heap/IncrementalSweeper.cpp

   1 /*
   2  * Copyright (C) 2012 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27 #include "IncrementalSweeper.h"
  28
  29 #include "DelayedReleaseScope.h"
  30 #include "Heap.h"
  31 #include "JSObject.h"
  32 #include "JSString.h"
  33 #include "MarkedBlock.h"
  34 #include "JSCInlines.h"
  35
  36 #include <wtf/HashSet.h>
  37 #include <wtf/WTFThreadData.h>
  38
  39 namespace JSC {
  40
  41 #if USE(CF)
  42
  43 static const double sweepTimeSlice = .01; // seconds
  44 static const double sweepTimeTotal = .10;
  45 static const double sweepTimeMultiplier = 1.0 / sweepTimeTotal;
  46
  47 IncrementalSweeper::IncrementalSweeper(Heap* heap, CFRunLoopRef runLoop)
  48     : HeapTimer(heap->vm(), runLoop)
  49     , m_currentBlockToSweepIndex(0)
  50     , m_blocksToSweep(heap->m_blockSnapshot)
  51 {
  52 }
  53
  54 PassOwnPtr<IncrementalSweeper> IncrementalSweeper::create(Heap* heap)
  55 {
  56     return adoptPtr(new IncrementalSweeper(heap, CFRunLoopGetCurrent()));
  57 }
  58
  59 void IncrementalSweeper::scheduleTimer()
  60 {
  61     CFRunLoopTimerSetNextFireDate(m_timer.get(), CFAbsoluteTimeGetCurrent() + (sweepTimeSlice * sweepTimeMultiplier));
  62 }
  63
  64 void IncrementalSweeper::cancelTimer()
  65 {
  66     CFRunLoopTimerSetNextFireDate(m_timer.get(), CFAbsoluteTimeGetCurrent() + s_decade);
  67 }
  68
  69 void IncrementalSweeper::doWork()
  70 {
  71     doSweep(WTF::monotonicallyIncreasingTime());
  72 }
  73
  74 void IncrementalSweeper::doSweep(double sweepBeginTime)
  75 {
  76     DelayedReleaseScope scope(m_vm->heap.m_objectSpace);
  77     while (m_currentBlockToSweepIndex < m_blocksToSweep.size()) {
  78         sweepNextBlock();
  79
  80         double elapsedTime = WTF::monotonicallyIncreasingTime() - sweepBeginTime;
  81         if (elapsedTime < sweepTimeSlice)
  82             continue;
  83
  84         scheduleTimer();
  85         return;
  86     }
  87
  88     m_blocksToSweep.clear();
  89     cancelTimer();
  90 }
  91
  92 void IncrementalSweeper::sweepNextBlock()
  93 {
  94     while (m_currentBlockToSweepIndex < m_blocksToSweep.size()) {
  95         MarkedBlock* block = m_blocksToSweep[m_currentBlockToSweepIndex++];
  96
  97         if (!block->needsSweeping())
  98             continue;
  99
 100         block->sweep();
 101         m_vm->heap.objectSpace().freeOrShrinkBlock(block);
 102         return;
 103     }
 104 }
 105
 106 void IncrementalSweeper::startSweeping(Vector<MarkedBlock*>& blockSnapshot)
 107 {
 108     m_blocksToSweep = blockSnapshot;
 109     m_currentBlockToSweepIndex = 0;
 110     scheduleTimer();
 111 }
 112
 113 void IncrementalSweeper::willFinishSweeping()
 114 {
 115     m_currentBlockToSweepIndex = 0;
 116     m_blocksToSweep.clear();
 117     if (m_vm)
 118         cancelTimer();
 119 }
 120
 121 #else
 122
 123 IncrementalSweeper::IncrementalSweeper(VM* vm)
 124     : HeapTimer(vm)
 125 {
 126 }
 127
 128 void IncrementalSweeper::doWork()
 129 {
 130 }
 131
 132 PassOwnPtr<IncrementalSweeper> IncrementalSweeper::create(Heap* heap)
 133 {
 134     return adoptPtr(new IncrementalSweeper(heap->vm()));
 135 }
 136
 137 void IncrementalSweeper::startSweeping(Vector<MarkedBlock*>&)
 138 {
 139 }
 140
 141 void IncrementalSweeper::willFinishSweeping()
 142 {
 143 }
 144
 145 void IncrementalSweeper::sweepNextBlock()
 146 {
 147 }
 148
 149 #endif
 150
 151 } // namespace JSC