Github user kiszk commented on a diff in the pull request:
https://github.com/apache/spark/pull/19222#discussion_r147573486
--- Diff:
common/unsafe/src/main/java/org/apache/spark/unsafe/memory/MemoryBlock.java ---
@@ -17,47 +17,168 @@
package org.apache.spark.unsafe.memory;
-import javax.annotation.Nullable;
-
import org.apache.spark.unsafe.Platform;
+import javax.annotation.Nullable;
+
/**
- * A consecutive block of memory, starting at a {@link MemoryLocation}
with a fixed size.
+ * A declaration of interfaces of MemoryBlock classes .
*/
-public class MemoryBlock extends MemoryLocation {
+public abstract class MemoryBlock {
+ @Nullable
+ protected final Object obj;
- private final long length;
+ protected final long offset;
+
+ protected final long length;
/**
* Optional page number; used when this MemoryBlock represents a page
allocated by a
- * TaskMemoryManager. This field is public so that it can be modified by
the TaskMemoryManager,
- * which lives in a different package.
+ * TaskMemoryManager. This field can be updated using setPageNumber
method so that
+ * this can be modified by the TaskMemoryManager, which lives in a
different package.
*/
- public int pageNumber = -1;
+ private int pageNumber = -1;
public MemoryBlock(@Nullable Object obj, long offset, long length) {
- super(obj, offset);
+ this.obj = obj;
+ this.offset = offset;
this.length = length;
}
+ public MemoryBlock() {
+ this(null, 0, 0);
+ }
+
+ public final Object getBaseObject() {
+ return obj;
+ }
+
+ public final long getBaseOffset() {
+ return offset;
+ }
+
/**
* Returns the size of the memory block.
*/
- public long size() {
+ public final long size() {
return length;
}
- /**
- * Creates a memory block pointing to the memory used by the long array.
- */
- public static MemoryBlock fromLongArray(final long[] array) {
- return new MemoryBlock(array, Platform.LONG_ARRAY_OFFSET, array.length
* 8L);
+ public final void setPageNumber(int pageNum) {
+ pageNumber = pageNum;
+ }
+
+ public final int getPageNumber() {
+ return pageNumber;
}
/**
* Fills the memory block with the specified byte value.
*/
- public void fill(byte value) {
+ public final void fill(byte value) {
Platform.setMemory(obj, offset, length, value);
}
+
+ /**
+ * Instantiate the same type of MemoryBlock with new offset and size
+ */
+ public abstract MemoryBlock allocate(long offset, long size);
+
+
+ public abstract int getInt(long offset);
+
+ public abstract void putInt(long offset, int value);
+
+ public abstract boolean getBoolean(long offset);
+
+ public abstract void putBoolean(long offset, boolean value);
+
+ public abstract byte getByte(long offset);
+
+ public abstract void putByte(long offset, byte value);
+
+ public abstract short getShort(long offset);
+
+ public abstract void putShort(long offset, short value);
+
+ public abstract long getLong(long offset);
+
+ public abstract void putLong(long offset, long value);
+
+ public abstract float getFloat(long offset);
+
+ public abstract void putFloat(long offset, float value);
+
+ public abstract double getDouble(long offset);
+
+ public abstract void putDouble(long offset, double value);
+
+ public abstract Object getObjectVolatile(long offset);
+
+ public abstract void putObjectVolatile(long offset, Object value);
+
+ public static final void copyMemory(
--- End diff --
`copyMemory` has two kinds of arguments: `src` and `dst`.
If we make them non-static method, it is not easy to understand whether
`this` is `src` or `dst`. If we keep method name `MemoryBlock.copy`, I think
that it is good to keep current form (it is common in `memcpy`).
Or, can we prepare two methods `MemoryBlock.copyFrom(srcOffset, dst...)`
and `MemoryBlock.copyTo(src..., dstOffset)`.
@cloud-fan What do you think?
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