[dpdk-dev] [PATCH] vhost: add API for getting last_idx of vrings

[Stojaczyk, DariuszX]

It can be abandoned. I can see Zhihong added equivalent APIs called rte_vhost_get_vring_base/set_vring_base back in April.

> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas at monjalon.net]
> Sent: Thursday, July 26, 2018 5:44 PM
> To: Maxime Coquelin <maxime.coquelin at redhat.com>; Kulasek, TomaszX
> <tomaszx.kulasek at intel.com>
> Cc: dev at dpdk.org; yliu at fridaylinux.org; Verkamp, Daniel
> <daniel.verkamp at intel.com>; Harris, James R <james.r.harris at intel.com>;
> Wodkowski, PawelX <pawelx.wodkowski at intel.com>; Stojaczyk, DariuszX
> <dariuszx.stojaczyk at intel.com>
> Subject: Re: [dpdk-dev] [PATCH] vhost: add API for getting last_idx of vrings
> 
> What is the status of this patch?
> 
> 19/04/2018 16:57, Maxime Coquelin:
> > Hi Tomasz,
> >
> > On 03/28/2018 11:31 AM, Kulasek, TomaszX wrote:
> > > Hi Maxime,
> > >
> > >> -----Original Message-----
> > >> From: Maxime Coquelin [mailto:maxime.coquelin at redhat.com]
> > >> Sent: Wednesday, March 28, 2018 10:57
> > >> To: Kulasek, TomaszX <tomaszx.kulasek at intel.com>; yliu at fridaylinux.org
> > >> Cc: Verkamp, Daniel <daniel.verkamp at intel.com>; Harris, James R
> > >> <james.r.harris at intel.com>; Wodkowski, PawelX
> <pawelx.wodkowski at intel.com>;
> > >> dev at dpdk.org; Stojaczyk, DariuszX <dariuszx.stojaczyk at intel.com>
> > >> Subject: Re: [dpdk-dev] [PATCH] vhost: add API for getting last_idx of vrings
> > >>
> > >> Hi Tomasz,
> > >>
> > >> On 03/05/2018 04:59 PM, Tomasz Kulasek wrote:
> > >>> vhost-net devices might keep track of last descriptors indices by
> > >>> themselves, and assuming they initially start at 0, but that is not the
> > >>> case for vhost-scsi. Initial last descriptor indices are set via
> > >>> VHOST_USER_SET_VRING_BASE message, and we cannot possibly predict
> what
> > >>> will they be. Setting these to vqueue->used->idx is also not an option,
> > >>> because there might be some yet unprocessed requests between these and
> > >>> the actual last_idx. This patch adds API for getting/setting last
> > >>> descriptor indices of vrings, so that they can be synchronized between
> > >>> user-device and rte_vhost.
> > >>>
> > >>> The last_idx flow could be as following:
> > >>>
> > >>>    * vhost start,
> > >>>    * received SET_VRING_BASE msg, last_idx is set on rte_vhost side,
> > >>>    * created user-device, last_idx pulled from rte_vhost,
> > >>>    * requests are being processed by user-device, last_idx changes,
> > >>>    * destroyed user-device, last_idx pushed to rte_vhost,
> > >>>    * at this point, vrings could be recreated and another SET_VRING_BASE
> > >>>      message could arrive, so last_idx would be set
> > >>>    * recreated user-device, last_idx pulled from rte_vhost.
> > >>>
> > >>>
> > >>> Signed-off-by: Dariusz Stojaczyk <dariuszx.stojaczyk at intel.com>
> > >>> Signed-off-by: Tomasz Kulasek <tomaszx.kulasek at intel.com>
> > >>> ---
> > >>>    lib/librte_vhost/rte_vhost.h | 24 ++++++++++++++++++++++++
> > >>>    lib/librte_vhost/vhost.c     | 27 +++++++++++++++++++++++++++
> > >>>    2 files changed, 51 insertions(+)
> > >>>
> > >>
> > >> I agree with the patch, but it is missing the declaration of the new API
> > >> in rte_vhost_version.map.
> > >>
> > >> Thanks,
> > >> Maxime
> > >
> > > Yes, I will send v2.
> >
> > Do you plan to send v2 for v18.02?
> > It can still make it to -rc2 if you post it early next week.
> >
> > Thanks,
> > Maxime
> >
> > > Tomasz
> > >
> >
> 
> 
> 
>