From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Creekmore Subject: Re: [PATCH v5 2/5] build: Hook the schedulers into Kconfig Date: Thu, 14 Jan 2016 11:22:04 -0600 Message-ID: References: <1452782954-56016-1-git-send-email-jonathan.creekmore@gmail.com> <1452782954-56016-3-git-send-email-jonathan.creekmore@gmail.com> <5697D71D02000078000C6DE6@prv-mh.provo.novell.com> <1452789256.32341.10.camel@citrix.com> <5697DE6F02000078000C6E6D@prv-mh.provo.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta4.messagelabs.com ([85.158.143.247]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aJlb6-00051c-Ow for xen-devel@lists.xenproject.org; Thu, 14 Jan 2016 17:22:08 +0000 Received: by mail-yk0-f194.google.com with SMTP id k129so38458524yke.3 for ; Thu, 14 Jan 2016 09:22:07 -0800 (PST) In-reply-to: <5697DE6F02000078000C6E6D@prv-mh.provo.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: George Dunlap , Jonathan Creekmore , Dario Faggioli , Ian Campbell , xen-devel@lists.xenproject.org List-Id: xen-devel@lists.xenproject.org Jan Beulich writes: >>>> On 14.01.16 at 17:34, wrote: >> On Thu, 2016-01-14 at 10:23 -0600, Jonathan Creekmore wrote: >>> Jan Beulich writes: >>> >>> > > > > On 14.01.16 at 15:49, wrote: >>> > > --- a/xen/common/Kconfig >>> > > +++ b/xen/common/Kconfig >>> > > @@ -51,4 +51,63 @@ config KEXEC >>> > > >>> > > If unsure, say Y. >>> > > >>> > > +# Enable schedulers >>> > > +menu "Schedulers" >>> > > + visible if EXPERT = "y" >>> > > + >>> > > +config SCHED_CREDIT >>> > > + bool >>> > > + default y >>> > > + ---help--- >>> > > + The traditional credit scheduler is a general purpose >>> > > scheduler. >>> > >>> > So is this option now useful for anything? >>> >>> It keeps the code between all of the schedulers consistent (all of them >>> have a #define if they are compiled it) >> >> FWIW I think this (consistency) is a reasonable argument for having this >> option even if it doesn't actually do anything. > > While I can see your point, I dislike useless clutter in .config (also > on Linux, where I every once in a while send some cleanup > patches). > >>> > > +choice >>> > > + prompt "Default Scheduler?" >>> > > + default SCHED_CREDIT_DEFAULT if SCHED_CREDIT >>> > > + default SCHED_CREDIT2_DEFAULT if SCHED_CREDIT2 >>> > > + default SCHED_RTDS_DEFAULT if SCHED_RTDS >>> > > + default SCHED_ARINC653_DEFAULT if SCHED_ARINC653 >>> > >>> > And certainly all these defaults are now pointless, considering >>> > that the condition of the first one is "if y". >>> >>> Yes, I could rip all of those out now since credit is always the >>> default. I left it in there for the ideal case that credit didn't have >>> to be special cased but, at this point, I will rip it out if you want. >> >> What is the behaviour of the above set of "default"s if more than one of >> the SCHED_* is enabled? Does it pick the first, last, one at random? > > The first for which the condition is true. Absolutely correct. The first true condition is the one that is chosen. >> If credit is now always the default I think that would be better expressed >> with a single "default SCHED_CREDIT_DEFAULT". > > Indeed. And that is what I have already done for a v6 that I am sitting on to see if I get more review comments.