Re: [Xenomai-core] Potential problem with rt_eepro100

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

Jan Kiszka wrote:
> Am 05.11.2010 00:25, Gilles Chanteperdrix wrote:
>> Jan Kiszka wrote:
>>> Am 04.11.2010 23:08, Gilles Chanteperdrix wrote:
>>>> Jan Kiszka wrote:
>>>>> rework. Safer for now is likely to revert 56ff4329ff, keeping nucleus
>>>>> debugging off.
>>>> That is not enough.
>>> It is, I've reviewed the code today.
>> The fallouts I am talking about are:
>> 47dac49c71e89b684203e854d1b0172ecacbc555
> 
> Not related.
> 
>> 38f2ca83a8e63cc94eaa911ff1c0940c884b5078
> 
> An optimization.
> 
>> 5e7cfa5c25672e4478a721eadbd6f6c5b4f88a2f
> 
> That fall out of that commit is fixed in my series.
> 
>>>> This commit was followed by several others to "fix
>>>> the fix". You know how things are, someone proposes a fix, which fixes
>>>> things for him, but it breaks in the other people configurations (one of
>>>> the fallouts was a complete revamp of include/asm-arm/atomic.h for
>>>> instance).
>>>>
>>> I've pushed a series that reverts that commit, then fixes and cleans up
>>> on top of it. Just pushed if you want to take a look. We can find some
>>> alternative debugging mechanism independently (though I'm curious to see
>>> it - it still makes no sense to me).
>> Since the fix is simply a modification to what we have currently. I
>> would prefer if we did not remove it. In fact, I think it would be
>> simpler if we started from what we currently have than reverting past
>> patches.
> 
> Look at the series, it goes step by step to an IMHO clean state. We can
> pull out the debugging check removal, though, if you prefer to work on
> top of the existing code.

>From my point of view, Anders looks for something that works, so 
following the rules that the minimal set of changes minimize the chances
of introducing new bugs while cleaning, I would go for the minimal set 
of changes, such as:

diff --git a/include/nucleus/sched.h b/include/nucleus/sched.h
index df56417..8150510 100644
--- a/include/nucleus/sched.h
+++ b/include/nucleus/sched.h
@@ -165,28 +165,27 @@ struct xnsched_class {
 #endif /* CONFIG_SMP */
 
 /* Test all resched flags from the given scheduler mask. */
-static inline int xnsched_resched_p(struct xnsched *sched)
+static inline int xnsched_remote_resched_p(struct xnsched *sched)
 {
-	return testbits(sched->status, XNRESCHED);
+	return !xnarch_cpus_empty(current_sched->resched);
 }
 
-static inline int xnsched_self_resched_p(struct xnsched *sched)
+static inline int xnsched_resched_p(struct xnsched *sched)
 {
 	return testbits(sched->status, XNRESCHED);
 }
 
 /* Set self resched flag for the given scheduler. */
 #define xnsched_set_self_resched(__sched__) do {		\
-  setbits((__sched__)->status, XNRESCHED);			\
+  __setbits((__sched__)->status, XNRESCHED);			\
 } while (0)
 
 /* Set specific resched flag into the local scheduler mask. */
 #define xnsched_set_resched(__sched__) do {				\
   xnsched_t *current_sched = xnpod_current_sched();			\
-  setbits(current_sched->status, XNRESCHED);				\
+  __setbits(current_sched->status, XNRESCHED);				\
   if (current_sched != (__sched__))	{				\
       xnarch_cpu_set(xnsched_cpu(__sched__), current_sched->resched);	\
-      setbits((__sched__)->status, XNRESCHED);				\
   }									\
 } while (0)
 
diff --git a/ksrc/nucleus/pod.c b/ksrc/nucleus/pod.c
index 862838c..4cb707a 100644
--- a/ksrc/nucleus/pod.c
+++ b/ksrc/nucleus/pod.c
@@ -276,18 +276,16 @@ EXPORT_SYMBOL_GPL(xnpod_fatal_helper);
 
 void xnpod_schedule_handler(void) /* Called with hw interrupts off. */
 {
-	xnsched_t *sched;
+	xnsched_t *sched = xnpod_current_sched();
 
 	trace_mark(xn_nucleus, sched_remote, MARK_NOARGS);
 #if defined(CONFIG_SMP) && defined(CONFIG_XENO_OPT_PRIOCPL)
-	sched = xnpod_current_sched();
 	if (testbits(sched->status, XNRPICK)) {
 		clrbits(sched->status, XNRPICK);
 		xnshadow_rpi_check();
 	}
-#else
-	(void)sched;
 #endif /* CONFIG_SMP && CONFIG_XENO_OPT_PRIOCPL */
+	xnsched_set_self_resched(sched);
 	xnpod_schedule();
 }
 
@@ -2174,7 +2172,7 @@ static inline int __xnpod_test_resched(struct xnsched *sched)
 	int resched = testbits(sched->status, XNRESCHED);
 #ifdef CONFIG_SMP
 	/* Send resched IPI to remote CPU(s). */
-	if (unlikely(xnsched_resched_p(sched))) {
+	if (unlikely(xnsched_remote_resched_p(sched))) {
 		xnarch_send_ipi(sched->resched);
 		xnarch_cpus_clear(sched->resched);
 	}
diff --git a/ksrc/nucleus/timer.c b/ksrc/nucleus/timer.c
index 1fe3331..a0ac627 100644
--- a/ksrc/nucleus/timer.c
+++ b/ksrc/nucleus/timer.c
@@ -97,7 +97,7 @@ void xntimer_next_local_shot(xnsched_t *sched)
 	__clrbits(sched->status, XNHDEFER);
 	timer = aplink2timer(h);
 	if (unlikely(timer == &sched->htimer)) {
-		if (xnsched_self_resched_p(sched) ||
+		if (xnsched_resched_p(sched) ||
 		    !xnthread_test_state(sched->curr, XNROOT)) {
 			h = xntimerq_it_next(&sched->timerqueue, &it, h);
 			if (h) {


-- 
                                                                Gilles.