[IA64] Prefetch mmap_sem in ia64_do_page_fault()
[IA64] Prefetch mmap_sem in ia64_do_page_fault()

Take a hint from an x86_64 optimization by Arjan van de Ven and use it
for ia64.  See a9ba9a3b3897561d01e04cd21433746df46548c0

Prefetch the mmap_sem, which is critical for the performance of the page fault
handler.

Note: mm may be NULL but I guess that is safe.
See 458f935527372499b714bf4f8e646a68bb0f52e3

Signed-off-by: Christoph Lameter <a2610c5c148280bb6730402b12a8276c2f194fbe@sgi.com>
Signed-off-by: Tony Luck <e7984595ec0368ff920a7b3521dc7093683f6f26@intel.com>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas