Re: [Xen-devel] [PATCH v2 3/3] tmem: allow tmem to be disabled with Kconfig

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 16.03.16 at 08:35, <konrad.wilk@xxxxxxxxxx> wrote:
> On Tue, Mar 15, 2016 at 03:18:50PM -0500, Doug Goldstein wrote:
>> Wrap the various tmem functions with the Kconfig generated CONFIG_TMEM
>> option allowing users to build Xen without tmem support.
> 
> I ended with this change on top of yours (which I will squash):
> 
> The 'bool "tmem" so that if I did make an change in .config
> file it would still take effect even if I forgot XEN_CONFIG_EXPERT.
> 
> Otherwise it would keep on making it
> 
> CONFIG_TMEM=y
> instead of the
> 
> # CONFIG_TMEM is not set.
> 
> which I wrote in the .config file.
> 
> From b9d173eb0e0e1274c784fde5580b119d6f7b4bdc Mon Sep 17 00:00:00 2001
> From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Date: Wed, 16 Mar 2016 03:28:39 -0400
> Subject: [PATCH] squash!     tmem: allow tmem to be disabled with Kconfig
> 
> ---
>  xen/common/Kconfig | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/common/Kconfig b/xen/common/Kconfig
> index 39b0fa7..5bd8a84 100644
> --- a/xen/common/Kconfig
> +++ b/xen/common/Kconfig
> @@ -87,16 +87,21 @@ config LATE_HWDOM
>  
>         If unsure, say N.
>  
> -# Enables transactional memory support
> +# Enables transcendent memory support
>  config TMEM
>       def_bool y
> -     prompt "Transactional Memory Support" if EXPERT = "y"
> +     bool "tmem"
> +     prompt "Transcendent Memory Support" if EXPERT = "y"
>       ---help---
>         Transcendent memory allows PV-aware guests to collaborate on memory
>         usage. Guests can 'swap' their memory to the hypervisor or have an
>         collective pool of memory shared across guests. The end result is
>         less memory usage by guests allowing higher guest density.
>  
> +       You also have to enable it on the Xen commandline by using tmem=1
> +
> +       If unsure, say Y.

But that will, afaict, disable tmem by default. Forgetting to set
XEN_CONFIG_EXPERT is, well, a mistake that results in a config
change just like the one you've observed.

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel