On Tue, Feb 10, 2015 at 03:27:52PM -0500, [email protected] wrote:
> From: Rik van Riel <[email protected]>
> 
> Only run vtime_user_enter, vtime_user_exit, and the user enter & exit
> trace points when we are entering or exiting user state, respectively.
> 
> The KVM code in guest_enter and guest_exit already take care of calling
> vtime_guest_enter and vtime_guest_exit, respectively.
> 
> The RCU code only distinguishes between "idle" and "not idle or kernel".
> There should be no need to add an additional (unused) state there.
> 
> Signed-off-by: Rik van Riel <[email protected]>

Reviewed-by: Paul E. McKenney <[email protected]>

> ---
>  kernel/context_tracking.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
> index 38e38aeac8b9..0e4e318d5ea4 100644
> --- a/kernel/context_tracking.c
> +++ b/kernel/context_tracking.c
> @@ -77,7 +77,6 @@ void context_tracking_enter(enum ctx_state state)
>       local_irq_save(flags);
>       if ( __this_cpu_read(context_tracking.state) != state) {
>               if (__this_cpu_read(context_tracking.active)) {
> -                     trace_user_enter(0);
>                       /*
>                        * At this stage, only low level arch entry code 
> remains and
>                        * then we'll run in userspace. We can assume there 
> won't be
> @@ -85,7 +84,10 @@ void context_tracking_enter(enum ctx_state state)
>                        * user_exit() or rcu_irq_enter(). Let's remove RCU's 
> dependency
>                        * on the tick.
>                        */
> -                     vtime_user_enter(current);
> +                     if (state == IN_USER) {
> +                             trace_user_enter(0);
> +                             vtime_user_enter(current);
> +                     }
>                       rcu_user_enter();
>               }
>               /*
> @@ -143,8 +145,10 @@ void context_tracking_exit(enum ctx_state state)
>                        * RCU core about that (ie: we may need the tick again).
>                        */
>                       rcu_user_exit();
> -                     vtime_user_exit(current);
> -                     trace_user_exit(0);
> +                     if (state == IN_USER) {
> +                             vtime_user_exit(current);
> +                             trace_user_exit(0);
> +                     }
>               }
>               __this_cpu_write(context_tracking.state, IN_KERNEL);
>       }
> -- 
> 1.9.3
> 

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