22 Sep, 2009

2 commits

  • 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
    Signed-off-by: Michael S. Tsirkin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Michael S. Tsirkin
     
  • Anyone who wants to do copy to/from user from a kernel thread, needs
    use_mm (like what fs/aio has). Move that into mm/, to make reusing and
    exporting easier down the line, and make aio use it. Next intended user,
    besides aio, will be vhost-net.

    Acked-by: Andrea Arcangeli
    Signed-off-by: Michael S. Tsirkin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Michael S. Tsirkin