nohz: nohz full depends on irq work self IPI support
authorFrederic Weisbecker <fweisbec@gmail.com>
Sun, 17 Aug 2014 23:36:07 +0000 (01:36 +0200)
committerFrederic Weisbecker <fweisbec@gmail.com>
Sat, 13 Sep 2014 16:46:41 +0000 (18:46 +0200)
commit9b01f5bf3999a3db5b1bbd9fdfd80d8d304e94ee
tree6536b57cc841ab42187b94245ca7fddf192a12ba
parent4327b15f64b2580dad40d2674d50fc44f1b699c1
nohz: nohz full depends on irq work self IPI support

The nohz full functionality depends on IRQ work to trigger its own
interrupts. As it's used to restart the tick, we can't rely on the tick
fallback for irq work callbacks, ie: we can't use the tick to restart
the tick itself.

Lets reject the full dynticks initialization if that arch support isn't
available.

As a side effect, this makes sure that nohz kick is never called from
the tick. That otherwise would result in illegal hrtimer self-cancellation
and lockup.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
kernel/time/tick-sched.c