src/java.base/share/classes/java/lang/ThreadLocal.java

rev 50167 : 8202788: Explicitly reclaim cached thread-local direct buffers at thread exit
Reviewed-by:

*** 26,35 ****
--- 26,36 ----
  package java.lang;
  import java.lang.ref.*;
  import java.util.Objects;
  import java.util.concurrent.atomic.AtomicInteger;
  import java.util.function.Supplier;
+ import jdk.internal.misc.JdkThreadLocal;
  
  /**
   * This class provides thread-local variables.  These variables differ from
   * their normal counterparts in that each thread that accesses one (via its
   * {@code get} or {@code set} method) has its own, independently initialized
*** 82,91 ****
--- 83,109 ----
       * are used by the same threads, while remaining well-behaved in
       * less common cases.
       */
      private final int threadLocalHashCode = nextHashCode();
  
+     static void callThreadTerminated(ThreadLocalMap map) {
+         if (map == null) {
+             return;
+         }
+ 
+         // We expect to have a very small number of hooks and
+         // potentially a lot of entries in the map. So, it should be
+         // faster to iterate over the hooks and do look-ups on the map
+         // instead of iterating over the map.
+         JdkThreadLocal.forEach(tl -> {
+             final ThreadLocalMap.Entry entry = map.getEntry(tl);
+             if (entry != null) {
+                 tl.callThreadTerminated(entry.value);
+             }
+         });
+     }
+ 
      /**
       * The next hash code to be given out. Updated atomically. Starts at
       * zero.
       */
      private static AtomicInteger nextHashCode =