jdk8-mips64-public/hotspot: src/share/vm/utilities/hashtable.cpp@ace99a6ffc83 (annotated)

src/share/vm/utilities/hashtable.cpp@ace99a6ffc83 (annotated)

src/share/vm/utilities/hashtable.cpp

Wed, 04 Jul 2012 15:55:45 -0400

author: coleenp
date: Wed, 04 Jul 2012 15:55:45 -0400
changeset 3904: ace99a6ffc83
parent 3900: d2a62e0f25eb
child 3963: 5e2dc722e70d
permissions: -rw-r--r--

7181200: JVM new hashing code breaks SA in product mode
Summary: Made new_hash() overloaded rather than a virtual function so SA code doesn't need to be changed.
Reviewed-by: kvn, acorn, dholmes, fparain

 /*
  * Copyright (c) 2003, 2012, 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.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #include "precompiled.hpp"
 #include "classfile/altHashing.hpp"
 #include "classfile/javaClasses.hpp"
 #include "memory/allocation.inline.hpp"
 #include "memory/filemap.hpp"
 #include "memory/resourceArea.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/safepoint.hpp"
 #include "utilities/dtrace.hpp"
 #include "utilities/hashtable.hpp"
 #include "utilities/hashtable.inline.hpp"
 // This is a generic hashtable, designed to be used for the symbol
 // and string tables.
 //
 // It is implemented as an open hash table with a fixed number of buckets.
 //
 // %note:
 //  - HashtableEntrys are allocated in blocks to reduce the space overhead.
 template <MEMFLAGS F> BasicHashtableEntry<F>* BasicHashtable<F>::new_entry(unsigned int hashValue) {
   BasicHashtableEntry<F>* entry;
   if (_free_list) {
     entry = _free_list;
     _free_list = _free_list->next();
   } else {
     if (_first_free_entry + _entry_size >= _end_block) {
       int block_size = MIN2(512, MAX2((int)_table_size / 2, (int)_number_of_entries));
       int len = _entry_size * block_size;
       len = 1 << log2_intptr(len); // round down to power of 2
       assert(len >= _entry_size, "");
       _first_free_entry = NEW_C_HEAP_ARRAY2(char, len, F, CURRENT_PC);
       _end_block = _first_free_entry + len;
     }
     entry = (BasicHashtableEntry<F>*)_first_free_entry;
     _first_free_entry += _entry_size;
   }
   assert(_entry_size % HeapWordSize == 0, "");
   entry->set_hash(hashValue);
   return entry;
 }
 template <class T, MEMFLAGS F> HashtableEntry<T, F>* Hashtable<T, F>::new_entry(unsigned int hashValue, T obj) {
   HashtableEntry<T, F>* entry;
   entry = (HashtableEntry<T, F>*)BasicHashtable<F>::new_entry(hashValue);
   entry->set_literal(obj);
   return entry;
 }
 // Check to see if the hashtable is unbalanced.  The caller set a flag to
 // rehash at the next safepoint.  If this bucket is 60 times greater than the
 // expected average bucket length, it's an unbalanced hashtable.
 // This is somewhat an arbitrary heuristic but if one bucket gets to
 // rehash_count which is currently 100, there's probably something wrong.
 template <MEMFLAGS F> bool BasicHashtable<F>::check_rehash_table(int count) {
   assert(table_size() != 0, "underflow");
   if (count > (((double)number_of_entries()/(double)table_size())*rehash_multiple)) {
     // Set a flag for the next safepoint, which should be at some guaranteed
     // safepoint interval.
     return true;
   }
   return false;
 }
 template <class T, MEMFLAGS F> jint Hashtable<T, F>::_seed = 0;
 template <class T, MEMFLAGS F> unsigned int Hashtable<T, F>::new_hash(Symbol* sym) {
   ResourceMark rm;
   // Use alternate hashing algorithm on this symbol.
   return AltHashing::murmur3_32(seed(), (const jbyte*)sym->as_C_string(), sym->utf8_length());
 }
 template <class T, MEMFLAGS F> unsigned int Hashtable<T, F>::new_hash(oop string) {
   ResourceMark rm;
   int length;
   jchar* chars = java_lang_String::as_unicode_string(string, length);
   // Use alternate hashing algorithm on the string
   return AltHashing::murmur3_32(seed(), chars, length);
 }
 // Create a new table and using alternate hash code, populate the new table
 // with the existing elements.   This can be used to change the hash code
 // and could in the future change the size of the table.
 template <class T, MEMFLAGS F> void Hashtable<T, F>::move_to(Hashtable<T, F>* new_table) {
   // Initialize the global seed for hashing.
   _seed = AltHashing::compute_seed();
   assert(seed() != 0, "shouldn't be zero");
   int saved_entry_count = this->number_of_entries();
   // Iterate through the table and create a new entry for the new table
   for (int i = 0; i < new_table->table_size(); ++i) {
     for (HashtableEntry<T, F>* p = bucket(i); p != NULL; ) {
       HashtableEntry<T, F>* next = p->next();
       T string = p->literal();
       // Use alternate hashing algorithm on the symbol in the first table
       unsigned int hashValue = new_hash(string);
       // Get a new index relative to the new table (can also change size)
       int index = new_table->hash_to_index(hashValue);
       p->set_hash(hashValue);
       // Keep the shared bit in the Hashtable entry to indicate that this entry
       // can't be deleted.   The shared bit is the LSB in the _next field so
       // walking the hashtable past these entries requires
       // BasicHashtableEntry::make_ptr() call.
       bool keep_shared = p->is_shared();
       unlink_entry(p);
       new_table->add_entry(index, p);
       if (keep_shared) {
         p->set_shared();
       }
       p = next;
     }
   }
   // give the new table the free list as well
   new_table->copy_freelist(this);
   assert(new_table->number_of_entries() == saved_entry_count, "lost entry on dictionary copy?");
   // Destroy memory used by the buckets in the hashtable.  The memory
   // for the elements has been used in a new table and is not
   // destroyed.  The memory reuse will benefit resizing the SystemDictionary
   // to avoid a memory allocation spike at safepoint.
   BasicHashtable<F>::free_buckets();
 }
 template <MEMFLAGS F> void BasicHashtable<F>::free_buckets() {
   if (NULL != _buckets) {
     // Don't delete the buckets in the shared space.  They aren't
     // allocated by os::malloc
     if (!UseSharedSpaces ||
         !FileMapInfo::current_info()->is_in_shared_space(_buckets)) {
        FREE_C_HEAP_ARRAY(HashtableBucket, _buckets, F);
     }
     _buckets = NULL;
   }
 }
 // Reverse the order of elements in the hash buckets.
 template <MEMFLAGS F> void BasicHashtable<F>::reverse() {
   for (int i = 0; i < _table_size; ++i) {
     BasicHashtableEntry<F>* new_list = NULL;
     BasicHashtableEntry<F>* p = bucket(i);
     while (p != NULL) {
       BasicHashtableEntry<F>* next = p->next();
       p->set_next(new_list);
       new_list = p;
       p = next;
     }
     *bucket_addr(i) = new_list;
   }
 }
 // Copy the table to the shared space.
 template <MEMFLAGS F> void BasicHashtable<F>::copy_table(char** top, char* end) {
   // Dump the hash table entries.
   intptr_t *plen = (intptr_t*)(*top);
   *top += sizeof(*plen);
   int i;
   for (i = 0; i < _table_size; ++i) {
     for (BasicHashtableEntry<F>** p = _buckets[i].entry_addr();
                               *p != NULL;
                                p = (*p)->next_addr()) {
       if (*top + entry_size() > end) {
         report_out_of_shared_space(SharedMiscData);
       }
       *p = (BasicHashtableEntry<F>*)memcpy(*top, *p, entry_size());
       *top += entry_size();
     }
   }
   *plen = (char*)(*top) - (char*)plen - sizeof(*plen);
   // Set the shared bit.
   for (i = 0; i < _table_size; ++i) {
     for (BasicHashtableEntry<F>* p = bucket(i); p != NULL; p = p->next()) {
       p->set_shared();
     }
   }
 }
 // Reverse the order of elements in the hash buckets.
 template <class T, MEMFLAGS F> void Hashtable<T, F>::reverse(void* boundary) {
   for (int i = 0; i < this->table_size(); ++i) {
     HashtableEntry<T, F>* high_list = NULL;
     HashtableEntry<T, F>* low_list = NULL;
     HashtableEntry<T, F>* last_low_entry = NULL;
     HashtableEntry<T, F>* p = bucket(i);
     while (p != NULL) {
       HashtableEntry<T, F>* next = p->next();
       if ((void*)p->literal() >= boundary) {
         p->set_next(high_list);
         high_list = p;
       } else {
         p->set_next(low_list);
         low_list = p;
         if (last_low_entry == NULL) {
           last_low_entry = p;
         }
       }
       p = next;
     }
     if (low_list != NULL) {
       *bucket_addr(i) = low_list;
       last_low_entry->set_next(high_list);
     } else {
       *bucket_addr(i) = high_list;
     }
   }
 }
 // Dump the hash table buckets.
 template <MEMFLAGS F> void BasicHashtable<F>::copy_buckets(char** top, char* end) {
   intptr_t len = _table_size * sizeof(HashtableBucket<F>);
   *(intptr_t*)(*top) = len;
   *top += sizeof(intptr_t);
   *(intptr_t*)(*top) = _number_of_entries;
   *top += sizeof(intptr_t);
   if (*top + len > end) {
     report_out_of_shared_space(SharedMiscData);
   }
   _buckets = (HashtableBucket<F>*)memcpy(*top, _buckets, len);
   *top += len;
 }
 #ifndef PRODUCT
 template <class T, MEMFLAGS F> void Hashtable<T, F>::print() {
   ResourceMark rm;
   for (int i = 0; i < BasicHashtable<F>::table_size(); i++) {
     HashtableEntry<T, F>* entry = bucket(i);
     while(entry != NULL) {
       tty->print("%d : ", i);
       entry->literal()->print();
       tty->cr();
       entry = entry->next();
     }
   }
 }
 template <MEMFLAGS F> void BasicHashtable<F>::verify() {
   int count = 0;
   for (int i = 0; i < table_size(); i++) {
     for (BasicHashtableEntry<F>* p = bucket(i); p != NULL; p = p->next()) {
       ++count;
     }
   }
   assert(count == number_of_entries(), "number of hashtable entries incorrect");
 }
 #endif // PRODUCT
 #ifdef ASSERT
 template <MEMFLAGS F> void BasicHashtable<F>::verify_lookup_length(double load) {
   if ((double)_lookup_length / (double)_lookup_count > load * 2.0) {
     warning("Performance bug: SystemDictionary lookup_count=%d "
             "lookup_length=%d average=%lf load=%f",
             _lookup_count, _lookup_length,
             (double) _lookup_length / _lookup_count, load);
   }
 }
 #endif
 // Explicitly instantiate these types
 template class Hashtable<constantPoolOop, mtClass>;
 template class Hashtable<Symbol*, mtSymbol>;
 template class Hashtable<klassOop, mtClass>;
 template class Hashtable<oop, mtClass>;
 #ifdef SOLARIS
 template class Hashtable<oop, mtSymbol>;
 #endif
 template class Hashtable<oopDesc*, mtSymbol>;
 template class Hashtable<Symbol*, mtClass>;
 template class HashtableEntry<Symbol*, mtSymbol>;
 template class HashtableEntry<Symbol*, mtClass>;
 template class HashtableEntry<oop, mtSymbol>;
 template class BasicHashtableEntry<mtSymbol>;
 template class BasicHashtableEntry<mtCode>;
 template class BasicHashtable<mtClass>;
 template class BasicHashtable<mtSymbol>;
 template class BasicHashtable<mtCode>;
 template class BasicHashtable<mtInternal>;

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/utilities/hashtable.cpp@ace99a6ffc83 (annotated)

src/share/vm/utilities/hashtable.cpp