Re: [Xenomai-core] False positive XENO_BUGON(NUCLEUS, need_resched == 0)?
On Mon, 2010-08-30 at 17:39 +0200, Jan Kiszka wrote:
Philippe Gerum wrote:
Ok, Gilles did not grumble at you, so I'm daring the following patch,
since I agree with you here. Totally untested, not even compiled, just
for the fun of getting lockups and/or threads in limbos. Nah, just
kidding, your shiny SMP box should be bricked even before that:
diff --git a/include/nucleus/sched.h b/include/nucleus/sched.h
index f75c6f6..6ad66ba 100644
--- a/include/nucleus/sched.h
+++ b/include/nucleus/sched.h
@@ -184,10 +184,9 @@ static inline int xnsched_self_resched_p(struct
xnsched *sched)
#define xnsched_set_resched(__sched__) do {
\
xnsched_t *current_sched = xnpod_current_sched();
\
xnarch_cpu_set(xnsched_cpu(__sched__), current_sched-resched); \
To increase the probability of regressions: What about moving the above
line...
- if (unlikely(current_sched != (__sched__)))
\
- xnarch_cpu_set(xnsched_cpu(__sched__), (__sched__)-resched);
\
setbits(current_sched-status, XNRESCHED);
\
- /* remote will set XNRESCHED locally in the IPI handler */
\
+ if (current_sched != (__sched__))
\
+ setbits((__sched__)-status, XNRESCHED);
\
...into this conditional block? Then you should be able to...
} while (0)
void xnsched_zombie_hooks(struct xnthread *thread);
diff --git a/ksrc/nucleus/pod.c b/ksrc/nucleus/pod.c
index 623bdff..cff76c2 100644
--- a/ksrc/nucleus/pod.c
+++ b/ksrc/nucleus/pod.c
@@ -285,13 +285,6 @@ void xnpod_schedule_handler(void) /* Called with hw
interrupts off. */
xnshadow_rpi_check();
}
#endif /* CONFIG_SMP CONFIG_XENO_OPT_PRIOCPL */
- /*
-* xnsched_set_resched() did set the resched mask remotely. We
-* just need to make sure that our rescheduling request won't
-* be filtered out locally when testing for XNRESCHED
-* presence.
-*/
- setbits(sched-status, XNRESCHED);
xnpod_schedule();
}
@@ -2167,10 +2160,10 @@ static inline int __xnpod_test_resched(struct
xnsched *sched)
{
int cpu = xnsched_cpu(sched), resched;
- resched = xnarch_cpu_isset(cpu, sched-resched);
- xnarch_cpu_clear(cpu, sched-resched);
+ resched = testbits(sched-status, XNRESCHED);
#ifdef CONFIG_SMP
/* Send resched IPI to remote CPU(s). */
+ xnarch_cpu_clear(cpu, sched-resched);
...drop the line above as well.
if (unlikely(xnsched_resched_p(sched))) {
xnarch_send_ipi(sched-resched);
xnarch_cpus_clear(sched-resched);
Yes, I do think that we are way too stable on SMP boxes these days.
Let's merge this as well to bring the fun back.
--
Philippe.
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Re: [Xenomai-core] False positive XENO_BUGON(NUCLEUS, need_resched == 0)?
On Tue, 2010-08-31 at 09:09 +0200, Philippe Gerum wrote:
On Mon, 2010-08-30 at 17:39 +0200, Jan Kiszka wrote:
Philippe Gerum wrote:
Ok, Gilles did not grumble at you, so I'm daring the following patch,
since I agree with you here. Totally untested, not even compiled, just
for the fun of getting lockups and/or threads in limbos. Nah, just
kidding, your shiny SMP box should be bricked even before that:
diff --git a/include/nucleus/sched.h b/include/nucleus/sched.h
index f75c6f6..6ad66ba 100644
--- a/include/nucleus/sched.h
+++ b/include/nucleus/sched.h
@@ -184,10 +184,9 @@ static inline int xnsched_self_resched_p(struct
xnsched *sched)
#define xnsched_set_resched(__sched__) do {
\
xnsched_t *current_sched = xnpod_current_sched();
\
xnarch_cpu_set(xnsched_cpu(__sched__), current_sched-resched);
\
To increase the probability of regressions: What about moving the above
line...
- if (unlikely(current_sched != (__sched__)))
\
- xnarch_cpu_set(xnsched_cpu(__sched__), (__sched__)-resched);
\
setbits(current_sched-status, XNRESCHED);
\
- /* remote will set XNRESCHED locally in the IPI handler */
\
+ if (current_sched != (__sched__))
\
+ setbits((__sched__)-status, XNRESCHED);
\
...into this conditional block? Then you should be able to...
} while (0)
void xnsched_zombie_hooks(struct xnthread *thread);
diff --git a/ksrc/nucleus/pod.c b/ksrc/nucleus/pod.c
index 623bdff..cff76c2 100644
--- a/ksrc/nucleus/pod.c
+++ b/ksrc/nucleus/pod.c
@@ -285,13 +285,6 @@ void xnpod_schedule_handler(void) /* Called with hw
interrupts off. */
xnshadow_rpi_check();
}
#endif /* CONFIG_SMP CONFIG_XENO_OPT_PRIOCPL */
- /*
- * xnsched_set_resched() did set the resched mask remotely. We
- * just need to make sure that our rescheduling request won't
- * be filtered out locally when testing for XNRESCHED
- * presence.
- */
- setbits(sched-status, XNRESCHED);
xnpod_schedule();
}
@@ -2167,10 +2160,10 @@ static inline int __xnpod_test_resched(struct
xnsched *sched)
{
int cpu = xnsched_cpu(sched), resched;
- resched = xnarch_cpu_isset(cpu, sched-resched);
- xnarch_cpu_clear(cpu, sched-resched);
+ resched = testbits(sched-status, XNRESCHED);
#ifdef CONFIG_SMP
/* Send resched IPI to remote CPU(s). */
+ xnarch_cpu_clear(cpu, sched-resched);
...drop the line above as well.
if (unlikely(xnsched_resched_p(sched))) {
xnarch_send_ipi(sched-resched);
xnarch_cpus_clear(sched-resched);
Yes, I do think that we are way too stable on SMP boxes these days.
Let's merge this as well to bring the fun back.
All worked according to plan, this introduced a nice lockup under
switchtest load. Unfortunately, a solution exists to fix it:
--- a/include/nucleus/sched.h
+++ b/include/nucleus/sched.h
@@ -176,17 +176,17 @@ static inline int xnsched_self_resched_p(struct xnsched
*sched)
/* Set self resched flag for the given scheduler. */
#define xnsched_set_self_resched(__sched__) do { \
- xnarch_cpu_set(xnsched_cpu(__sched__), (__sched__)-resched); \
setbits((__sched__)-status, XNRESCHED); \
} while (0)
--
Philippe.
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[Xenomai-core] [PULL-REQUEST] assorted fixes and updates for 2.5.x
The following changes since commit 004f652d31d2e3b9b995850dbefcf12bc6dbd96d: Gilles Chanteperdrix (1): Fix typo in edaf1e2e54343b6e4bf5cf6ece9175ec0ab21cad are available in the git repository at: ssh+git://g...@xenomai.org/xenomai-rpm.git for-upstream Philippe Gerum (16): powerpc: upgrade I-pipe support to 2.6.34.4-powerpc-2.10-04 nucleus: demote RPI boost upon linux-originated signal blackfin: upgrade I-pipe support to 2.6.35.2-blackfin-1.15-00 nucleus: requeue blocked non-periodic timers properly x86: upgrade I-pipe support to 2.6.32.20-x86-2.7-02, 2.6.34.5-x86-2.7-03 arm: force enable preemptible switch support in SMP mode arm: enable VFP support in SMP arm: use rthal_processor_id() over non-linux contexts powerpc: resync thread switch code with mainline = 2.6.32 x86: increase SMP calibration value nucleus/sched: move locking to resume_rpi/suspend_rpi hal/generic: inline APC scheduling code nucleus, posix: use fast APC scheduling call nucleus/shadow: shorten the uninterruptible path to secondary mode nucleus/sched: prevent remote wakeup from triggering a debug assertion powerpc: upgrade I-pipe support to 2.6.35.4-powerpc-2.11-00 -- Philippe. ___ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
