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SubjectRe: Why can't I set the priority of softirq-hrt? (Re: 2.6.17-rt1)
From


On Fri, 23 Jun 2006, Esben Nielsen wrote:

> On Thu, 22 Jun 2006, Thomas Gleixner wrote:
>
>> On Thu, 2006-06-22 at 19:06 +0100, Esben Nielsen wrote:
>> > >
>> > > Thats a seperate issue. Though you are right.
>> >
>> > Why not use my original patch and solve both issues?
>> > I have even updated it to avoid the double traversal. It also removes
>> > one other traversal which shouldn't be needed. (I have not had time
>> > to boot the kernel with it, though, but it does compile...:-)
>>
>
> Let me comment on your last sentence first:
>
>> We want an immidate propagation.
> There is no such thing as "immidiate". The most you can say is that when you
> return from setscheduler() everything is taken care off. I agree - it has to
> be like that. But I just want to add _effectively_ taken care off. I.e. when
> the within the time setscheduler() has returned _and_ the the relevant
> priorities have time to run things get fixed. No, the users should not have
> to worry about the priorities hanging around, but the system can wait with
> fixing them it is relavant.
>
>> Simply because it does not solve following scenario:
>>
>> High prio task is blocked on lock and boosts 3 other tasks. Now the
>> higher prrio watchdog detects that the high prio task is stuck and
>> lowers the priority. You can wake it up as long as you want, the boosted
>> task is still busy looping.
>
> Yes, you are right. I have thought about how to fix it, but it will be rather
> ugly. I'll try to see what I can do though, but I am afraid the patch might
> get too big. :-(
>
> (
> The same problem may actually always have been present in another corner
> situation:
> A boosts B whichs is blocked interruptible on a lock a boosts C, which
> again boosts D (etc.). A and B are signalled roughly at the same time. A
> wakes up first a decrease the priority of B but not C, because the B runs on
> another CPU, but with lower priority and fixes C. A then stops because C is
> fixed. but D still have the A's priority and preempts B, which should fix it,
> but has it's low priority back.
> This situation is not bad because A has already been in the and therefore
> the designer has to think that C D etc already got it's priority. That A is
> later on interrupted shouldn't matter.
> )
>


I did get around to make something. Besides solving the problems already
discussed it solves and obvious problem not yet discussed:

Let us say you have a RT and a non-RT task sharing a mutex on a UP
machine.
1. The non-RT takes the mutex.
2. The RT tries to lock on the mutex with a 10 ms timeout.
3. The non-RT task is boostet to the RT's prio.
4. The non-RT task runs for 20 ms.
5. The non-RT task unlocks the mutex and is deboosted.
6. Now the RT task wakes up - after 20 ms.

The problem is clear: The RT task never gets the CPU even when it is timed
out because the non-RT has the same prio and is already running. The
timeout signal sends the RT task into the scheduler after the boosted
non-RT task because everything is scheduled in FIFO order.

Notice: I have not yet tested this because I haven't got around to get a
glibc with support for PI futexes. Where do I download that by the way?

So what do my patch do:

1) A new priority attribute, boosting_prio, is added to the task struct.
This priority is the maximum priority the task is boosting another to.
Neither the PI code itself, nor setscheduler() will ever lower the
priority below this point. boosting_prio is initialized MAX_PRIO and then
raised (numerically lowered :-), never lowered, every time the task is
boosting another until the task is leaving the lock() operation due to a
signal or timeout or because it is woken up.

2) The scheduler is modified such that tasks with boosting_prio!=MAX_PRIO
is scheduled in LIFO order rather than FIFO. In other words: Tasks which
are inside a rtmutex/lock locking operation will get their priority raised
by a half and preempt other tasks having the same prioriy.

The net effect of all this is that the priority debooting, which is
needed when a task times out, is signalled or setscheduler() is called,
while the task is in a lock operation, runs in the task context itself,
and the task is ensured to be able to preempt any of the tasks it has boosted.
If the task gets the lock it will loose it will not be woken up in LIFO
order, because it will stop boosting anything before being woken up.
An odd effect is that after setscheduler() is used to lower a task's
priority, it stays at a seemingly high priority while it is still blocked,
but the task actually running in the critical section has the correct low
priority. This is because boosting_prio is always set back to MAX_RT when
the task leaves the lock operation.

Missing:
task->boosting_prio is protected by task->pi_lock. However, the scheduler
reads task->boosting_prio without having that lock. I do not know enough
of memory barriers to be able to insert them correctly. And it might be
that the implicicit memory barriers from the pi_lock and the runqueue lock
might be enoguh for all actual ways through the code.

I used Thomas's patch for the rt-tester, slightly modified. This is
supposed to be applied first, as you really ought to apply the test before
fixing the problem, to at least see that your test catches the problem.
I have attached my slightly modified version, but Thomas's version might
be ok, but the main patch might not applie cleanly to the rttester
scripts.

Will try to inline the main patch here so we can discuss it. I hope the
white spaces are ok.

Esben


Index: linux-2.6.17-rt4/kernel/rtmutex.c
===================================================================
--- linux-2.6.17-rt4.orig/kernel/rtmutex.c
+++ linux-2.6.17-rt4/kernel/rtmutex.c
@@ -121,7 +121,7 @@ static inline void init_lists(struct rt_
* Return task->normal_prio when the waiter list is empty or when
* the waiter is not allowed to do priority boosting
*/
-int rt_mutex_getprio(struct task_struct *task)
+static int rt_mutex_getprio_real(struct task_struct *task)
{
if (likely(!task_has_pi_waiters(task)))
return task->normal_prio;
@@ -130,6 +130,11 @@ int rt_mutex_getprio(struct task_struct
task->normal_prio);
}

+int rt_mutex_getprio(struct task_struct *task)
+{
+ return min(rt_mutex_getprio_real(task), task->boosting_prio);
+}
+
/*
* Adjust the priority of a task, after its pi_waiters got modified.
*
@@ -152,11 +157,12 @@ static void __rt_mutex_adjust_prio(struc
* of task. We do not use the spin_xx_mutex() variants here as we are
* outside of the debug path.)
*/
-static void rt_mutex_adjust_prio(struct task_struct *task)
+static void rt_mutex_adjust_prio_final(struct task_struct *task)
{
unsigned long flags;

spin_lock_irqsave(&task->pi_lock, flags);
+ task->boosting_prio = MAX_PRIO;
__rt_mutex_adjust_prio(task);
spin_unlock_irqrestore(&task->pi_lock, flags);
}
@@ -232,7 +238,8 @@ static int rt_mutex_adjust_prio_chain(ta
* When deadlock detection is off then we check, if further
* priority adjustment is necessary.
*/
- if (!detect_deadlock && waiter->list_entry.prio == task->prio)
+ if (!detect_deadlock &&
+ waiter->list_entry.prio == rt_mutex_getprio_real(task))
goto out_unlock_pi;

lock = waiter->lock;
@@ -254,7 +261,9 @@ static int rt_mutex_adjust_prio_chain(ta

/* Requeue the waiter */
plist_del(&waiter->list_entry, &lock->wait_list);
- waiter->list_entry.prio = task->prio;
+ waiter->list_entry.prio = rt_mutex_getprio_real(task);
+ task->boosting_prio = min(task->boosting_prio,
+ waiter->list_entry.prio);
plist_add(&waiter->list_entry, &lock->wait_list);

/* Release the task */
@@ -300,6 +309,18 @@ static int rt_mutex_adjust_prio_chain(ta
}

/*
+ * Calls the rt_mutex_adjust_prio_chain() above
+ * whith unlocking and locking lock->wait_lock.
+ */
+static void rt_mutex_adjust_prio_chain_unlock(struct rt_mutex *lock)
+{
+ spin_unlock(&lock->wait_lock);
+ get_task_struct(current);
+ rt_mutex_adjust_prio_chain(current, 0, NULL, NULL __IP__);
+ spin_lock(&lock->wait_lock);
+}
+
+/*
* Optimization: check if we can steal the lock from the
* assigned pending owner [which might not have taken the
* lock yet]:
@@ -309,6 +330,7 @@ static inline int try_to_steal_lock(stru
struct task_struct *pendowner = rt_mutex_owner(lock);
struct rt_mutex_waiter *next;
unsigned long flags;
+ int current_prio;

if (!rt_mutex_owner_pending(lock))
return 0;
@@ -316,8 +338,12 @@ static inline int try_to_steal_lock(stru
if (pendowner == current)
return 1;

+ spin_lock_irqsave(&current->pi_lock, flags);
+ current_prio = rt_mutex_getprio_real(current);
+ spin_unlock_irqrestore(&current->pi_lock, flags);
+
spin_lock_irqsave(&pendowner->pi_lock, flags);
- if (current->prio >= pendowner->prio) {
+ if (current_prio >= rt_mutex_getprio_real(pendowner)) {
spin_unlock_irqrestore(&pendowner->pi_lock, flags);
return 0;
}
@@ -335,6 +361,7 @@ static inline int try_to_steal_lock(stru
/* No chain handling, pending owner is not blocked on anything: */
next = rt_mutex_top_waiter(lock);
plist_del(&next->pi_list_entry, &pendowner->pi_waiters);
+ pendowner->boosting_prio = MAX_PRIO;
__rt_mutex_adjust_prio(pendowner);
spin_unlock_irqrestore(&pendowner->pi_lock, flags);

@@ -426,8 +453,8 @@ static int task_blocks_on_rt_mutex(struc
__rt_mutex_adjust_prio(current);
waiter->task = current;
waiter->lock = lock;
- plist_node_init(&waiter->list_entry, current->prio);
- plist_node_init(&waiter->pi_list_entry, current->prio);
+ plist_node_init(&waiter->list_entry, rt_mutex_getprio_real(current));
+ plist_node_init(&waiter->pi_list_entry, waiter->list_entry.prio);

/* Get the top priority waiter on the lock */
if (rt_mutex_has_waiters(lock))
@@ -435,7 +462,8 @@ static int task_blocks_on_rt_mutex(struc
plist_add(&waiter->list_entry, &lock->wait_list);

current->pi_blocked_on = waiter;
-
+ current->boosting_prio = min(current->boosting_prio,
+ waiter->list_entry.prio);
spin_unlock_irqrestore(&current->pi_lock, flags);

if (waiter == rt_mutex_top_waiter(lock)) {
@@ -499,7 +527,6 @@ static void wakeup_next_waiter(struct rt
plist_del(&waiter->pi_list_entry, &current->pi_waiters);
pendowner = waiter->task;
waiter->task = NULL;
-
rt_mutex_set_owner(lock, pendowner, RT_MUTEX_OWNER_PENDING);

spin_unlock_irqrestore(&current->pi_lock, flags);
@@ -518,6 +545,7 @@ static void wakeup_next_waiter(struct rt
WARN_ON(pendowner->pi_blocked_on->lock != lock);

pendowner->pi_blocked_on = NULL;
+ pendowner->boosting_prio = MAX_PRIO;

if (rt_mutex_has_waiters(lock)) {
struct rt_mutex_waiter *next;
@@ -525,6 +553,7 @@ static void wakeup_next_waiter(struct rt
next = rt_mutex_top_waiter(lock);
plist_add(&next->pi_list_entry, &pendowner->pi_waiters);
}
+ __rt_mutex_adjust_prio(pendowner);
spin_unlock_irqrestore(&pendowner->pi_lock, flags);

if (savestate)
@@ -539,7 +568,8 @@ static void wakeup_next_waiter(struct rt
* Must be called with lock->wait_lock held
*/
static void remove_waiter(struct rt_mutex *lock,
- struct rt_mutex_waiter *waiter __IP_DECL__)
+ struct rt_mutex_waiter *waiter
+ __IP_DECL__)
{
int first = (waiter == rt_mutex_top_waiter(lock));
int boost = 0;
@@ -621,7 +651,8 @@ static void fastcall noinline __sched
rt_lock_slowlock(struct rt_mutex *lock __IP_DECL__)
{
struct rt_mutex_waiter waiter;
- unsigned long saved_state, state; ;
+ unsigned long saved_state, state;
+ int adjust_prio_final = 0;

debug_rt_mutex_init_waiter(&waiter);
waiter.task = NULL;
@@ -661,12 +692,17 @@ rt_lock_slowlock(struct rt_mutex *lock _
* when we have been woken up by the previous owner
* but the lock got stolen by an higher prio task.
*/
- if (!waiter.task) {
+ if (!waiter.task)
task_blocks_on_rt_mutex(lock, &waiter, 0 __IP__);
/* Wakeup during boost ? */
- if (unlikely(!waiter.task))
+ else
+ rt_mutex_adjust_prio_chain_unlock(lock);
+
+ /*
+ * We got it while lock->wait_lock was unlocked ?
+ */
+ if (unlikely(!waiter.task))
continue;
- }

/*
* Prevent schedule() to drop BKL, while waiting for
@@ -699,8 +735,10 @@ rt_lock_slowlock(struct rt_mutex *lock _
* highest-prio waiter (due to SCHED_OTHER changing prio), then we
* can end up with a non-NULL waiter.task:
*/
- if (unlikely(waiter.task))
- remove_waiter(lock, &waiter __IP__);
+ if (unlikely(waiter.task)) {
+ remove_waiter(lock, &waiter __IP__);
+ adjust_prio_final = 1;
+ }
/*
* try_to_take_rt_mutex() sets the waiter bit
* unconditionally. We might have to fix that up:
@@ -709,7 +747,11 @@ rt_lock_slowlock(struct rt_mutex *lock _

spin_unlock(&lock->wait_lock);

+ if (adjust_prio_final)
+ rt_mutex_adjust_prio_final(current);
+
debug_rt_mutex_free_waiter(&waiter);
+ BUG_ON(current->boosting_prio != MAX_PRIO);
}

/*
@@ -735,7 +777,8 @@ rt_lock_slowunlock(struct rt_mutex *lock
spin_unlock(&lock->wait_lock);

/* Undo pi boosting.when necessary */
- rt_mutex_adjust_prio(current);
+ rt_mutex_adjust_prio_final(current);
+ BUG_ON(current->boosting_prio != MAX_PRIO);
}

void __lockfunc rt_lock(struct rt_mutex *lock)
@@ -795,6 +838,7 @@ rt_mutex_slowlock(struct rt_mutex *lock,
{
int ret = 0, saved_lock_depth = -1;
struct rt_mutex_waiter waiter;
+ int adjust_prio_final = 0;

debug_rt_mutex_init_waiter(&waiter);
waiter.task = NULL;
@@ -848,21 +892,28 @@ rt_mutex_slowlock(struct rt_mutex *lock,
* waiter.task is NULL the first time we come here and
* when we have been woken up by the previous owner
* but the lock got stolen by a higher prio task.
+ *
+ * If we get another kind of wakeup but can't get the lock
+ * we should try to adjust the priorities
*/
- if (!waiter.task) {
+ if (!waiter.task)
ret = task_blocks_on_rt_mutex(lock, &waiter,
detect_deadlock __IP__);
- /*
- * If we got woken up by the owner then start loop
- * all over without going into schedule to try
- * to get the lock now:
- */
- if (unlikely(!waiter.task))
- continue;
+ else
+ rt_mutex_adjust_prio_chain_unlock(lock);
+
+
+ /*
+ * If we got woken up by the owner then start loop
+ * all over without going into schedule to try
+ * to get the lock now:
+ */
+ if (unlikely(!waiter.task))
+ continue;
+
+ if (unlikely(ret))
+ break;

- if (unlikely(ret))
- break;
- }
saved_flags = current->flags & PF_NOSCHED;
current->flags &= ~PF_NOSCHED;

@@ -881,8 +932,13 @@ rt_mutex_slowlock(struct rt_mutex *lock,

set_current_state(TASK_RUNNING);

- if (unlikely(waiter.task))
+ if (unlikely(waiter.task)) {
remove_waiter(lock, &waiter __IP__);
+ adjust_prio_final = 1;
+ }
+ else if (unlikely(ret))
+ adjust_prio_final = 1;
+

/*
* try_to_take_rt_mutex() sets the waiter bit
@@ -892,17 +948,13 @@ rt_mutex_slowlock(struct rt_mutex *lock,

spin_unlock(&lock->wait_lock);

+ if (adjust_prio_final)
+ rt_mutex_adjust_prio_final(current);
+
/* Remove pending timer: */
if (unlikely(timeout))
hrtimer_cancel(&timeout->timer);

- /*
- * Readjust priority, when we did not get the lock. We might
- * have been the pending owner and boosted. Since we did not
- * take the lock, the PI boost has to go.
- */
- if (unlikely(ret))
- rt_mutex_adjust_prio(current);

/* Must we reaquire the BKL? */
if (unlikely(saved_lock_depth >= 0))
@@ -910,6 +962,8 @@ rt_mutex_slowlock(struct rt_mutex *lock,

debug_rt_mutex_free_waiter(&waiter);

+ BUG_ON(current->boosting_prio != MAX_PRIO);
+
return ret;
}

@@ -962,7 +1016,8 @@ rt_mutex_slowunlock(struct rt_mutex *loc
spin_unlock(&lock->wait_lock);

/* Undo pi boosting if necessary: */
- rt_mutex_adjust_prio(current);
+ rt_mutex_adjust_prio_final(current);
+ BUG_ON(current->boosting_prio != MAX_PRIO);
}

/*
Index: linux-2.6.17-rt4/kernel/sched.c
===================================================================
--- linux-2.6.17-rt4.orig/kernel/sched.c
+++ linux-2.6.17-rt4/kernel/sched.c
@@ -57,6 +57,8 @@

#include <asm/unistd.h>

+#include "rtmutex_common.h"
+
/*
* Convert user-nice values [ -20 ... 0 ... 19 ]
* to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
@@ -162,9 +164,8 @@
(JIFFIES_TO_NS(MAX_SLEEP_AVG * \
(MAX_BONUS / 2 + DELTA((p)) + 1) / MAX_BONUS - 1))

-#define TASK_PREEMPTS_CURR(p, rq) \
- ((p)->prio < (rq)->curr->prio)
-
+#define TASK_PREEMPTS(p,q) task_preempts(p,q)
+#define TASK_PREEMPTS_CURR(p, rq) TASK_PREEMPTS(p, (rq)->curr)
/*
* task_timeslice() scales user-nice values [ -20 ... 0 ... 19 ]
* to time slice values: [800ms ... 100ms ... 5ms]
@@ -399,6 +400,22 @@ static inline void finish_lock_switch(ru
}
#endif /* __ARCH_WANT_UNLOCKED_CTXSW */

+
+static inline int task_preempts(task_t *p, task_t *q)
+{
+ if (p->prio < q->prio)
+ return 1;
+
+#ifdef CONFIG_RT_MUTEXES
+ if (p->prio > q->prio)
+ return 0;
+
+ return p->boosting_prio != MAX_PRIO-1;
+#else
+ return 0;
+#endif
+}
+
/*
* task_rq_lock - lock the runqueue a given task resides on and disable
* interrupts. Note the ordering: we can safely lookup the task_rq without
@@ -646,7 +663,9 @@ static inline void sched_info_switch(tas
#define sched_info_switch(t, next) do { } while (0)
#endif /* CONFIG_SCHEDSTATS */

+#ifdef CONFIG_SMP
static __cacheline_aligned_in_smp atomic_t rt_overload;
+#endif

static inline void inc_rt_tasks(task_t *p, runqueue_t *rq)
{
@@ -710,7 +729,13 @@ static void enqueue_task(struct task_str
dump_stack();
}
sched_info_queued(p);
- list_add_tail(&p->run_list, array->queue + p->prio);
+#ifdef CONFIG_RT_MUTEXES
+ if (p->boosting_prio != MAX_PRIO)
+ list_add(&p->run_list, array->queue + p->prio);
+ else
+#endif
+ list_add_tail(&p->run_list, array->queue + p->prio);
+
__set_bit(p->prio, array->bitmap);
array->nr_active++;
p->array = array;
@@ -723,7 +748,12 @@ static void enqueue_task(struct task_str
*/
static void requeue_task(struct task_struct *p, prio_array_t *array)
{
- list_move_tail(&p->run_list, array->queue + p->prio);
+#ifdef CONFIG_RT_MUTEXES
+ if (p->boosting_prio != MAX_PRIO)
+ list_move(&p->run_list, array->queue + p->prio);
+ else
+#endif
+ list_move_tail(&p->run_list, array->queue + p->prio);
}

static inline void enqueue_task_head(struct task_struct *p, prio_array_t *array)
@@ -1313,7 +1343,7 @@ static void balance_rt_tasks(runqueue_t
* Do we have an RT task that preempts
* the to-be-scheduled task?
*/
- if (p && (p->prio < next->prio)) {
+ if (p && TASK_PREEMPTS(p, next)) {
WARN_ON(p == src_rq->curr);
WARN_ON(!p->array);
schedstat_inc(this_rq, rto_pulled);
@@ -1473,10 +1503,11 @@ static inline int wake_idle(int cpu, tas
static int try_to_wake_up(task_t *p, unsigned int state, int sync, int mutex)
{
int cpu, this_cpu, success = 0;
- runqueue_t *this_rq, *rq;
+ runqueue_t *rq;
unsigned long flags;
long old_state;
#ifdef CONFIG_SMP
+ runqueue_t *this_rq;
unsigned long load, this_load;
struct sched_domain *sd, *this_sd = NULL;
int new_cpu;
@@ -4351,6 +4382,14 @@ int setscheduler(struct task_struct *p,
resched_task(rq->curr);
}
task_rq_unlock(rq, &flags);
+
+ /*
+ * If the process is blocked on rt-mutex, it will now wake up and
+ * reinsert itself into the wait list and boost the owner correctly
+ */
+ if (p->pi_blocked_on)
+ wake_up_process_mutex(p);
+
spin_unlock_irqrestore(&p->pi_lock, fp);
return 0;
}
@@ -7086,4 +7125,3 @@ void notrace preempt_enable_no_resched(v

EXPORT_SYMBOL(preempt_enable_no_resched);
#endif
-
Index: linux-2.6.17-rt4/include/linux/sched.h
===================================================================
--- linux-2.6.17-rt4.orig/include/linux/sched.h
+++ linux-2.6.17-rt4/include/linux/sched.h
@@ -994,6 +994,13 @@ struct task_struct {
struct plist_head pi_waiters;
/* Deadlock detection and priority inheritance handling */
struct rt_mutex_waiter *pi_blocked_on;
+
+ /*
+ * Priority to which this task is boosting something. Don't lower the
+ * priority below this before the boosting is resolved;
+ */
+ int boosting_prio;
+
# ifdef CONFIG_DEBUG_RT_MUTEXES
raw_spinlock_t held_list_lock;
struct list_head held_list_head;
Index: linux-2.6.17-rt4/scripts/rt-tester/t5-l4-pi-boost-deboost.tst
===================================================================
--- linux-2.6.17-rt4.orig/scripts/rt-tester/t5-l4-pi-boost-deboost.tst
+++ linux-2.6.17-rt4/scripts/rt-tester/t5-l4-pi-boost-deboost.tst
@@ -113,22 +113,22 @@ T: prioeq: 3: 84
C: signal: 4: 0
W: unlocked: 4: 3
T: prioeq: 0: 83
-T: prioeq: 1: 83
-T: prioeq: 2: 83
-T: prioeq: 3: 83
+T: prioeq: 1: 84
+T: prioeq: 2: 84
+T: prioeq: 3: 84

# Signal T3
C: signal: 3: 0
W: unlocked: 3: 2
T: prioeq: 0: 82
-T: prioeq: 1: 82
-T: prioeq: 2: 82
+T: prioeq: 1: 84
+T: prioeq: 2: 84

# Signal T2
C: signal: 2: 0
W: unlocked: 2: 1
T: prioeq: 0: 81
-T: prioeq: 1: 81
+T: prioeq: 1: 84

# Signal T1
C: signal: 1: 0
Index: linux-2.6.17-rt4/kernel/fork.c
===================================================================
--- linux-2.6.17-rt4.orig/kernel/fork.c
+++ linux-2.6.17-rt4/kernel/fork.c
@@ -955,6 +955,7 @@ static inline void rt_mutex_init_task(st
spin_lock_init(&p->pi_lock);
plist_head_init(&p->pi_waiters, &p->pi_lock);
p->pi_blocked_on = NULL;
+ p->boosting_prio = MAX_PRIO;
# ifdef CONFIG_DEBUG_RT_MUTEXES
spin_lock_init(&p->held_list_lock);
INIT_LIST_HEAD(&p->held_list_head);
Index: linux-2.6.17-rt4/include/linux/rtmutex.h
===================================================================
--- linux-2.6.17-rt4.orig/include/linux/rtmutex.h
+++ linux-2.6.17-rt4/include/linux/rtmutex.h
@@ -116,6 +116,7 @@ extern void rt_mutex_unlock(struct rt_mu
# define INIT_RT_MUTEXES(tsk) \
.pi_waiters = PLIST_HEAD_INIT(tsk.pi_waiters, tsk.pi_lock), \
.pi_lock = RAW_SPIN_LOCK_UNLOCKED, \
+ .boosting_prio = MAX_PRIO \
INIT_RT_MUTEX_DEBUG(tsk)
#else
# define INIT_RT_MUTEXES(tsk)
Index: linux-2.6.17-rt4/scripts/rt-tester/t5-l4-pi-boost-deboost-setsched.tst
===================================================================
--- linux-2.6.17-rt4.orig/scripts/rt-tester/t5-l4-pi-boost-deboost-setsched.tst
+++ linux-2.6.17-rt4/scripts/rt-tester/t5-l4-pi-boost-deboost-setsched.tst
@@ -107,10 +107,10 @@ T: prioeq: 3: 84
# Reduce prio of T4
C: schedfifo: 4: 80
T: prioeq: 0: 83
-T: prioeq: 1: 83
-T: prioeq: 2: 83
-T: prioeq: 3: 83
-T: prioeq: 4: 80
+T: prioeq: 1: 84
+T: prioeq: 2: 84
+T: prioeq: 3: 84
+T: prioeq: 4: 84

# Increase prio of T4
C: schedfifo: 4: 84
@@ -139,36 +139,46 @@ T: prioeq: 4: 84
# Reduce prio of T3
C: schedfifo: 3: 83
T: prioeq: 0: 84
-T: prioeq: 1: 84
-T: prioeq: 2: 84
-T: prioeq: 3: 84
+T: prioeq: 1: 85
+T: prioeq: 2: 85
+T: prioeq: 3: 85
T: prioeq: 4: 84

# Signal T4
C: signal: 4: 0
W: unlocked: 4: 3
T: prioeq: 0: 83
-T: prioeq: 1: 83
-T: prioeq: 2: 83
-T: prioeq: 3: 83
+T: prioeq: 1: 85
+T: prioeq: 2: 85
+T: prioeq: 3: 85
+T: prioeq: 4: 84

# Signal T3
C: signal: 3: 0
W: unlocked: 3: 2
T: prioeq: 0: 82
-T: prioeq: 1: 82
-T: prioeq: 2: 82
+T: prioeq: 1: 85
+T: prioeq: 2: 85
+T: prioeq: 3: 83
+T: prioeq: 4: 84

# Signal T2
C: signal: 2: 0
W: unlocked: 2: 1
T: prioeq: 0: 81
-T: prioeq: 1: 81
+T: prioeq: 1: 85
+T: prioeq: 2: 82
+T: prioeq: 3: 83
+T: prioeq: 4: 84

# Signal T1
C: signal: 1: 0
W: unlocked: 1: 0
T: priolt: 0: 1
+T: prioeq: 1: 81
+T: prioeq: 2: 82
+T: prioeq: 3: 83
+T: prioeq: 4: 84

# Unlock and exit
C: unlock: 3: 3
@@ -180,3 +190,9 @@ W: unlocked: 3: 3
W: unlocked: 2: 2
W: unlocked: 1: 1
W: unlocked: 0: 0
+
+# Reset the -4 opcode from the signal
+C: reset: 1: 0
+C: reset: 2: 0
+C: reset: 3: 0
+C: reset: 4: 0
\ No newline at end of fileMake test suite setscheduler calls asynchronously. Remove the waits in the test
cases and add a new testcase to verify the correctness of the setscheduler
priority propagation
This is based on and almost identical to the one Thomas Gleixner sent out
earlier.
Index: linux-2.6.17-rt4/kernel/rtmutex-tester.c
===================================================================
--- linux-2.6.17-rt4.orig/kernel/rtmutex-tester.c
+++ linux-2.6.17-rt4/kernel/rtmutex-tester.c
@@ -55,7 +55,6 @@ enum test_opcodes {

static int handle_op(struct test_thread_data *td, int lockwakeup)
{
- struct sched_param schedpar;
int i, id, ret = -EINVAL;

switch(td->opcode) {
@@ -63,17 +62,6 @@ static int handle_op(struct test_thread_
case RTTEST_NOP:
return 0;

- case RTTEST_SCHEDOT:
- schedpar.sched_priority = 0;
- ret = sched_setscheduler(current, SCHED_NORMAL, &schedpar);
- if (!ret)
- set_user_nice(current, 0);
- return ret;
-
- case RTTEST_SCHEDRT:
- schedpar.sched_priority = td->opdata;
- return sched_setscheduler(current, SCHED_FIFO, &schedpar);
-
case RTTEST_LOCKCONT:
td->mutexes[td->opdata] = 1;
td->event = atomic_add_return(1, &rttest_event);
@@ -310,9 +298,10 @@ static int test_func(void *data)
static ssize_t sysfs_test_command(struct sys_device *dev, const char *buf,
size_t count)
{
+ struct sched_param schedpar;
struct test_thread_data *td;
char cmdbuf[32];
- int op, dat, tid;
+ int op, dat, tid, ret;

td = container_of(dev, struct test_thread_data, sysdev);
tid = td->sysdev.id;
@@ -334,6 +323,22 @@ static ssize_t sysfs_test_command(struct
return -EINVAL;

switch (op) {
+ case RTTEST_SCHEDOT:
+ schedpar.sched_priority = 0;
+ ret = sched_setscheduler(threads[tid], SCHED_NORMAL,
+ &schedpar);
+ if (ret)
+ return ret;
+ set_user_nice(current, 0);
+ break;
+
+ case RTTEST_SCHEDRT:
+ schedpar.sched_priority = dat;
+ ret = sched_setscheduler(threads[tid], SCHED_FIFO, &schedpar);
+ if (ret)
+ return ret;
+ break;
+
case RTTEST_SIGNAL:
send_sig(SIGHUP, threads[tid], 0);
break;
Index: linux-2.6.17-rt4/scripts/rt-tester/reset-tester.py
===================================================================
--- /dev/null
+++ linux-2.6.17-rt4/scripts/rt-tester/reset-tester.py
@@ -0,0 +1,18 @@
+#!/usr/bin/env python
+
+sysfsprefix = "/sys/devices/system/rttest/rttest"
+statusfile = "/status"
+commandfile = "/command"
+
+for i in range(0,8):
+ cmdstr = "%s:%s" %("99", "0")
+ fname = "%s%d%s" %(sysfsprefix, i, commandfile)
+
+ try:
+ fcmd = open(fname, 'w')
+ fcmd.write(cmdstr)
+ fcmd.close()
+ except Exception,ex:
+ print i
+ print ex
+
Index: linux-2.6.17-rt4/scripts/rt-tester/t2-l1-signal.tst
===================================================================
--- linux-2.6.17-rt4.orig/scripts/rt-tester/t2-l1-signal.tst
+++ linux-2.6.17-rt4/scripts/rt-tester/t2-l1-signal.tst
@@ -77,3 +77,6 @@ T: opcodeeq: 1: -4
# Unlock and exit
C: unlock: 0: 0
W: unlocked: 0: 0
+
+# Reset the -4 opcode from the signal
+C: reset: 1: 0
\ No newline at end of file
Index: linux-2.6.17-rt4/scripts/rt-tester/t3-l1-pi-signal.tst
===================================================================
--- linux-2.6.17-rt4.orig/scripts/rt-tester/t3-l1-pi-signal.tst
+++ linux-2.6.17-rt4/scripts/rt-tester/t3-l1-pi-signal.tst
@@ -98,4 +98,5 @@ C: unlock: 1: 0
W: unlocked: 1: 0


-
+# Reset the -4 opcode from the signal
+C: reset: 2: 0
\ No newline at end of file
Index: linux-2.6.17-rt4/scripts/rt-tester/t4-l2-pi-deboost.tst
===================================================================
--- linux-2.6.17-rt4.orig/scripts/rt-tester/t4-l2-pi-deboost.tst
+++ linux-2.6.17-rt4/scripts/rt-tester/t4-l2-pi-deboost.tst
@@ -125,3 +125,5 @@ W: unlocked: 2: 1
C: unlock: 0: 0
W: unlocked: 0: 0

+# Reset the -4 opcode from the signal
+C: reset: 3: 0
\ No newline at end of file
Index: linux-2.6.17-rt4/scripts/rt-tester/t5-l4-pi-boost-deboost-setsched.tst
===================================================================
--- /dev/null
+++ linux-2.6.17-rt4/scripts/rt-tester/t5-l4-pi-boost-deboost-setsched.tst
@@ -0,0 +1,182 @@
+#
+# rt-mutex test
+#
+# Op: C(ommand)/T(est)/W(ait)
+# | opcode
+# | | threadid: 0-7
+# | | | opcode argument
+# | | | |
+# C: lock: 0: 0
+#
+# Commands
+#
+# opcode opcode argument
+# schedother nice value
+# schedfifo priority
+# lock lock nr (0-7)
+# locknowait lock nr (0-7)
+# lockint lock nr (0-7)
+# lockintnowait lock nr (0-7)
+# lockcont lock nr (0-7)
+# unlock lock nr (0-7)
+# lockbkl lock nr (0-7)
+# unlockbkl lock nr (0-7)
+# signal thread to signal (0-7)
+# reset 0
+# resetevent 0
+#
+# Tests / Wait
+#
+# opcode opcode argument
+#
+# prioeq priority
+# priolt priority
+# priogt priority
+# nprioeq normal priority
+# npriolt normal priority
+# npriogt normal priority
+# locked lock nr (0-7)
+# blocked lock nr (0-7)
+# blockedwake lock nr (0-7)
+# unlocked lock nr (0-7)
+# lockedbkl dont care
+# blockedbkl dont care
+# unlockedbkl dont care
+# opcodeeq command opcode or number
+# opcodelt number
+# opcodegt number
+# eventeq number
+# eventgt number
+# eventlt number
+
+#
+# 5 threads 4 lock PI - modify priority of blocked threads
+#
+C: resetevent: 0: 0
+W: opcodeeq: 0: 0
+
+# Set schedulers
+C: schedother: 0: 0
+C: schedfifo: 1: 81
+C: schedfifo: 2: 82
+C: schedfifo: 3: 83
+C: schedfifo: 4: 84
+
+# T0 lock L0
+C: locknowait: 0: 0
+W: locked: 0: 0
+
+# T1 lock L1
+C: locknowait: 1: 1
+W: locked: 1: 1
+
+# T1 lock L0
+C: lockintnowait: 1: 0
+W: blocked: 1: 0
+T: prioeq: 0: 81
+
+# T2 lock L2
+C: locknowait: 2: 2
+W: locked: 2: 2
+
+# T2 lock L1
+C: lockintnowait: 2: 1
+W: blocked: 2: 1
+T: prioeq: 0: 82
+T: prioeq: 1: 82
+
+# T3 lock L3
+C: locknowait: 3: 3
+W: locked: 3: 3
+
+# T3 lock L2
+C: lockintnowait: 3: 2
+W: blocked: 3: 2
+T: prioeq: 0: 83
+T: prioeq: 1: 83
+T: prioeq: 2: 83
+
+# T4 lock L3
+C: lockintnowait: 4: 3
+W: blocked: 4: 3
+T: prioeq: 0: 84
+T: prioeq: 1: 84
+T: prioeq: 2: 84
+T: prioeq: 3: 84
+
+# Reduce prio of T4
+C: schedfifo: 4: 80
+T: prioeq: 0: 83
+T: prioeq: 1: 83
+T: prioeq: 2: 83
+T: prioeq: 3: 83
+T: prioeq: 4: 80
+
+# Increase prio of T4
+C: schedfifo: 4: 84
+T: prioeq: 0: 84
+T: prioeq: 1: 84
+T: prioeq: 2: 84
+T: prioeq: 3: 84
+T: prioeq: 4: 84
+
+# Reduce prio of T3
+C: schedfifo: 3: 80
+T: prioeq: 0: 84
+T: prioeq: 1: 84
+T: prioeq: 2: 84
+T: prioeq: 3: 84
+T: prioeq: 4: 84
+
+# Increase prio of T3
+C: schedfifo: 3: 85
+T: prioeq: 0: 85
+T: prioeq: 1: 85
+T: prioeq: 2: 85
+T: prioeq: 3: 85
+T: prioeq: 4: 84
+
+# Reduce prio of T3
+C: schedfifo: 3: 83
+T: prioeq: 0: 84
+T: prioeq: 1: 84
+T: prioeq: 2: 84
+T: prioeq: 3: 84
+T: prioeq: 4: 84
+
+# Signal T4
+C: signal: 4: 0
+W: unlocked: 4: 3
+T: prioeq: 0: 83
+T: prioeq: 1: 83
+T: prioeq: 2: 83
+T: prioeq: 3: 83
+
+# Signal T3
+C: signal: 3: 0
+W: unlocked: 3: 2
+T: prioeq: 0: 82
+T: prioeq: 1: 82
+T: prioeq: 2: 82
+
+# Signal T2
+C: signal: 2: 0
+W: unlocked: 2: 1
+T: prioeq: 0: 81
+T: prioeq: 1: 81
+
+# Signal T1
+C: signal: 1: 0
+W: unlocked: 1: 0
+T: priolt: 0: 1
+
+# Unlock and exit
+C: unlock: 3: 3
+C: unlock: 2: 2
+C: unlock: 1: 1
+C: unlock: 0: 0
+
+W: unlocked: 3: 3
+W: unlocked: 2: 2
+W: unlocked: 1: 1
+W: unlocked: 0: 0
Index: linux-2.6.17-rt4/scripts/rt-tester/t5-l4-pi-boost-deboost.tst
===================================================================
--- linux-2.6.17-rt4.orig/scripts/rt-tester/t5-l4-pi-boost-deboost.tst
+++ linux-2.6.17-rt4/scripts/rt-tester/t5-l4-pi-boost-deboost.tst
@@ -146,3 +146,5 @@ W: unlocked: 2: 2
W: unlocked: 1: 1
W: unlocked: 0: 0

+# Reset the -4 opcode from the signal
+C: reset: 4: 0
\ No newline at end of file
Index: linux-2.6.17-rt4/scripts/rt-tester/check-all.sh
===================================================================
--- linux-2.6.17-rt4.orig/scripts/rt-tester/check-all.sh
+++ linux-2.6.17-rt4/scripts/rt-tester/check-all.sh
@@ -18,4 +18,4 @@ testit t3-l1-pi-steal.tst
testit t3-l2-pi.tst
testit t4-l2-pi-deboost.tst
testit t5-l4-pi-boost-deboost.tst
-
+testit t5-l4-pi-boost-deboost-setsched.tst
\ No newline at end of file
\
 
 \ /
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