[ovirt-devel] Re: device compatibility interface for live migration with assigned devices

On 2020/8/5 上午10:16, Yan Zhao wrote: > On Wed, Aug 05, 2020 at 10:22:15AM +0800, Jason Wang wrote: > > On 2020/8/5 上午12:35, Cornelia Huck wrote: > > > [sorry about not chiming in earlier] > > > > > > On Wed, 29 Jul 2020 16:05:03 +0800 > > > Yan Zhao <yan.y.zhao(a)intel.com&gt; wrote: > > > > > > > On Mon, Jul 27, 2020 at 04:23:21PM -0600, Alex Williamson wrote: > > > (...) > > > > > > > > Based on the feedback we've received, the previously proposed interface > > > > > is not viable. I think there's agreement that the user needs to be > > > > > able to parse and interpret the version information. Using json seems > > > > > viable, but I don't know if it's the best option. Is there any > > > > > precedent of markup strings returned via sysfs we could follow? > > > I don't think encoding complex information in a sysfs file is a viable > > > approach. Quoting Documentation/filesystems/sysfs.rst: > > > > > > "Attributes should be ASCII text files, preferably with only one value > > > per file. It is noted that it may not be efficient to contain only one > > > value per file, so it is socially acceptable to express an array of > > > values of the same type. > > > Mixing types, expressing multiple lines of data, and doing fancy > > > formatting of data is heavily frowned upon." > > > > > > Even though this is an older file, I think these restrictions still > > > apply. > > > > +1, that's another reason why devlink(netlink) is better. > > > hi Jason, > do you have any materials or sample code about devlink, so we can have a good > study of it? > I found some kernel docs about it but my preliminary study didn't show me the > advantage of devlink. CC Jiri and Parav for a better answer for this. My understanding is that the following advantages are obvious (as I replied in another thread): - existing users (NIC, crypto, SCSI, ib), mature and stable - much better error reporting (ext_ack other than string or errno) - namespace aware - do not couple with kobject