[PATCH 04/17] score: Add thread actions

[Sebastian Huber]

On 2014-03-25 16:36, Gedare Bloom wrote:
> On Tue, Mar 25, 2014 at 8:49 AM, Sebastian Huber
> <sebastian.huber at embedded-brains.de> wrote:
>> Thread actions are the building block for efficient implementation of
>>    - Classic signals delivery,
>>    - POSIX signals delivery,
>>    - thread restart notification,
>>    - thread delete notification,
>>    - forced thread migration on SMP configurations, and
>>    - the Multiprocessor Resource Sharing Protocol (MrsP).
>> ---
>>   cpukit/score/include/rtems/score/thread.h     |   59 ++++++++++++++++++++++
>>   cpukit/score/include/rtems/score/threadimpl.h |   67 +++++++++++++++++++++++++
>>   cpukit/score/src/threaddispatch.c             |   33 ++++++++++++
>>   cpukit/score/src/threadinitialize.c           |    2 +
>>   4 files changed, 161 insertions(+), 0 deletions(-)
>>
>> diff --git a/cpukit/score/include/rtems/score/thread.h b/cpukit/score/include/rtems/score/thread.h
>> index 7147110..153537a 100644
>> --- a/cpukit/score/include/rtems/score/thread.h
>> +++ b/cpukit/score/include/rtems/score/thread.h
>> @@ -356,6 +356,62 @@ typedef enum {
>>   /** This macro defines the last API which has threads. */
>>   #define THREAD_API_LAST  THREAD_API_POSIX
>>
>> +typedef struct Thread_Action Thread_Action;
>> +
>> +/**
>> + * @brief Thread action handler.
>> + *
>> + * The thread action handler will be called with interrupts disabled and the
>> + * thread action lock acquired.  The handler must release the thread action
>> + * lock with _Thread_Action_release_and_ISR_enable().  So the thread action
>> + * lock can be used to protect private data fields of the particular action.
>> + *
> Why doesn't the caller of the handler release the lock and enable ISRs
> after the handler returns?

The handler may do complex things.  The thread terminate and restart extensions 
are called by such a handler.  They can do all sorts of stuff including 
blocking on a semaphore, IO operations, etc.

[...]
>> +RTEMS_INLINE_ROUTINE Per_CPU_Control *
>> +  _Thread_Action_ISR_disable_and_acquire_for_executing( ISR_Level *level )
>> +{
>> +  Per_CPU_Control *cpu;
>> +
>> +  _ISR_Disable_without_giant( *level );
>> +  cpu = _Per_CPU_Get();
>> +  _Per_CPU_Acquire( cpu );
>> +
>> +  return cpu;
>> +}
> Is this "for_executing" variant required for some SMP uses? On non-smp
> it is the same the next function. I do not see the function is used in
> this patch.

Its used in patch 14 (this is the main patch).

[...]

-- 
Sebastian Huber, embedded brains GmbH

Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone   : +49 89 189 47 41-16
Fax     : +49 89 189 47 41-09
E-Mail  : sebastian.huber at embedded-brains.de
PGP     : Public key available on request.

Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.