On 08/05/24 16:39, Frederic Weisbecker wrote:
> Le Tue, Apr 30, 2024 at 11:17:17AM +0200, Valentin Schneider a écrit :
>> The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
>> RCU_WATCHING, and the 'dynticks' prefix can be dropped without losing any
>> meaning.
>>
>> Suggested-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
>> Signed-off-by: Valentin Schneider <vschneid@xxxxxxxxxx>
>> ---
>> kernel/context_tracking.c | 20 ++++++++++----------
>> 1 file changed, 10 insertions(+), 10 deletions(-)
>>
>> diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
>> index 647939b0befd9..9c8f7b9191cd4 100644
>> --- a/kernel/context_tracking.c
>> +++ b/kernel/context_tracking.c
>> @@ -39,7 +39,7 @@ EXPORT_SYMBOL_GPL(context_tracking);
>> #define TPS(x) tracepoint_string(x)
>>
>> /* Record the current task on dyntick-idle entry. */
>> -static __always_inline void rcu_dynticks_task_enter(void)
>> +static __always_inline void rcu_task_enter(void)
>
> On a second thought, this should be the reverse. We are not
> telling anymore that we are entering dynticks mode from an
> RCU-task perspective. We are telling that we are exiting RCU-tasks
> because we are in eqs mode (even though this is mostly a concern
> for nohz_full here, as idle tasks are entirely quiescent states
> but anyway...).
>
> So this should be s/rcu_dynticks_task_enter/rcu_task_exit
>
That definitely makes more sense, thanks!
>> {
>> #if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL)
>> WRITE_ONCE(current->rcu_tasks_idle_cpu, smp_processor_id());
>> @@ -47,7 +47,7 @@ static __always_inline void rcu_dynticks_task_enter(void)
>> }
>>
>> /* Record no current task on dyntick-idle exit. */
>> -static __always_inline void rcu_dynticks_task_exit(void)
>> +static __always_inline void rcu_task_exit(void)
>
> And s/rcu_dynticks_task_exit/rcu_task_enter
>
>> {
>> #if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL)
>> WRITE_ONCE(current->rcu_tasks_idle_cpu, -1);
>> @@ -55,7 +55,7 @@ static __always_inline void rcu_dynticks_task_exit(void)
>> }
>>
>> /* Turn on heavyweight RCU tasks trace readers on idle/user entry. */
>> -static __always_inline void rcu_dynticks_task_trace_enter(void)
>> +static __always_inline void rcu_task_trace_enter(void)
>
> The same reverse naming goes for task_trace (even though I can't make
> sense right now of what the barrier it implies orders exactly, but that's
> another story)
Ack.
>
>> {
>> #ifdef CONFIG_TASKS_TRACE_RCU
>> if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB))
>> @@ -64,7 +64,7 @@ static __always_inline void rcu_dynticks_task_trace_enter(void)
>> }
>>
>> /* Turn off heavyweight RCU tasks trace readers on idle/user exit. */
>> -static __always_inline void rcu_dynticks_task_trace_exit(void)
>> +static __always_inline void rcu_task_trace_exit(void)
>> {
>> #ifdef CONFIG_TASKS_TRACE_RCU
>> if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB))
>> @@ -87,7 +87,7 @@ static noinstr void ct_kernel_exit_state(int offset)
>> * critical sections, and we also must force ordering with the
>> * next idle sojourn.
>> */
>> - rcu_dynticks_task_trace_enter(); // Before ->dynticks update!
>> + rcu_task_trace_enter(); // Before ->dynticks update!
>
> s/->dynticks/->state
>
>> seq = ct_state_inc(offset);
>> // RCU is no longer watching. Better be in extended quiescent state!
>> WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && (seq & CT_RCU_WATCHING));
>> @@ -109,7 +109,7 @@ static noinstr void ct_kernel_enter_state(int offset)
>> */
>> seq = ct_state_inc(offset);
>> // RCU is now watching. Better not be in an extended quiescent state!
>> - rcu_dynticks_task_trace_exit(); // After ->dynticks update!
>> + rcu_task_trace_exit(); // After ->dynticks update!
>
> ditto
I've got these fixed in 25/27, but I can fold it down into the patches that
touch the related areas.
>
> Thanks!
