From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH v3 2/5] build: Hook the schedulers into
 Kconfig
Date: Fri, 8 Jan 2016 15:54:34 +0000
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To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Jonathan Creekmore <jonathan.creekmore@gmail.com>
Cc: George Dunlap <george.dunlap@eu.citrix.com>, xen-devel@lists.xenproject.org, Dario Faggioli <dario.faggioli@citrix.com>
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On 08/01/16 15:47, Konrad Rzeszutek Wilk wrote:
> On Thu, Jan 07, 2016 at 11:29:18AM -0600, Jonathan Creekmore wrote:
>> Allow the schedulers to be independently enabled or disabled at
>> compile-time. To match existing behavior, all four schedulers are
>> compiled in by default, although the Credit2, RTDS, and ARINC653 are
>> marked EXPERIMENTAL to match their not currently supported status.
> By unmarking all of them in sequence I was able to get this:
>
> #
> # Schedulers
> #
> # CONFIG_SCHED_CREDIT is not set
> # CONFIG_SCHED_CREDIT2 is not set
> # CONFIG_SCHED_RTDS is not set
> # CONFIG_SCHED_ARINC653 is not set
> # CONFIG_SCHED_CREDIT_DEFAULT is not set
> # CONFIG_SCHED_CREDIT2_DEFAULT is not set
> # CONFIG_SCHED_RTDS_DEFAULT is not set
> # CONFIG_SCHED_ARINC653_DEFAULT is not set
> CONFIG_SCHED_DEFAULT="credit"
>
>
> And the hypervisor did build with:
>
> [konrad@char xen]$ nm --defined xen-syms |grep schedulers
> ffff82d080290d58 D __end_schedulers_array
> ffff82d080290d58 D __start_schedulers_array
>
> :-)
>
> Not exactly sure if there is some way to make us _not_ shoot
> ourselves in the foot by mistake.
>
> Perhaps the build should complain if the size of the
> __schedulers_array is zero?

Hmm yes - an ASSERT() at the bottom of the linker file would be a very
good defensive measure.

A hypervisor without any schedulers compiled in will be rather sad.

~Andrew