From: Yongji Xie <xieyongji@bytedance.com>
To: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
Stefano Garzarella <sgarzare@redhat.com>,
Parav Pandit <parav@nvidia.com>, Bob Liu <bob.liu@oracle.com>,
Christoph Hellwig <hch@infradead.org>,
Randy Dunlap <rdunlap@infradead.org>,
Matthew Wilcox <willy@infradead.org>,
viro@zeniv.linux.org.uk, Jens Axboe <axboe@kernel.dk>,
bcrl@kvack.org, Jonathan Corbet <corbet@lwn.net>,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, kvm@vger.kernel.org, linux-aio@kvack.org,
linux-fsdevel@vger.kernel.org
Subject: Re: Re: [RFC v4 10/11] vduse: Introduce a workqueue for irq injection
Date: Fri, 5 Mar 2021 11:30:24 +0800 [thread overview]
Message-ID: <CACycT3u0+LTbtFMS75grKGZ2mnXzHnKug+HGWbf+nqVybqwkZQ@mail.gmail.com> (raw)
In-Reply-To: <2d3418d9-856c-37ee-7614-af5b721becd7@redhat.com>
On Fri, Mar 5, 2021 at 11:05 AM Jason Wang <jasowang@redhat.com> wrote:
>
>
> On 2021/3/4 4:58 下午, Yongji Xie wrote:
> > On Thu, Mar 4, 2021 at 2:59 PM Jason Wang <jasowang@redhat.com> wrote:
> >>
> >> On 2021/2/23 7:50 下午, Xie Yongji wrote:
> >>> This patch introduces a workqueue to support injecting
> >>> virtqueue's interrupt asynchronously. This is mainly
> >>> for performance considerations which makes sure the push()
> >>> and pop() for used vring can be asynchronous.
> >>
> >> Do you have pref numbers for this patch?
> >>
> > No, I can do some tests for it if needed.
> >
> > Another problem is the VIRTIO_RING_F_EVENT_IDX feature will be useless
> > if we call irq callback in ioctl context. Something like:
> >
> > virtqueue_push();
> > virtio_notify();
> > ioctl()
> > -------------------------------------------------
> > irq_cb()
> > virtqueue_get_buf()
> >
> > The used vring is always empty each time we call virtqueue_push() in
> > userspace. Not sure if it is what we expected.
>
>
> I'm not sure I get the issue.
>
> THe used ring should be filled by virtqueue_push() which is done by
> userspace before?
>
After userspace call virtqueue_push(), it always call virtio_notify()
immediately. In traditional VM (vhost-vdpa) cases, virtio_notify()
will inject an irq to VM and return, then vcpu thread will call
interrupt handler. But in container (virtio-vdpa) cases,
virtio_notify() will call interrupt handler directly. So it looks like
we have to optimize the virtio-vdpa cases. But one problem is we don't
know whether we are in the VM user case or container user case.
Thanks,
Yongji
next prev parent reply other threads:[~2021-03-05 3:30 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-23 11:50 [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
2021-02-23 11:50 ` [RFC v4 01/11] eventfd: Increase the recursion depth of eventfd_signal() Xie Yongji
2021-03-02 6:44 ` Jason Wang
2021-03-02 10:32 ` Yongji Xie
2021-02-23 11:50 ` [RFC v4 02/11] vhost-vdpa: protect concurrent access to vhost device iotlb Xie Yongji
2021-03-02 6:47 ` Jason Wang
2021-03-02 10:20 ` Yongji Xie
2021-02-23 11:50 ` [RFC v4 03/11] vhost-iotlb: Add an opaque pointer for vhost IOTLB Xie Yongji
2021-03-02 6:49 ` Jason Wang
2021-02-23 11:50 ` [RFC v4 04/11] vdpa: Add an opaque pointer for vdpa_config_ops.dma_map() Xie Yongji
2021-03-02 6:50 ` Jason Wang
2021-02-23 11:50 ` [RFC v4 05/11] vdpa: Support transferring virtual addressing during DMA mapping Xie Yongji
2021-03-03 10:52 ` Mika Penttilä
2021-03-03 12:45 ` Yongji Xie
2021-03-03 13:38 ` Mika Penttilä
2021-03-04 3:07 ` Jason Wang
2021-03-04 5:40 ` Yongji Xie
2021-02-23 11:50 ` [RFC v4 06/11] vduse: Implement an MMU-based IOMMU driver Xie Yongji
2021-03-04 4:20 ` Jason Wang
2021-03-04 5:12 ` Yongji Xie
2021-03-05 3:35 ` Jason Wang
2021-03-05 6:15 ` Yongji Xie
[not found] ` <4db35f8c-ee3a-90fb-8d14-5d6014b4f6fa@redhat.com>
2021-03-05 7:13 ` Yongji Xie
2021-03-05 7:27 ` Jason Wang
2021-03-05 7:59 ` Yongji Xie
2021-03-08 3:17 ` Jason Wang
2021-03-08 3:45 ` Yongji Xie
2021-03-08 3:52 ` Jason Wang
2021-03-08 5:05 ` Yongji Xie
2021-03-08 7:04 ` Jason Wang
2021-03-08 7:08 ` Yongji Xie
2021-02-23 11:50 ` [RFC v4 07/11] vduse: Introduce VDUSE - vDPA Device in Userspace Xie Yongji
2021-03-04 6:27 ` Jason Wang
2021-03-04 8:05 ` Yongji Xie
2021-03-05 3:20 ` Jason Wang
2021-03-05 3:49 ` Yongji Xie
2021-03-10 12:58 ` Jason Wang
2021-03-11 2:28 ` Yongji Xie
2021-02-23 11:50 ` [RFC v4 08/11] vduse: Add config interrupt support Xie Yongji
2021-02-23 11:50 ` [RFC v4 09/11] Documentation: Add documentation for VDUSE Xie Yongji
2021-03-04 6:39 ` Jason Wang
2021-03-04 10:35 ` Yongji Xie
2021-02-23 11:50 ` [RFC v4 10/11] vduse: Introduce a workqueue for irq injection Xie Yongji
2021-03-04 6:59 ` Jason Wang
2021-03-04 8:58 ` Yongji Xie
2021-03-05 3:04 ` Jason Wang
2021-03-05 3:30 ` Yongji Xie [this message]
2021-03-05 3:42 ` Jason Wang
2021-03-05 6:36 ` Yongji Xie
2021-03-05 7:01 ` Jason Wang
2021-03-05 7:27 ` Yongji Xie
2021-03-05 7:36 ` Jason Wang
2021-03-05 8:12 ` Yongji Xie
2021-03-08 3:04 ` Jason Wang
2021-03-08 4:50 ` Yongji Xie
2021-03-08 7:01 ` Jason Wang
2021-03-08 7:16 ` Yongji Xie
2021-03-08 7:29 ` Jason Wang
2021-02-23 11:50 ` [RFC v4 11/11] vduse: Support binding irq to the specified cpu Xie Yongji
2021-03-04 7:30 ` Jason Wang
2021-03-04 8:19 ` Yongji Xie
2021-03-05 3:11 ` Jason Wang
2021-03-05 3:37 ` Yongji Xie
2021-03-05 3:44 ` Jason Wang
2021-03-05 6:40 ` Yongji Xie
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