Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <Yza1u1KfKa7ycQm0@T590> <Yzs9xQlVuW41TuNC@fedora>
 <YzwARuAZdaoGTUfP@T590> <CAJSP0QXVK=wUy_JgJ9NmNMtKTRoRX0MwOZUuFWU-1mVWWKij8A@mail.gmail.com>
 <20221006101400.GC7636@redhat.com>
In-Reply-To: <20221006101400.GC7636@redhat.com>
From:   Stefan Hajnoczi <stefanha@gmail.com>
Date:   Wed, 12 Oct 2022 10:15:28 -0400
Message-ID: <CAJSP0QXbnhkVgfgMfC=MAyvF63Oof_ZGDvNFhniDCvVY-f6Hmw@mail.gmail.com>
Subject: Re: ublk-qcow2: ublk-qcow2 is available
To:     "Richard W.M. Jones" <rjones@redhat.com>
Cc:     Ming Lei <tom.leiming@gmail.com>,
        Stefan Hajnoczi <stefanha@redhat.com>,
        io-uring@vger.kernel.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Kirill Tkhai <kirill.tkhai@openvz.org>,
        Manuel Bentele <development@manuel-bentele.de>,
        qemu-devel@nongnu.org, Kevin Wolf <kwolf@redhat.com>,
        Xie Yongji <xieyongji@bytedance.com>,
        "Denis V. Lunev" <den@openvz.org>,
        Stefano Garzarella <sgarzare@redhat.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Thu, 6 Oct 2022 at 06:14, Richard W.M. Jones <rjones@redhat.com> wrote:
>
> On Tue, Oct 04, 2022 at 09:53:32AM -0400, Stefan Hajnoczi wrote:
> > qemu-nbd doesn't use io_uring to handle the backend IO,
>
> Would this be fixed by your (not yet upstream) libblkio driver for
> qemu?

I was wrong, qemu-nbd has syntax to use io_uring:

  $ qemu-nbd ... --image-opts driver=file,filename=test.img,aio=io_uring

The new libblkio driver will also support io_uring, but QEMU's
built-in io_uring support is already available and can be used as
shown above.

Stefan