Hi, > -----Original Message----- > From: Maxime Coquelin <[email protected]> > Sent: Tuesday, April 13, 2021 4:51 PM > To: Hu, Jiayu <[email protected]>; Jiang, Cheng1 <[email protected]>; > Xia, Chenbo <[email protected]>; Thomas Monjalon > <[email protected]> > Cc: [email protected]; Yang, YvonneX <[email protected]>; Wang, Yinan > <[email protected]>; [email protected] > Subject: Re: [PATCH] examples/vhost: fix ioat ring space in callbacks > > > > On 4/7/21 9:54 AM, Hu, Jiayu wrote: > > Hi Maxime, > > > >> -----Original Message----- > >> From: Maxime Coquelin <[email protected]> > >> Sent: Wednesday, April 7, 2021 3:48 PM > >> To: Jiang, Cheng1 <[email protected]>; Xia, Chenbo > >> <[email protected]>; Thomas Monjalon <[email protected]> > >> Cc: [email protected]; Hu, Jiayu <[email protected]>; Yang, YvonneX > >> <[email protected]>; Wang, Yinan <[email protected]>; > >> [email protected] > >> 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: [email protected] > >>> > >>> Signed-off-by: Cheng Jiang <[email protected]> > >>> --- > >>> 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- > bruc > > [email protected]/ > > OK, thanks for the pointer. > > While this new API is being reviewed, and for LTS, let's pick your patch. As > soon as Bruce patch is merged, please send a new patch on top to make use > of this API.
Sure, thanks a lot. Cheng > > Reviewed-by: Maxime Coquelin <[email protected]> > > Thanks, > Maxime > > > Thanks, > > Jiayu > >> > >>> dma_info->nr++; > >>> i++; > >>> } > >>> > >
