1 /*

     2  * Copyright (c) 1997, 2015, 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  */

    24 

    25 #ifndef SHARE_VM_MEMORY_HEAP_HPP

    26 #define SHARE_VM_MEMORY_HEAP_HPP

    27 

    28 #include "code/codeBlob.hpp"

    29 #include "memory/allocation.hpp"

    30 #include "memory/virtualspace.hpp"

    31 #include "utilities/macros.hpp"

    32 

    33 // Blocks

    34 

    35 class HeapBlock VALUE_OBJ_CLASS_SPEC {

    36   friend class VMStructs;

    37 

    38  public:

    39   struct Header {

    40     size_t  _length;                             // the length in segments

    41     bool    _used;                               // Used bit

    42   };

    43 

    44  protected:

    45   union {

    46     Header _header;

    47     int64_t _padding[ (sizeof(Header) + sizeof(int64_t)-1) / sizeof(int64_t) ];

    48                         // pad to 0 mod 8

    49   };

    50 

    51  public:

    52   // Initialization

    53   void initialize(size_t length)                 { _header._length = length; set_used(); }

    54 

    55   // Accessors

    56   void* allocated_space() const                  { return (void*)(this + 1); }

    57   size_t length() const                          { return _header._length; }

    58 

    59   // Used/free

    60   void set_used()                                { _header._used = true; }

    61   void set_free()                                { _header._used = false; }

    62   bool free()                                    { return !_header._used; }

    63 };

    64 

    65 class FreeBlock: public HeapBlock {

    66   friend class VMStructs;

    67  protected:

    68   FreeBlock* _link;

    69 

    70  public:

    71   // Initialization

    72   void initialize(size_t length)             { HeapBlock::initialize(length); _link= NULL; }

    73 

    74   // Merging

    75   void set_length(size_t l)                  { _header._length = l; }

    76 

    77   // Accessors

    78   FreeBlock* link() const                    { return _link; }

    79   void set_link(FreeBlock* link)             { _link = link; }

    80 };

    81 

    82 class CodeHeap : public CHeapObj<mtCode> {

    83   friend class VMStructs;

    84  protected:

    85   VirtualSpace _memory;                          // the memory holding the blocks

    86   VirtualSpace _segmap;                          // the memory holding the segment map

    87 

    88   size_t       _number_of_committed_segments;

    89   size_t       _number_of_reserved_segments;

    90   size_t       _segment_size;

    91   int          _log2_segment_size;

    92 

    93   size_t       _next_segment;

    94 

    95   FreeBlock*   _freelist;

    96   size_t       _freelist_segments;               // No. of segments in freelist

    97   int          _freelist_length;

    98   size_t       _max_allocated_capacity;          // Peak capacity that was allocated during lifetime of the heap

    99 

   100   const char*  _name;                            // Name of the CodeHeap

   101   const int    _code_blob_type;                  // CodeBlobType it contains

   102   int          _blob_count;                      // Number of CodeBlobs

   103   int          _nmethod_count;                   // Number of nmethods

   104   int          _adapter_count;                   // Number of adapters

   105   int          _full_count;                      // Number of times the code heap was full

   106 

   107 

   108   enum { free_sentinel = 0xFF };

   109 

   110   // Helper functions

   111   size_t   size_to_segments(size_t size) const { return (size + _segment_size - 1) >> _log2_segment_size; }

   112   size_t   segments_to_size(size_t number_of_segments) const { return number_of_segments << _log2_segment_size; }

   113 

   114   size_t   segment_for(void* p) const            { return ((char*)p - _memory.low()) >> _log2_segment_size; }

   115   bool     is_segment_unused(int val) const      { return val == free_sentinel; }

   116   HeapBlock* block_at(size_t i) const            { return (HeapBlock*)(_memory.low() + (i << _log2_segment_size)); }

   117 

   118   void  mark_segmap_as_free(size_t beg, size_t end);

   119   void  mark_segmap_as_used(size_t beg, size_t end);

   120 

   121   // Freelist management helpers

   122   FreeBlock* following_block(FreeBlock* b);

   123   void insert_after(FreeBlock* a, FreeBlock* b);

   124   bool merge_right (FreeBlock* a);

   125 

   126   // Toplevel freelist management

   127   void add_to_freelist(HeapBlock* b);

   128   FreeBlock* search_freelist(size_t length);

   129 

   130   // Iteration helpers

   131   void*      next_used(HeapBlock* b) const;

   132   HeapBlock* first_block() const;

   133   HeapBlock* next_block(HeapBlock* b) const;

   134   HeapBlock* block_start(void* p) const;

   135 

   136   // to perform additional actions on creation of executable code

   137   void on_code_mapping(char* base, size_t size);

   138   void clear();                                 // clears all heap contents

   139 

   140  public:

   141   CodeHeap(const char* name, const int code_blob_type);

   142 

   143   // Heap extents

   144   bool  reserve(ReservedSpace rs, size_t committed_size, size_t segment_size);

   145   bool  expand_by(size_t size);                  // expands committed memory by size

   146 

   147   // Memory allocation

   148   void* allocate (size_t size); // Allocate 'size' bytes in the code cache or return NULL

   149   void  deallocate(void* p);    // Deallocate memory

   150 

   151   // Attributes

   152   char* low_boundary() const                     { return _memory.low_boundary(); }

   153   char* high() const                             { return _memory.high(); }

   154   char* high_boundary() const                    { return _memory.high_boundary(); }

   155 

   156   bool contains(const void* p) const             { return low_boundary() <= p && p < high(); }

   157   bool contains_blob(const CodeBlob* blob) const { return contains(blob->code_begin()); }

   158 

   159   virtual void* find_start(void* p)     const;   // returns the block containing p or NULL

   160   virtual CodeBlob* find_blob_unsafe(void* start) const;

   161   size_t alignment_unit()       const;           // alignment of any block

   162   size_t alignment_offset()     const;           // offset of first byte of any block, within the enclosing alignment unit

   163   static size_t header_size();                   // returns the header size for each heap block

   164 

   165   size_t allocated_in_freelist() const           { return _freelist_segments * CodeCacheSegmentSize; }

   166   int    freelist_length()       const           { return _freelist_length; } // number of elements in the freelist

   167 

   168   // returns the first block or NULL

   169   virtual void* first() const                    { return next_used(first_block()); }

   170   // returns the next block given a block p or NULL

   171   virtual void* next(void* p) const              { return next_used(next_block(block_start(p))); }

   172 

   173   // Statistics

   174   size_t capacity() const;

   175   size_t max_capacity() const;

   176   int    allocated_segments() const;

   177   size_t allocated_capacity() const;

   178   size_t max_allocated_capacity() const          { return _max_allocated_capacity; }

   179   size_t unallocated_capacity() const            { return max_capacity() - allocated_capacity(); }

   180 

   181   // Returns true if the CodeHeap contains CodeBlobs of the given type

   182   bool accepts(int code_blob_type) const         { return (_code_blob_type == CodeBlobType::All) ||

   183                                                           (_code_blob_type == code_blob_type); }

   184   int code_blob_type() const                     { return _code_blob_type; }

   185 

   186   // Debugging / Profiling

   187   const char* name() const                       { return _name; }

   188   int         blob_count()                       { return _blob_count; }

   189   int         nmethod_count()                    { return _nmethod_count; }

   190   void    set_nmethod_count(int count)           {        _nmethod_count = count; }

   191   int         adapter_count()                    { return _adapter_count; }

   192   void    set_adapter_count(int count)           {        _adapter_count = count; }

   193   int         full_count()                       { return _full_count; }

   194   void        report_full()                      {        _full_count++; }

   195 

   196 private:

   197   size_t heap_unallocated_capacity() const;

   198 

   199 public:

   200   // Debugging

   201   void verify() PRODUCT_RETURN;

   202   void print()  PRODUCT_RETURN;

   203 };

   204 

   205 #endif // SHARE_VM_MEMORY_HEAP_HPP