Should take another look at this issue from the host-side (xen tools). We should at least try reproducing with F16/rawhide guests to see what happens, and if the result is worse.
We should look at fixing blkback first, possibly with a backport of 6f5986bce558, then we can double check userspace after. Moving to kernel-xen.
This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux release for currently deployed products. This request is not yet committed for inclusion in a release.
*** This bug has been marked as a duplicate of bug 794806 ***