jdk8-mips64-public/hotspot: src/share/vm/memory/metablock.hpp@685df3c6f84b (annotated)

src/share/vm/memory/metablock.hpp@685df3c6f84b (annotated)

src/share/vm/memory/metablock.hpp

Tue, 18 Sep 2012 23:35:42 -0700

author: jmasa
date: Tue, 18 Sep 2012 23:35:42 -0700
changeset 4196: 685df3c6f84b
child 5705: 335b388c4b28
permissions: -rw-r--r--

7045397: NPG: Add freelists to class loader arenas.
Reviewed-by: coleenp, stefank, jprovino, ohair

 /*
  * Copyright (c) 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.
  *
  */
 #ifndef SHARE_VM_MEMORY_METABLOCK_HPP
 #define SHARE_VM_MEMORY_METABLOCK_HPP
 // Metablock are the unit of allocation from a Chunk.  It is initialized
 // with the size of the requested allocation.  That size is overwritten
 // once the allocation returns.
 //
 // A Metablock may be reused by its SpaceManager but are never moved between
 // SpaceManagers.  There is no explicit link to the Metachunk
 // from which it was allocated.  Metablock may be deallocated and
 // put on a freelist but the space is never freed, rather
 // the Metachunk it is a part of will be deallocated when it's
 // associated class loader is collected.
 class Metablock VALUE_OBJ_CLASS_SPEC {
   friend class VMStructs;
  private:
   // Used to align the allocation (see below).
   union block_t {
     void* _data[3];
     struct header_t {
       size_t _word_size;
       Metablock* _next;
       Metablock* _prev;
     } _header;
   } _block;
   static size_t _min_block_byte_size;
   static size_t _overhead;
   typedef union block_t Block;
   typedef struct header_t Header;
   const Block* block() const { return &_block; }
   const Block::header_t* header() const { return &(block()->_header); }
  public:
   static Metablock* initialize(MetaWord* p, size_t word_size);
   // This places the body of the block at a 2 word boundary
   // because every block starts on a 2 word boundary.  Work out
   // how to make the body on a 2 word boundary if the block
   // starts on a arbitrary boundary.  JJJ
   size_t word_size() const  { return header()->_word_size; }
   void set_word_size(size_t v) { _block._header._word_size = v; }
   size_t size() const volatile { return _block._header._word_size; }
   void set_size(size_t v) { _block._header._word_size = v; }
   Metablock* next() const { return header()->_next; }
   void set_next(Metablock* v) { _block._header._next = v; }
   Metablock* prev() const { return header()->_prev; }
   void set_prev(Metablock* v) { _block._header._prev = v; }
   static size_t min_block_byte_size() { return _min_block_byte_size; }
   static size_t overhead() { return _overhead; }
   bool is_free()                 { return header()->_word_size != 0; }
   void clear_next()              { set_next(NULL); }
   void link_prev(Metablock* ptr) { set_prev(ptr); }
   uintptr_t* end()              { return ((uintptr_t*) this) + size(); }
   bool cantCoalesce() const     { return false; }
   void link_next(Metablock* ptr) { set_next(ptr); }
   void link_after(Metablock* ptr){
     link_next(ptr);
     if (ptr != NULL) ptr->link_prev(this);
   }
   // Should not be needed in a free list of Metablocks
   void markNotFree()            { ShouldNotReachHere(); }
   // Debug support
 #ifdef ASSERT
   void* prev_addr() const { return (void*)&_block._header._prev; }
   void* next_addr() const { return (void*)&_block._header._next; }
   void* size_addr() const { return (void*)&_block._header._word_size; }
 #endif
   bool verify_chunk_in_free_list(Metablock* tc) const { return true; }
   bool verify_par_locked() { return true; }
   void assert_is_mangled() const {/* Don't check "\*/}
 };
 #endif // SHARE_VM_MEMORY_METABLOCK_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/memory/metablock.hpp@685df3c6f84b (annotated)

src/share/vm/memory/metablock.hpp