On Tue, 2013-01-08 at 03:08 +0100, Frederic Weisbecker wrote:
> diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
> index c952770..bd461ad 100644
> --- a/kernel/context_tracking.c
> +++ b/kernel/context_tracking.c
> @@ -56,7 +56,7 @@ void user_enter(void)
> local_irq_save(flags);
> if (__this_cpu_read(context_tracking.active) &&
> __this_cpu_read(context_tracking.state) != IN_USER) {
> - __this_cpu_write(context_tracking.state, IN_USER);
> + vtime_user_enter(current);
> /*
> * At this stage, only low level arch entry code remains and
> * then we'll run in userspace. We can assume there won't be
> @@ -65,6 +65,7 @@ void user_enter(void)
> * on the tick.
> */
> rcu_user_enter();
Hmm, the rcu_user_enter() can do quite a bit. Too bad we are accounting
it as user time. I wonder if we could move the vtime_user_enter() below
it. But then if vtime_user_enter() calls rcu_read_lock() it breaks.
The notorious chicken vs egg ordeal!
-- Steve
> + __this_cpu_write(context_tracking.state, IN_USER);
> }
> local_irq_restore(flags);
> }
> @@ -90,12 +91,13 @@ void user_exit(void)
>
> local_irq_save(flags);
> if (__this_cpu_read(context_tracking.state) == IN_USER) {
> - __this_cpu_write(context_tracking.state, IN_KERNEL);
> /*
> * We are going to run code that may use RCU. Inform
> * RCU core about that (ie: we may need the tick again).
> */
> rcu_user_exit();
> + vtime_user_exit(current);
> + __this_cpu_write(context_tracking.state, IN_KERNEL);
> }
> local_irq_restore(flags);
> }
--
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