jdk8-mips64-public/hotspot: src/share/vm/utilities/hashtable.inline.hpp@c96030fff130

6684579: SoftReference processing can be made more efficient
Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not.
Reviewed-by: jmasa

     1 /*

     2  * Copyright 2003 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    25 // Inline function definitions for hashtable.hpp.

    28 // --------------------------------------------------------------------------

    29 // Hash function

    31 // We originally used hashpjw, but hash P(31) gives just as good results

    32 // and is slighly faster. We would like a hash function that looks at every

    33 // character, since package names have large common prefixes, and also because

    34 // hash_or_fail does error checking while iterating.

    36 // hash P(31) from Kernighan & Ritchie

    38 inline unsigned int Hashtable::hash_symbol(const char* s, int len) {

    39   unsigned int h = 0;

    40   while (len-- > 0) {

    41     h = 31*h + (unsigned) *s;

    42     s++;

    43   }

    44   return h;

    45 }

    48 // --------------------------------------------------------------------------

    50 // Initialize a table.

    52 inline BasicHashtable::BasicHashtable(int table_size, int entry_size) {

    53   // Called on startup, no locking needed

    54   initialize(table_size, entry_size, 0);

    55   _buckets = NEW_C_HEAP_ARRAY(HashtableBucket, table_size);

    56   for (int index = 0; index < _table_size; index++) {

    57     _buckets[index].clear();

    58   }

    59 }

    62 inline BasicHashtable::BasicHashtable(int table_size, int entry_size,

    63                                       HashtableBucket* buckets,

    64                                       int number_of_entries) {

    65   // Called on startup, no locking needed

    66   initialize(table_size, entry_size, number_of_entries);

    67   _buckets = buckets;

    68 }

    71 inline void BasicHashtable::initialize(int table_size, int entry_size,

    72                                        int number_of_entries) {

    73   // Called on startup, no locking needed

    74   _table_size = table_size;

    75   _entry_size = entry_size;

    76   _free_list = NULL;

    77   _first_free_entry = NULL;

    78   _end_block = NULL;

    79   _number_of_entries = number_of_entries;

    80 #ifdef ASSERT

    81   _lookup_count = 0;

    82   _lookup_length = 0;

    83 #endif

    84 }

    87 // The following method is MT-safe and may be used with caution.

    88 inline BasicHashtableEntry* BasicHashtable::bucket(int i) {

    89   return _buckets[i].get_entry();

    90 }

    93 inline void HashtableBucket::set_entry(BasicHashtableEntry* l) {

    94   // Warning: Preserve store ordering.  The SystemDictionary is read

    95   //          without locks.  The new SystemDictionaryEntry must be

    96   //          complete before other threads can be allowed to see it

    97   //          via a store to _buckets[index].

    98   OrderAccess::release_store_ptr(&_entry, l);

    99 }

   102 inline BasicHashtableEntry* HashtableBucket::get_entry() const {

   103   // Warning: Preserve load ordering.  The SystemDictionary is read

   104   //          without locks.  The new SystemDictionaryEntry must be

   105   //          complete before other threads can be allowed to see it

   106   //          via a store to _buckets[index].

   107   return (BasicHashtableEntry*) OrderAccess::load_ptr_acquire(&_entry);

   108 }

   111 inline void BasicHashtable::set_entry(int index, BasicHashtableEntry* entry) {

   112   _buckets[index].set_entry(entry);

   113 }

   116 inline void BasicHashtable::add_entry(int index, BasicHashtableEntry* entry) {

   117   entry->set_next(bucket(index));

   118   _buckets[index].set_entry(entry);

   119   ++_number_of_entries;

   120 }

   122 inline void BasicHashtable::free_entry(BasicHashtableEntry* entry) {

   123   entry->set_next(_free_list);

   124   _free_list = entry;

   125   --_number_of_entries;

   126 }

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

src/share/vm/utilities/hashtable.inline.hpp@c96030fff130

src/share/vm/utilities/hashtable.inline.hpp