Messages in this thread | | | Subject | Re: [PATCH 03/33] cputime: Generic on-demand virtual cputime accounting | From | Steven Rostedt <> | Date | Tue, 08 Jan 2013 15:26:11 -0500 |
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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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