On 09/25/2014 09:25 AM, Martin Kelly wrote:
> On Mon, Sep 15, 2014 at 9:20 PM, Martin Kelly <mar...@martingkelly.com> wrote:
>> checkpatch emits several warnings for context_tracking.c, which are
>> fixed in this patch:
>>
>> - No space after "("
>> - Lines longer than 80 characters
>>
>> Signed-off-by: Martin Kelly <martk...@amazon.com>
>> ---
>> kernel/context_tracking.c | 40 +++++++++++++++++++++-------------------
>> 1 file changed, 21 insertions(+), 19 deletions(-)
>>
>> diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
>> index 5664985..bf29065 100644
>> --- a/kernel/context_tracking.c
>> +++ b/kernel/context_tracking.c
>> @@ -54,8 +54,8 @@ void context_tracking_user_enter(void)
>> /*
>> * Repeat the user_enter() check here because some archs may be
>> calling
>> * this from asm and if no CPU needs context tracking, they shouldn't
>> - * go further. Repeat the check here until they support the inline
>> static
>> - * key check.
>> + * go further. Repeat the check here until they support the inline
>> + * static key check.
>> */
>> if (!context_tracking_is_enabled())
>> return;
>> @@ -75,31 +75,33 @@ void context_tracking_user_enter(void)
>> WARN_ON_ONCE(!current->mm);
>>
>> local_irq_save(flags);
>> - if ( __this_cpu_read(context_tracking.state) != IN_USER) {
>> + if (__this_cpu_read(context_tracking.state) != IN_USER) {
>> 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
>> - * any RCU read-side critical section until the next
>> call to
>> - * user_exit() or rcu_irq_enter(). Let's remove
>> RCU's dependency
>> - * on the tick.
>> + * At this stage, only low level arch entry code
>> + * remains and then we'll run in userspace. We can
>> + * assume there won't be any RCU read-side critical
>> + * section until the next call to user_exit() or
>> + * rcu_irq_enter(). Let's remove RCU's dependency on
>> + * the tick.
>> */
>> vtime_user_enter(current);
>> rcu_user_enter();
>> }
>> /*
>> - * Even if context tracking is disabled on this CPU, because
>> it's outside
>> - * the full dynticks mask for example, we still have to keep
>> track of the
>> - * context transitions and states to prevent inconsistency
>> on those of
>> - * other CPUs.
>> - * If a task triggers an exception in userspace, sleep on
>> the exception
>> - * handler and then migrate to another CPU, that new CPU
>> must know where
>> - * the exception returns by the time we call
>> exception_exit().
>> - * This information can only be provided by the previous CPU
>> when it called
>> - * exception_enter().
>> - * OTOH we can spare the calls to vtime and RCU when
>> context_tracking.active
>> - * is false because we know that CPU is not tickless.
>> + * Even if context tracking is disabled on this CPU, because
>> + * it's outside the full dynticks mask for example, we still
>> + * have to keep track of the context transitions and states
>> to
>> + * prevent inconsistency on those of other CPUs. If a task
>> + * triggers an exception in userspace, sleep on the exception
>> + * handler and then migrate to another CPU, that new CPU must
>> + * know where the exception returns by the time we call
>> + * exception_exit(). This information can only be provided
>> by
>> + * the previous CPU when it called exception_enter(). OTOH
>> we
>> + * can spare the calls to vtime and RCU when
>> + * context_tracking.active is false because we know that CPU
>> is
>> + * not tickless.
>> */
>> __this_cpu_write(context_tracking.state, IN_USER);
>> }
>> --
>> 2.1.0
>>
>
> (ping)
>
(re-ping)
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