[PATCH 14/14] score: Avoid Giant lock for scheduler set/get
Gedare Bloom
gedare at rtems.org
Thu May 12 01:05:45 UTC 2016
patch set looks good to me.
On Wed, May 11, 2016 at 9:23 AM, Sebastian Huber
<sebastian.huber at embedded-brains.de> wrote:
> Update #2555.
> ---
> cpukit/rtems/src/taskgetscheduler.c | 52 +++++++++++-------------
> cpukit/rtems/src/tasksetscheduler.c | 50 +++++++++++++----------
> cpukit/score/include/rtems/score/schedulerimpl.h | 42 ++++++++++++++-----
> cpukit/score/include/rtems/score/threadimpl.h | 8 ++++
> cpukit/score/include/rtems/score/threadqimpl.h | 26 ++++++++++--
> 5 files changed, 113 insertions(+), 65 deletions(-)
>
> diff --git a/cpukit/rtems/src/taskgetscheduler.c b/cpukit/rtems/src/taskgetscheduler.c
> index 47895a4..9d8bbb6 100644
> --- a/cpukit/rtems/src/taskgetscheduler.c
> +++ b/cpukit/rtems/src/taskgetscheduler.c
> @@ -24,37 +24,31 @@ rtems_status_code rtems_task_get_scheduler(
> rtems_id *scheduler_id
> )
> {
> - rtems_status_code sc;
> -
> - if ( scheduler_id != NULL ) {
> - Thread_Control *the_thread;
> - Objects_Locations location;
> - const Scheduler_Control *scheduler;
> -
> - the_thread = _Thread_Get( task_id, &location );
> -
> - switch ( location ) {
> - case OBJECTS_LOCAL:
> - scheduler = _Scheduler_Get( the_thread );
> - *scheduler_id = _Scheduler_Build_id(
> - _Scheduler_Get_index( scheduler )
> - );
> - _Objects_Put( &the_thread->Object );
> - sc = RTEMS_SUCCESSFUL;
> - break;
> + Thread_Control *the_thread;
> + ISR_lock_Context lock_context;
> + const Scheduler_Control *scheduler;
> +
> + if ( scheduler_id == NULL ) {
> + return RTEMS_INVALID_ADDRESS;
> + }
> +
> + the_thread = _Thread_Get_interrupt_disable( task_id, &lock_context );
> +
> + if ( the_thread == NULL ) {
> #if defined(RTEMS_MULTIPROCESSING)
> - case OBJECTS_REMOTE:
> - _Thread_Dispatch();
> - sc = RTEMS_ILLEGAL_ON_REMOTE_OBJECT;
> - break;
> -#endif
> - default:
> - sc = RTEMS_INVALID_ID;
> - break;
> + if ( _Thread_MP_Is_remote( task_id ) ) {
> + return RTEMS_ILLEGAL_ON_REMOTE_OBJECT;
> }
> - } else {
> - sc = RTEMS_INVALID_ADDRESS;
> +#endif
> +
> + return RTEMS_INVALID_ID;
> }
>
> - return sc;
> + _Thread_State_acquire_critical( the_thread, &lock_context );
> +
> + scheduler = _Scheduler_Get( the_thread );
> + *scheduler_id = _Scheduler_Build_id( _Scheduler_Get_index( scheduler ) );
> +
> + _Thread_State_release( the_thread, &lock_context );
> + return RTEMS_SUCCESSFUL;
> }
> diff --git a/cpukit/rtems/src/tasksetscheduler.c b/cpukit/rtems/src/tasksetscheduler.c
> index e055530..428ef3d 100644
> --- a/cpukit/rtems/src/tasksetscheduler.c
> +++ b/cpukit/rtems/src/tasksetscheduler.c
> @@ -24,34 +24,40 @@ rtems_status_code rtems_task_set_scheduler(
> rtems_id scheduler_id
> )
> {
> - rtems_status_code sc;
> const Scheduler_Control *scheduler;
> + Thread_Control *the_thread;
> + ISR_lock_Context lock_context;
> + ISR_lock_Context state_lock_context;
> + Per_CPU_Control *cpu_self;
> + void *lock;
> + bool ok;
>
> - if ( _Scheduler_Get_by_id( scheduler_id, &scheduler ) ) {
> - Thread_Control *the_thread;
> - Objects_Locations location;
> + if ( !_Scheduler_Get_by_id( scheduler_id, &scheduler ) ) {
> + return RTEMS_INVALID_ID;
> + }
>
> - the_thread = _Thread_Get( task_id, &location );
> + the_thread = _Thread_Get_interrupt_disable( task_id, &lock_context );
>
> - switch ( location ) {
> - case OBJECTS_LOCAL:
> - _Scheduler_Set( scheduler, the_thread );
> - _Objects_Put( &the_thread->Object );
> - sc = RTEMS_SUCCESSFUL;
> - break;
> + if ( the_thread == NULL ) {
> #if defined(RTEMS_MULTIPROCESSING)
> - case OBJECTS_REMOTE:
> - _Thread_Dispatch();
> - sc = RTEMS_ILLEGAL_ON_REMOTE_OBJECT;
> - break;
> -#endif
> - default:
> - sc = RTEMS_INVALID_ID;
> - break;
> + if ( _Thread_MP_Is_remote( task_id ) ) {
> + return RTEMS_ILLEGAL_ON_REMOTE_OBJECT;
> }
> - } else {
> - sc = RTEMS_INVALID_ID;
> +#endif
> +
> + return RTEMS_INVALID_ID;
> }
>
> - return sc;
> + cpu_self = _Thread_Dispatch_disable_critical( &lock_context );
> + _ISR_lock_ISR_enable( &lock_context );
> +
> + lock = _Thread_Lock_acquire( the_thread, &lock_context );
> + _Thread_State_acquire_critical( the_thread, &state_lock_context );
> +
> + ok = _Scheduler_Set( scheduler, the_thread );
> +
> + _Thread_State_release_critical( the_thread, &state_lock_context );
> + _Thread_Lock_release( lock, &lock_context );
> + _Thread_Dispatch_enable( cpu_self );
> + return ok ? RTEMS_SUCCESSFUL : RTEMS_INCORRECT_STATE;
> }
> diff --git a/cpukit/score/include/rtems/score/schedulerimpl.h b/cpukit/score/include/rtems/score/schedulerimpl.h
> index c149a9e..2e5b025 100644
> --- a/cpukit/score/include/rtems/score/schedulerimpl.h
> +++ b/cpukit/score/include/rtems/score/schedulerimpl.h
> @@ -599,25 +599,45 @@ RTEMS_INLINE_ROUTINE bool _Scheduler_Has_processor_ownership(
> #endif
> }
>
> -RTEMS_INLINE_ROUTINE void _Scheduler_Set(
> +RTEMS_INLINE_ROUTINE bool _Scheduler_Set(
> const Scheduler_Control *scheduler,
> Thread_Control *the_thread
> )
> {
> #if defined(RTEMS_SMP)
> - const Scheduler_Control *current_scheduler = _Scheduler_Get( the_thread );
> -
> - if ( current_scheduler != scheduler ) {
> - _Thread_Set_state( the_thread, STATES_MIGRATING );
> - _Scheduler_Node_destroy( current_scheduler, the_thread );
> - the_thread->Scheduler.own_control = scheduler;
> - the_thread->Scheduler.control = scheduler;
> - _Scheduler_Node_initialize( scheduler, the_thread );
> - _Scheduler_Update_priority( the_thread, the_thread->current_priority );
> - _Thread_Clear_state( the_thread, STATES_MIGRATING );
> + const Scheduler_Control *current_scheduler;
> + States_Control current_state;
> +
> + current_scheduler = _Scheduler_Get( the_thread );
> +
> + if ( current_scheduler == scheduler ) {
> + return true;
> + }
> +
> + if ( _Thread_Owns_resources( the_thread ) ) {
> + return false;
> + }
> +
> + current_state = the_thread->current_state;
> +
> + if ( _States_Is_ready( current_state ) ) {
> + _Scheduler_Block( the_thread );
> }
> +
> + _Scheduler_Node_destroy( current_scheduler, the_thread );
> + the_thread->Scheduler.own_control = scheduler;
> + the_thread->Scheduler.control = scheduler;
> + _Scheduler_Node_initialize( scheduler, the_thread );
> + _Scheduler_Update_priority( the_thread, the_thread->current_priority );
> +
> + if ( _States_Is_ready( current_state ) ) {
> + _Scheduler_Unblock( the_thread );
> + }
> +
> + return true;
> #else
> (void) scheduler;
> + return true;
> #endif
> }
>
> diff --git a/cpukit/score/include/rtems/score/threadimpl.h b/cpukit/score/include/rtems/score/threadimpl.h
> index 931eec0..1ea49dd 100644
> --- a/cpukit/score/include/rtems/score/threadimpl.h
> +++ b/cpukit/score/include/rtems/score/threadimpl.h
> @@ -359,6 +359,14 @@ RTEMS_INLINE_ROUTINE Thread_Control *_Thread_State_acquire_for_executing(
> return executing;
> }
>
> +RTEMS_INLINE_ROUTINE void _Thread_State_release_critical(
> + Thread_Control *the_thread,
> + ISR_lock_Context *lock_context
> +)
> +{
> + _Thread_queue_Release_critical( &the_thread->Join_queue, lock_context );
> +}
> +
> RTEMS_INLINE_ROUTINE void _Thread_State_release(
> Thread_Control *the_thread,
> ISR_lock_Context *lock_context
> diff --git a/cpukit/score/include/rtems/score/threadqimpl.h b/cpukit/score/include/rtems/score/threadqimpl.h
> index e6cd401..ec222bd 100644
> --- a/cpukit/score/include/rtems/score/threadqimpl.h
> +++ b/cpukit/score/include/rtems/score/threadqimpl.h
> @@ -108,7 +108,7 @@ RTEMS_INLINE_ROUTINE void _Thread_queue_Queue_do_acquire_critical(
> _Thread_queue_Queue_do_acquire_critical( queue, lock_context )
> #endif
>
> -RTEMS_INLINE_ROUTINE void _Thread_queue_Queue_release(
> +RTEMS_INLINE_ROUTINE void _Thread_queue_Queue_release_critical(
> Thread_queue_Queue *queue,
> ISR_lock_Context *lock_context
> )
> @@ -118,7 +118,18 @@ RTEMS_INLINE_ROUTINE void _Thread_queue_Queue_release(
> &queue->Lock,
> &lock_context->Lock_context.Stats_context
> );
> +#else
> + (void) queue;
> + (void) lock_context;
> #endif
> +}
> +
> +RTEMS_INLINE_ROUTINE void _Thread_queue_Queue_release(
> + Thread_queue_Queue *queue,
> + ISR_lock_Context *lock_context
> +)
> +{
> + _Thread_queue_Queue_release_critical( queue, lock_context );
> _ISR_lock_ISR_enable( lock_context );
> }
>
> @@ -159,7 +170,7 @@ RTEMS_INLINE_ROUTINE bool _Thread_queue_Is_lock_owner(
> }
> #endif
>
> -RTEMS_INLINE_ROUTINE void _Thread_queue_Release(
> +RTEMS_INLINE_ROUTINE void _Thread_queue_Release_critical(
> Thread_queue_Control *the_thread_queue,
> ISR_lock_Context *lock_context
> )
> @@ -170,12 +181,21 @@ RTEMS_INLINE_ROUTINE void _Thread_queue_Release(
> the_thread_queue->owner = SMP_LOCK_NO_OWNER;
> #endif
> #endif
> - _Thread_queue_Queue_release(
> + _Thread_queue_Queue_release_critical(
> &the_thread_queue->Queue,
> lock_context
> );
> }
>
> +RTEMS_INLINE_ROUTINE void _Thread_queue_Release(
> + Thread_queue_Control *the_thread_queue,
> + ISR_lock_Context *lock_context
> +)
> +{
> + _Thread_queue_Release_critical( the_thread_queue, lock_context );
> + _ISR_lock_ISR_enable( lock_context );
> +}
> +
> Thread_Control *_Thread_queue_Do_dequeue(
> Thread_queue_Control *the_thread_queue,
> const Thread_queue_Operations *operations
> --
> 1.8.4.5
>
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