Changeset 173080 in webkit

Timestamp:

Aug 28, 2014 2:08:26 PM (10 years ago)

Author:

psolanki@apple.com

Message:

WebContent hangs under SharedBuffer::duplicateDataBufferIfNecessary() while browsing some websites
​https://bugs.webkit.org/show_bug.cgi?id=136347
<rdar://problem/18073745>

Reviewed by Andreas Kling.

When passing data to ImageIO, we create a copy if we have to reallocate the buffer. We would
set the size of the new buffer to be the size of the SharedBuffer data. This causes memory
churn since we would create a new buffer for every data chunk we get. Fix this by at least
doubling the capacity of the buffer when we duplicate it.

• platform/SharedBuffer.cpp:

(WebCore::SharedBuffer::duplicateDataBufferIfNecessary):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/SharedBuffer.cpp (modified) (2 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2014-08-28  Pratik Solanki  <psolanki@apple.com>
+
+        WebContent hangs under SharedBuffer::duplicateDataBufferIfNecessary() while browsing some websites
+        https://bugs.webkit.org/show_bug.cgi?id=136347
+        <rdar://problem/18073745>
+
+        Reviewed by Andreas Kling.
+
+        When passing data to ImageIO, we create a copy if we have to reallocate the buffer. We would
+        set the size of the new buffer to be the size of the SharedBuffer data. This causes memory
+        churn since we would create a new buffer for every data chunk we get. Fix this by at least
+        doubling the capacity of the buffer when we duplicate it.
+
+        * platform/SharedBuffer.cpp:
+        (WebCore::SharedBuffer::duplicateDataBufferIfNecessary):
+
 2014-08-28  Dan Bernstein  <mitz@apple.com>
 

trunk/Source/WebCore/platform/SharedBuffer.cpp

@@ -28 +28 @@
 #include "SharedBuffer.h"
 
+#include <algorithm>
 #include <wtf/PassOwnPtr.h>
 #include <wtf/unicode/UTF8.h>
@@ -352 +353 @@
 void SharedBuffer::duplicateDataBufferIfNecessary() const
 {
-    if (m_buffer->hasOneRef() || m_size <= m_buffer->data.capacity())
+    size_t currentCapacity = m_buffer->data.capacity();
+    if (m_buffer->hasOneRef() || m_size <= currentCapacity)
         return;
 
+    size_t newCapacity = std::max(static_cast<size_t>(m_size), currentCapacity * 2);
     RefPtr<DataBuffer> newBuffer = adoptRef(new DataBuffer);
-    newBuffer->data.reserveInitialCapacity(m_size);
+    newBuffer->data.reserveInitialCapacity(newCapacity);
     newBuffer->data = m_buffer->data;
     m_buffer = newBuffer.release();