duke@435: /*
xdono@631:  * Copyright 2001-2008 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: class CompactibleFreeListSpace;
duke@435: 
duke@435: // A class for maintaining a free list of FreeChunk's.  The FreeList
duke@435: // maintains a the structure of the list (head, tail, etc.) plus
duke@435: // statistics for allocations from the list.  The links between items
duke@435: // are not part of FreeList.  The statistics are
duke@435: // used to make decisions about coalescing FreeChunk's when they
duke@435: // are swept during collection.
duke@435: //
duke@435: // See the corresponding .cpp file for a description of the specifics
duke@435: // for that implementation.
duke@435: 
duke@435: class Mutex;
duke@435: 
duke@435: class FreeList VALUE_OBJ_CLASS_SPEC {
duke@435:   friend class CompactibleFreeListSpace;
dcubed@587:   friend class VMStructs;
ysr@447:   friend class printTreeCensusClosure;
duke@435:   FreeChunk*    _head;          // List of free chunks
duke@435:   FreeChunk*    _tail;          // Tail of list of free chunks
duke@435:   size_t        _size;          // Size in Heap words of each chunks
duke@435:   ssize_t       _count;         // Number of entries in list
duke@435:   size_t        _hint;          // next larger size list with a positive surplus
duke@435: 
duke@435:   AllocationStats _allocation_stats;            // statistics for smart allocation
duke@435: 
duke@435: #ifdef ASSERT
duke@435:   Mutex*        _protecting_lock;
duke@435: #endif
duke@435: 
duke@435:   // Asserts false if the protecting lock (if any) is not held.
duke@435:   void assert_proper_lock_protection_work() const PRODUCT_RETURN;
duke@435:   void assert_proper_lock_protection() const {
duke@435: #ifdef ASSERT
duke@435:     if (_protecting_lock != NULL)
duke@435:       assert_proper_lock_protection_work();
duke@435: #endif
duke@435:   }
duke@435: 
duke@435:   // Initialize the allocation statistics.
duke@435:  protected:
duke@435:   void init_statistics();
duke@435:   void set_count(ssize_t v) { _count = v;}
ysr@447:   void increment_count()    { _count++; }
duke@435:   void decrement_count() {
duke@435:     _count--;
ysr@447:     assert(_count >= 0, "Count should not be negative");
ysr@447:   }
duke@435: 
duke@435:  public:
duke@435:   // Constructor
duke@435:   // Construct a list without any entries.
duke@435:   FreeList();
duke@435:   // Construct a list with "fc" as the first (and lone) entry in the list.
duke@435:   FreeList(FreeChunk* fc);
duke@435:   // Construct a list which will have a FreeChunk at address "addr" and
duke@435:   // of size "size" as the first (and lone) entry in the list.
duke@435:   FreeList(HeapWord* addr, size_t size);
duke@435: 
duke@435:   // Reset the head, tail, hint, and count of a free list.
duke@435:   void reset(size_t hint);
duke@435: 
duke@435:   // Declare the current free list to be protected by the given lock.
duke@435: #ifdef ASSERT
duke@435:   void set_protecting_lock(Mutex* protecting_lock) {
duke@435:     _protecting_lock = protecting_lock;
duke@435:   }
duke@435: #endif
duke@435: 
duke@435:   // Accessors.
duke@435:   FreeChunk* head() const {
duke@435:     assert_proper_lock_protection();
duke@435:     return _head;
duke@435:   }
duke@435:   void set_head(FreeChunk* v) {
duke@435:     assert_proper_lock_protection();
duke@435:     _head = v;
duke@435:     assert(!_head || _head->size() == _size, "bad chunk size");
duke@435:   }
duke@435:   // Set the head of the list and set the prev field of non-null
duke@435:   // values to NULL.
duke@435:   void link_head(FreeChunk* v) {
duke@435:     assert_proper_lock_protection();
duke@435:     set_head(v);
duke@435:     // If this method is not used (just set the head instead),
duke@435:     // this check can be avoided.
duke@435:     if (v != NULL) {
duke@435:       v->linkPrev(NULL);
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   FreeChunk* tail() const {
duke@435:     assert_proper_lock_protection();
duke@435:     return _tail;
duke@435:   }
duke@435:   void set_tail(FreeChunk* v) {
duke@435:     assert_proper_lock_protection();
duke@435:     _tail = v;
duke@435:     assert(!_tail || _tail->size() == _size, "bad chunk size");
duke@435:   }
duke@435:   // Set the tail of the list and set the next field of non-null
duke@435:   // values to NULL.
duke@435:   void link_tail(FreeChunk* v) {
duke@435:     assert_proper_lock_protection();
duke@435:     set_tail(v);
duke@435:     if (v != NULL) {
duke@435:       v->clearNext();
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   // No locking checks in read-accessors: lock-free reads (only) are benign.
duke@435:   // Readers are expected to have the lock if they are doing work that
duke@435:   // requires atomicity guarantees in sections of code.
duke@435:   size_t size() const {
duke@435:     return _size;
duke@435:   }
duke@435:   void set_size(size_t v) {
duke@435:     assert_proper_lock_protection();
duke@435:     _size = v;
duke@435:   }
duke@435:   ssize_t count() const {
duke@435:     return _count;
duke@435:   }
duke@435:   size_t hint() const {
duke@435:     return _hint;
duke@435:   }
duke@435:   void set_hint(size_t v) {
duke@435:     assert_proper_lock_protection();
duke@435:     assert(v == 0 || _size < v, "Bad hint"); _hint = v;
duke@435:   }
duke@435: 
duke@435:   // Accessors for statistics
duke@435:   AllocationStats* allocation_stats() {
duke@435:     assert_proper_lock_protection();
duke@435:     return &_allocation_stats;
duke@435:   }
duke@435: 
duke@435:   ssize_t desired() const {
duke@435:     return _allocation_stats.desired();
duke@435:   }
ysr@447:   void set_desired(ssize_t v) {
ysr@447:     assert_proper_lock_protection();
ysr@447:     _allocation_stats.set_desired(v);
ysr@447:   }
duke@435:   void compute_desired(float inter_sweep_current,
duke@435:                        float inter_sweep_estimate) {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.compute_desired(_count,
duke@435:                                       inter_sweep_current,
duke@435:                                       inter_sweep_estimate);
duke@435:   }
duke@435:   ssize_t coalDesired() const {
duke@435:     return _allocation_stats.coalDesired();
duke@435:   }
duke@435:   void set_coalDesired(ssize_t v) {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.set_coalDesired(v);
duke@435:   }
duke@435: 
duke@435:   ssize_t surplus() const {
duke@435:     return _allocation_stats.surplus();
duke@435:   }
duke@435:   void set_surplus(ssize_t v) {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.set_surplus(v);
duke@435:   }
duke@435:   void increment_surplus() {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.increment_surplus();
duke@435:   }
duke@435:   void decrement_surplus() {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.decrement_surplus();
duke@435:   }
duke@435: 
duke@435:   ssize_t bfrSurp() const {
duke@435:     return _allocation_stats.bfrSurp();
duke@435:   }
duke@435:   void set_bfrSurp(ssize_t v) {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.set_bfrSurp(v);
duke@435:   }
duke@435:   ssize_t prevSweep() const {
duke@435:     return _allocation_stats.prevSweep();
duke@435:   }
duke@435:   void set_prevSweep(ssize_t v) {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.set_prevSweep(v);
duke@435:   }
duke@435:   ssize_t beforeSweep() const {
duke@435:     return _allocation_stats.beforeSweep();
duke@435:   }
duke@435:   void set_beforeSweep(ssize_t v) {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.set_beforeSweep(v);
duke@435:   }
duke@435: 
duke@435:   ssize_t coalBirths() const {
duke@435:     return _allocation_stats.coalBirths();
duke@435:   }
duke@435:   void set_coalBirths(ssize_t v) {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.set_coalBirths(v);
duke@435:   }
duke@435:   void increment_coalBirths() {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.increment_coalBirths();
duke@435:   }
duke@435: 
duke@435:   ssize_t coalDeaths() const {
duke@435:     return _allocation_stats.coalDeaths();
duke@435:   }
duke@435:   void set_coalDeaths(ssize_t v) {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.set_coalDeaths(v);
duke@435:   }
duke@435:   void increment_coalDeaths() {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.increment_coalDeaths();
duke@435:   }
duke@435: 
duke@435:   ssize_t splitBirths() const {
duke@435:     return _allocation_stats.splitBirths();
duke@435:   }
duke@435:   void set_splitBirths(ssize_t v) {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.set_splitBirths(v);
duke@435:   }
duke@435:   void increment_splitBirths() {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.increment_splitBirths();
duke@435:   }
duke@435: 
duke@435:   ssize_t splitDeaths() const {
duke@435:     return _allocation_stats.splitDeaths();
duke@435:   }
duke@435:   void set_splitDeaths(ssize_t v) {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.set_splitDeaths(v);
duke@435:   }
duke@435:   void increment_splitDeaths() {
duke@435:     assert_proper_lock_protection();
duke@435:     _allocation_stats.increment_splitDeaths();
duke@435:   }
duke@435: 
duke@435:   NOT_PRODUCT(
duke@435:     // For debugging.  The "_returnedBytes" in all the lists are summed
duke@435:     // and compared with the total number of bytes swept during a
duke@435:     // collection.
duke@435:     size_t returnedBytes() const { return _allocation_stats.returnedBytes(); }
duke@435:     void set_returnedBytes(size_t v) { _allocation_stats.set_returnedBytes(v); }
duke@435:     void increment_returnedBytes_by(size_t v) {
duke@435:       _allocation_stats.set_returnedBytes(_allocation_stats.returnedBytes() + v);
duke@435:     }
duke@435:   )
duke@435: 
duke@435:   // Unlink head of list and return it.  Returns NULL if
duke@435:   // the list is empty.
duke@435:   FreeChunk* getChunkAtHead();
duke@435: 
duke@435:   // Remove the first "n" or "count", whichever is smaller, chunks from the
duke@435:   // list, setting "fl", which is required to be empty, to point to them.
duke@435:   void getFirstNChunksFromList(size_t n, FreeList* fl);
duke@435: 
duke@435:   // Unlink this chunk from it's free list
duke@435:   void removeChunk(FreeChunk* fc);
duke@435: 
duke@435:   // Add this chunk to this free list.
duke@435:   void returnChunkAtHead(FreeChunk* fc);
duke@435:   void returnChunkAtTail(FreeChunk* fc);
duke@435: 
duke@435:   // Similar to returnChunk* but also records some diagnostic
duke@435:   // information.
duke@435:   void returnChunkAtHead(FreeChunk* fc, bool record_return);
duke@435:   void returnChunkAtTail(FreeChunk* fc, bool record_return);
duke@435: 
duke@435:   // Prepend "fl" (whose size is required to be the same as that of "this")
duke@435:   // to the front of "this" list.
duke@435:   void prepend(FreeList* fl);
duke@435: 
duke@435:   // Verify that the chunk is in the list.
duke@435:   // found.  Return NULL if "fc" is not found.
duke@435:   bool verifyChunkInFreeLists(FreeChunk* fc) const;
ysr@447: 
ysr@447:   // Printing support
ysr@447:   static void print_labels_on(outputStream* st, const char* c);
ysr@447:   void print_on(outputStream* st, const char* c = NULL) const;
duke@435: };