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

 /*

  * Copyright (c) 2003, 2008, 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.

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  */

 // All heaps contains a "permanent generation," containing permanent

 // (reflective) objects.  This is like a regular generation in some ways,

 // but unlike one in others, and so is split apart.

 class PermanentGenerationSpec;

 // This is the "generation" view of a CompactingPermGen.

 // NOTE: the shared spaces used for CDS are here handled in

 // a somewhat awkward and potentially buggy fashion, see CR 6801625.

 // This infelicity should be fixed, see CR 6897789.

 class CompactingPermGenGen: public OneContigSpaceCardGeneration {

   friend class VMStructs;

   // Abstractly, this is a subtype that gets access to protected fields.

   friend class CompactingPermGen;

 private:

   // Shared spaces

   PermanentGenerationSpec* _spec;

   size_t _shared_space_size;

   VirtualSpace _ro_vs;

   VirtualSpace _rw_vs;

   VirtualSpace _md_vs;

   VirtualSpace _mc_vs;

   BlockOffsetSharedArray* _ro_bts;

   BlockOffsetSharedArray* _rw_bts;

   OffsetTableContigSpace* _ro_space;

   OffsetTableContigSpace* _rw_space;

   // With shared spaces there is a dichotomy in the use of the

   // _virtual_space of the generation.  There is a portion of the

   // _virtual_space that is used for the unshared part of the

   // permanent generation and a portion that is reserved for the shared part.

   // The _reserved field in the generation represents both the

   // unshared and shared parts of the generation.  The _reserved

   // variable is initialized for only the unshared part but is

   // later extended to include the shared part during initialization

   // if shared spaces are being used.

   // The reserved size for the _virtual_space for CompactingPermGenGen

   // is the size of the space for the permanent generation including the

   // the shared spaces.  This can be seen by the use of MaxPermSize

   // in the allocation of PermanentGenerationSpec.  The space for the

   // shared spaces is committed separately (???).

   // In general at initialization only a part of the

   // space for the unshared part of the permanent generation is

   // committed and more is committed as the permanent generation is

   // grown.  In growing the permanent generation the capacity() and

   // max_capacity() of the generation are used.  For the permanent

   // generation (implemented with a CompactingPermGenGen) the capacity()

   // is taken from the capacity of the space (_the_space variable used for the

   // unshared part of the generation) and the max_capacity() is based

   // on the size of the _reserved variable (which includes the size of the

   // shared spaces) minus the size of the shared spaces.

   // These values are redundant, but are called out separately to avoid

   // going through heap/space/gen pointers for performance.

   static HeapWord* unshared_bottom;

   static HeapWord* unshared_end;

   static HeapWord* shared_bottom;

   static HeapWord* readonly_bottom;

   static HeapWord* readonly_end;

   static HeapWord* readwrite_bottom;

   static HeapWord* readwrite_end;

   static HeapWord* miscdata_bottom;

   static HeapWord* miscdata_end;

   static HeapWord* misccode_bottom;

   static HeapWord* misccode_end;

   static HeapWord* shared_end;

   // List of klassOops whose vtbl entries are used to patch others.

   static void**        _vtbl_list;

   // Performance Counters

   GenerationCounters*  _gen_counters;

   CSpaceCounters*      _space_counters;

   void initialize_performance_counters();

 public:

   enum {

     vtbl_list_size = 16, // number of entries in the shared space vtable list.

     num_virtuals = 200   // number of virtual methods in Klass (or

                          // subclass) objects, or greater.

   };

   enum {

     ro = 0,  // read-only shared space in the heap

     rw = 1,  // read-write shared space in the heap

     md = 2,  // miscellaneous data for initializing tables, etc.

     mc = 3,  // miscellaneous code - vtable replacement.

     n_regions = 4

   };

   CompactingPermGenGen(ReservedSpace rs, ReservedSpace shared_rs,

                        size_t initial_byte_size, int level, GenRemSet* remset,

                        ContiguousSpace* space,

                        PermanentGenerationSpec* perm_spec);

   const char* name() const {

     return "compacting perm gen";

   }

   const char* short_name() const {

     return "Perm";

   }

   // Return the maximum capacity for the object space.  This

   // explicitly does not include the shared spaces.

   size_t max_capacity() const;

   void update_counters();

   void compute_new_size() {

     assert(false, "Should not call this -- handled at PermGen level.");

   }

   bool must_be_youngest() const { return false; }

   bool must_be_oldest() const { return false; }

   OffsetTableContigSpace* ro_space() const { return _ro_space; }

   OffsetTableContigSpace* rw_space() const { return _rw_space; }

   VirtualSpace*           md_space()       { return &_md_vs; }

   VirtualSpace*           mc_space()       { return &_mc_vs; }

   ContiguousSpace* unshared_space() const { return _the_space; }

   static bool inline is_shared(const oopDesc* p) {

     return (HeapWord*)p >= shared_bottom && (HeapWord*)p < shared_end;

   }

   // RedefineClasses note: this tester is used to check residence of

   // the specified oop in the shared readonly space and not whether

   // the oop is readonly.

   static bool inline is_shared_readonly(const oopDesc* p) {

     return (HeapWord*)p >= readonly_bottom && (HeapWord*)p < readonly_end;

   }

   // RedefineClasses note: this tester is used to check residence of

   // the specified oop in the shared readwrite space and not whether

   // the oop is readwrite.

   static bool inline is_shared_readwrite(const oopDesc* p) {

     return (HeapWord*)p >= readwrite_bottom && (HeapWord*)p < readwrite_end;

   }

   bool is_in_unshared(const void* p) const {

     return OneContigSpaceCardGeneration::is_in(p);

   }

   bool is_in_shared(const void* p) const {

    return p >= shared_bottom && p < shared_end;

    }

   inline bool is_in(const void* p) const {

     return is_in_unshared(p) || is_in_shared(p);

   }

   inline PermanentGenerationSpec* spec() const { return _spec; }

   inline void set_spec(PermanentGenerationSpec* spec) { _spec = spec; }

   void pre_adjust_pointers();

   void adjust_pointers();

   void space_iterate(SpaceClosure* blk, bool usedOnly = false);

   void print_on(outputStream* st) const;

   void younger_refs_iterate(OopsInGenClosure* blk);

   void compact();

   void post_compact();

   size_t contiguous_available() const;

   void clear_remembered_set();

   void invalidate_remembered_set();

   inline bool block_is_obj(const HeapWord* addr) const {

     if      (addr < the_space()->top()) return true;

     else if (addr < the_space()->end()) return false;

     else if (addr < ro_space()->top())  return true;

     else if (addr < ro_space()->end())  return false;

     else if (addr < rw_space()->top())  return true;

     else                                return false;

   }

   inline size_t block_size(const HeapWord* addr) const {

     if (addr < the_space()->top()) {

       return oop(addr)->size();

     }

     else if (addr < the_space()->end()) {

       assert(addr == the_space()->top(), "non-block head arg to block_size");

       return the_space()->end() - the_space()->top();

     }

     else if (addr < ro_space()->top()) {

       return oop(addr)->size();

     }

     else if (addr < ro_space()->end()) {

       assert(addr == ro_space()->top(), "non-block head arg to block_size");

       return ro_space()->end() - ro_space()->top();

     }

     else if (addr < rw_space()->top()) {

       return oop(addr)->size();

     }

     else {

       assert(addr == rw_space()->top(), "non-block head arg to block_size");

       return rw_space()->end() - rw_space()->top();

     }

   }

   static void generate_vtable_methods(void** vtbl_list,

                                       void** vtable,

                                       char** md_top, char* md_end,

                                       char** mc_top, char* mc_end);

   void verify(bool allow_dirty);

   // Serialization

   static void initialize_oops() KERNEL_RETURN;

   static void serialize_oops(SerializeOopClosure* soc);

   void serialize_bts(SerializeOopClosure* soc);

   // Initiate dumping of shared file.

   static jint dump_shared(GrowableArray<oop>* class_promote_order, TRAPS);

   // JVM/TI RedefineClasses() support:

   // Remap the shared readonly space to shared readwrite, private if

   // sharing is enabled. Simply returns true if sharing is not enabled

   // or if the remapping has already been done by a prior call.

   static bool remap_shared_readonly_as_readwrite();

 };