From: "Hu, Jiayu" <jiayu.hu@intel.com>
To: Maxime Coquelin <maxime.coquelin@redhat.com>,
"Jiang, Cheng1" <cheng1.jiang@intel.com>,
"Xia, Chenbo" <chenbo.xia@intel.com>,
"Thomas Monjalon" <thomas@monjalon.net>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
"Yang, YvonneX" <yvonnex.yang@intel.com>,
"Wang, Yinan" <yinan.wang@intel.com>,
"stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] examples/vhost: fix ioat ring space in callbacks
Date: Wed, 7 Apr 2021 07:54:15 +0000 [thread overview]
Message-ID: <13e28ecd418142fda75873f7a0bc2b4d@intel.com> (raw)
In-Reply-To: <23c4f6e7-4895-44b7-4ff0-3a02f9f3f86a@redhat.com>
Hi Maxime,
> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Wednesday, April 7, 2021 3:48 PM
> To: Jiang, Cheng1 <cheng1.jiang@intel.com>; Xia, Chenbo
> <chenbo.xia@intel.com>; Thomas Monjalon <thomas@monjalon.net>
> Cc: dev@dpdk.org; Hu, Jiayu <jiayu.hu@intel.com>; Yang, YvonneX
> <yvonnex.yang@intel.com>; Wang, Yinan <yinan.wang@intel.com>;
> stable@dpdk.org
> Subject: Re: [PATCH] examples/vhost: fix ioat ring space in callbacks
>
>
>
> On 3/17/21 6:40 AM, Cheng Jiang wrote:
> > We use ioat ring space for determining if ioat callbacks can enqueue a
> > packet to ioat device. But there is one slot can't be used in ioat
> > ring due to the ioat driver design, so we need to reduce one slot in
> > ioat ring to prevent ring size mismatch in ioat callbacks.
> >
> > Fixes: 2aa47e94bfb2 ("examples/vhost: add ioat ring space count and
> check")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Cheng Jiang <Cheng1.jiang@intel.com>
> > ---
> > examples/vhost/ioat.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/examples/vhost/ioat.c b/examples/vhost/ioat.c
> > index 60b73be93..9cb5e0d50 100644
> > --- a/examples/vhost/ioat.c
> > +++ b/examples/vhost/ioat.c
> > @@ -113,7 +113,7 @@ open_ioat(const char *value)
> > goto out;
> > }
> > rte_rawdev_start(dev_id);
> > - cb_tracker[dev_id].ioat_space = IOAT_RING_SIZE;
> > + cb_tracker[dev_id].ioat_space = IOAT_RING_SIZE - 1;
>
> That really comforts me in thinking we need a generic abstraction for
> DMA devices. How is the application developer supposed to know that
> the DMA driver has such weird limitations?
>
> Can the driver be fixed to have a proper behavior?
Here is the patch of providing capacity check API for DMA:
http://patches.dpdk.org/project/dpdk/patch/20210318182042.43658-6-bruce.richardson@intel.com/
Thanks,
Jiayu
>
> > dma_info->nr++;
> > i++;
> > }
> >
next prev parent reply other threads:[~2021-04-07 7:54 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-17 5:40 Cheng Jiang
2021-03-17 6:58 ` Hu, Jiayu
2021-04-07 7:47 ` Maxime Coquelin
2021-04-07 7:54 ` Hu, Jiayu [this message]
2021-04-13 8:50 ` Maxime Coquelin
2021-04-13 9:55 ` Jiang, Cheng1
2021-04-07 8:26 ` Thomas Monjalon
2021-04-07 8:43 ` Thomas Monjalon
2021-04-18 15:10 ` Liang Ma
2021-04-07 8:48 ` Maxime Coquelin
2021-04-28 2:09 ` Xia, Chenbo
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