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

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

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

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.
  *
  */
 # include "incls/_precompiled.incl"
 # include "incls/_freeList.cpp.incl"
 // Free list.  A FreeList is used to access a linked list of chunks
 // of space in the heap.  The head and tail are maintained so that
 // items can be (as in the current implementation) added at the
 // at the tail of the list and removed from the head of the list to
 // maintain a FIFO queue.
 FreeList::FreeList() :
   _head(NULL), _tail(NULL)
 #ifdef ASSERT
   , _protecting_lock(NULL)
 #endif
 {
   _size         = 0;
   _count        = 0;
   _hint         = 0;
   init_statistics();
 }
 FreeList::FreeList(FreeChunk* fc) :
   _head(fc), _tail(fc)
 #ifdef ASSERT
   , _protecting_lock(NULL)
 #endif
 {
   _size         = fc->size();
   _count        = 1;
   _hint         = 0;
   init_statistics();
 #ifndef PRODUCT
   _allocation_stats.set_returnedBytes(size() * HeapWordSize);
 #endif
 }
 FreeList::FreeList(HeapWord* addr, size_t size) :
   _head((FreeChunk*) addr), _tail((FreeChunk*) addr)
 #ifdef ASSERT
   , _protecting_lock(NULL)
 #endif
 {
   assert(size > sizeof(FreeChunk), "size is too small");
   head()->setSize(size);
   _size         = size;
   _count        = 1;
   init_statistics();
 #ifndef PRODUCT
   _allocation_stats.set_returnedBytes(_size * HeapWordSize);
 #endif
 }
 void FreeList::reset(size_t hint) {
   set_count(0);
   set_head(NULL);
   set_tail(NULL);
   set_hint(hint);
 }
 void FreeList::init_statistics(bool split_birth) {
   _allocation_stats.initialize(split_birth);
 }
 FreeChunk* FreeList::getChunkAtHead() {
   assert_proper_lock_protection();
   assert(head() == NULL || head()->prev() == NULL, "list invariant");
   assert(tail() == NULL || tail()->next() == NULL, "list invariant");
   FreeChunk* fc = head();
   if (fc != NULL) {
     FreeChunk* nextFC = fc->next();
     if (nextFC != NULL) {
       // The chunk fc being removed has a "next".  Set the "next" to the
       // "prev" of fc.
       nextFC->linkPrev(NULL);
     } else { // removed tail of list
       link_tail(NULL);
     }
     link_head(nextFC);
     decrement_count();
   }
   assert(head() == NULL || head()->prev() == NULL, "list invariant");
   assert(tail() == NULL || tail()->next() == NULL, "list invariant");
   return fc;
 }
 void FreeList::getFirstNChunksFromList(size_t n, FreeList* fl) {
   assert_proper_lock_protection();
   assert(fl->count() == 0, "Precondition");
   if (count() > 0) {
     int k = 1;
     fl->set_head(head()); n--;
     FreeChunk* tl = head();
     while (tl->next() != NULL && n > 0) {
       tl = tl->next(); n--; k++;
     }
     assert(tl != NULL, "Loop Inv.");
     // First, fix up the list we took from.
     FreeChunk* new_head = tl->next();
     set_head(new_head);
     set_count(count() - k);
     if (new_head == NULL) {
       set_tail(NULL);
     } else {
       new_head->linkPrev(NULL);
     }
     // Now we can fix up the tail.
     tl->linkNext(NULL);
     // And return the result.
     fl->set_tail(tl);
     fl->set_count(k);
   }
 }
 // Remove this chunk from the list
 void FreeList::removeChunk(FreeChunk*fc) {
    assert_proper_lock_protection();
    assert(head() != NULL, "Remove from empty list");
    assert(fc != NULL, "Remove a NULL chunk");
    assert(size() == fc->size(), "Wrong list");
    assert(head() == NULL || head()->prev() == NULL, "list invariant");
    assert(tail() == NULL || tail()->next() == NULL, "list invariant");
    FreeChunk* prevFC = fc->prev();
    FreeChunk* nextFC = fc->next();
    if (nextFC != NULL) {
      // The chunk fc being removed has a "next".  Set the "next" to the
      // "prev" of fc.
      nextFC->linkPrev(prevFC);
    } else { // removed tail of list
      link_tail(prevFC);
    }
    if (prevFC == NULL) { // removed head of list
      link_head(nextFC);
      assert(nextFC == NULL || nextFC->prev() == NULL,
        "Prev of head should be NULL");
    } else {
      prevFC->linkNext(nextFC);
      assert(tail() != prevFC || prevFC->next() == NULL,
        "Next of tail should be NULL");
    }
    decrement_count();
 #define TRAP_CODE 1
 #if TRAP_CODE
    if (head() == NULL) {
      guarantee(tail() == NULL, "INVARIANT");
      guarantee(count() == 0, "INVARIANT");
    }
 #endif
    // clear next and prev fields of fc, debug only
    NOT_PRODUCT(
      fc->linkPrev(NULL);
      fc->linkNext(NULL);
    )
    assert(fc->isFree(), "Should still be a free chunk");
    assert(head() == NULL || head()->prev() == NULL, "list invariant");
    assert(tail() == NULL || tail()->next() == NULL, "list invariant");
    assert(head() == NULL || head()->size() == size(), "wrong item on list");
    assert(tail() == NULL || tail()->size() == size(), "wrong item on list");
 }
 // Add this chunk at the head of the list.
 void FreeList::returnChunkAtHead(FreeChunk* chunk, bool record_return) {
   assert_proper_lock_protection();
   assert(chunk != NULL, "insert a NULL chunk");
   assert(size() == chunk->size(), "Wrong size");
   assert(head() == NULL || head()->prev() == NULL, "list invariant");
   assert(tail() == NULL || tail()->next() == NULL, "list invariant");
   FreeChunk* oldHead = head();
   assert(chunk != oldHead, "double insertion");
   chunk->linkAfter(oldHead);
   link_head(chunk);
   if (oldHead == NULL) { // only chunk in list
     assert(tail() == NULL, "inconsistent FreeList");
     link_tail(chunk);
   }
   increment_count(); // of # of chunks in list
   DEBUG_ONLY(
     if (record_return) {
       increment_returnedBytes_by(size()*HeapWordSize);
     }
   )
   assert(head() == NULL || head()->prev() == NULL, "list invariant");
   assert(tail() == NULL || tail()->next() == NULL, "list invariant");
   assert(head() == NULL || head()->size() == size(), "wrong item on list");
   assert(tail() == NULL || tail()->size() == size(), "wrong item on list");
 }
 void FreeList::returnChunkAtHead(FreeChunk* chunk) {
   assert_proper_lock_protection();
   returnChunkAtHead(chunk, true);
 }
 // Add this chunk at the tail of the list.
 void FreeList::returnChunkAtTail(FreeChunk* chunk, bool record_return) {
   assert_proper_lock_protection();
   assert(head() == NULL || head()->prev() == NULL, "list invariant");
   assert(tail() == NULL || tail()->next() == NULL, "list invariant");
   assert(chunk != NULL, "insert a NULL chunk");
   assert(size() == chunk->size(), "wrong size");
   FreeChunk* oldTail = tail();
   assert(chunk != oldTail, "double insertion");
   if (oldTail != NULL) {
     oldTail->linkAfter(chunk);
   } else { // only chunk in list
     assert(head() == NULL, "inconsistent FreeList");
     link_head(chunk);
   }
   link_tail(chunk);
   increment_count();  // of # of chunks in list
   DEBUG_ONLY(
     if (record_return) {
       increment_returnedBytes_by(size()*HeapWordSize);
     }
   )
   assert(head() == NULL || head()->prev() == NULL, "list invariant");
   assert(tail() == NULL || tail()->next() == NULL, "list invariant");
   assert(head() == NULL || head()->size() == size(), "wrong item on list");
   assert(tail() == NULL || tail()->size() == size(), "wrong item on list");
 }
 void FreeList::returnChunkAtTail(FreeChunk* chunk) {
   returnChunkAtTail(chunk, true);
 }
 void FreeList::prepend(FreeList* fl) {
   assert_proper_lock_protection();
   if (fl->count() > 0) {
     if (count() == 0) {
       set_head(fl->head());
       set_tail(fl->tail());
       set_count(fl->count());
     } else {
       // Both are non-empty.
       FreeChunk* fl_tail = fl->tail();
       FreeChunk* this_head = head();
       assert(fl_tail->next() == NULL, "Well-formedness of fl");
       fl_tail->linkNext(this_head);
       this_head->linkPrev(fl_tail);
       set_head(fl->head());
       set_count(count() + fl->count());
     }
     fl->set_head(NULL);
     fl->set_tail(NULL);
     fl->set_count(0);
   }
 }
 // verifyChunkInFreeLists() is used to verify that an item is in this free list.
 // It is used as a debugging aid.
 bool FreeList::verifyChunkInFreeLists(FreeChunk* fc) const {
   // This is an internal consistency check, not part of the check that the
   // chunk is in the free lists.
   guarantee(fc->size() == size(), "Wrong list is being searched");
   FreeChunk* curFC = head();
   while (curFC) {
     // This is an internal consistency check.
     guarantee(size() == curFC->size(), "Chunk is in wrong list.");
     if (fc == curFC) {
       return true;
     }
     curFC = curFC->next();
   }
   return false;
 }
 #ifndef PRODUCT
 void FreeList::verify_stats() const {
   // The +1 of the LH comparand is to allow some "looseness" in
   // checking: we usually call this interface when adding a block
   // and we'll subsequently update the stats; we cannot update the
   // stats beforehand because in the case of the large-block BT
   // dictionary for example, this might be the first block and
   // in that case there would be no place that we could record
   // the stats (which are kept in the block itself).
   assert(_allocation_stats.prevSweep() + _allocation_stats.splitBirths() + 1   // Total Stock + 1
           >= _allocation_stats.splitDeaths() + (ssize_t)count(), "Conservation Principle");
 }
 void FreeList::assert_proper_lock_protection_work() const {
   assert(_protecting_lock != NULL, "Don't call this directly");
   assert(ParallelGCThreads > 0, "Don't call this directly");
   Thread* thr = Thread::current();
   if (thr->is_VM_thread() || thr->is_ConcurrentGC_thread()) {
     // assert that we are holding the freelist lock
   } else if (thr->is_GC_task_thread()) {
     assert(_protecting_lock->owned_by_self(), "FreeList RACE DETECTED");
   } else if (thr->is_Java_thread()) {
     assert(!SafepointSynchronize::is_at_safepoint(), "Should not be executing");
   } else {
     ShouldNotReachHere();  // unaccounted thread type?
   }
 }
 #endif
 // Print the "label line" for free list stats.
 void FreeList::print_labels_on(outputStream* st, const char* c) {
   st->print("%16s\t", c);
   st->print("%14s\t"    "%14s\t"    "%14s\t"    "%14s\t"    "%14s\t"
             "%14s\t"    "%14s\t"    "%14s\t"    "%14s\t"    "%14s\t"    "\n",
             "bfrsurp", "surplus", "desired", "prvSwep", "bfrSwep",
             "count",   "cBirths", "cDeaths", "sBirths", "sDeaths");
 }
 // Print the AllocationStats for the given free list. If the second argument
 // to the call is a non-null string, it is printed in the first column;
 // otherwise, if the argument is null (the default), then the size of the
 // (free list) block is printed in the first column.
 void FreeList::print_on(outputStream* st, const char* c) const {
   if (c != NULL) {
     st->print("%16s", c);
   } else {
     st->print(SIZE_FORMAT_W(16), size());
   }
   st->print("\t"
            SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t"
            SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\n",
            bfrSurp(),             surplus(),             desired(),             prevSweep(),           beforeSweep(),
            count(),               coalBirths(),          coalDeaths(),          splitBirths(),         splitDeaths());
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

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

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