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<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/201929">201929</a></dd>
<dt>Author</dt> <dd>simon.fraser@apple.com</dd>
<dt>Date</dt> <dd>2016-06-10 11:01:54 -0700 (Fri, 10 Jun 2016)</dd>
</dl>
<h3>Log Message</h3>
<pre>[iOS WK2] Rare RELEASE_ASSERT under RemoteLayerTreeDrawingArea::flushLayers()
https://bugs.webkit.org/show_bug.cgi?id=158622
rdar://problem/26609452
Reviewed by Tim Horton.
It's possible for a CADisplayLink to fire after being paused sometimes, possibly
when an app is running another CADisplayLink whose callback takes some time. When
this happens, RemoteLayerTreeDrawingAreaProxy could erroneously send a second
didUpdate() to the web process between commits, which would clear the m_waitingForBackingStoreSwap
flag too early, and allow a subsequent RemoteLayerTreeDrawingArea::flushLayers()
to proceed when the m_pendingBackingStoreFlusher was still flushing.
Fix by preventing two didUpdates from being sent from the UI process between
commits.
Not easily testable.
* UIProcess/mac/RemoteLayerTreeDrawingAreaProxy.h:
* UIProcess/mac/RemoteLayerTreeDrawingAreaProxy.mm:
(WebKit::RemoteLayerTreeDrawingAreaProxy::commitLayerTree):
(WebKit::RemoteLayerTreeDrawingAreaProxy::didRefreshDisplay):</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkSourceWebKit2ChangeLog">trunk/Source/WebKit2/ChangeLog</a></li>
<li><a href="#trunkSourceWebKit2UIProcessmacRemoteLayerTreeDrawingAreaProxyh">trunk/Source/WebKit2/UIProcess/mac/RemoteLayerTreeDrawingAreaProxy.h</a></li>
<li><a href="#trunkSourceWebKit2UIProcessmacRemoteLayerTreeDrawingAreaProxymm">trunk/Source/WebKit2/UIProcess/mac/RemoteLayerTreeDrawingAreaProxy.mm</a></li>
</ul>
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<div id="patch">
<h3>Diff</h3>
<a id="trunkSourceWebKit2ChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebKit2/ChangeLog (201928 => 201929)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebKit2/ChangeLog 2016-06-10 17:04:11 UTC (rev 201928)
+++ trunk/Source/WebKit2/ChangeLog 2016-06-10 18:01:54 UTC (rev 201929)
</span><span class="lines">@@ -1,3 +1,28 @@
</span><ins>+2016-06-10 Simon Fraser <simon.fraser@apple.com>
+
+ [iOS WK2] Rare RELEASE_ASSERT under RemoteLayerTreeDrawingArea::flushLayers()
+ https://bugs.webkit.org/show_bug.cgi?id=158622
+ rdar://problem/26609452
+
+ Reviewed by Tim Horton.
+
+ It's possible for a CADisplayLink to fire after being paused sometimes, possibly
+ when an app is running another CADisplayLink whose callback takes some time. When
+ this happens, RemoteLayerTreeDrawingAreaProxy could erroneously send a second
+ didUpdate() to the web process between commits, which would clear the m_waitingForBackingStoreSwap
+ flag too early, and allow a subsequent RemoteLayerTreeDrawingArea::flushLayers()
+ to proceed when the m_pendingBackingStoreFlusher was still flushing.
+
+ Fix by preventing two didUpdates from being sent from the UI process between
+ commits.
+
+ Not easily testable.
+
+ * UIProcess/mac/RemoteLayerTreeDrawingAreaProxy.h:
+ * UIProcess/mac/RemoteLayerTreeDrawingAreaProxy.mm:
+ (WebKit::RemoteLayerTreeDrawingAreaProxy::commitLayerTree):
+ (WebKit::RemoteLayerTreeDrawingAreaProxy::didRefreshDisplay):
+
</ins><span class="cx"> 2016-06-10 Carlos Garcia Campos <cgarcia@igalia.com>
</span><span class="cx">
</span><span class="cx"> [Threaded Compositor] Content and viewport sizes are mixed
</span></span></pre></div>
<a id="trunkSourceWebKit2UIProcessmacRemoteLayerTreeDrawingAreaProxyh"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebKit2/UIProcess/mac/RemoteLayerTreeDrawingAreaProxy.h (201928 => 201929)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebKit2/UIProcess/mac/RemoteLayerTreeDrawingAreaProxy.h 2016-06-10 17:04:11 UTC (rev 201928)
+++ trunk/Source/WebKit2/UIProcess/mac/RemoteLayerTreeDrawingAreaProxy.h 2016-06-10 18:01:54 UTC (rev 201929)
</span><span class="lines">@@ -91,6 +91,7 @@
</span><span class="cx">
</span><span class="cx"> RemoteLayerTreeHost m_remoteLayerTreeHost;
</span><span class="cx"> bool m_isWaitingForDidUpdateGeometry { false };
</span><ins>+ bool m_haveSentDidUpdateSinceLastCommit { false };
</ins><span class="cx">
</span><span class="cx"> WebCore::IntSize m_lastSentSize;
</span><span class="cx">
</span></span></pre></div>
<a id="trunkSourceWebKit2UIProcessmacRemoteLayerTreeDrawingAreaProxymm"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebKit2/UIProcess/mac/RemoteLayerTreeDrawingAreaProxy.mm (201928 => 201929)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebKit2/UIProcess/mac/RemoteLayerTreeDrawingAreaProxy.mm 2016-06-10 17:04:11 UTC (rev 201928)
+++ trunk/Source/WebKit2/UIProcess/mac/RemoteLayerTreeDrawingAreaProxy.mm 2016-06-10 18:01:54 UTC (rev 201929)
</span><span class="lines">@@ -219,6 +219,8 @@
</span><span class="cx">
</span><span class="cx"> m_webPageProxy.layerTreeCommitComplete();
</span><span class="cx">
</span><ins>+ m_haveSentDidUpdateSinceLastCommit = false;
+
</ins><span class="cx"> #if PLATFORM(IOS)
</span><span class="cx"> [m_displayLinkHandler schedule];
</span><span class="cx"> #else
</span><span class="lines">@@ -389,6 +391,11 @@
</span><span class="cx"> if (!m_webPageProxy.isValid())
</span><span class="cx"> return;
</span><span class="cx">
</span><ins>+ if (m_haveSentDidUpdateSinceLastCommit)
+ return;
+
+ m_haveSentDidUpdateSinceLastCommit = true;
+
</ins><span class="cx"> // Waiting for CA to commit is insufficient, because the render server can still be
</span><span class="cx"> // using our backing store. We can improve this by waiting for the render server to commit
</span><span class="cx"> // if we find API to do so, but for now we will make extra buffers if need be.
</span></span></pre>
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