Messages in this thread Patch in this message | | | Date | Mon, 15 Feb 2021 19:10:27 +0100 | From | Sebastian Andrzej Siewior <> | Subject | [PATCH RT] smp: Wake ksoftirqd on PREEMPT_RT instead do_softirq(). |
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The softirq implementation on PREEMPT_RT does not provide do_softirq(). The other user of do_softirq() is replaced with a local_bh_disable() + enable() around the possible raise-softirq invocation. This can not be done here because migration_cpu_stop() is invoked with disabled preemption.
Wake the softirq thread on PREEMPT_RT if there are any pending softirqs.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- kernel/smp.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)
--- a/kernel/smp.c +++ b/kernel/smp.c @@ -450,8 +450,18 @@ void flush_smp_call_function_from_idle(v local_irq_save(flags); flush_smp_call_function_queue(true); - if (local_softirq_pending()) - do_softirq(); + + if (local_softirq_pending()) { + + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) { + do_softirq(); + } else { + struct task_struct *ksoftirqd = this_cpu_ksoftirqd(); + + if (ksoftirqd && ksoftirqd->state != TASK_RUNNING) + wake_up_process(ksoftirqd); + } + } local_irq_restore(flags); }
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