Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 4a79d76de1f311ddb588f5f3671c973baa203c46
https://github.com/WebKit/WebKit/commit/4a79d76de1f311ddb588f5f3671c973baa203c46
Author: Ben Nham <[email protected]>
Date: 2026-09-30 (Wed, 30 Sep 2026)
Changed paths:
M Source/WebKit/UIProcess/RemoteLayerTree/RemoteLayerTreeNode.mm
M Tools/TestWebKitAPI/Tests/WebKit/WKWebView/SiteIsolation.mm
Log Message:
-----------
[Site Isolation] Avoid calling -addSublayer: on hosted frame's root layer on
every commit
https://bugs.webkit.org/show_bug.cgi?id=325683
rdar://problem/188740987
Reviewed by Simon Fraser.
RemoteLayerTreeHost::updateLayerTree() calls
RemoteLayerTreeNode::addToHostingNode() for every
transaction from remote frame processes. This then unconditionally calls
-[CALayer addSublayer:] to
add the root layer to the hosting layer.
If the root layer is already a sublayer of the hosting layer, this adds some
extra cost to each
transaction, since -addSublayer: actually removes the layer, re-adds it, and
then marks the layer
hierarchy as dirty for the subsequent CATransaction.
Instead, skip calling -addSublayer: if the root layer is already a sublayer of
the hosting layer.
This should be safe as the root layer should be the only sublayer of the
hosting layer (we added a
new debug assert to check this).
Test: Tools/TestWebKitAPI/Tests/WebKit/WKWebView/SiteIsolation.mm
* Source/WebKit/UIProcess/RemoteLayerTree/RemoteLayerTreeNode.mm:
(WebKit::RemoteLayerTreeNode::addToHostingNode):
* Tools/TestWebKitAPI/Tests/WebKit/WKWebView/SiteIsolation.mm:
(TestWebKitAPI::(SiteIsolation,
CommitsFromCrossSiteIframeDoNotReparentItsLayers)):
Canonical link: https://commits.webkit.org/322302@main
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