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: <20221227022528.609839-1-mie@igel.co.jp> <20221227022528.609839-3-mie@igel.co.jp>
 <CACGkMEtAaYpuZtS0gx_m931nFzcvqSNK9BhvUZH_tZXTzjgQCg@mail.gmail.com>
 <20221227020425-mutt-send-email-mst@kernel.org> <CANXvt5pXkS=TTOU0+Lkx6CjcV7xvDHRS6FbFikJ4Ww8832sg8g@mail.gmail.com>
 <20221227025534-mutt-send-email-mst@kernel.org>
In-Reply-To: <20221227025534-mutt-send-email-mst@kernel.org>
From:   Shunsuke Mie <mie@igel.co.jp>
Date:   Tue, 27 Dec 2022 16:57:12 +0900
Message-ID: <CANXvt5qh885mi7shJ9jiZbCBeSVR7=bDhx29GnpL1ZHymb_Rxw@mail.gmail.com>
Subject: Re: [RFC PATCH 2/9] vringh: remove vringh_iov and unite to vringh_kiov
To:     "Michael S. Tsirkin" <mst@redhat.com>
Cc:     Jason Wang <jasowang@redhat.com>,
        Rusty Russell <rusty@rustcorp.com.au>, kvm@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

2022=E5=B9=B412=E6=9C=8827=E6=97=A5(=E7=81=AB) 16:56 Michael S. Tsirkin <ms=
t@redhat.com>:
>
> On Tue, Dec 27, 2022 at 04:13:49PM +0900, Shunsuke Mie wrote:
> > 2022=E5=B9=B412=E6=9C=8827=E6=97=A5(=E7=81=AB) 16:05 Michael S. Tsirkin=
 <mst@redhat.com>:
> > >
> > > On Tue, Dec 27, 2022 at 02:04:03PM +0800, Jason Wang wrote:
> > > > On Tue, Dec 27, 2022 at 10:25 AM Shunsuke Mie <mie@igel.co.jp> wrot=
e:
> > > > >
> > > > > struct vringh_iov is defined to hold userland addresses. However,=
 to use
> > > > > common function, __vring_iov, finally the vringh_iov converts to =
the
> > > > > vringh_kiov with simple cast. It includes compile time check code=
 to make
> > > > > sure it can be cast correctly.
> > > > >
> > > > > To simplify the code, this patch removes the struct vringh_iov an=
d unifies
> > > > > APIs to struct vringh_kiov.
> > > > >
> > > > > Signed-off-by: Shunsuke Mie <mie@igel.co.jp>
> > > >
> > > > While at this, I wonder if we need to go further, that is, switch t=
o
> > > > using an iov iterator instead of a vringh customized one.
> > > >
> > > > Thanks
> > >
> > > Possibly, but when doing changes like this one needs to be careful
> > > to avoid breaking all the inlining tricks vringh relies on for
> > > performance.
> > Definitely, I'm evaluating the performance using vringh_test. I'll add =
a
> > result of the evaluation. But, If there are other evaluation methods, c=
ould you
> > please tell me?
>
> high level tests over virtio blk and net are possible, but let's
> start with vringh_test.
Ok, I'll do it.
> > > --
> > > MST
> > >
> >
> > Best,
> > Shunsuke
>