diff --git a/buffer/src/main/java/io/netty/buffer/PoolArena.java b/buffer/src/main/java/io/netty/buffer/PoolArena.java
index 57c4385e92..348b24f6c8 100644
--- a/buffer/src/main/java/io/netty/buffer/PoolArena.java
+++ b/buffer/src/main/java/io/netty/buffer/PoolArena.java
@@ -188,10 +188,19 @@ abstract class PoolArena<T> {
 
         if ((reqCapacity & 0xFFFFFE00) != 0) { // >= 512
             // Doubled
-            int normalizedCapacity = 512;
-            while (normalizedCapacity < reqCapacity) {
-                normalizedCapacity <<= 1;
+
+            int normalizedCapacity = reqCapacity;
+            normalizedCapacity |= normalizedCapacity >>>  1;
+            normalizedCapacity |= normalizedCapacity >>>  2;
+            normalizedCapacity |= normalizedCapacity >>>  4;
+            normalizedCapacity |= normalizedCapacity >>>  8;
+            normalizedCapacity |= normalizedCapacity >>> 16;
+            normalizedCapacity ++;
+
+            if (normalizedCapacity < 0) {
+                normalizedCapacity >>>= 1;
             }
+
             return normalizedCapacity;
         }
 
diff --git a/transport/src/main/java/io/netty/channel/AdaptiveRecvByteBufAllocator.java b/transport/src/main/java/io/netty/channel/AdaptiveRecvByteBufAllocator.java
index 4c123840b0..9827beeeae 100644
--- a/transport/src/main/java/io/netty/channel/AdaptiveRecvByteBufAllocator.java
+++ b/transport/src/main/java/io/netty/channel/AdaptiveRecvByteBufAllocator.java
@@ -44,23 +44,12 @@ public class AdaptiveRecvByteBufAllocator implements RecvByteBufAllocator {
 
     static {
         List<Integer> sizeTable = new ArrayList<Integer>();
-        for (int i = 1; i <= 8; i ++) {
+        for (int i = 16; i < 512; i += 16) {
             sizeTable.add(i);
         }
 
-        for (int i = 4; i < 32; i ++) {
-            long v = 1L << i;
-            long inc = v >>> 4;
-            v -= inc << 3;
-
-            for (int j = 0; j < 8; j ++) {
-                v += inc;
-                if (v > Integer.MAX_VALUE) {
-                    sizeTable.add(Integer.MAX_VALUE);
-                } else {
-                    sizeTable.add((int) v);
-                }
-            }
+        for (int i = 512; i > 0; i <<= 1) {
+            sizeTable.add(i);
         }
 
         SIZE_TABLE = new int[sizeTable.size()];