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/*
* Region Manager
*
*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/system.h>
#include <rtems/rtems/status.h>
#include <rtems/rtems/support.h>
#include <rtems/score/object.h>
#include <rtems/rtems/options.h>
#include <rtems/rtems/region.h>
#include <rtems/score/states.h>
#include <rtems/score/thread.h>
#include <rtems/score/apimutex.h>
/*
* _Region_Process_queue
*
* If enough memory is available to satisfy the rtems_region_get_segment of
* the first blocked task, then that task and as many subsequent tasks as
* possible will be unblocked with their requests satisfied.
*
* Input parameters:
* the_region - the region
*
* Output parameters:
* none
*/
void _Region_Process_queue(
Region_Control *the_region
)
{
Thread_Control *the_thread;
void *the_segment;
/*
* Switch from using the memory allocation mutex to using a
* dispatching disabled critical section. We have to do this
* because this thread may unblock one or more threads that were
* waiting on memory.
*
* NOTE: Be sure to disable dispatching before unlocking the mutex
* since we do not want to open a window where a context
* switch could occur.
*/
_Thread_Disable_dispatch();
_RTEMS_Unlock_allocator();
/*
* NOTE: The following loop is O(n) where n is the number of
* threads whose memory request is satisfied.
*/
for ( ; ; ) {
the_thread = _Thread_queue_First( &the_region->Wait_queue );
if ( the_thread == NULL )
break;
the_segment = (void **) _Region_Allocate_segment(
the_region,
the_thread->Wait.count
);
if ( the_segment == NULL )
break;
*(void **)the_thread->Wait.return_argument = the_segment;
the_region->number_of_used_blocks += 1;
_Thread_queue_Extract( &the_region->Wait_queue, the_thread );
the_thread->Wait.return_code = RTEMS_SUCCESSFUL;
}
_Thread_Enable_dispatch();
}
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