src/share/vm/gc_implementation/g1/dirtyCardQueue.hpp

Fri, 01 Oct 2010 16:43:05 -0400

author
tonyp
date
Fri, 01 Oct 2010 16:43:05 -0400
changeset 2197
6e0aac35bfa9
parent 2060
2d160770d2e5
child 2314
f95d63e2154a
permissions
-rw-r--r--

6980838: G1: guarantee(false) failed: thread has an unexpected active value in its SATB queue
Summary: Under certain circumstances a safepoint could happen between a JavaThread object being created and that object being added to the Java threads list. This could cause the active field of that thread's SATB queue to get out-of-sync with respect to the other Java threads. The solution is to activate the SATB queue, when necessary, before adding the thread to the Java threads list, not when the JavaThread object is created. The changeset also includes a small fix to rename the surrogate locker thread from "Surrogate Locker Thread (CMS)" to "Surrogate Locker Thread (Concurrent GC)" since it's also used in G1.
Reviewed-by: iveresov, ysr, johnc, jcoomes

     1 /*
     2  * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.
     8  *
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    12  * version 2 for more details (a copy is included in the LICENSE file that
    13  * accompanied this code).
    14  *
    15  * You should have received a copy of the GNU General Public License version
    16  * 2 along with this work; if not, write to the Free Software Foundation,
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    18  *
    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    20  * or visit www.oracle.com if you need additional information or have any
    21  * questions.
    22  *
    23  */
    25 class FreeIdSet;
    27 // A closure class for processing card table entries.  Note that we don't
    28 // require these closure objects to be stack-allocated.
    29 class CardTableEntryClosure: public CHeapObj {
    30 public:
    31   // Process the card whose card table entry is "card_ptr".  If returns
    32   // "false", terminate the iteration early.
    33   virtual bool do_card_ptr(jbyte* card_ptr, int worker_i = 0) = 0;
    34 };
    36 // A ptrQueue whose elements are "oops", pointers to object heads.
    37 class DirtyCardQueue: public PtrQueue {
    38 public:
    39   DirtyCardQueue(PtrQueueSet* qset_, bool perm = false) :
    40     // Dirty card queues are always active, so we create them with their
    41     // active field set to true.
    42     PtrQueue(qset_, perm, true /* active */) { }
    44   // Apply the closure to all elements, and reset the index to make the
    45   // buffer empty.  If a closure application returns "false", return
    46   // "false" immediately, halting the iteration.  If "consume" is true,
    47   // deletes processed entries from logs.
    48   bool apply_closure(CardTableEntryClosure* cl,
    49                      bool consume = true,
    50                      size_t worker_i = 0);
    52   // Apply the closure to all elements of "buf", down to "index"
    53   // (inclusive.)  If returns "false", then a closure application returned
    54   // "false", and we return immediately.  If "consume" is true, entries are
    55   // set to NULL as they are processed, so they will not be processed again
    56   // later.
    57   static bool apply_closure_to_buffer(CardTableEntryClosure* cl,
    58                                       void** buf, size_t index, size_t sz,
    59                                       bool consume = true,
    60                                       int worker_i = 0);
    61   void **get_buf() { return _buf;}
    62   void set_buf(void **buf) {_buf = buf;}
    63   size_t get_index() { return _index;}
    64   void reinitialize() { _buf = 0; _sz = 0; _index = 0;}
    65 };
    69 class DirtyCardQueueSet: public PtrQueueSet {
    70   CardTableEntryClosure* _closure;
    72   DirtyCardQueue _shared_dirty_card_queue;
    74   // Override.
    75   bool mut_process_buffer(void** buf);
    77   // Protected by the _cbl_mon.
    78   FreeIdSet* _free_ids;
    80   // The number of completed buffers processed by mutator and rs thread,
    81   // respectively.
    82   jint _processed_buffers_mut;
    83   jint _processed_buffers_rs_thread;
    85 public:
    86   DirtyCardQueueSet(bool notify_when_complete = true);
    88   void initialize(Monitor* cbl_mon, Mutex* fl_lock,
    89                   int process_completed_threshold,
    90                   int max_completed_queue,
    91                   Mutex* lock, PtrQueueSet* fl_owner = NULL);
    93   // The number of parallel ids that can be claimed to allow collector or
    94   // mutator threads to do card-processing work.
    95   static size_t num_par_ids();
    97   static void handle_zero_index_for_thread(JavaThread* t);
    99   // Register "blk" as "the closure" for all queues.  Only one such closure
   100   // is allowed.  The "apply_closure_to_completed_buffer" method will apply
   101   // this closure to a completed buffer, and "iterate_closure_all_threads"
   102   // applies it to partially-filled buffers (the latter should only be done
   103   // with the world stopped).
   104   void set_closure(CardTableEntryClosure* closure);
   106   // If there is a registered closure for buffers, apply it to all entries
   107   // in all currently-active buffers.  This should only be applied at a
   108   // safepoint.  (Currently must not be called in parallel; this should
   109   // change in the future.)  If "consume" is true, processed entries are
   110   // discarded.
   111   void iterate_closure_all_threads(bool consume = true,
   112                                    size_t worker_i = 0);
   114   // If there exists some completed buffer, pop it, then apply the
   115   // registered closure to all its elements, nulling out those elements
   116   // processed.  If all elements are processed, returns "true".  If no
   117   // completed buffers exist, returns false.  If a completed buffer exists,
   118   // but is only partially completed before a "yield" happens, the
   119   // partially completed buffer (with its processed elements set to NULL)
   120   // is returned to the completed buffer set, and this call returns false.
   121   bool apply_closure_to_completed_buffer(int worker_i = 0,
   122                                          int stop_at = 0,
   123                                          bool during_pause = false);
   125   // If there exists some completed buffer, pop it, then apply the
   126   // specified closure to all its elements, nulling out those elements
   127   // processed.  If all elements are processed, returns "true".  If no
   128   // completed buffers exist, returns false.  If a completed buffer exists,
   129   // but is only partially completed before a "yield" happens, the
   130   // partially completed buffer (with its processed elements set to NULL)
   131   // is returned to the completed buffer set, and this call returns false.
   132   bool apply_closure_to_completed_buffer(CardTableEntryClosure* cl,
   133                                          int worker_i = 0,
   134                                          int stop_at = 0,
   135                                          bool during_pause = false);
   137   // Helper routine for the above.
   138   bool apply_closure_to_completed_buffer_helper(CardTableEntryClosure* cl,
   139                                                 int worker_i,
   140                                                 BufferNode* nd);
   142   BufferNode* get_completed_buffer(int stop_at);
   144   // Applies the current closure to all completed buffers,
   145   // non-consumptively.
   146   void apply_closure_to_all_completed_buffers();
   148   DirtyCardQueue* shared_dirty_card_queue() {
   149     return &_shared_dirty_card_queue;
   150   }
   152   // Deallocate any completed log buffers
   153   void clear();
   155   // If a full collection is happening, reset partial logs, and ignore
   156   // completed ones: the full collection will make them all irrelevant.
   157   void abandon_logs();
   159   // If any threads have partial logs, add them to the global list of logs.
   160   void concatenate_logs();
   161   void clear_n_completed_buffers() { _n_completed_buffers = 0;}
   163   jint processed_buffers_mut() {
   164     return _processed_buffers_mut;
   165   }
   166   jint processed_buffers_rs_thread() {
   167     return _processed_buffers_rs_thread;
   168   }
   170 };

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