Mercurial > hg > graal-compiler
view src/share/vm/memory/freeList.hpp @ 12090:8009adb44523
Merge
author | jmasa |
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date | Thu, 22 Aug 2013 14:03:47 -0700 |
parents | 7c5a1b62f53d |
children | de6a9e811145 |
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/* * Copyright (c) 2001, 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_FREELIST_HPP #define SHARE_VM_MEMORY_FREELIST_HPP #include "gc_implementation/shared/allocationStats.hpp" class CompactibleFreeListSpace; // A class for maintaining a free list of Chunk's. The FreeList // maintains a the structure of the list (head, tail, etc.) plus // statistics for allocations from the list. The links between items // are not part of FreeList. The statistics are // used to make decisions about coalescing Chunk's when they // are swept during collection. // // See the corresponding .cpp file for a description of the specifics // for that implementation. class Mutex; template <class Chunk_t> class FreeList VALUE_OBJ_CLASS_SPEC { friend class CompactibleFreeListSpace; friend class VMStructs; private: Chunk_t* _head; // Head of list of free chunks Chunk_t* _tail; // Tail of list of free chunks size_t _size; // Size in Heap words of each chunk ssize_t _count; // Number of entries in list protected: #ifdef ASSERT Mutex* _protecting_lock; #endif // Asserts false if the protecting lock (if any) is not held. void assert_proper_lock_protection_work() const PRODUCT_RETURN; void assert_proper_lock_protection() const { #ifdef ASSERT if (_protecting_lock != NULL) assert_proper_lock_protection_work(); #endif } void increment_count() { _count++; } void decrement_count() { _count--; assert(_count >= 0, "Count should not be negative"); } public: // Constructor // Construct a list without any entries. FreeList(); // Do initialization void initialize(); // Reset the head, tail, and count of a free list. void reset(); // Declare the current free list to be protected by the given lock. #ifdef ASSERT Mutex* protecting_lock() const { return _protecting_lock; } void set_protecting_lock(Mutex* v) { _protecting_lock = v; } #endif // Accessors. Chunk_t* head() const { assert_proper_lock_protection(); return _head; } void set_head(Chunk_t* v) { assert_proper_lock_protection(); _head = v; assert(!_head || _head->size() == _size, "bad chunk size"); } // Set the head of the list and set the prev field of non-null // values to NULL. void link_head(Chunk_t* v); Chunk_t* tail() const { assert_proper_lock_protection(); return _tail; } void set_tail(Chunk_t* v) { assert_proper_lock_protection(); _tail = v; assert(!_tail || _tail->size() == _size, "bad chunk size"); } // Set the tail of the list and set the next field of non-null // values to NULL. void link_tail(Chunk_t* v) { assert_proper_lock_protection(); set_tail(v); if (v != NULL) { v->clear_next(); } } // No locking checks in read-accessors: lock-free reads (only) are benign. // Readers are expected to have the lock if they are doing work that // requires atomicity guarantees in sections of code. size_t size() const { return _size; } void set_size(size_t v) { assert_proper_lock_protection(); _size = v; } ssize_t count() const { return _count; } void set_count(ssize_t v) { _count = v;} size_t get_better_size() { return size(); } size_t returned_bytes() const { ShouldNotReachHere(); return 0; } void set_returned_bytes(size_t v) {} void increment_returned_bytes_by(size_t v) {} // Unlink head of list and return it. Returns NULL if // the list is empty. Chunk_t* get_chunk_at_head(); // Remove the first "n" or "count", whichever is smaller, chunks from the // list, setting "fl", which is required to be empty, to point to them. void getFirstNChunksFromList(size_t n, FreeList<Chunk_t>* fl); // Unlink this chunk from it's free list void remove_chunk(Chunk_t* fc); // Add this chunk to this free list. void return_chunk_at_head(Chunk_t* fc); void return_chunk_at_tail(Chunk_t* fc); // Similar to returnChunk* but also records some diagnostic // information. void return_chunk_at_head(Chunk_t* fc, bool record_return); void return_chunk_at_tail(Chunk_t* fc, bool record_return); // Prepend "fl" (whose size is required to be the same as that of "this") // to the front of "this" list. void prepend(FreeList<Chunk_t>* fl); // Verify that the chunk is in the list. // found. Return NULL if "fc" is not found. bool verify_chunk_in_free_list(Chunk_t* fc) const; // Printing support static void print_labels_on(outputStream* st, const char* c); void print_on(outputStream* st, const char* c = NULL) const; }; #endif // SHARE_VM_MEMORY_FREELIST_HPP