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Re: [Xen-devel] [PATCH v5 07/10] arm: add a tiny kconfig configuration


On 12/06/18 16:55, Stefano Stabellini wrote:
On Tue, 12 Jun 2018, Julien Grall wrote:
Hi Stefano,

On 12/06/18 01:50, Stefano Stabellini wrote:
On Tue, 5 Jun 2018, Julien Grall wrote:
Hi Stefano,

On 04/06/18 18:24, Stefano Stabellini wrote:
Add a tiny kconfig configuration. Enabled NULL and Credit schedulers.
Support only 8 cpus. It only carries non-default options (use make

I don't see where 8 CPUs would only be supported as the default value is
   I need to update the commit message reflecting the changes to the patch

olddefconfig to produce a complete .config file).

With all the series I did the following things:
        1) copy tiny.config to .config
        2) make olddefconfig
        3) make menuconfig and select QEMU

After 1) the numbers of CPUs are set to 128. After 3) I would expect the
number of CPUs to go down to 8. Unfortunately this is not the cases.

So your command does not seem to be enough here.

NR_CPUS cannot go down. It is a limitation of Kconfig, similar to the
fact that option cannot be de-selected.

It is not 1) that sets NR_CPUS to 128, it would be 2) above. For this to
work you have to skip 2) and just do:

        - copy tiny.config to .config
        - make menuconfig and select QEMU

Well I suggested a way during one of our recent chat and I am a bit surprised
this was not considered here.

For reminder, the way was to provide a makefile target that will select tiny
and the platform at the same time.

make tiny_defconfig PLAT=qemu

I prefer not to add additional targets

I think it would make easier for user to select any config and the platform. It is one command over 3 that can mistakenly be misused.

Anyway, sooner or later we will want to have such target in Xen.


Julien Grall

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