Date:   Fri, 27 Jan 2023 03:22:16 -0500
From:   "Michael S. Tsirkin" <mst@redhat.com>
To:     Yongji Xie <xieyongji@bytedance.com>
Cc:     Christoph Hellwig <hch@lst.de>, Jason Wang <jasowang@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        virtualization <virtualization@lists.linux-foundation.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 01/11] genirq/affinity:: Export
 irq_create_affinity_masks()
Message-ID: <20230127032039-mutt-send-email-mst@kernel.org>
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On Mon, Dec 19, 2022 at 05:36:02PM +0800, Yongji Xie wrote:
> On Mon, Dec 19, 2022 at 3:33 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Mon, Dec 05, 2022 at 04:41:17PM +0800, Xie Yongji wrote:
> > > Export irq_create_affinity_masks() so that some modules
> > > can make use of it to implement interrupt affinity
> > > spreading mechanism.
> > >
> > > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> >
> > So this got nacked, what's the plan now?
> >
> 
> I‘d like to check with Christoph again first.
> 
> Hi Christoph,
> 
> Jason will post some patches to get rid of the DMA API for vDPA
> simulators. And the irq affinity algorithm is independent of the IRQ
> subsystem IIUC. So could you allow this patch so that we can reuse the
> algorithm to select the best CPU (per-cpu affinity if possible, or at
> least per-node) to run the virtqueue's irq callback.
> 
> Thanks,
> Yongji

I think you need to explain why you are building low level
affinity masks.  what's the plan now?

> > > ---
> > >  kernel/irq/affinity.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > >
> > > diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
> > > index d9a5c1d65a79..f074a7707c6d 100644
> > > --- a/kernel/irq/affinity.c
> > > +++ b/kernel/irq/affinity.c
> > > @@ -487,6 +487,7 @@ irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
> > >
> > >       return masks;
> > >  }
> > > +EXPORT_SYMBOL_GPL(irq_create_affinity_masks);
> > >
> > >  /**
> > >   * irq_calc_affinity_vectors - Calculate the optimal number of vectors
> > > --
> > > 2.20.1
> >