke
+ * the syscall {@code madvise()} to advise how OS kernel should handle paging after opening a file.
+ * For this to work, Java code must be able to call native code. If this is not allowed, a warning
+ * is logged. To enable native access for Lucene in a modularized application, pass {@code
+ * --enable-native-access=org.apache.lucene.core} to the Java command line. If Lucene is running in
+ * a classpath-based application, use {@code --enable-native-access=ALL-UNNAMED}.
  *
  * <p><b>NOTE:</b> Accessing this class either directly or indirectly from a thread while it's
  * interrupted can close the underlying channel immediately if at the same time the thread is
@@ -345,6 +352,8 @@ IndexInput openInput(Path path, IOContext context, int chunkSizePower, boolean p
 
     String getUnmapNotSupportedReason();
 
+    boolean supportsMadvise();
+
     default IOException convertMapFailedIOException(
         IOException ioe, String resourceDescription, long bufSize) {
       final String originalMessage;
@@ -441,6 +450,14 @@ private static MMapIndexInputProvider lookupProvider() {
     return new MappedByteBufferIndexInputProvider();
   }
 
+  /**
+   * Returns true, if MMapDirectory uses the platform's {@code madvise()} syscall to advise how OS
+   * kernel should handle paging after opening a file.
+   */
+  public static boolean supportsMadvise() {
+    return PROVIDER.supportsMadvise();
+  }
+
   static {
     PROVIDER = doPrivileged(MMapDirectory::lookupProvider);
     DEFAULT_MAX_CHUNK_SIZE = PROVIDER.getDefaultMaxChunkSize();

lucene/core/src/java/org/apache/lucene/store/MappedByteBufferIndexInputProvider.java

@@ -97,6 +97,11 @@ public String getUnmapNotSupportedReason() {
     return unmapNotSupportedReason;
   }
 
+  @Override
+  public boolean supportsMadvise() {
+    return false;
+  }
+
   /** Maps a file into a set of buffers */
   final ByteBuffer[] map(
       String resourceDescription, FileChannel fc, int chunkSizePower, boolean preload, long length)

lucene/core/src/java19/org/apache/lucene/store/MemorySegmentIndexInputProvider.java

@@ -81,6 +81,11 @@ public String getUnmapNotSupportedReason() {
     return null;
   }
 
+  @Override
+  public boolean supportsMadvise() {
+    return false;
+  }
+
   private final MemorySegment[] map(
       MemorySession session,
       String resourceDescription,

lucene/core/src/java20/org/apache/lucene/store/MemorySegmentIndexInputProvider.java

@@ -81,6 +81,11 @@ public String getUnmapNotSupportedReason() {
     return null;
   }
 
+  @Override
+  public boolean supportsMadvise() {
+    return false;
+  }
+
   private final MemorySegment[] map(
       Arena arena,
       String resourceDescription,

lucene/core/src/java21/org/apache/lucene/store/MemorySegmentIndexInputProvider.java

@@ -23,14 +23,18 @@
 import java.nio.channels.FileChannel.MapMode;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
+import java.util.Optional;
 import java.util.logging.Logger;
 import org.apache.lucene.util.Constants;
 import org.apache.lucene.util.Unwrappable;
 
 @SuppressWarnings("preview")
 final class MemorySegmentIndexInputProvider implements MMapDirectory.MMapIndexInputProvider {
 
+  private final Optional<NativeAccess> nativeAccess;
+
   public MemorySegmentIndexInputProvider() {
+    this.nativeAccess = NativeAccess.getImplementation();
     var log = Logger.getLogger(getClass().getName());
     log.info(
         "Using MemorySegmentIndexInput with Java 21 or later; to disable start with -D"
@@ -54,7 +58,7 @@ public IndexInput openInput(Path path, IOContext context, int chunkSizePower, bo
           MemorySegmentIndexInput.newInstance(
               resourceDescription,
               arena,
-              map(arena, resourceDescription, fc, chunkSizePower, preload, fileSize),
+              map(arena, resourceDescription, fc, context, chunkSizePower, preload, fileSize),
               fileSize,
               chunkSizePower);
       success = true;
@@ -81,10 +85,16 @@ public String getUnmapNotSupportedReason() {
     return null;
   }
 
+  @Override
+  public boolean supportsMadvise() {
+    return nativeAccess.isPresent();
+  }
+
   private final MemorySegment[] map(
       Arena arena,
       String resourceDescription,
       FileChannel fc,
+      IOContext context,
       int chunkSizePower,
       boolean preload,
       long length)
@@ -109,8 +119,12 @@ private final MemorySegment[] map(
       } catch (IOException ioe) {
         throw convertMapFailedIOException(ioe, resourceDescription, segSize);
       }
+      // if preload apply it without madvise.
+      // if chunk size is too small (2 MiB), disable madvise support (incorrect alignment)
       if (preload) {
         segment.load();
+      } else if (nativeAccess.isPresent() && chunkSizePower >= 21) {
+        nativeAccess.get().madvise(segment, context);
       }
       segments[segNr] = segment;
       startOffset += segSize;

lucene/core/src/java21/org/apache/lucene/store/NativeAccess.java

@@ -0,0 +1,39 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.lucene.store;
+
+import java.io.IOException;
+import java.lang.foreign.MemorySegment;
+import java.util.Optional;
+import org.apache.lucene.util.Constants;
+
+@SuppressWarnings("preview")
+abstract class NativeAccess {
+
+  /** Invoke the {@code madvise} call for the given {@link MemorySegment}. */
+  public abstract void madvise(MemorySegment segment, IOContext context) throws IOException;
+
+  /**
+   * Return the NativeAccess instance for this platform. At moment we only support Linux and MacOS
+   */
+  public static Optional<NativeAccess> getImplementation() {
+    if (Constants.LINUX || Constants.MAC_OS_X) {
+      return PosixNativeAccess.getInstance();
+    }
+    return Optional.empty();
+  }
+}