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genirq: honour default IRQ affinity setting during migration

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Userspace can set the default IRQ affinity setting by writing into
/proc/irq/default_smp_affinity file. When an IRQ affinity is
broken during isolation/hotplug,override the affinity to online and
un-isolated CPUs from the default affinity CPUs. If no such CPU
is available, then only override with cpu_online_mask.

Change-Id: I7578728ed0d7c17c5890d9916cfd6451d1968568
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
This commit is contained in:
Pavankumar Kondeti 2017-06-16 09:36:25 +05:30
parent cd6d19b8e4
commit 971af7d6ed
1 changed files with 12 additions and 1 deletions
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13
kernel/irq/cpuhotplug.c
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@ -36,10 +36,21 @@ static bool migrate_one_irq(struct irq_desc *desc)
affinity = &available_cpus;
if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
/*
* The order of preference for selecting a fallback CPU is
*
* (1) online and un-isolated CPU from default affinity
* (2) online and un-isolated CPU
* (3) online CPU
*/
cpumask_andnot(&available_cpus, cpu_online_mask,
cpu_isolated_mask);
if (cpumask_empty(affinity))
if (cpumask_intersects(&available_cpus, irq_default_affinity))
cpumask_and(&available_cpus, &available_cpus,
irq_default_affinity);
else if (cpumask_empty(&available_cpus))
affinity = cpu_online_mask;
/*
* We are overriding the affinity with all online and
* un-isolated cpus. irq_set_affinity_locked() call