Using per cpu atomics for the vm statistics reduces their overhead.
And in the case of x86 we are guaranteed that they will never race even
in the lax form used for vm statistics.
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NChristoph Lameter <cl@linux-foundation.org>
Signed-off-by: NTejun Heo <tj@kernel.org>