Commit c7e6d704 authored Jul 31, 2019 by Anna-Maria Gleixner Committed by Thomas Gleixner Aug 01, 2019

itimers: Prepare for PREEMPT_RT



Use the hrtimer_cancel_wait_running() synchronization mechanism to prevent
priority inversion and live locks on PREEMPT_RT.

As a benefit the retry loop gains the missing cpu_relax() on !RT.

[ tglx: Split out of combo patch ]

Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190730223828.690771827@linutronix.de

parent a125ecc1

kernel/time/itimer.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -213,6 +213,7 @@ again:
		/* We are sharing ->siglock with it_real_fn() */
		if (hrtimer_try_to_cancel(timer) < 0) {
		spin_unlock_irq(&tsk->sighand->siglock);
		hrtimer_cancel_wait_running(timer);
		goto again;
		}
		expires = timeval_to_ktime(value->it_value);

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