jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/concurrentMarkSweep/freeList.hpp@3bfae429e2cf (annotated)

src/share/vm/gc_implementation/concurrentMarkSweep/freeList.hpp@3bfae429e2cf (annotated)

src/share/vm/gc_implementation/concurrentMarkSweep/freeList.hpp

Mon, 03 May 2010 10:24:51 -0700

author: ysr
date: Mon, 03 May 2010 10:24:51 -0700
changeset 1873: 3bfae429e2cf
parent 1580: e018e6884bd8
child 1907: c18cbe5936b8
permissions: -rw-r--r--

6948537: CMS: BOT walkers observe out-of-thin-air zeros on sun4v sparc/CMT
Summary: On sun4v/CMT avoid use of memset() in BOT updates so as to prevent concurrent BOT readers from seeing the phantom zeros arising from memset()'s use of BIS.
Reviewed-by: jmasa, johnc, minqi, poonam, tonyp

 /*
  * Copyright 2001-2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  */
 class CompactibleFreeListSpace;
 // A class for maintaining a free list of FreeChunk'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 FreeChunk's when they
 // are swept during collection.
 //
 // See the corresponding .cpp file for a description of the specifics
 // for that implementation.
 class Mutex;
 class TreeList;
 class FreeList VALUE_OBJ_CLASS_SPEC {
   friend class CompactibleFreeListSpace;
   friend class VMStructs;
   friend class PrintTreeCensusClosure;
  protected:
   TreeList* _parent;
   TreeList* _left;
   TreeList* _right;
  private:
   FreeChunk*    _head;          // Head of list of free chunks
   FreeChunk*    _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
   size_t        _hint;          // next larger size list with a positive surplus
   AllocationStats _allocation_stats; // allocation-related statistics
 #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
   }
   // Initialize the allocation statistics.
  protected:
   void init_statistics(bool split_birth = false);
   void set_count(ssize_t v) { _count = v;}
   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();
   // Construct a list with "fc" as the first (and lone) entry in the list.
   FreeList(FreeChunk* fc);
   // Construct a list which will have a FreeChunk at address "addr" and
   // of size "size" as the first (and lone) entry in the list.
   FreeList(HeapWord* addr, size_t size);
   // Reset the head, tail, hint, and count of a free list.
   void reset(size_t hint);
   // Declare the current free list to be protected by the given lock.
 #ifdef ASSERT
   void set_protecting_lock(Mutex* protecting_lock) {
     _protecting_lock = protecting_lock;
   }
 #endif
   // Accessors.
   FreeChunk* head() const {
     assert_proper_lock_protection();
     return _head;
   }
   void set_head(FreeChunk* 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(FreeChunk* v) {
     assert_proper_lock_protection();
     set_head(v);
     // If this method is not used (just set the head instead),
     // this check can be avoided.
     if (v != NULL) {
       v->linkPrev(NULL);
     }
   }
   FreeChunk* tail() const {
     assert_proper_lock_protection();
     return _tail;
   }
   void set_tail(FreeChunk* 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(FreeChunk* v) {
     assert_proper_lock_protection();
     set_tail(v);
     if (v != NULL) {
       v->clearNext();
     }
   }
   // 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;
   }
   size_t hint() const {
     return _hint;
   }
   void set_hint(size_t v) {
     assert_proper_lock_protection();
     assert(v == 0 || _size < v, "Bad hint"); _hint = v;
   }
   // Accessors for statistics
   AllocationStats* allocation_stats() {
     assert_proper_lock_protection();
     return &_allocation_stats;
   }
   ssize_t desired() const {
     return _allocation_stats.desired();
   }
   void set_desired(ssize_t v) {
     assert_proper_lock_protection();
     _allocation_stats.set_desired(v);
   }
   void compute_desired(float inter_sweep_current,
                        float inter_sweep_estimate,
                        float intra_sweep_estimate) {
     assert_proper_lock_protection();
     _allocation_stats.compute_desired(_count,
                                       inter_sweep_current,
                                       inter_sweep_estimate,
                                       intra_sweep_estimate);
   }
   ssize_t coalDesired() const {
     return _allocation_stats.coalDesired();
   }
   void set_coalDesired(ssize_t v) {
     assert_proper_lock_protection();
     _allocation_stats.set_coalDesired(v);
   }
   ssize_t surplus() const {
     return _allocation_stats.surplus();
   }
   void set_surplus(ssize_t v) {
     assert_proper_lock_protection();
     _allocation_stats.set_surplus(v);
   }
   void increment_surplus() {
     assert_proper_lock_protection();
     _allocation_stats.increment_surplus();
   }
   void decrement_surplus() {
     assert_proper_lock_protection();
     _allocation_stats.decrement_surplus();
   }
   ssize_t bfrSurp() const {
     return _allocation_stats.bfrSurp();
   }
   void set_bfrSurp(ssize_t v) {
     assert_proper_lock_protection();
     _allocation_stats.set_bfrSurp(v);
   }
   ssize_t prevSweep() const {
     return _allocation_stats.prevSweep();
   }
   void set_prevSweep(ssize_t v) {
     assert_proper_lock_protection();
     _allocation_stats.set_prevSweep(v);
   }
   ssize_t beforeSweep() const {
     return _allocation_stats.beforeSweep();
   }
   void set_beforeSweep(ssize_t v) {
     assert_proper_lock_protection();
     _allocation_stats.set_beforeSweep(v);
   }
   ssize_t coalBirths() const {
     return _allocation_stats.coalBirths();
   }
   void set_coalBirths(ssize_t v) {
     assert_proper_lock_protection();
     _allocation_stats.set_coalBirths(v);
   }
   void increment_coalBirths() {
     assert_proper_lock_protection();
     _allocation_stats.increment_coalBirths();
   }
   ssize_t coalDeaths() const {
     return _allocation_stats.coalDeaths();
   }
   void set_coalDeaths(ssize_t v) {
     assert_proper_lock_protection();
     _allocation_stats.set_coalDeaths(v);
   }
   void increment_coalDeaths() {
     assert_proper_lock_protection();
     _allocation_stats.increment_coalDeaths();
   }
   ssize_t splitBirths() const {
     return _allocation_stats.splitBirths();
   }
   void set_splitBirths(ssize_t v) {
     assert_proper_lock_protection();
     _allocation_stats.set_splitBirths(v);
   }
   void increment_splitBirths() {
     assert_proper_lock_protection();
     _allocation_stats.increment_splitBirths();
   }
   ssize_t splitDeaths() const {
     return _allocation_stats.splitDeaths();
   }
   void set_splitDeaths(ssize_t v) {
     assert_proper_lock_protection();
     _allocation_stats.set_splitDeaths(v);
   }
   void increment_splitDeaths() {
     assert_proper_lock_protection();
     _allocation_stats.increment_splitDeaths();
   }
   NOT_PRODUCT(
     // For debugging.  The "_returnedBytes" in all the lists are summed
     // and compared with the total number of bytes swept during a
     // collection.
     size_t returnedBytes() const { return _allocation_stats.returnedBytes(); }
     void set_returnedBytes(size_t v) { _allocation_stats.set_returnedBytes(v); }
     void increment_returnedBytes_by(size_t v) {
       _allocation_stats.set_returnedBytes(_allocation_stats.returnedBytes() + v);
     }
   )
   // Unlink head of list and return it.  Returns NULL if
   // the list is empty.
   FreeChunk* getChunkAtHead();
   // 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* fl);
   // Unlink this chunk from it's free list
   void removeChunk(FreeChunk* fc);
   // Add this chunk to this free list.
   void returnChunkAtHead(FreeChunk* fc);
   void returnChunkAtTail(FreeChunk* fc);
   // Similar to returnChunk* but also records some diagnostic
   // information.
   void returnChunkAtHead(FreeChunk* fc, bool record_return);
   void returnChunkAtTail(FreeChunk* 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* fl);
   // Verify that the chunk is in the list.
   // found.  Return NULL if "fc" is not found.
   bool verifyChunkInFreeLists(FreeChunk* fc) const;
   // Stats verification
   void verify_stats() const PRODUCT_RETURN;
   // Printing support
   static void print_labels_on(outputStream* st, const char* c);
   void print_on(outputStream* st, const char* c = NULL) const;
 };

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/concurrentMarkSweep/freeList.hpp@3bfae429e2cf (annotated)

src/share/vm/gc_implementation/concurrentMarkSweep/freeList.hpp