tree 6e0cc9e1e3f29b36ec3d7acfaf863cf9bb39ea5b
parent 3d2d827f5ca5e32816194119d5c980c7e04474a6
author Michael S. Tsirkin <mst@redhat.com> 1253577832 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1253629062 -0700

mm: reduce atomic use on use_mm fast path

When the mm being switched to matches the active mm, we don't need to
increment and then drop the mm count.  In a simple benchmark this happens
in about 50% of time.  Making that conditional reduces contention on that
cacheline on SMP systems.

Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>