Can you confirm the difference between this bug and bug #729088 ?
*** Bug 729088 has been marked as a duplicate of this bug. ***
in kernel-2.6.18-238.24.1.el5 linux-2.6-fs-gfs2-no-exclusive-glocks-on-mmapped-read-only-fs.patch
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHSA-2011-1321.html
Technical note added. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. New Contents: Performance issues occurred when multiple nodes attempted to call mmap() on the same inode at the same time on a GFS2 file system, as it was using an exclusive glock. With this update, a shared lock is used when "noatime" is set on the mount, allowing mmap() operations to occur in parallel, fixing this bug. Note that this issue only refers to mmap() system calls, and not to subsequent page faults.