jdk8-mips64-public/hotspot: comparison src/share/vm/memory/heap.hpp

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+:f90c822e73f8
+/*
+* Copyright (c) 1997, 2013, 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_HEAP_HPP
+#define SHARE_VM_MEMORY_HEAP_HPP
+#include "memory/allocation.hpp"
+#include "runtime/virtualspace.hpp"
+// Blocks
+class HeapBlock VALUE_OBJ_CLASS_SPEC {
+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(); }
+// 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; }
+// Merging
+void set_length(size_t l)                  { _header._length = l; }
+// Accessors
+FreeBlock* link() const                    { return _link; }
+void set_link(FreeBlock* link)             { _link = link; }
+};
+class CodeHeap : public CHeapObj<mtCode> {
+friend class VMStructs;
+private:
+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;
+size_t       _freelist_segments;               // No. of segments in freelist
+// 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; }
+HeapBlock* block_at(size_t i) const            { return (HeapBlock*)(_memory.low() + (i << _log2_segment_size)); }
+void  mark_segmap_as_free(size_t beg, size_t end);
+void  mark_segmap_as_used(size_t beg, size_t end);
+// Freelist management helpers
+FreeBlock* following_block(FreeBlock *b);
+void insert_after(FreeBlock* a, FreeBlock* b);
+void merge_right (FreeBlock* a);
+// Toplevel freelist management
+void add_to_freelist(HeapBlock *b);
+FreeBlock* search_freelist(size_t length, bool is_critical);
+// Iteration helpers
+void*      next_free(HeapBlock* b) const;
+HeapBlock* first_block() const;
+HeapBlock* next_block(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();
+// Heap extents
+bool  reserve(size_t reserved_size, size_t committed_size, size_t segment_size);
+void  release();                               // releases all allocated memory
+bool  expand_by(size_t size);                  // expands commited memory by size
+void  shrink_by(size_t size);                  // shrinks commited memory by size
+void  clear();                                 // clears all heap contents
+// Memory allocation
+void* allocate  (size_t size, bool is_critical);  // allocates a block of size or returns NULL
+void  deallocate(void* p);                     // deallocates a block
+// Attributes
+char* low_boundary() const                     { return _memory.low_boundary (); }
+char* high() const                             { return _memory.high(); }
+char* high_boundary() const                    { return _memory.high_boundary(); }
+bool  contains(const void* p) const            { return low_boundary() <= p && p < high(); }
+void* find_start(void* p) const;              // returns the block containing p or NULL
+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();                  // returns the header size for each heap block
+// Iteration
+// returns the first block or NULL
+void* first() const       { return next_free(first_block()); }
+// returns the next block given a block p or NULL
+void* next(void* p) const { return next_free(next_block(block_start(p))); }
+// Statistics
+size_t capacity() const;
+size_t max_capacity() const;
+size_t allocated_capacity() const;
+size_t unallocated_capacity() const            { return max_capacity() - allocated_capacity(); }
+private:
+size_t heap_unallocated_capacity() const;
+public:
+// Debugging
+void verify();
+void print()  PRODUCT_RETURN;
+};
+#endif // SHARE_VM_MEMORY_HEAP_HPP

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

comparison: src/share/vm/memory/heap.hpp

src/share/vm/memory/heap.hpp