Commit-ID: 511ba86e1d386f671084b5d0e6f110bb30b8eeb2
Gitweb: http://git.kernel.org/tip/511ba86e1d386f671084b5d0e6f110bb30b8eeb2
Author: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
AuthorDate: Sat, 23 Mar 2013 09:36:36 -0400
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Wed, 10 Apr 2013 11:25:10 -0700
x86, mm: Patch out arch_flush_lazy_mmu_mode() when running on bare metal
Invoking arch_flush_lazy_mmu_mode() results in calls to
preempt_enable()/disable() which may have performance impact.
Since lazy MMU is not used on bare metal we can patch away
arch_flush_lazy_mmu_mode() so that it is never called in such
environment.
[ hpa: the previous patch "Fix vmalloc_fault oops during lazy MMU
updates" may cause a minor performance regression on
bare metal. This patch resolves that performance regression. It is
somewhat unclear to me if this is a good -stable candidate. ]