src/java.base/share/classes/sun/nio/ch/Util.java

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

*** 33,42 ****
--- 33,43 ----
  import java.security.AccessController;
  import java.security.PrivilegedAction;
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.Set;
+ import jdk.internal.misc.JdkThreadLocal;
  import jdk.internal.misc.Unsafe;
  import sun.security.action.GetPropertyAction;
  import java.io.IOException;
  
  public class Util {
*** 49,64 ****
      // The max size allowed for a cached temp buffer, in bytes
      private static final long MAX_CACHED_BUFFER_SIZE = getMaxCachedBufferSize();
  
      // Per-thread cache of temporary direct buffers
      private static ThreadLocal<BufferCache> bufferCache =
!         new ThreadLocal<BufferCache>()
      {
          @Override
          protected BufferCache initialValue() {
              return new BufferCache();
          }
      };
  
      /**
       * Returns the max size allowed for a cached temp buffers, in
       * bytes. It defaults to Long.MAX_VALUE. It can be set with the
--- 50,70 ----
      // The max size allowed for a cached temp buffer, in bytes
      private static final long MAX_CACHED_BUFFER_SIZE = getMaxCachedBufferSize();
  
      // Per-thread cache of temporary direct buffers
      private static ThreadLocal<BufferCache> bufferCache =
!         new JdkThreadLocal<>()
      {
          @Override
          protected BufferCache initialValue() {
              return new BufferCache();
          }
+ 
+         @Override
+         protected void threadTerminated(BufferCache cache) {
+             cache.freeAll();
+         }
      };
  
      /**
       * Returns the max size allowed for a cached temp buffers, in
       * bytes. It defaults to Long.MAX_VALUE. It can be set with the
*** 203,212 ****
--- 209,237 ----
              buffers[start] = null;
              start = next(start);
              count--;
              return buf;
          }
+ 
+         void freeAll() {
+             if (isEmpty()) {
+                 return;
+             }
+ 
+             for (int i = 0; i < buffers.length; i += 1) {
+                 final ByteBuffer buf = buffers[i];
+                 if (buf == null) {
+                     continue;
+                 }
+ 
+                 free(buf);
+                 // just in case
+                 buffers[i] = null;
+             }
+             // just in case
+             count = 0;
+         }
      }
  
      /**
       * Returns a temporary buffer of at least the given size
       */