[RFC PATCH V2 4/4] arm64: mm: implement get_user_pages_fast

On Fri, Feb 7, 2014 at 12:18 AM, Steve Capper [off-list ref] wrote:

An implementation of get_user_pages_fast for arm64. It is based on the
arm implementation (it has the added ability to walk huge puds) which
is loosely on the PowerPC implementation. We disable interrupts in the
walker to prevent the call_rcu_sched pagetable freeing code from
running under us.

We also explicitly fire an IPI in the Transparent HugePage splitting
case to prevent splits from interfering with the fast_gup walker.
As THP splits are relatively rare, this should not have a noticable
overhead.

Signed-off-by: Steve Capper <redacted>

Tested-by: Ming Lei <redacted>

Thanks,
--
Ming Lei