Re: [Xen-devel] Criteria for checking in core scheduling series

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Fri, Sep 06, 2019 at 12:46:03PM +0000, Lars Kurth wrote:
> 
> 
> On 06/09/2019, 12:09, "George Dunlap" <george.dunlap@xxxxxxxxxx> wrote:
> 
>     There was a discussion on the community call about the core scheduling
>     series being developed by Juergen Gross [1].  The conclusion can be
>     summarized as follows:
>     
>     * We normally wait to check in series until they are quite good -- all
>     the i's dotted and all the t's crossed
>     
>     * This is for several reasons; primarily because once code gets checked
>     in, it rarely gets looked at again.  In particular, there's nothing
>     stopping the submitter from neglecting to do important clean-ups, in
>     spite of their best intentions; leaving the maintainer or the rest of
>     the community to do it.
>     
>     * However, for particularly long, complicated series like the core
>     scheduling series, this can have significant downsides.  Rebasing a
>     60-patch branch regularly is a lot of churn for little value; and core
>     parts of the series which are mostly complete are currently only getting
>     sporadic dev testing rather than the wide range of testing they would
>     get from being in staging.
>     
>     * XenServer and SuSE are both long-term community members with a strong
>     incentive to maintain and improve the feature; so the risk of the
>     feature being left for the community to maintian is relatively now.
>     
>     With all those things in mind, the conclusion was to lower the
>     "check-in" threshold from what it normally is, in order to allow the
>     series to be checked in in the near future, in enough time at least for
>     the "default off" to be well-tested by the 4.13 release.
>     
>     The criteria we sketched out were:
>     
>     * All the patches still need appropriate Ack / R-b's
>     
>     * There should be reason to believe that the series will have little to
>     no impact on "thread mode" (threads being the unit of scheduling; i.e.,
>     the status quo)
>     
>     WRT the second point, apparently XenServer have been testing the series
>     regularly for some time, and are satisfied from a testing perspective
>     that there is no significant degradation for the series when in "thread
>     mode".
>     
>     So this would really be a recommendation / license to the various
>     maintainers involved; primarily Dario, I think (since I probably won't
>     have time to review the series).
>     
>     No decisions are official until discussed on xen-devel; so the decision
>     will not be considered official until a few days have passed without
>     objection.  And of course, if anyone at the meeting had a different
>     understanding of what was said, or has something to add, please do so.
>     
> I believe the following people were on the community call and did NOT have 
> objections when asked
> Sergey, Jan, Juergen, Andrew, George, Roger, Christopher Clark, Daniel P 
> Smith, Rich (list may be incomplete)

I have no objection with this going in on the above terms.

Thanks for writing this down.

Roger.

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