[dpdk-dev] [PATCH 02/22] bus/vdev: enable one device scan

[Zhang, Qi Z]

> -----Original Message-----
> From: Shreyansh Jain [mailto:shreyansh.jain at nxp.com]
> Sent: Friday, June 8, 2018 8:08 PM
> To: Zhang, Qi Z <qi.z.zhang at intel.com>
> Cc: thomas at monjalon.net; Burakov, Anatoly <anatoly.burakov at intel.com>;
> Ananyev, Konstantin <konstantin.ananyev at intel.com>; dev at dpdk.org;
> Richardson, Bruce <bruce.richardson at intel.com>; Yigit, Ferruh
> <ferruh.yigit at intel.com>; Shelton, Benjamin H
> <benjamin.h.shelton at intel.com>; Vangati, Narender
> <narender.vangati at intel.com>
> Subject: Re: [dpdk-dev] [PATCH 02/22] bus/vdev: enable one device scan
> 
> On 6/7/2018 6:08 PM, Qi Zhang wrote:
> > Implemented the bus ops scan_one, besides this improve the scan
> > efficiency in hotplug case, it aslo avoid sync IPC invoke (which
>                                   ^^^^
>                                   also
> 
> > happens in vdev->scan on secondary process). The benifit is it
>                                                     ^^^^^^^
>                                                     benefit
> 
> > removes the potiential deadlock in the case when secondary process
>                ^^^^^^^^^^
>                potential
> 
> > receive a request from primary process to attach a new device, since
> > vdev->scan will be invoked on mp thread itself at this case.
>                                                   ^^^^^^^
>                                                   in that
> 
> 
> Besides the above spells, is it possible to re-write the commit?
> You mention it "...improves the scan efficiency..." - how? Is that an implicit
> output of introducing the new scan_one for vdev?

"Improve scan efficiency" should be general to all buses in hot plug case.
since compare to bus->scan, bus->scan_one no need to iterate all devargs.
But yes, it's not the original purpose for this patch set, but a bonus.

I will re-write comment with below format to make it more clear.
The patch implemented bus ops scan_one for vdev, it gives two benefits
1. improve scan efficiency ....
2. avoid sync IPC invoke .....

Regards
Qi

> 
> >
> > Signed-off-by: Qi Zhang <qi.z.zhang at intel.com>
> > ---
> >   drivers/bus/vdev/vdev.c | 30 ++++++++++++++++++++++++++++++
> >   1 file changed, 30 insertions(+)
> >
> > diff --git a/drivers/bus/vdev/vdev.c b/drivers/bus/vdev/vdev.c index
> > 6139dd551..cdbd77df0 100644
> > --- a/drivers/bus/vdev/vdev.c
> > +++ b/drivers/bus/vdev/vdev.c
> > @@ -467,6 +467,35 @@ vdev_scan(void)
> >   	return 0;
> >   }
> >
> 
> [...]