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author | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2014-07-04 14:34:23 +0200 |
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committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2014-07-09 10:05:17 +0200 |
commit | 5c3d2509593476869e791111cd3d93cc1e840b3a (patch) | |
tree | 2f642fcce66748460f0f823fbeb6f292267b8cd0 /cpukit/score/src/schedulerdefaultaskforhelp.c | |
parent | schedulerpriorityaffinitysmp.c: Add period at end of sentence (diff) | |
download | rtems-5c3d2509593476869e791111cd3d93cc1e840b3a.tar.bz2 |
score: Implement scheduler helping protocol
The following scheduler operations return a thread in need for help
- unblock,
- change priority, and
- yield.
A thread in need for help is a thread that encounters a scheduler state
change from scheduled to ready or a thread that cannot be scheduled in
an unblock operation. Such a thread can ask threads which depend on
resources owned by this thread for help.
Add a new ask for help scheduler operation. This operation is used by
_Scheduler_Ask_for_help() to help threads in need for help returned by
the operations mentioned above. This operation is also used by
_Scheduler_Thread_change_resource_root() in case the root of a resource
sub-tree changes. A use case is the ownership change of a resource.
In case it is not possible to schedule a thread in need for help, then
the corresponding scheduler node will be placed into the set of ready
scheduler nodes of the scheduler instance. Once a state change from
ready to scheduled happens for this scheduler node it may be used to
schedule the thread in need for help.
Diffstat (limited to '')
-rw-r--r-- | cpukit/score/src/schedulerdefaultaskforhelp.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/cpukit/score/src/schedulerdefaultaskforhelp.c b/cpukit/score/src/schedulerdefaultaskforhelp.c new file mode 100644 index 0000000000..b69524846b --- /dev/null +++ b/cpukit/score/src/schedulerdefaultaskforhelp.c @@ -0,0 +1,26 @@ +/* + * Copyright (c) 2014 embedded brains GmbH + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.org/license/LICENSE. + */ + +#if HAVE_CONFIG_H + #include "config.h" +#endif + +#include <rtems/score/scheduler.h> + +Thread_Control *_Scheduler_default_Ask_for_help( + const Scheduler_Control *scheduler, + Thread_Control *offers_help, + Thread_Control *needs_help +) +{ + (void) scheduler; + (void) offers_help; + (void) needs_help; + + return NULL; +} |