From: Ming Lei <ming.lei@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
"Martin K . Petersen" <martin.petersen@oracle.com>,
linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
linux-scsi@vger.kernel.org, Sagi Grimberg <sagi@grimberg.me>,
Daniel Wagner <dwagner@suse.de>, Wen Xiong <wenxiong@us.ibm.com>,
John Garry <john.garry@huawei.com>,
Hannes Reinecke <hare@suse.de>, Keith Busch <kbusch@kernel.org>,
Damien Le Moal <damien.lemoal@wdc.com>,
Jason Wang <jasowang@redhat.com>,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH V2 5/6] virtio: add one field into virtio_device for recording if device uses managed irq
Date: Mon, 5 Jul 2021 10:48:53 +0800 [thread overview]
Message-ID: <YOJzFe3xcLK279Wv@T590> (raw)
In-Reply-To: <20210702115430-mutt-send-email-mst@kernel.org>
On Fri, Jul 02, 2021 at 11:55:40AM -0400, Michael S. Tsirkin wrote:
> On Fri, Jul 02, 2021 at 11:05:54PM +0800, Ming Lei wrote:
> > blk-mq needs to know if the device uses managed irq, so add one field
> > to virtio_device for recording if device uses managed irq.
> >
> > If the driver use managed irq, this flag has to be set so it can be
> > passed to blk-mq.
> >
> > Cc: "Michael S. Tsirkin" <mst@redhat.com>
> > Cc: Jason Wang <jasowang@redhat.com>
> > Cc: virtualization@lists.linux-foundation.org
> > Signed-off-by: Ming Lei <ming.lei@redhat.com>
>
>
> The API seems somewhat confusing. virtio does not request
> a managed irq as such, does it? I think it's a decision taken
> by the irq core.
vp_request_msix_vectors():
if (desc) {
flags |= PCI_IRQ_AFFINITY;
desc->pre_vectors++; /* virtio config vector */
vdev->use_managed_irq = true;
}
err = pci_alloc_irq_vectors_affinity(vp_dev->pci_dev, nvectors,
nvectors, flags, desc);
Managed irq is used once PCI_IRQ_AFFINITY is passed to
pci_alloc_irq_vectors_affinity().
>
> Any way to query the irq to find out if it's managed?
So far the managed info isn't exported via /proc/irq, but if one irq is
managed, its smp_affinity & smp_affinity_list attributes can't be
changed successfully.
If irq's debugfs is enabled, this info can be retrieved.
Thanks,
Ming
next prev parent reply other threads:[~2021-07-05 2:49 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-02 15:05 [PATCH V2 0/6] blk-mq: fix blk_mq_alloc_request_hctx Ming Lei
2021-07-02 15:05 ` [PATCH V2 1/6] blk-mq: prepare for not deactivating hctx if managed irq isn't used Ming Lei
2021-07-02 15:05 ` [PATCH V2 2/6] nvme: pci: pass BLK_MQ_F_MANAGED_IRQ to blk-mq Ming Lei
2021-07-02 15:05 ` [PATCH V2 3/6] scsi: add flag of .use_managed_irq to 'struct Scsi_Host' Ming Lei
2021-07-05 9:25 ` John Garry
2021-07-05 9:55 ` Ming Lei
2021-07-06 5:37 ` Christoph Hellwig
2021-07-06 7:41 ` Ming Lei
2021-07-06 10:32 ` Hannes Reinecke
2021-07-07 10:53 ` Ming Lei
2021-07-02 15:05 ` [PATCH V2 4/6] scsi: set shost->use_managed_irq if driver uses managed irq Ming Lei
2021-07-05 7:35 ` John Garry
2021-07-06 5:38 ` Christoph Hellwig
2021-07-02 15:05 ` [PATCH V2 5/6] virtio: add one field into virtio_device for recording if device " Ming Lei
2021-07-02 15:55 ` Michael S. Tsirkin
2021-07-05 2:48 ` Ming Lei [this message]
2021-07-05 3:59 ` Jason Wang
2021-07-06 5:42 ` Christoph Hellwig
2021-07-06 7:53 ` Ming Lei
2021-07-07 9:06 ` Thomas Gleixner
2021-07-07 9:42 ` Ming Lei
2021-07-07 14:05 ` Christoph Hellwig
2021-07-08 6:34 ` Ming Lei
2021-07-02 15:05 ` [PATCH V2 6/6] blk-mq: don't deactivate hctx if managed irq isn't used Ming Lei
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