From: Thomas Gleixner <tglx@linutronix.de>
To: Wei Gong <gongwei833x@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] genirq: avoid long loops in handle_edge_irq
Date: Thu, 28 Sep 2023 11:28:10 +0200 [thread overview]
Message-ID: <87bkdmfxzp.ffs@tglx> (raw)
In-Reply-To: <ZRTjgdptO5jswGwC@MacBook-Pro-3.local>
On Thu, Sep 28 2023 at 10:22, Wei Gong wrote:
> On Wed, Sep 27, 2023 at 05:25:24PM +0200, Thomas Gleixner wrote:
>> On Wed, Sep 27 2023 at 15:53, Wei Gong wrote:
>> > O Tue, Sep 26, 2023 at 02:28:21PM +0200, Thomas Gleixner wrote:
>> >> On Mon, Sep 25 2023 at 10:51, Wei Gong wrote:
>> >> > diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
>> >> > index dc94e0bf2c94..6da455e1a692 100644
>> >> > --- a/kernel/irq/chip.c
>> >> > +++ b/kernel/irq/chip.c
>> >> > @@ -831,7 +831,8 @@ void handle_edge_irq(struct irq_desc *desc)
>> >> > handle_irq_event(desc);
>> >> >
>> >> > } while ((desc->istate & IRQS_PENDING) &&
>> >> > - !irqd_irq_disabled(&desc->irq_data));
>> >> > + !irqd_irq_disabled(&desc->irq_data) &&
>> >> > + cpumask_test_cpu(smp_processor_id(), irq_data_get_affinity_mask(&desc->irq_data)));
>> >>
>> >> Assume affinty mask has CPU0 and CPU1 set and the loop is on CPU0, but
>> >> the effective affinity is on CPU1 then how is this going to move the
>> >> interrupt?
>> >
>> > Loop is on the CPU0 means that the previous effective affinity was on CPU0.
>> > When the previous effective affinity is a subset of the new affinity mask,
>> > the effective affinity will not be updated.
>>
>> That's an implementation detail of a particular interrupt chip driver,
>> but not a general guaranteed behaviour.
>>
>
> Can replacing irq_data_get_affinity_mask with irq_data_get_effective_affinity_mask
> solve this issue?
Yes.
prev parent reply other threads:[~2023-09-28 9:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-25 2:51 [PATCH v2] genirq: avoid long loops in handle_edge_irq Wei Gong
2023-09-26 12:28 ` Thomas Gleixner
2023-09-27 7:53 ` Wei Gong
2023-09-27 15:25 ` Thomas Gleixner
2023-09-28 2:22 ` Wei Gong
2023-09-28 9:28 ` Thomas Gleixner [this message]
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