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<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/184706">184706</a></dd>
<dt>Author</dt> <dd>matthew_hanson@apple.com</dd>
<dt>Date</dt> <dd>2015-05-20 23:39:35 -0700 (Wed, 20 May 2015)</dd>
</dl>
<h3>Log Message</h3>
<pre>Merge <a href="http://trac.webkit.org/projects/webkit/changeset/184652">r184652</a>. rdar://problem/21002666</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#branchessafari6011322branchSourceJavaScriptCoreChangeLog">branches/safari-601.1.32.2-branch/Source/JavaScriptCore/ChangeLog</a></li>
<li><a href="#branchessafari6011322branchSourceJavaScriptCoreheapHeapcpp">branches/safari-601.1.32.2-branch/Source/JavaScriptCore/heap/Heap.cpp</a></li>
<li><a href="#branchessafari6011322branchSourceJavaScriptCoreheapIncrementalSweepercpp">branches/safari-601.1.32.2-branch/Source/JavaScriptCore/heap/IncrementalSweeper.cpp</a></li>
<li><a href="#branchessafari6011322branchSourceJavaScriptCoreheapIncrementalSweeperh">branches/safari-601.1.32.2-branch/Source/JavaScriptCore/heap/IncrementalSweeper.h</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="branchessafari6011322branchSourceJavaScriptCoreChangeLog"></a>
<div class="modfile"><h4>Modified: branches/safari-601.1.32.2-branch/Source/JavaScriptCore/ChangeLog (184705 => 184706)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.32.2-branch/Source/JavaScriptCore/ChangeLog 2015-05-21 06:39:32 UTC (rev 184705)
+++ branches/safari-601.1.32.2-branch/Source/JavaScriptCore/ChangeLog 2015-05-21 06:39:35 UTC (rev 184706)
</span><span class="lines">@@ -1,3 +1,42 @@
</span><ins>+2015-05-20 Matthew Hanson <matthew_hanson@apple.com>
+
+ Merge r184652. rdar://problem/21002666
+
+ 2015-05-20 Andreas Kling <akling@apple.com>
+
+ Eden collections should extend the IncrementalSweeper work list, not replace it.
+ <https://webkit.org/b/145213>
+ <rdar://problem/21002666>
+
+ Reviewed by Geoffrey Garen.
+
+ After an eden collection, the garbage collector was adding all MarkedBlocks containing
+ new objects to the IncrementalSweeper's work list, to make sure they didn't have to
+ wait until the next full collection before getting swept.
+
+ Or at least, that's what it thought it was doing. It turns out that IncrementalSweeper's
+ internal work list is really just a reference to Heap::m_blockSnapshot. I didn't realize
+ this when writing the post-eden sweep code, and instead made eden collections cancel
+ all pending sweeps and *replace* them with the list of blocks with new objects.
+
+ This made it so that rapidly occurring eden collections could prevent large numbers of
+ heap blocks from ever getting swept. This would manifest as accumulation of MarkedBlocks
+ when a system under heavy load was also allocating short lived objects at a high rate.
+ Things would eventually get cleaned up when there was a lull and a full collection was
+ allowed to run its heap sweep to completion.
+
+ Fix this by moving all management of the block snapshot to Heap. snapshotMarkedSpace()
+ now handles eden collections by merging the list of blocks with new objects into the
+ existing block snapshot.
+
+ * heap/Heap.cpp:
+ (JSC::Heap::snapshotMarkedSpace):
+ (JSC::Heap::notifyIncrementalSweeper):
+ * heap/IncrementalSweeper.cpp:
+ (JSC::IncrementalSweeper::startSweeping):
+ (JSC::IncrementalSweeper::addBlocksAndContinueSweeping): Deleted.
+ * heap/IncrementalSweeper.h:
+
</ins><span class="cx"> 2015-05-18 Matthew Hanson <matthew_hanson@apple.com>
</span><span class="cx">
</span><span class="cx"> Merge r184510. rdar://problem/21004989
</span></span></pre></div>
<a id="branchessafari6011322branchSourceJavaScriptCoreheapHeapcpp"></a>
<div class="modfile"><h4>Modified: branches/safari-601.1.32.2-branch/Source/JavaScriptCore/heap/Heap.cpp (184705 => 184706)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.32.2-branch/Source/JavaScriptCore/heap/Heap.cpp 2015-05-21 06:39:32 UTC (rev 184705)
+++ branches/safari-601.1.32.2-branch/Source/JavaScriptCore/heap/Heap.cpp 2015-05-21 06:39:35 UTC (rev 184706)
</span><span class="lines">@@ -1207,9 +1207,12 @@
</span><span class="cx"> {
</span><span class="cx"> GCPHASE(SnapshotMarkedSpace);
</span><span class="cx">
</span><del>- if (m_operationInProgress == EdenCollection)
- m_blockSnapshot = m_objectSpace.blocksWithNewObjects();
- else {
</del><ins>+ if (m_operationInProgress == EdenCollection) {
+ m_blockSnapshot.appendVector(m_objectSpace.blocksWithNewObjects());
+ // Sort and deduplicate the block snapshot since we might be appending to an unfinished work list.
+ std::sort(m_blockSnapshot.begin(), m_blockSnapshot.end());
+ m_blockSnapshot.shrink(std::unique(m_blockSnapshot.begin(), m_blockSnapshot.end()) - m_blockSnapshot.begin());
+ } else {
</ins><span class="cx"> m_blockSnapshot.resizeToFit(m_objectSpace.blocks().set().size());
</span><span class="cx"> MarkedBlockSnapshotFunctor functor(m_blockSnapshot);
</span><span class="cx"> m_objectSpace.forEachBlock(functor);
</span><span class="lines">@@ -1225,13 +1228,13 @@
</span><span class="cx"> void Heap::notifyIncrementalSweeper()
</span><span class="cx"> {
</span><span class="cx"> GCPHASE(NotifyIncrementalSweeper);
</span><del>- if (m_operationInProgress == EdenCollection)
- m_sweeper->addBlocksAndContinueSweeping(WTF::move(m_blockSnapshot));
- else {
</del><ins>+
+ if (m_operationInProgress == FullCollection) {
</ins><span class="cx"> if (!m_logicallyEmptyWeakBlocks.isEmpty())
</span><span class="cx"> m_indexOfNextLogicallyEmptyWeakBlockToSweep = 0;
</span><del>- m_sweeper->startSweeping(WTF::move(m_blockSnapshot));
</del><span class="cx"> }
</span><ins>+
+ m_sweeper->startSweeping();
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> void Heap::rememberCurrentlyExecutingCodeBlocks()
</span></span></pre></div>
<a id="branchessafari6011322branchSourceJavaScriptCoreheapIncrementalSweepercpp"></a>
<div class="modfile"><h4>Modified: branches/safari-601.1.32.2-branch/Source/JavaScriptCore/heap/IncrementalSweeper.cpp (184705 => 184706)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.32.2-branch/Source/JavaScriptCore/heap/IncrementalSweeper.cpp 2015-05-21 06:39:32 UTC (rev 184705)
+++ branches/safari-601.1.32.2-branch/Source/JavaScriptCore/heap/IncrementalSweeper.cpp 2015-05-21 06:39:35 UTC (rev 184706)
</span><span class="lines">@@ -101,21 +101,11 @@
</span><span class="cx"> return m_vm->heap.sweepNextLogicallyEmptyWeakBlock();
</span><span class="cx"> }
</span><span class="cx">
</span><del>-void IncrementalSweeper::startSweeping(Vector<MarkedBlock*>&& blockSnapshot)
</del><ins>+void IncrementalSweeper::startSweeping()
</ins><span class="cx"> {
</span><del>- m_blocksToSweep = WTF::move(blockSnapshot);
</del><span class="cx"> scheduleTimer();
</span><span class="cx"> }
</span><span class="cx">
</span><del>-void IncrementalSweeper::addBlocksAndContinueSweeping(Vector<MarkedBlock*>&& blockSnapshot)
-{
- Vector<MarkedBlock*> blocks = WTF::move(blockSnapshot);
- m_blocksToSweep.appendVector(blocks);
- std::sort(m_blocksToSweep.begin(), m_blocksToSweep.end());
- m_blocksToSweep.shrink(std::unique(m_blocksToSweep.begin(), m_blocksToSweep.end()) - m_blocksToSweep.begin());
- scheduleTimer();
-}
-
</del><span class="cx"> void IncrementalSweeper::willFinishSweeping()
</span><span class="cx"> {
</span><span class="cx"> m_blocksToSweep.clear();
</span><span class="lines">@@ -134,14 +124,10 @@
</span><span class="cx"> {
</span><span class="cx"> }
</span><span class="cx">
</span><del>-void IncrementalSweeper::startSweeping(Vector<MarkedBlock*>&&)
</del><ins>+void IncrementalSweeper::startSweeping()
</ins><span class="cx"> {
</span><span class="cx"> }
</span><span class="cx">
</span><del>-void IncrementalSweeper::addBlocksAndContinueSweeping(Vector<MarkedBlock*>&&)
-{
-}
-
</del><span class="cx"> void IncrementalSweeper::willFinishSweeping()
</span><span class="cx"> {
</span><span class="cx"> }
</span></span></pre></div>
<a id="branchessafari6011322branchSourceJavaScriptCoreheapIncrementalSweeperh"></a>
<div class="modfile"><h4>Modified: branches/safari-601.1.32.2-branch/Source/JavaScriptCore/heap/IncrementalSweeper.h (184705 => 184706)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.32.2-branch/Source/JavaScriptCore/heap/IncrementalSweeper.h 2015-05-21 06:39:32 UTC (rev 184705)
+++ branches/safari-601.1.32.2-branch/Source/JavaScriptCore/heap/IncrementalSweeper.h 2015-05-21 06:39:35 UTC (rev 184706)
</span><span class="lines">@@ -44,8 +44,7 @@
</span><span class="cx"> explicit IncrementalSweeper(VM*);
</span><span class="cx"> #endif
</span><span class="cx">
</span><del>- void startSweeping(Vector<MarkedBlock*>&&);
- void addBlocksAndContinueSweeping(Vector<MarkedBlock*>&&);
</del><ins>+ void startSweeping();
</ins><span class="cx">
</span><span class="cx"> JS_EXPORT_PRIVATE virtual void doWork() override;
</span><span class="cx"> bool sweepNextBlock();
</span></span></pre>
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