unsafe/memory/MemoryAllocator.java

0001 /*
0002  * Licensed to the Apache Software Foundation (ASF) under one or more
0003  * contributor license agreements.  See the NOTICE file distributed with
0004  * this work for additional information regarding copyright ownership.
0005  * The ASF licenses this file to You under the Apache License, Version 2.0
0006  * (the "License"); you may not use this file except in compliance with
0007  * the License.  You may obtain a copy of the License at
0008  *
0009  *    http://www.apache.org/licenses/LICENSE-2.0
0010  *
0011  * Unless required by applicable law or agreed to in writing, software
0012  * distributed under the License is distributed on an "AS IS" BASIS,
0013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0014  * See the License for the specific language governing permissions and
0015  * limitations under the License.
0016  */
0017
0018 package org.apache.spark.unsafe.memory;
0019
0020 public interface MemoryAllocator {
0021
0022   /**
0023    * Whether to fill newly allocated and deallocated memory with 0xa5 and 0x5a bytes respectively.
0024    * This helps catch misuse of uninitialized or freed memory, but imposes some overhead.
0025    */
0026   boolean MEMORY_DEBUG_FILL_ENABLED = Boolean.parseBoolean(
0027     System.getProperty("spark.memory.debugFill", "false"));
0028
0029   // Same as jemalloc's debug fill values.
0030   byte MEMORY_DEBUG_FILL_CLEAN_VALUE = (byte)0xa5;
0031   byte MEMORY_DEBUG_FILL_FREED_VALUE = (byte)0x5a;
0032
0033   /**
0034    * Allocates a contiguous block of memory. Note that the allocated memory is not guaranteed
0035    * to be zeroed out (call `fill(0)` on the result if this is necessary).
0036    */
0037   MemoryBlock allocate(long size) throws OutOfMemoryError;
0038
0039   void free(MemoryBlock memory);
0040
0041   MemoryAllocator UNSAFE = new UnsafeMemoryAllocator();
0042
0043   MemoryAllocator HEAP = new HeapMemoryAllocator();
0044 }