Re: [PATCH 04/15] genirq: Support dynamic migration for managed interrupts

[Frederic Weisbecker <frederic@kernel.org>]

Le Wed, Mar 25, 2026 at 05:09:35PM +0800, Qiliang Yuan a écrit :
> Managed interrupts currently have their affinity determined once,
> honoring boot-time isolation settings. There is no mechanism to migrate
> them when housekeeping boundaries change at runtime.
> 
> Enable managed interrupts to respond dynamically to housekeeping updates.
> 
> This ensures that managed interrupts are migrated away from newly
> isolated CPUs or redistributed when housekeeping CPUs are added.
> 
> Signed-off-by: Qiliang Yuan <realwujing@gmail.com>
> ---
>  kernel/irq/manage.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 49 insertions(+)
> 
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index 349ae7979da0e..f2cba3d7ef624 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -2811,3 +2811,52 @@ bool irq_check_status_bit(unsigned int irq, unsigned int bitmask)
>  	return res;
>  }
>  EXPORT_SYMBOL_GPL(irq_check_status_bit);
> +
> +#ifdef CONFIG_SMP
> +static int irq_housekeeping_reconfigure(struct notifier_block *nb,
> +				       unsigned long action, void *data)
> +{
> +	struct housekeeping_update *upd = data;
> +	unsigned int irq;
> +
> +	if (action != HK_UPDATE_MASK || upd->type != HK_TYPE_MANAGED_IRQ)
> +		return NOTIFY_OK;
> +
> +	irq_lock_sparse();
> +	for_each_active_irq(irq) {
> +		struct irq_data *irqd;
> +		struct irq_desc *desc;
> +
> +		desc = irq_to_desc(irq);
> +		if (!desc)
> +			continue;
> +
> +		scoped_guard(raw_spinlock_irqsave, &desc->lock) {
> +			irqd = irq_desc_get_irq_data(desc);
> +			if (!irqd_affinity_is_managed(irqd) || !desc->action ||
> +			    !irq_data_get_irq_chip(irqd))
> +				continue;
> +
> +			/*
> +			 * Re-apply existing affinity to honor the new
> +			 * housekeeping mask via __irq_set_affinity() logic.
> +			 */
> +			irq_set_affinity_locked(irqd, irq_data_get_affinity_mask(irqd), false);
> +		}
> +	}
> +	irq_unlock_sparse();
> +
> +	return NOTIFY_OK;
> +}
> +
> +static struct notifier_block irq_housekeeping_nb = {
> +	.notifier_call = irq_housekeeping_reconfigure,
> +};
> +
> +static int __init irq_init_housekeeping_notifier(void)
> +{
> +	housekeeping_register_notifier(&irq_housekeeping_nb);
> +	return 0;
> +}
> +core_initcall(irq_init_housekeeping_notifier);
> +#endif

We probably want to do that for HK_TYPE_DOMAIN update on housekeeping_update().

Thanks.

> 
> -- 
> 2.43.0
> 

-- 
Frederic Weisbecker
SUSE Labs