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

[Carlo Nonato <carlo.nonato@xxxxxxxxxxxxxxx>]

Hi Stefano, Julien,

On Thu, Jan 4, 2024 at 10:43 PM Stefano Stabellini
<sstabellini@xxxxxxxxxx> wrote:
>
> On Thu, 4 Jan 2024, Julien Grall wrote:
> > 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?
>
> That's reasonable

I would put it under "Resource management" features. Are you ok with it?

Thanks.