Add RAMCloud related memo

- Mark original TableEnumerator, which had performance issue.
- Add notes about what is limiting the multi operation limit.

Change-Id: I8b9adc601b16cd4bf98f2d571e822077bf75f2d7
diff --git a/src/main/java/edu/stanford/ramcloud/JRamCloud.java b/src/main/java/edu/stanford/ramcloud/JRamCloud.java
index ffc092f..e8aba19 100644
--- a/src/main/java/edu/stanford/ramcloud/JRamCloud.java
+++ b/src/main/java/edu/stanford/ramcloud/JRamCloud.java
@@ -208,6 +208,7 @@
         final public long nextHash;
     }
 
+    @Deprecated
     public class TableEnumerator {
         private long tableEnumeratorObjectPointer = 0;
         private long ramCloudObjectPointer = 0;
diff --git a/src/main/java/net/onrc/onos/core/datastore/ramcloud/RCClient.java b/src/main/java/net/onrc/onos/core/datastore/ramcloud/RCClient.java
index aea77fc..c651e5f 100644
--- a/src/main/java/net/onrc/onos/core/datastore/ramcloud/RCClient.java
+++ b/src/main/java/net/onrc/onos/core/datastore/ramcloud/RCClient.java
@@ -47,10 +47,27 @@
     // FIXME These constants should be defined by JRamCloud
     public static final int STATUS_OK = 0;
 
-    // FIXME come up with a proper way to retrieve configuration
+    /**
+     * Maximum number of Multi-Read operations which can be executed in
+     * one RPC call.
+     *
+     *  There are multiple factors which determines this limit.
+     *  - RAMCloud RPC size limit of 8MB.
+     *  - JNI implementation store the RPC result on stack.
+     *    (Increasing the stack-size limit will help relaxing this limit.)
+     */
     public static final int MAX_MULTI_READS = Math.max(1, Integer
             .valueOf(System.getProperty("ramcloud.max_multi_reads", "400")));
 
+    /**
+     * Maximum number of Multi-Write operations which can be executed in
+     * one RPC call.
+     *
+     *  There are multiple factors which determines this limit.
+     *  - RAMCloud RPC size limit of 8MB.
+     *  - JNI implementation store the RPC result on stack.
+     *    (Increasing the stack-size limit will help relaxing this limit.)
+     */
     public static final int MAX_MULTI_WRITES = Math.max(1, Integer
             .valueOf(System.getProperty("ramcloud.max_multi_writes", "800")));