We have a lot of SharedBuffers that are smaller than one segment (4096 bytes), and there's quite a lot of spill in the internal Vectors.
Created attachment 174868 [details] Patch
Comment on attachment 174868 [details] Patch Clearing flags on attachment: 174868 Committed r135098: <http://trac.webkit.org/changeset/135098>
All reviewed patches have been landed. Closing bug.