linux-kernel - Re: [PATCH 0/3] fix interrupt swamp in NVMe

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Message-ID: <20190820150511.GD11202@localhost.localdomain>
Date:   Tue, 20 Aug 2019 09:05:11 -0600
From:   Keith Busch <kbusch@...nel.org>
To:     John Garry <john.garry@...wei.com>
Cc:     Ming Lei <tom.leiming@...il.com>,
        "longli@...uxonhyperv.com" <longli@...uxonhyperv.com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "Busch, Keith" <keith.busch@...el.com>, Jens Axboe <axboe@...com>,
        Christoph Hellwig <hch@....de>,
        Sagi Grimberg <sagi@...mberg.me>,
        linux-nvme <linux-nvme@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Long Li <longli@...rosoft.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        chenxiang <chenxiang66@...ilicon.com>
Subject: Re: [PATCH 0/3] fix interrupt swamp in NVMe

On Tue, Aug 20, 2019 at 01:59:32AM -0700, John Garry wrote:
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index e8f7f179bf77..cb483a055512 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -966,9 +966,13 @@ irq_thread_check_affinity(struct irq_desc *desc, 
> struct irqaction *action)
>   	 * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
>   	 */
>   	if (cpumask_available(desc->irq_common_data.affinity)) {
> +		struct irq_data *irq_data = &desc->irq_data;
>   		const struct cpumask *m;
> 
> -		m = irq_data_get_effective_affinity_mask(&desc->irq_data);
> +		if (action->flags & IRQF_IRQ_AFFINITY)
> +			m = desc->irq_common_data.affinity;
> +		else
> +			m = irq_data_get_effective_affinity_mask(irq_data);
>   		cpumask_copy(mask, m);
>   	} else {
>   		valid = false;
> -- 
> 2.17.1
> 
> As Ming mentioned in that same thread, we could even make this policy 
> for managed interrupts.

Ack, I really like this option!