If we enqueue a work while in dyntick idle mode and the arch doesn't
have self-IPI support, we may not find an opportunity to run the work
before a while.
In this case, exit the idle loop to re-evaluate irq_work_needs_cpu()
and restart the tick.
Signed-off-by: Frederic Weisbecker <fweis...@gmail.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Paul Gortmaker <paul.gortma...@windriver.com>
---
kernel/irq_work.c | 11 +++++++++++
1 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index ce72b20..b500271 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -76,6 +76,17 @@ static void __irq_work_queue(struct irq_work *work)
*/
if (!arch_irq_work_has_ipi() || tick_nohz_tick_stopped())
arch_irq_work_raise();
+
+ /*
+ * If we rely on the timer tick or some obscure way to run the
work
+ * while the CPU is in dyntick idle mode, we may not have an
opportunity
+ * to do so before a while. Let's just exit the idle loop and
hope we
+ * haven't yet reached the last need_resched() check before the
CPU goes
+ * to low power mode.
+ */
+ if (!arch_irq_work_has_ipi() && tick_nohz_tick_stopped()
+ && is_idle_task(current))
+ set_need_resched();
}
out:
preempt_enable();
--
1.7.5.4
--
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