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Commit 3a424f64 authored by Pavankumar Kondeti's avatar Pavankumar Kondeti Committed by Satya Durga Srinivasu Prabhala
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genirq: Honour IRQ's affinity hint during migration 



An IRQ affinity is broken during hotplug/isolation when there
are no online and un-isolated CPUs in the current affinity mask.
An online and un-isolated CPU from the irq_default_affinity mask
(i.e /proc/irq/default_smp_affinity) is used as the current
affinity. However Individual IRQs can have their affinity hint
set via irq_set_affinity_hint() API. When such hint is available,
use it instead of the irq_default_affinity which is a system level
setting.

Change-Id: I53a537582ec4e1aed0c59b49f4fd5b6ca7c0c332
Signed-off-by: default avatarPavankumar Kondeti <pkondeti@codeaurora.org>
Signed-off-by: default avatarSatya Durga Srinivasu Prabhala <satyap@codeaurora.org>
parent 281266a3

kernel/irq/cpuhotplug.c

+6 −2
Original line number Diff line number Diff line
@@ -116,6 +116,8 @@ static bool migrate_one_irq(struct irq_desc *desc) 
	affinity = &available_cpus;



	if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {

		const struct cpumask *default_affinity;



		/*

		 * If the interrupt is managed, then shut it down and leave

		 * the affinity untouched.
@@ -125,6 +127,8 @@ static bool migrate_one_irq(struct irq_desc *desc) 
			irq_shutdown(desc);

			return false;

		}



		default_affinity = desc->affinity_hint ? : irq_default_affinity;

		/*

		 * The order of preference for selecting a fallback CPU is

		 *
@@ -134,9 +138,9 @@ static bool migrate_one_irq(struct irq_desc *desc) 
		 */

		cpumask_andnot(&available_cpus, cpu_online_mask,

							cpu_isolated_mask);

		if (cpumask_intersects(&available_cpus, irq_default_affinity))

		if (cpumask_intersects(&available_cpus, default_affinity))

			cpumask_and(&available_cpus, &available_cpus,

							irq_default_affinity);

							default_affinity);

		else if (cpumask_empty(&available_cpus))

			affinity = cpu_online_mask;