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<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/168589">168589</a></dd>
<dt>Author</dt> <dd>timothy_horton@apple.com</dd>
<dt>Date</dt> <dd>2014-05-10 17:53:31 -0700 (Sat, 10 May 2014)</dd>
</dl>
<h3>Log Message</h3>
<pre>[iOS WebKit2] REGRESSION (<a href="http://trac.webkit.org/projects/webkit/changeset/168493">r168493</a>): Canvasmark 2013 benchmark always hits the RELEASE_ASSERT in RemoteLayerTreeDrawingArea::flushLayers()
https://bugs.webkit.org/show_bug.cgi?id=132783
<rdar://problem/16877326>
Reviewed by Anders Carlsson.
* WebProcess/WebPage/mac/RemoteLayerTreeDrawingArea.mm:
(WebKit::RemoteLayerTreeDrawingArea::BackingStoreFlusher::flush):
There's a race window between the BackingStoreFlusher sending the new
layer tree to the UI process and updating m_hasFlushed where we can
get a reply back in (on the Web process main thread) from the UI process
that we committed the new layer tree (didUpdate).
This will cause the RELEASE_ASSERT in flushLayers() to fire incorrectly.
Since the RELEASE_ASSERT is there only to avoid painting garbage, move
our code to set m_hasFlushed=true to after we finish calling CGContextFlush
on all of the contexts, instead of after we send the layer tree commit message,
which will remove the race entirely.</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkSourceWebKit2ChangeLog">trunk/Source/WebKit2/ChangeLog</a></li>
<li><a href="#trunkSourceWebKit2WebProcessWebPagemacRemoteLayerTreeDrawingAreamm">trunk/Source/WebKit2/WebProcess/WebPage/mac/RemoteLayerTreeDrawingArea.mm</a></li>
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<h3>Diff</h3>
<a id="trunkSourceWebKit2ChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebKit2/ChangeLog (168588 => 168589)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebKit2/ChangeLog 2014-05-11 00:30:19 UTC (rev 168588)
+++ trunk/Source/WebKit2/ChangeLog 2014-05-11 00:53:31 UTC (rev 168589)
</span><span class="lines">@@ -1,3 +1,23 @@
</span><ins>+2014-05-10 Tim Horton <timothy_horton@apple.com>
+
+ [iOS WebKit2] REGRESSION (r168493): Canvasmark 2013 benchmark always hits the RELEASE_ASSERT in RemoteLayerTreeDrawingArea::flushLayers()
+ https://bugs.webkit.org/show_bug.cgi?id=132783
+ <rdar://problem/16877326>
+
+ Reviewed by Anders Carlsson.
+
+ * WebProcess/WebPage/mac/RemoteLayerTreeDrawingArea.mm:
+ (WebKit::RemoteLayerTreeDrawingArea::BackingStoreFlusher::flush):
+ There's a race window between the BackingStoreFlusher sending the new
+ layer tree to the UI process and updating m_hasFlushed where we can
+ get a reply back in (on the Web process main thread) from the UI process
+ that we committed the new layer tree (didUpdate).
+ This will cause the RELEASE_ASSERT in flushLayers() to fire incorrectly.
+ Since the RELEASE_ASSERT is there only to avoid painting garbage, move
+ our code to set m_hasFlushed=true to after we finish calling CGContextFlush
+ on all of the contexts, instead of after we send the layer tree commit message,
+ which will remove the race entirely.
+
</ins><span class="cx"> 2014-05-10 Anders Carlsson <andersca@apple.com>
</span><span class="cx">
</span><span class="cx"> ASSERTION FAILED: !m_connection under RunJavaScriptAlert
</span></span></pre></div>
<a id="trunkSourceWebKit2WebProcessWebPagemacRemoteLayerTreeDrawingAreamm"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebKit2/WebProcess/WebPage/mac/RemoteLayerTreeDrawingArea.mm (168588 => 168589)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebKit2/WebProcess/WebPage/mac/RemoteLayerTreeDrawingArea.mm 2014-05-11 00:30:19 UTC (rev 168588)
+++ trunk/Source/WebKit2/WebProcess/WebPage/mac/RemoteLayerTreeDrawingArea.mm 2014-05-11 00:53:31 UTC (rev 168589)
</span><span class="lines">@@ -336,9 +336,9 @@
</span><span class="cx">
</span><span class="cx"> for (auto& context : m_contextsToFlush)
</span><span class="cx"> CGContextFlush(context.get());
</span><ins>+ m_hasFlushed = true;
</ins><span class="cx">
</span><span class="cx"> m_connection->sendMessage(std::move(m_commitEncoder));
</span><del>- m_hasFlushed = true;
</del><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> } // namespace WebKit
</span></span></pre>
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