src/java.security.jgss/share/classes/sun/security/krb5/internal/rcache/AuthList.java

rev 48894 : 8197518: Kerberos krb5 authentication: AuthList's put method leads to performance issue

*** 1,7 ****
  /*
!  * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
--- 1,7 ----
  /*
!  * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
*** 53,62 ****
--- 53,65 ----
  public class AuthList {
  
      private final LinkedList<AuthTimeWithHash> entries;
      private final int lifespan;
  
+     // entries.getLast().ctime, updated after each cleanup.
+     private volatile int oldestTime = Integer.MIN_VALUE;
+ 
      /**
       * Constructs a AuthList.
       */
      public AuthList(int lifespan) {
          this.lifespan = lifespan;
*** 70,79 ****
--- 73,84 ----
      public void put(AuthTimeWithHash t, KerberosTime currentTime)
              throws KrbApErrException {
  
          if (entries.isEmpty()) {
              entries.addFirst(t);
+             oldestTime = t.ctime;
+             return;
          } else {
              AuthTimeWithHash temp = entries.getFirst();
              int cmp = temp.compareTo(t);
              if (cmp < 0) {
                  // This is the most common case, newly received authenticator
*** 104,131 ****
              }
          }
  
          // let us cleanup while we are here
          long timeLimit = currentTime.getSeconds() - lifespan;
          ListIterator<AuthTimeWithHash> it = entries.listIterator(0);
!         AuthTimeWithHash temp = null;
!         int index = -1;
          while (it.hasNext()) {
              // search expired timestamps.
              temp = it.next();
              if (temp.ctime < timeLimit) {
!                 index = entries.indexOf(temp);
                  break;
              }
          }
!         // It would be nice if LinkedList has a method called truncate(index).
!         if (index > -1) {
!             do {
!                 // remove expired timestamps from the list.
!                 entries.removeLast();
!             } while(entries.size() > index);
          }
      }
  
      public boolean isEmpty() {
          return entries.isEmpty();
      }
--- 109,146 ----
              }
          }
  
          // let us cleanup while we are here
          long timeLimit = currentTime.getSeconds() - lifespan;
+         long veryOld = timeLimit - (lifespan > 60 ? 60 : lifespan);
+ 
+         // Only trigger a cleanup when very old entries exist
+         // (lifespan + 1 min ago). This ensures a cleanup is done
+         // at most every minute.
+         if (oldestTime > veryOld) {
+             return;
+         }
+ 
+         // and we remove the *enough* old ones (1 lifetime ago)
          ListIterator<AuthTimeWithHash> it = entries.listIterator(0);
!         AuthTimeWithHash temp;
          while (it.hasNext()) {
              // search expired timestamps.
              temp = it.next();
              if (temp.ctime < timeLimit) {
!                 // It would be nice if ListIterator has a method called stripHere()
!                 while (!entries.isEmpty()) {
!                     if (entries.removeLast() == temp) {
                          break;
                      }
                  }
!                 break;
!             }
          }
+ 
+         AuthTimeWithHash last = entries.peekLast();
+         oldestTime = last == null ? Integer.MIN_VALUE : last.ctime;
      }
  
      public boolean isEmpty() {
          return entries.isEmpty();
      }