diff options
Diffstat (limited to 'kernel/irq/cpuhotplug.c')
| -rw-r--r-- | kernel/irq/cpuhotplug.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c index 6c8e154c7384..4684b7595e63 100644 --- a/kernel/irq/cpuhotplug.c +++ b/kernel/irq/cpuhotplug.c @@ -36,10 +36,32 @@ 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 + * below notify this mask to PM QOS affinity listener. + * That results in applying the CPU_DMA_LATENCY QOS + * to all the CPUs specified in the mask. But the low + * level irqchip driver sets the affinity of an irq + * to only one CPU. So pick only one CPU from the + * prepared mask while overriding the user affinity. + */ + affinity = cpumask_of(cpumask_any(affinity)); ret = true; } |