Messages in this thread Patch in this message | | | From | Sebastian Andrzej Siewior <> | Subject | [PATCH 07/16] softirq: Fix nohz pending issue for real | Date | Wed, 13 Feb 2013 17:12:02 +0100 |
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From: Thomas Gleixner <tglx@linutronix.de>
We really need to iterate through all softirqs to find a potentially blocked runner.
T1 runs softirq X (that cleared pending bit for X)
Interrupt raises softirq Y
T1 gets blocked on a lock and lock owner is not runnable
T1 schedules out
CPU goes idle and complains about pending softirq Y.
Now iterating over all softirqs lets us find the runner for X and eliminate Y from the to warn about list as well.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- kernel/softirq.c | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/kernel/softirq.c b/kernel/softirq.c index 385fcea..1a0145a 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -100,20 +100,15 @@ void softirq_check_pending_idle(void) { static int rate_limit; struct softirq_runner *sr = &__get_cpu_var(softirq_runners); - u32 warnpending, pending = local_softirq_pending(); + u32 warnpending = local_softirq_pending(); + int i; if (rate_limit >= 10) return; - warnpending = pending; - - while (pending) { - struct task_struct *tsk; - int i = __ffs(pending); - - pending &= ~(1 << i); + for (i = 0; i < NR_SOFTIRQS; i++) { + struct task_struct *tsk = sr->runner[i]; - tsk = sr->runner[i]; /* * The wakeup code in rtmutex.c wakes up the task * _before_ it sets pi_blocked_on to NULL under -- 1.7.10.4
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