[rtems commit] score: Rework _Thread_Restart_other()
Sebastian Huber
sebh at rtems.org
Fri May 20 05:58:42 UTC 2016
Module: rtems
Branch: master
Commit: 862a0eeb1197539c0e69381cb5aaccb9e1c64c0f
Changeset: http://git.rtems.org/rtems/commit/?id=862a0eeb1197539c0e69381cb5aaccb9e1c64c0f
Author: Sebastian Huber <sebastian.huber at embedded-brains.de>
Date: Fri May 13 11:22:39 2016 +0200
score: Rework _Thread_Restart_other()
Rework _Thread_Restart_other() to use _Thread_Change_life_locked().
Cope with concurrent change requests by means of a pending request
counter.
Update #2555.
Update #2626.
---
cpukit/libmisc/monitor/mon-prmisc.c | 2 +-
cpukit/score/include/rtems/score/statesimpl.h | 4 +-
cpukit/score/include/rtems/score/thread.h | 5 ++
cpukit/score/src/threadrestart.c | 88 ++++++++++++++++++++++++---
4 files changed, 87 insertions(+), 12 deletions(-)
diff --git a/cpukit/libmisc/monitor/mon-prmisc.c b/cpukit/libmisc/monitor/mon-prmisc.c
index 4c7ee9d..a49b084 100644
--- a/cpukit/libmisc/monitor/mon-prmisc.c
+++ b/cpukit/libmisc/monitor/mon-prmisc.c
@@ -116,7 +116,7 @@ rtems_monitor_dump_priority(rtems_task_priority priority)
static const rtems_assoc_t rtems_monitor_state_assoc[] = {
{ "DELAY", STATES_DELAYING, 0 },
{ "DORM", STATES_DORMANT, 0 },
- { "RESTA", STATES_RESTARTING, 0 },
+ { "LIFE", STATES_LIFE_IS_CHANGING, 0 },
{ "SUSP", STATES_SUSPENDED, 0 },
{ "Wbar", STATES_WAITING_FOR_BARRIER, 0 },
{ "Wbuf", STATES_WAITING_FOR_BUFFER, 0 },
diff --git a/cpukit/score/include/rtems/score/statesimpl.h b/cpukit/score/include/rtems/score/statesimpl.h
index 8aebba0..a560329 100644
--- a/cpukit/score/include/rtems/score/statesimpl.h
+++ b/cpukit/score/include/rtems/score/statesimpl.h
@@ -78,8 +78,8 @@ extern "C" {
#define STATES_WAITING_FOR_BSD_WAKEUP 0x80000
/** This macro corresponds to a task being a zombie. */
#define STATES_ZOMBIE 0x200000
-/** This macro corresponds to a task restarting. */
-#define STATES_RESTARTING 0x800000
+/** This macro corresponds to a task those life is changing. */
+#define STATES_LIFE_IS_CHANGING 0x800000
/** This macro corresponds to a task waiting for a join. */
#define STATES_WAITING_FOR_JOIN 0x1000000
/** This macro corresponds to a task waiting for a <sys/lock.h> mutex. */
diff --git a/cpukit/score/include/rtems/score/thread.h b/cpukit/score/include/rtems/score/thread.h
index 9b35b85..6d41d4d 100644
--- a/cpukit/score/include/rtems/score/thread.h
+++ b/cpukit/score/include/rtems/score/thread.h
@@ -543,6 +543,11 @@ typedef struct {
* @brief The current thread life state.
*/
Thread_Life_state state;
+
+ /**
+ * @brief The count of pending life change requests.
+ */
+ uint32_t pending_life_change_requests;
} Thread_Life_control;
#if defined(RTEMS_SMP)
diff --git a/cpukit/score/src/threadrestart.c b/cpukit/score/src/threadrestart.c
index 8adbfa2..4abfd55 100644
--- a/cpukit/score/src/threadrestart.c
+++ b/cpukit/score/src/threadrestart.c
@@ -368,7 +368,7 @@ static void _Thread_Start_life_change(
the_thread->budget_algorithm = the_thread->Start.budget_algorithm;
the_thread->budget_callout = the_thread->Start.budget_callout;
- _Thread_Set_state( the_thread, STATES_RESTARTING );
+ _Thread_Set_state( the_thread, STATES_LIFE_IS_CHANGING );
_Thread_queue_Extract_with_proxy( the_thread );
_Thread_Timer_remove( the_thread );
_Thread_Raise_real_priority( the_thread, priority );
@@ -407,6 +407,64 @@ static void _Thread_Request_life_change(
}
}
+static void _Thread_Add_life_change_request( Thread_Control *the_thread )
+{
+ uint32_t pending_requests;
+
+ _Assert( _Thread_State_is_owner( the_thread ) );
+
+ pending_requests = the_thread->Life.pending_life_change_requests;
+ the_thread->Life.pending_life_change_requests = pending_requests + 1;
+
+ if ( pending_requests == 0 ) {
+ _Thread_Set_state_locked( the_thread, STATES_LIFE_IS_CHANGING );
+ }
+}
+
+static void _Thread_Remove_life_change_request( Thread_Control *the_thread )
+{
+ ISR_lock_Context lock_context;
+ uint32_t pending_requests;
+
+ _Thread_State_acquire( the_thread, &lock_context );
+
+ pending_requests = the_thread->Life.pending_life_change_requests;
+ the_thread->Life.pending_life_change_requests = pending_requests - 1;
+
+ if ( pending_requests == 1 ) {
+ /*
+ * Do not remove states used for thread queues to avoid race conditions on
+ * SMP configurations. We could interrupt an extract operation on another
+ * processor disregarding the thread wait flags. Rely on
+ * _Thread_queue_Extract_with_proxy() for removal of these states.
+ */
+ _Thread_Clear_state_locked(
+ the_thread,
+ STATES_LIFE_IS_CHANGING | STATES_SUSPENDED
+ | ( STATES_BLOCKED & ~STATES_LOCALLY_BLOCKED )
+ );
+ }
+
+ _Thread_State_release( the_thread, &lock_context );
+}
+
+static void _Thread_Finalize_life_change(
+ Thread_Control *the_thread,
+ Priority_Control priority
+)
+{
+ _Thread_queue_Extract_with_proxy( the_thread );
+ _Thread_Timer_remove( the_thread );
+ _Thread_Change_priority(
+ the_thread,
+ priority,
+ NULL,
+ _Thread_Raise_real_priority_filter,
+ false
+ );
+ _Thread_Remove_life_change_request( the_thread );
+}
+
void _Thread_Join(
Thread_Control *the_thread,
States_Control waiting_for_join,
@@ -486,7 +544,8 @@ bool _Thread_Restart_other(
ISR_lock_Context *lock_context
)
{
- Per_CPU_Control *cpu_self;
+ Thread_Life_state previous;
+ Per_CPU_Control *cpu_self;
_Thread_State_acquire_critical( the_thread, lock_context );
@@ -496,16 +555,27 @@ bool _Thread_Restart_other(
}
the_thread->Start.Entry = *entry;
+ previous = _Thread_Change_life_locked(
+ the_thread,
+ 0,
+ THREAD_LIFE_RESTARTING,
+ 0
+ );
cpu_self = _Thread_Dispatch_disable_critical( lock_context );
- _Thread_State_release( the_thread, lock_context );
- _Thread_Request_life_change(
- the_thread,
- NULL,
- the_thread->Start.initial_priority,
- THREAD_LIFE_RESTARTING
- );
+ if ( _Thread_Is_life_change_allowed( previous ) ) {
+ _Thread_Add_life_change_request( the_thread );
+ _Thread_State_release( the_thread, lock_context );
+
+ _Thread_Finalize_life_change(
+ the_thread,
+ the_thread->Start.initial_priority
+ );
+ } else {
+ _Thread_Clear_state_locked( the_thread, STATES_SUSPENDED );
+ _Thread_State_release( the_thread, lock_context );
+ }
_Thread_Dispatch_enable( cpu_self );
return true;
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