Changeset 206916 in webkit

Timestamp:

Oct 7, 2016 9:41:48 AM (8 years ago)

Author:

Alan Bujtas

Message:

​https://vuldb.com/?cvssv3.2012 takes long time to load.
​https://bugs.webkit.org/show_bug.cgi?id=162994
<rdar://problem/28593746>

Reviewed by Darin Adler.

Source/WebCore:

Stop visiting cousins when we hit the style sharing search threshold.

In addition to mistakenly ignoring the threshold at SharingResolver::findSibling(), we
continued on searching for cousin elements.

Test: fast/selectors/slow-style-sharing-with-long-cousin-list.html

• style/StyleSharingResolver.cpp:

(WebCore::Style::SharingResolver::resolve):
(WebCore::Style::SharingResolver::findSibling):
(WebCore::Style::SharingResolver::locateCousinList):

LayoutTests:

It takes ~100 seconds to run this test case without the fix (300ms with the fix).
Surely it will timeout if it gets regressed.

• fast/selectors/slow-style-sharing-with-long-cousin-list-expected.txt: Added.
• fast/selectors/slow-style-sharing-with-long-cousin-list.html: Added.
• platform/mac/TestExpectations: Skip perf test in debug.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/selectors/slow-style-sharing-with-long-cousin-list-expected.txt (added)
• LayoutTests/fast/selectors/slow-style-sharing-with-long-cousin-list.html (added)
• LayoutTests/platform/mac/TestExpectations (modified) (1 diff)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/style/StyleSharingResolver.cpp (modified) (3 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2016-10-07  Zalan Bujtas  <zalan@apple.com>
+
+        https://vuldb.com/?cvssv3.2012 takes long time to load.
+        https://bugs.webkit.org/show_bug.cgi?id=162994
+        <rdar://problem/28593746>
+
+        Reviewed by Darin Adler.
+
+        It takes ~100 seconds to run this test case without the fix (300ms with the fix).
+        Surely it will timeout if it gets regressed. 
+
+        * fast/selectors/slow-style-sharing-with-long-cousin-list-expected.txt: Added.
+        * fast/selectors/slow-style-sharing-with-long-cousin-list.html: Added.
+        * platform/mac/TestExpectations: Skip perf test in debug.
+
 2016-10-07  Ryan Haddad  <ryanhaddad@apple.com>
 

trunk/LayoutTests/platform/mac/TestExpectations

@@ -1468 +1468 @@
 fast/text/variations/order.html [ Crash ]
 animations/font-variation-settings-order.html [ Crash ]
+
+[ Debug ] fast/selectors/slow-style-sharing-with-long-cousin-list.html [ Skip ]

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2016-10-07  Zalan Bujtas  <zalan@apple.com>
+
+        https://vuldb.com/?cvssv3.2012 takes long time to load.
+        https://bugs.webkit.org/show_bug.cgi?id=162994
+        <rdar://problem/28593746>
+
+        Reviewed by Darin Adler.
+
+        Stop visiting cousins when we hit the style sharing search threshold.
+
+        In addition to mistakenly ignoring the threshold at SharingResolver::findSibling(), we
+        continued on searching for cousin elements. 
+
+        Test: fast/selectors/slow-style-sharing-with-long-cousin-list.html
+
+        * style/StyleSharingResolver.cpp:
+        (WebCore::Style::SharingResolver::resolve):
+        (WebCore::Style::SharingResolver::findSibling):
+        (WebCore::Style::SharingResolver::locateCousinList):
+
 2016-10-07  Romain Bellessort  <romain.bellessort@crf.canon.fr>
 

trunk/Source/WebCore/style/StyleSharingResolver.cpp

@@ -116 +116 @@
         if (shareElement)
             break;
+        if (count >= cStyleSearchThreshold)
+            break;
         cousinList = locateCousinList(cousinList->parentElement());
     }
@@ -145 +147 @@
         if (canShareStyleWithElement(context, downcast<StyledElement>(*node)))
             break;
-        if (count++ == cStyleSearchThreshold)
+        if (count++ >= cStyleSearchThreshold)
             return nullptr;
     }
@@ -153 +155 @@
 Node* SharingResolver::locateCousinList(const Element* parent) const
 {
-    const unsigned maximumSearchCount = 10;
-    for (unsigned count = 0; count < maximumSearchCount; ++count) {
+    for (unsigned count = 0; count < cStyleSearchThreshold; ++count) {
         auto* elementSharingParentStyle = m_elementsSharingStyle.get(parent);
         if (!elementSharingParentStyle)