8281631: HashMap copy constructor and putAll can over-allocate table

Reviewed-by: smarks
openjdk · Mar 16, 2022 · 3e39304 · 3e39304 · openjdk-notifier · Mar 16, 2022
1 parent 0cf291b
commit 3e39304
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Showing 4 changed files with 258 additions and 72 deletions.
diff --git a/src/java.base/share/classes/java/util/HashMap.java b/src/java.base/share/classes/java/util/HashMap.java
@@ -495,9 +495,9 @@ final void putMapEntries(Map<? extends K, ? extends V> m, boolean evict) {
         int s = m.size();
         if (s > 0) {
             if (table == null) { // pre-size
-                float ft = ((float)s / loadFactor) + 1.0F;
-                int t = ((ft < (float)MAXIMUM_CAPACITY) ?
-                         (int)ft : MAXIMUM_CAPACITY);
+                double dt = Math.ceil(s / (double)loadFactor);
+                int t = ((dt < (double)MAXIMUM_CAPACITY) ?
+                         (int)dt : MAXIMUM_CAPACITY);
                 if (t > threshold)
                     threshold = tableSizeFor(t);
             } else {
@@ -1527,12 +1527,12 @@ private void readObject(ObjectInputStream s)
         } else if (mappings == 0) {
             // use defaults
         } else if (mappings > 0) {
-            float fc = (float)mappings / lf + 1.0f;
-            int cap = ((fc < DEFAULT_INITIAL_CAPACITY) ?
+            double dc = Math.ceil(mappings / (double)lf);
+            int cap = ((dc < DEFAULT_INITIAL_CAPACITY) ?
                        DEFAULT_INITIAL_CAPACITY :
-                       (fc >= MAXIMUM_CAPACITY) ?
+                       (dc >= MAXIMUM_CAPACITY) ?
                        MAXIMUM_CAPACITY :
-                       tableSizeFor((int)fc));
+                       tableSizeFor((int)dc));
             float ft = (float)cap * lf;
             threshold = ((cap < MAXIMUM_CAPACITY && ft < MAXIMUM_CAPACITY) ?
                          (int)ft : Integer.MAX_VALUE);

diff --git a/src/java.base/share/classes/java/util/WeakHashMap.java b/src/java.base/share/classes/java/util/WeakHashMap.java
@@ -213,9 +213,7 @@ public WeakHashMap(int initialCapacity, float loadFactor) {
         if (loadFactor <= 0 || Float.isNaN(loadFactor))
             throw new IllegalArgumentException("Illegal Load factor: "+
                                                loadFactor);
-        int capacity = 1;
-        while (capacity < initialCapacity)
-            capacity <<= 1;
+        int capacity = HashMap.tableSizeFor(initialCapacity);
         table = newTable(capacity);
         this.loadFactor = loadFactor;
         threshold = (int)(capacity * loadFactor);
@@ -251,7 +249,7 @@ public WeakHashMap() {
      * @since   1.3
      */
     public WeakHashMap(Map<? extends K, ? extends V> m) {
-        this(Math.max((int) ((float)m.size() / DEFAULT_LOAD_FACTOR + 1.0F),
+        this(Math.max((int) Math.ceil(m.size() / (double)DEFAULT_LOAD_FACTOR),
                 DEFAULT_INITIAL_CAPACITY),
              DEFAULT_LOAD_FACTOR);
         putAll(m);
@@ -468,7 +466,7 @@ public V put(K key, V value) {
         modCount++;
         Entry<K,V> e = tab[i];
         tab[i] = new Entry<>(k, value, queue, h, e);
-        if (++size >= threshold)
+        if (++size > threshold)
             resize(tab.length * 2);
         return null;
     }
@@ -557,7 +555,7 @@ public void putAll(Map<? extends K, ? extends V> m) {
          * to at most one extra resize.
          */
         if (numKeysToBeAdded > threshold) {
-            int targetCapacity = (int)(numKeysToBeAdded / loadFactor + 1);
+            int targetCapacity = (int)Math.ceil(numKeysToBeAdded / (double)loadFactor);
             if (targetCapacity > MAXIMUM_CAPACITY)
                 targetCapacity = MAXIMUM_CAPACITY;
             int newCapacity = table.length;

diff --git a/test/jdk/ProblemList.txt b/test/jdk/ProblemList.txt
@@ -542,6 +542,7 @@ java/lang/invoke/LFCaching/LFMultiThreadCachingTest.java        8151492 generic-
 java/lang/invoke/LFCaching/LFGarbageCollectedTest.java          8078602 generic-all
 java/lang/invoke/lambda/LambdaFileEncodingSerialization.java    8249079 linux-x64
 java/lang/invoke/RicochetTest.java                              8251969 generic-all
+java/lang/Enum/ConstantDirectoryOptimalCapacity.java            8282120 generic-all
 
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