jdk8-mips64-public/hotspot: src/share/vm/memory/freeBlockDictionary.hpp@2c022e432e10

8024974: Incorrect use of GC_locker::is_active()
Summary: SymbolTable and StringTable can make calls to GC_locker::is_active() outside a safepoint. This isn't safe because the GC_locker active state (lock count) is only updated at a safepoint and only remains valid as long as _needs_gc is true. However, outside a safepoint_needs_gc can change to false at any time, which makes it impossible to do a correct call to is_active() in that context. In this case these calls can just be removed since the input argument to basic_add() should never be on the heap and so there's no need to check the GC_locker state. This change also adjusts the assert() in is_active() to makes sure all calls to this function are always done under a safepoint.
Reviewed-by: brutisso, dcubed
Contributed-by: per.liden@oracle.com

     1 /*

     2  * Copyright (c) 2001, 2012, 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 #ifndef SHARE_VM_MEMORY_FREEBLOCKDICTIONARY_HPP

    26 #define SHARE_VM_MEMORY_FREEBLOCKDICTIONARY_HPP

    28 #include "memory/allocation.hpp"

    29 #include "runtime/mutex.hpp"

    30 #include "utilities/debug.hpp"

    31 #include "utilities/globalDefinitions.hpp"

    32 #include "utilities/ostream.hpp"

    34 // A FreeBlockDictionary is an abstract superclass that will allow

    35 // a number of alternative implementations in the future.

    36 template <class Chunk>

    37 class FreeBlockDictionary: public CHeapObj<mtGC> {

    38  public:

    39   enum Dither {

    40     atLeast,

    41     exactly,

    42     roughly

    43   };

    44   enum DictionaryChoice {

    45     dictionaryBinaryTree = 0,

    46     dictionarySplayTree  = 1,

    47     dictionarySkipList   = 2

    48   };

    50  private:

    51   // This field is added and can be set to point to the

    52   // the Mutex used to synchronize access to the

    53   // dictionary so that assertion checking can be done.

    54   // For example it is set to point to _parDictionaryAllocLock.

    55   NOT_PRODUCT(Mutex* _lock;)

    57  public:

    58   virtual void       remove_chunk(Chunk* fc) = 0;

    59   virtual Chunk*     get_chunk(size_t size, Dither dither = atLeast) = 0;

    60   virtual void       return_chunk(Chunk* chunk) = 0;

    61   virtual size_t     total_chunk_size(debug_only(const Mutex* lock)) const = 0;

    62   virtual size_t     max_chunk_size()   const = 0;

    63   virtual size_t     min_size()        const = 0;

    64   // Reset the dictionary to the initial conditions for a single

    65   // block.

    66   virtual void       reset(HeapWord* addr, size_t size) = 0;

    67   virtual void       reset() = 0;

    69   virtual void       dict_census_update(size_t size, bool split, bool birth) = 0;

    70   virtual bool       coal_dict_over_populated(size_t size) = 0;

    71   virtual void       begin_sweep_dict_census(double coalSurplusPercent,

    72                        float inter_sweep_current, float inter_sweep_estimate,

    73                        float intra__sweep_current) = 0;

    74   virtual void       end_sweep_dict_census(double splitSurplusPercent) = 0;

    75   virtual Chunk*     find_largest_dict() const = 0;

    76   // verify that the given chunk is in the dictionary.

    77   virtual bool verify_chunk_in_free_list(Chunk* tc) const = 0;

    79   // Sigma_{all_free_blocks} (block_size^2)

    80   virtual double sum_of_squared_block_sizes() const = 0;

    82   virtual Chunk* find_chunk_ends_at(HeapWord* target) const = 0;

    83   virtual void inc_total_size(size_t v) = 0;

    84   virtual void dec_total_size(size_t v) = 0;

    86   NOT_PRODUCT (

    87     virtual size_t   sum_dict_returned_bytes() = 0;

    88     virtual void     initialize_dict_returned_bytes() = 0;

    89     virtual size_t   total_count() = 0;

    90   )

    92   virtual void       report_statistics() const {

    93     gclog_or_tty->print("No statistics available");

    94   }

    96   virtual void       print_dict_census() const = 0;

    97   virtual void       print_free_lists(outputStream* st) const = 0;

    99   virtual void       verify()         const = 0;

   101   Mutex* par_lock()                const PRODUCT_RETURN0;

   102   void   set_par_lock(Mutex* lock)       PRODUCT_RETURN;

   103   void   verify_par_locked()       const PRODUCT_RETURN;

   104 };

   106 #endif // SHARE_VM_MEMORY_FREEBLOCKDICTIONARY_HPP

Mercurial > jdk8-mips64-public > hotspot / file revision

src/share/vm/memory/freeBlockDictionary.hpp@2c022e432e10

src/share/vm/memory/freeBlockDictionary.hpp