Re: [PATCH v5 01/13] xen/common: add cache coloring common code

[Julien Grall <julien@xxxxxxx>]

Hi,

On 02/01/2024 09:51, Carlo Nonato wrote:
> This commit adds the Last Level Cache (LLC) coloring common header, Kconfig
> options and functions. Since this is an arch specific feature, actual
> implementation is postponed to later patches and Kconfig options are placed
> under xen/arch.
>
> LLC colors are a property of the domain, so the domain struct has to be
> extended.
>
> Based on original work from: Luca Miccio <lucmiccio@xxxxxxxxx>
>
> Signed-off-by: Carlo Nonato <carlo.nonato@xxxxxxxxxxxxxxx>
> Signed-off-by: Marco Solieri <marco.solieri@xxxxxxxxxxxxxxx>
> ---
> v5:
> - used - instead of _ for filenames
> - removed domain_create_llc_colored()
> - removed stub functions
> - coloring domain fields are now #ifdef protected
> v4:
> - Kconfig options moved to xen/arch
> - removed range for CONFIG_NR_LLC_COLORS
> - added "llc_coloring_enabled" global to later implement the boot-time
>    switch
> - added domain_create_llc_colored() to be able to pass colors
> - added is_domain_llc_colored() macro
> ---
>   xen/arch/Kconfig               | 16 ++++++++++++
>   xen/common/Kconfig             |  3 +++
>   xen/common/domain.c            |  4 +++
>   xen/common/keyhandler.c        |  4 +++
>   xen/include/xen/llc-coloring.h | 46 ++++++++++++++++++++++++++++++++++
>   xen/include/xen/sched.h        |  5 ++++
>   6 files changed, 78 insertions(+)
>   create mode 100644 xen/include/xen/llc-coloring.h
>
> diff --git a/xen/arch/Kconfig b/xen/arch/Kconfig
> index 67ba38f32f..aad7e9da38 100644
> --- a/xen/arch/Kconfig
> +++ b/xen/arch/Kconfig
> @@ -31,3 +31,19 @@ config NR_NUMA_NODES
>           associated with multiple-nodes management. It is the upper bound of
>           the number of NUMA nodes that the scheduler, memory allocation and
>           other NUMA-aware components can handle.
> +
> +config LLC_COLORING
> +       bool "Last Level Cache (LLC) coloring" if EXPERT
While look at the rest of the series, I noticed that SUPPORT.md is not 
updated. Can this be done?
I think the feature should be in experimental for now. We can decide to 
switch to tech preview before Xen 4.19 is out and the support is completed.
Stefano, what do you think?

Cheers

--
Julien Grall