Commit 8f31a984 authored Jun 20, 2017 by Thomas Gleixner

genirq/cpuhotplug: Avoid irq affinity setting for single targets

Avoid trying to add a newly online CPU to the effective affinity mask of an
started up interrupt. That interrupt will either stay on the already online
CPU or move around for no value.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235447.431321047@linutronix.de

parent d52dd441

kernel/irq/cpuhotplug.c

+10 −2

Original line number	Diff line number	Diff line
		@@ -148,9 +148,17 @@ static void irq_restore_affinity_of_irq(struct irq_desc *desc, unsigned int cpu)
		!irq_data_get_irq_chip(data) \|\| !cpumask_test_cpu(cpu, affinity))
		return;

		if (irqd_is_managed_and_shutdown(data))
		if (irqd_is_managed_and_shutdown(data)) {
		irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
		else
		return;
		}

		/*
		* If the interrupt can only be directed to a single target
		* CPU then it is already assigned to a CPU in the affinity
		* mask. No point in trying to move it around.
		*/
		if (!irqd_is_single_target(data))
		irq_set_affinity_locked(data, affinity, false);
		}