From: Jason Wang <jasowang@redhat.com> To: Yongji Xie <xieyongji@bytedance.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: [RFC v4 10/11] vduse: Introduce a workqueue for irq injection Date: Fri, 5 Mar 2021 11:42:31 +0800 [thread overview] Message-ID: <b3faa4a6-a65b-faf7-985a-b2771533c8bb@redhat.com> (raw) In-Reply-To: <CACycT3u0+LTbtFMS75grKGZ2mnXzHnKug+HGWbf+nqVybqwkZQ@mail.gmail.com> On 2021/3/5 11:30 上午, Yongji Xie wrote: > 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. Yes, but I still don't get why used ring is empty after the ioctl()? Used ring does not use bounce page so it should be visible to the kernel driver. What did I miss :) ? Thanks > > Thanks, > Yongji >
WARNING: multiple messages have this Message-ID (diff)
From: Jason Wang <jasowang@redhat.com> To: Yongji Xie <xieyongji@bytedance.com> Cc: Jens Axboe <axboe@kernel.dk>, Jonathan Corbet <corbet@lwn.net>, kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>, linux-aio@kvack.org, netdev@vger.kernel.org, Randy Dunlap <rdunlap@infradead.org>, Matthew Wilcox <willy@infradead.org>, virtualization@lists.linux-foundation.org, Christoph Hellwig <hch@infradead.org>, Bob Liu <bob.liu@oracle.com>, bcrl@kvack.org, viro@zeniv.linux.org.uk, Stefan Hajnoczi <stefanha@redhat.com>, linux-fsdevel@vger.kernel.org Subject: Re: [RFC v4 10/11] vduse: Introduce a workqueue for irq injection Date: Fri, 5 Mar 2021 11:42:31 +0800 [thread overview] Message-ID: <b3faa4a6-a65b-faf7-985a-b2771533c8bb@redhat.com> (raw) In-Reply-To: <CACycT3u0+LTbtFMS75grKGZ2mnXzHnKug+HGWbf+nqVybqwkZQ@mail.gmail.com> On 2021/3/5 11:30 上午, Yongji Xie wrote: > 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. Yes, but I still don't get why used ring is empty after the ioctl()? Used ring does not use bounce page so it should be visible to the kernel driver. What did I miss :) ? Thanks > > Thanks, > Yongji > _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2021-03-05 3:42 UTC|newest] Thread overview: 96+ 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 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 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 2021-03-02 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 2021-03-02 6:50 ` Jason Wang 2021-02-23 11:50 ` [RFC v4 05/11] vdpa: Support transferring virtual addressing during DMA mapping Xie Yongji 2021-02-24 7:37 ` Dan Carpenter 2021-02-24 7:37 ` Dan Carpenter 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 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 4:20 ` Jason Wang 2021-03-04 5:12 ` Yongji Xie 2021-03-05 3:35 ` Jason Wang 2021-03-05 3:35 ` Jason Wang 2021-03-05 6:15 ` Yongji Xie 2021-03-05 6:51 ` Jason Wang 2021-03-05 7:13 ` Yongji Xie 2021-03-05 7:27 ` Jason Wang 2021-03-05 7:27 ` Jason Wang 2021-03-05 7:59 ` Yongji Xie 2021-03-08 3:17 ` Jason Wang 2021-03-08 3:17 ` Jason Wang 2021-03-08 3:45 ` Yongji Xie 2021-03-08 3:52 ` Jason Wang 2021-03-08 3:52 ` Jason Wang 2021-03-08 5:05 ` Yongji Xie 2021-03-08 7:04 ` Jason Wang 2021-03-08 7:04 ` 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 2021-02-23 15:44 ` kernel test robot 2021-02-23 20:24 ` kernel test robot 2021-03-04 6:27 ` Jason Wang 2021-03-04 6:27 ` Jason Wang 2021-03-04 8:05 ` Yongji Xie 2021-03-05 3:20 ` Jason Wang 2021-03-05 3:20 ` Jason Wang 2021-03-05 3:49 ` Yongji Xie 2021-03-10 12:58 ` Jason Wang 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 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 6:59 ` Jason Wang 2021-03-04 8:58 ` Yongji Xie 2021-03-05 3:04 ` Jason Wang 2021-03-05 3:04 ` Jason Wang 2021-03-05 3:30 ` Yongji Xie 2021-03-05 3:42 ` Jason Wang [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 7:01 ` Jason Wang 2021-03-05 7:27 ` Yongji Xie 2021-03-05 7:36 ` Jason Wang 2021-03-05 7:36 ` Jason Wang 2021-03-05 8:12 ` Yongji Xie 2021-03-08 3:04 ` Jason Wang 2021-03-08 3:04 ` Jason Wang 2021-03-08 4:50 ` Yongji Xie 2021-03-08 7:01 ` Jason Wang 2021-03-08 7:01 ` Jason Wang 2021-03-08 7:16 ` Yongji Xie 2021-03-08 7:29 ` Jason Wang 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 7:30 ` Jason Wang 2021-03-04 8:19 ` Yongji Xie 2021-03-05 3:11 ` Jason Wang 2021-03-05 3:11 ` Jason Wang 2021-03-05 3:37 ` Yongji Xie 2021-03-05 3:44 ` Jason Wang 2021-03-05 3:44 ` Jason Wang 2021-03-05 6:40 ` Yongji Xie
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