heap/GCThreadSharedData.cpp

   1 /*
   2  * Copyright (C) 2009, 2011 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 "GCThreadSharedData.h"
  28
  29 #include "CopyVisitor.h"
  30 #include "CopyVisitorInlines.h"
  31 #include "GCThread.h"
  32 #include "MarkStack.h"
  33 #include "JSCInlines.h"
  34 #include "SlotVisitor.h"
  35 #include "SlotVisitorInlines.h"
  36 #include "VM.h"
  37
  38 namespace JSC {
  39
  40 #if ENABLE(PARALLEL_GC)
  41 void GCThreadSharedData::resetChildren()
  42 {
  43     for (size_t i = 0; i < m_gcThreads.size(); ++i)
  44         m_gcThreads[i]->slotVisitor()->reset();
  45 }
  46
  47 size_t GCThreadSharedData::childVisitCount()
  48 {
  49     unsigned long result = 0;
  50     for (unsigned i = 0; i < m_gcThreads.size(); ++i)
  51         result += m_gcThreads[i]->slotVisitor()->visitCount();
  52     return result;
  53 }
  54
  55 size_t GCThreadSharedData::childBytesVisited()
  56 {
  57     size_t result = 0;
  58     for (unsigned i = 0; i < m_gcThreads.size(); ++i)
  59         result += m_gcThreads[i]->slotVisitor()->bytesVisited();
  60     return result;
  61 }
  62
  63 size_t GCThreadSharedData::childBytesCopied()
  64 {
  65     size_t result = 0;
  66     for (unsigned i = 0; i < m_gcThreads.size(); ++i)
  67         result += m_gcThreads[i]->slotVisitor()->bytesCopied();
  68     return result;
  69 }
  70 #endif
  71
  72 GCThreadSharedData::GCThreadSharedData(VM* vm)
  73     : m_vm(vm)
  74     , m_copiedSpace(&vm->heap.m_storageSpace)
  75     , m_shouldHashCons(false)
  76     , m_sharedMarkStack()
  77     , m_numberOfActiveParallelMarkers(0)
  78     , m_parallelMarkersShouldExit(false)
  79     , m_copyIndex(0)
  80     , m_numberOfActiveGCThreads(0)
  81     , m_gcThreadsShouldWait(false)
  82     , m_currentPhase(NoPhase)
  83 {
  84 #if ENABLE(PARALLEL_GC)
  85     // Grab the lock so the new GC threads can be properly initialized before they start running.
  86     std::unique_lock<std::mutex> lock(m_phaseMutex);
  87     for (unsigned i = 1; i < Options::numberOfGCMarkers(); ++i) {
  88         m_numberOfActiveGCThreads++;
  89         GCThread* newThread = new GCThread(*this, std::make_unique<SlotVisitor>(*this), std::make_unique<CopyVisitor>(*this));
  90         ThreadIdentifier threadID = createThread(GCThread::gcThreadStartFunc, newThread, "JavaScriptCore::Marking");
  91         newThread->initializeThreadID(threadID);
  92         m_gcThreads.append(newThread);
  93     }
  94
  95     // Wait for all the GCThreads to get to the right place.
  96     m_activityConditionVariable.wait(lock, [this] { return !m_numberOfActiveGCThreads; });
  97 #endif
  98 }
  99
 100 GCThreadSharedData::~GCThreadSharedData()
 101 {
 102 #if ENABLE(PARALLEL_GC)
 103     // Destroy our marking threads.
 104     {
 105         std::lock_guard<std::mutex> markingLock(m_markingMutex);
 106         std::lock_guard<std::mutex> phaseLock(m_phaseMutex);
 107         ASSERT(m_currentPhase == NoPhase);
 108         m_parallelMarkersShouldExit = true;
 109         m_gcThreadsShouldWait = false;
 110         m_currentPhase = Exit;
 111         m_phaseConditionVariable.notify_all();
 112     }
 113     for (unsigned i = 0; i < m_gcThreads.size(); ++i) {
 114         waitForThreadCompletion(m_gcThreads[i]->threadID());
 115         delete m_gcThreads[i];
 116     }
 117 #endif
 118 }
 119
 120 void GCThreadSharedData::reset()
 121 {
 122     ASSERT(m_sharedMarkStack.isEmpty());
 123
 124     m_weakReferenceHarvesters.removeAll();
 125
 126     if (m_shouldHashCons) {
 127         m_vm->resetNewStringsSinceLastHashCons();
 128         m_shouldHashCons = false;
 129     }
 130 }
 131
 132 void GCThreadSharedData::startNextPhase(GCPhase phase)
 133 {
 134     std::lock_guard<std::mutex> lock(m_phaseMutex);
 135     ASSERT(!m_gcThreadsShouldWait);
 136     ASSERT(m_currentPhase == NoPhase);
 137     m_gcThreadsShouldWait = true;
 138     m_currentPhase = phase;
 139     m_phaseConditionVariable.notify_all();
 140 }
 141
 142 void GCThreadSharedData::endCurrentPhase()
 143 {
 144     ASSERT(m_gcThreadsShouldWait);
 145     std::unique_lock<std::mutex> lock(m_phaseMutex);
 146     m_currentPhase = NoPhase;
 147     m_gcThreadsShouldWait = false;
 148     m_phaseConditionVariable.notify_all();
 149     m_activityConditionVariable.wait(lock, [this] { return !m_numberOfActiveGCThreads; });
 150 }
 151
 152 void GCThreadSharedData::didStartMarking()
 153 {
 154     if (m_vm->heap.operationInProgress() == FullCollection) {
 155 #if ENABLE(PARALLEL_GC)
 156         m_opaqueRoots.clear();
 157 #else
 158         ASSERT(m_opaqueRoots.isEmpty());
 159 #endif
 160 }
 161     std::lock_guard<std::mutex> lock(m_markingMutex);
 162     m_parallelMarkersShouldExit = false;
 163     startNextPhase(Mark);
 164 }
 165
 166 void GCThreadSharedData::didFinishMarking()
 167 {
 168     {
 169         std::lock_guard<std::mutex> lock(m_markingMutex);
 170         m_parallelMarkersShouldExit = true;
 171         m_markingConditionVariable.notify_all();
 172     }
 173
 174     ASSERT(m_currentPhase == Mark);
 175     endCurrentPhase();
 176 }
 177
 178 void GCThreadSharedData::didStartCopying()
 179 {
 180     {
 181         SpinLockHolder locker(&m_copyLock);
 182         if (m_vm->heap.operationInProgress() == EdenCollection) {
 183             // Reset the vector to be empty, but don't throw away the backing store.
 184             m_blocksToCopy.shrink(0);
 185             for (CopiedBlock* block = m_copiedSpace->m_newGen.fromSpace->head(); block; block = block->next())
 186                 m_blocksToCopy.append(block);
 187         } else {
 188             ASSERT(m_vm->heap.operationInProgress() == FullCollection);
 189             WTF::copyToVector(m_copiedSpace->m_blockSet, m_blocksToCopy);
 190         }
 191         m_copyIndex = 0;
 192     }
 193
 194     // We do this here so that we avoid a race condition where the main thread can
 195     // blow through all of the copying work before the GCThreads fully wake up.
 196     // The GCThreads then request a block from the CopiedSpace when the copying phase
 197     // has completed, which isn't allowed.
 198     for (size_t i = 0; i < m_gcThreads.size(); i++)
 199         m_gcThreads[i]->copyVisitor()->startCopying();
 200
 201     startNextPhase(Copy);
 202 }
 203
 204 void GCThreadSharedData::didFinishCopying()
 205 {
 206     ASSERT(m_currentPhase == Copy);
 207     endCurrentPhase();
 208 }
 209
 210 } // namespace JSC