linux CPU hotplug中断迁移

CPU热插拔中断迁移

最新推荐文章于 2024-05-11 15:45:28 发布

原创最新推荐文章于 2024-05-11 15:45:28 发布 · 2.2k 阅读

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CC 4.0 BY-SA版权

本文介绍了一种在CPU热插拔过程中实现中断迁移的方法。该方法通过设置新的CPU亲和性来完成从旧CPU到新CPU的中断迁移。当某个CPU被标记为离线时，会将该CPU上的所有中断迁移到其他可用CPU上。

找到当前CPU上的中断，通过cpu_online_mask和affinity找到新的CPU，通过

desc->chip->set_affinity进行迁移和route

#ifdef CONFIG_HOTPLUG_CPU

static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu)
{
pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->cpu, cpu);

spin_lock_irq(&desc->lock);
desc->chip->set_affinity(irq, cpumask_of(cpu));
spin_unlock_irq(&desc->lock);
}

/*
* The CPU has been marked offline. Migrate IRQs off this CPU. If
* the affinity settings do not allow other CPUs, force them onto any
* available CPU.
*/
void migrate_irqs(void)
{
unsigned int i, cpu = smp_processor_id();

for (i = 0; i < NR_IRQS; i++) {
struct irq_desc *desc = irq_desc + i;

if (desc->cpu == cpu) {
unsigned int newcpu = cpumask_any_and(desc->affinity,
cpu_online_mask);
if (newcpu >= nr_cpu_ids) {
if (printk_ratelimit())
printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
i, cpu);

cpumask_setall(desc->affinity);
newcpu = cpumask_any_and(desc->affinity,
cpu_online_mask);
}

route_irq(desc, i, newcpu);
}
}
}
#endif /* CONFIG_HOTPLUG_CPU */