Module: xenomai-rpm
Branch: for-upstream
Commit: e10a88e8cd9ef54a14ac36359b16dcd71e299df7
URL:
http://git.xenomai.org/?p=xenomai-rpm.git;a=commit;h=e10a88e8cd9ef54a14ac36359b16dcd71e299df7
Author: Philippe Gerum <r...@xenomai.org>
Date: Mon Aug 16 17:21:15 2010 +0200
nucleus: demote RPI boost upon linux-originated signal
This patch clears the RPI boost for any relaxed thread which is
getting a signal while running, so that it won't keep a boosted
priority to process asynchronous linux-originated events, such as
termination signals.
Rationale: RPI is mainly for preventing priority inversion during
normal operations in secondary mode, handling signals should not apply
there, since this would also boost low-priority cleanup work, which is
unwanted. The thread may get RPI-boosted again the next time it
resumes for suspension, linux-wise (if ever it does).
---
ksrc/nucleus/shadow.c | 23 ++++++++++++++++++++---
1 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/ksrc/nucleus/shadow.c b/ksrc/nucleus/shadow.c
index 9c801aa..52ee381 100644
--- a/ksrc/nucleus/shadow.c
+++ b/ksrc/nucleus/shadow.c
@@ -2641,7 +2641,7 @@ static inline void do_sigwake_event(struct task_struct *p)
struct xnthread *thread = xnshadow_thread(p);
spl_t s;
- if (!thread)
+ if (thread == NULL)
return;
xnlock_get_irqsave(&nklock, s);
@@ -2660,8 +2660,25 @@ static inline void do_sigwake_event(struct task_struct
*p)
}
}
- if (xnthread_test_state(thread, XNRELAX))
- goto unlock_and_exit;
+ /*
+ * If a relaxed thread is getting a signal while running, we
+ * force it out of RPI, so that it won't keep a boosted
+ * priority to process asynchronous linux-originated events,
+ * such as termination signals. RPI is mainly for preventing
+ * priority inversion during normal operations in secondary
+ * mode, handling signals should not apply there, since this
+ * would also boost low-priority cleanup work, which is
+ * unwanted. The thread may get RPI-boosted again the next
+ * time it resumes for suspension, linux-wise (if ever it
+ * does).
+ */
+ if (xnthread_test_state(thread, XNRELAX)) {
+ xnlock_put_irqrestore(&nklock, s);
+ rpi_pop(thread);
+ xnpod_schedule();
+ return;
+ }
+
/*
* If we are kicking a shadow thread in primary mode, make
* sure Linux won't schedule in its mate under our feet as a
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