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Diffstat (limited to 'cpukit/score/src/threadchangepriority.c')
-rw-r--r-- | cpukit/score/src/threadchangepriority.c | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/cpukit/score/src/threadchangepriority.c b/cpukit/score/src/threadchangepriority.c new file mode 100644 index 0000000000..9a0e6936a2 --- /dev/null +++ b/cpukit/score/src/threadchangepriority.c @@ -0,0 +1,109 @@ +/* + * Thread Handler + * + * + * COPYRIGHT (c) 1989-1998. + * On-Line Applications Research Corporation (OAR). + * Copyright assigned to U.S. Government, 1994. + * + * The license and distribution terms for this file may be + * found in found in the file LICENSE in this distribution or at + * http://www.OARcorp.com/rtems/license.html. + * + * $Id$ + */ + +#include <rtems/system.h> +#include <rtems/score/apiext.h> +#include <rtems/score/context.h> +#include <rtems/score/interr.h> +#include <rtems/score/isr.h> +#include <rtems/score/object.h> +#include <rtems/score/priority.h> +#include <rtems/score/states.h> +#include <rtems/score/sysstate.h> +#include <rtems/score/thread.h> +#include <rtems/score/threadq.h> +#include <rtems/score/userext.h> +#include <rtems/score/wkspace.h> + +/*PAGE + * + * _Thread_Change_priority + * + * This kernel routine changes the priority of the thread. The + * thread chain is adjusted if necessary. + * + * Input parameters: + * the_thread - pointer to thread control block + * new_priority - ultimate priority + * prepend_it - TRUE if the thread should be prepended to the chain + * + * Output parameters: NONE + * + * INTERRUPT LATENCY: + * ready chain + * select heir + */ + +void _Thread_Change_priority( + Thread_Control *the_thread, + Priority_Control new_priority, + boolean prepend_it +) +{ + ISR_Level level; + /* boolean do_prepend = FALSE; */ + + /* + * If this is a case where prepending the task to its priority is + * potentially desired, then we need to consider whether to do it. + * This usually occurs when a task lowers its priority implcitly as + * the result of losing inherited priority. Normal explicit priority + * change calls (e.g. rtems_task_set_priority) should always do an + * append not a prepend. + */ + + /* + * Techically, the prepend should conditional on the thread lowering + * its priority but that does allow cxd2004 of the acvc 2.0.1 to + * pass with rtems 4.0.0. This should change when gnat redoes its + * priority scheme. + */ +/* + if ( prepend_it && + _Thread_Is_executing( the_thread ) && + new_priority >= the_thread->current_priority ) + prepend_it = TRUE; +*/ + + _Thread_Set_transient( the_thread ); + + if ( the_thread->current_priority != new_priority ) + _Thread_Set_priority( the_thread, new_priority ); + + _ISR_Disable( level ); + + the_thread->current_state = + _States_Clear( STATES_TRANSIENT, the_thread->current_state ); + + if ( ! _States_Is_ready( the_thread->current_state ) ) { + _ISR_Enable( level ); + return; + } + + _Priority_Add_to_bit_map( &the_thread->Priority_map ); + if ( prepend_it ) + _Chain_Prepend_unprotected( the_thread->ready, &the_thread->Object.Node ); + else + _Chain_Append_unprotected( the_thread->ready, &the_thread->Object.Node ); + + _ISR_Flash( level ); + + _Thread_Calculate_heir(); + + if ( !_Thread_Is_executing_also_the_heir() && + _Thread_Executing->is_preemptible ) + _Context_Switch_necessary = TRUE; + _ISR_Enable( level ); +} |