Ziele Untersuchung
mit Columbo Integrität von
Datenbanken Interaktion und
Portierbarkeit Ergonomie der
Schnittstellen

Angebot Produkte Projekt Beratung

Mittel Analytik Modellierung Sprachen Algebra Logik Hardware Denken Kreativität

Zusammenhänge Gesellschaft Wirtschaft Branche Firma


products/sources/formale Sprachen/Java/Openjdk/src/hotspot/share/memory/ (Sun/Oracle ^©) Datei vom 13.11.2022 mit Größe 10 kB

Quelle heap.hpp Sprache: C

/*
* Copyright (c) 1997, 2022, 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_MEMORY_HEAP_HPP
#define SHARE_MEMORY_HEAP_HPP

#include "code/codeBlob.hpp"
#include "memory/allocation.hpp"
#include "memory/virtualspace.hpp"
#include "runtime/atomic.hpp"
#include "utilities/macros.hpp"

// Blocks

class HeapBlock {
  friend class VMStructs;

public:
  struct Header {
    size_t  _length;                             // the length in segments
    bool    _used;                               // Used bit
  };

protected:
  union {
    Header _header;
    int64_t _padding[ (sizeof(Header) + sizeof(int64_t)-1) / sizeof(int64_t) ];
                        // pad to 0 mod 8
  };

public:
  // Initialization
  void initialize(size_t length)                 { _header._length = length; set_used(); }
  // Merging/splitting
  void set_length(size_t length)                 { _header._length = length; }

  // Accessors
  void* allocated_space() const                  { return (void*)(this + 1); }
  size_t length() const                          { return _header._length; }

  // Used/free
  void set_used()                                { _header._used = true; }
  void set_free()                                { _header._used = false; }
  bool free()                                    { return !_header._used; }
};

class FreeBlock: public HeapBlock {
  friend class VMStructs;
protected:
  FreeBlock* _link;

public:
  // Initialization
  void initialize(size_t length)             { HeapBlock::initialize(length); _link= NULL; }

  // Accessors
  FreeBlock* link() const                    { return _link; }
  void set_link(FreeBlock* link)             { _link = link; }
};

class CodeHeap : public CHeapObj<mtCode> {
  friend class VMStructs;
protected:
  VirtualSpace _memory;                          // the memory holding the blocks
  VirtualSpace _segmap;                          // the memory holding the segment map

  size_t       _number_of_committed_segments;
  size_t       _number_of_reserved_segments;
  size_t       _segment_size;
  int          _log2_segment_size;

  size_t       _next_segment;

  FreeBlock*   _freelist;
  FreeBlock*   _last_insert_point;               // last insert point in add_to_freelist
  size_t       _freelist_segments;               // No. of segments in freelist
  int          _freelist_length;
  size_t       _max_allocated_capacity;          // Peak capacity that was allocated during lifetime of the heap

  const char*  _name;                            // Name of the CodeHeap
  const CodeBlobType _code_blob_type;            // CodeBlobType it contains
  int          _blob_count;                      // Number of CodeBlobs
  int          _nmethod_count;                   // Number of nmethods
  int          _adapter_count;                   // Number of adapters
  int          _full_count;                      // Number of times the code heap was full
  int          _fragmentation_count;             // #FreeBlock joins without fully initializing segment map elements.

  enum { free_sentinel = 0xFF };
  static const int fragmentation_limit = 10000;  // defragment after that many potential fragmentations.
  static const int freelist_limit = 100;         // improve insert point search if list is longer than this limit.
  static char  segmap_template[free_sentinel+1];

  // Helper functions
  size_t   size_to_segments(size_t size) const { return (size + _segment_size - 1) >> _log2_segment_size; }
  size_t   segments_to_size(size_t number_of_segments) const { return number_of_segments << _log2_segment_size; }

  size_t   segment_for(void* p) const            { return ((char*)p - _memory.low()) >> _log2_segment_size; }
  bool     is_segment_unused(int val) const      { return val == free_sentinel; }
  void*    address_for(size_t i) const           { return (void*)(_memory.low() + segments_to_size(i)); }
  void*    find_block_for(void* p) const;
  HeapBlock* block_at(size_t i) const            { return (HeapBlock*)address_for(i); }

  // These methods take segment map indices as range boundaries
  void mark_segmap_as_free(size_t beg, size_t end);
  void mark_segmap_as_used(size_t beg, size_t end, bool is_FreeBlock_join);
  void invalidate(size_t beg, size_t end, size_t header_bytes);
  void clear(size_t beg, size_t end);
  void clear();                                 // clears all heap contents
  static void init_segmap_template();

  // Freelist management helpers
  FreeBlock* following_block(FreeBlock* b);
  void insert_after(FreeBlock* a, FreeBlock* b);
  bool merge_right (FreeBlock* a);

  // Toplevel freelist management
  void add_to_freelist(HeapBlock* b);
  HeapBlock* search_freelist(size_t length);

  // Iteration helpers
  void*      next_used(HeapBlock* b) const;
  HeapBlock* block_start(void* p) const;

  // to perform additional actions on creation of executable code
  void on_code_mapping(char* base, size_t size);

public:
  CodeHeap(const char* name, const CodeBlobType code_blob_type);

  // Heap extents
  bool  reserve(ReservedSpace rs, size_t committed_size, size_t segment_size);
  bool  expand_by(size_t size);                  // expands committed memory by size

  // Memory allocation
  void* allocate (size_t size); // Allocate 'size' bytes in the code cache or return NULL
  void  deallocate(void* p);    // Deallocate memory
  // Free the tail of segments allocated by the last call to 'allocate()' which exceed 'used_size'.
  // ATTENTION: this is only safe to use if there was no other call to 'allocate()' after
  //            'p' was allocated. Only intended for freeing memory which would be otherwise
  //            wasted after the interpreter generation because we don't know the interpreter size
  //            beforehand and we also can't easily relocate the interpreter to a new location.
  void  deallocate_tail(void* p, size_t used_size);

  // Boundaries of committed space.
  char* low()  const                             { return _memory.low(); }
  char* high() const                             { return _memory.high(); }
  // Boundaries of reserved space.
  char* low_boundary() const                     { return _memory.low_boundary(); }
  char* high_boundary() const                    { return _memory.high_boundary(); }

  // Containment means "contained in committed space".
  bool contains(const void* p) const             { return low() <= p && p < high(); }
  bool contains_blob(const CodeBlob* blob) const {
    return contains((void*)blob);
  }

  virtual void* find_start(void* p)     const;   // returns the block containing p or NULL
  virtual CodeBlob* find_blob(void* start) const;
  size_t alignment_unit()       const;           // alignment of any block
  size_t alignment_offset()     const;           // offset of first byte of any block, within the enclosing alignment unit
  static size_t header_size()         { return sizeof(HeapBlock); } // returns the header size for each heap block

  size_t segment_size()         const { return _segment_size; }  // for CodeHeapState
  HeapBlock* first_block() const;                                // for CodeHeapState
  HeapBlock* next_block(HeapBlock* b) const;                     // for CodeHeapState
  HeapBlock* split_block(HeapBlock* b, size_t split_seg);        // split one block into two

  FreeBlock* freelist()         const { return _freelist; }      // for CodeHeapState

  size_t allocated_in_freelist() const           { return _freelist_segments * CodeCacheSegmentSize; }
  int    freelist_length()       const           { return _freelist_length; } // number of elements in the freelist

  // returns the first block or NULL
  virtual void* first() const                    { return next_used(first_block()); }
  // returns the next block given a block p or NULL
  virtual void* next(void* p) const              { return next_used(next_block(block_start(p))); }

  // Statistics
  size_t capacity() const;
  size_t max_capacity() const;
  int    allocated_segments() const;
  size_t allocated_capacity() const;
  size_t max_allocated_capacity() const          { return _max_allocated_capacity; }
  size_t unallocated_capacity() const            { return max_capacity() - allocated_capacity(); }

  // Returns true if the CodeHeap contains CodeBlobs of the given type
  bool accepts(CodeBlobType code_blob_type) const{ return (_code_blob_type == CodeBlobType::All) ||
                                                          (_code_blob_type == code_blob_type); }
  CodeBlobType code_blob_type() const            { return _code_blob_type; }

  // Debugging / Profiling
  const char* name() const                       { return _name; }
  int         blob_count()                       { return _blob_count; }
  int         nmethod_count()                    { return _nmethod_count; }
  void    set_nmethod_count(int count)           {        _nmethod_count = count; }
  int         adapter_count()                    { return _adapter_count; }
  void    set_adapter_count(int count)           {        _adapter_count = count; }
  int         full_count()                       { return _full_count; }
  int         report_full()                      { return Atomic::add(&_full_count, 1); }

private:
  size_t heap_unallocated_capacity() const;
  int defrag_segmap(bool do_defrag);
  int segmap_hops(size_t beg, size_t end);

public:
  // Debugging
  void verify() PRODUCT_RETURN;
  void print()  PRODUCT_RETURN;
};

#endif // SHARE_MEMORY_HEAP_HPP

quality100%

¤ Dauer der Verarbeitung: 0.19 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.