Re: [PATCH v7 06/14] tools: add support for cache coloring configuration

From: Carlo Nonato <carlo.nonato@minervasys.tech>
To: Anthony PERARD <anthony.perard@cloud.com>
Cc: xen-devel@lists.xenproject.org, Juergen Gross <jgross@suse.com>,
	 Marco Solieri <marco.solieri@minervasys.tech>
Subject: Re: [PATCH v7 06/14] tools: add support for cache coloring configuration
Date: Mon, 25 Mar 2024 12:44:42 +0100	[thread overview]
Message-ID: <CAG+AhRUeCB+HpBcX7W7rKvS-SG468t5BHbHnnK1MtHAob_wfqw@mail.gmail.com> (raw)
In-Reply-To: <9784c247-592b-460a-b6d4-3ab4cdf87b77@perard>

Hi Anthony,

On Mon, Mar 25, 2024 at 11:55 AM Anthony PERARD
<anthony.perard@cloud.com> wrote:
>
> On Fri, Mar 15, 2024 at 11:58:54AM +0100, Carlo Nonato wrote:
> > diff --git a/tools/libs/light/libxl_create.c b/tools/libs/light/libxl_create.c
> > index 5546335973..79f206f616 100644
> > --- a/tools/libs/light/libxl_create.c
> > +++ b/tools/libs/light/libxl_create.c
> > @@ -726,6 +726,15 @@ int libxl__domain_make(libxl__gc *gc, libxl_domain_config *d_config,
> >              /* A new domain now exists */
> >              *domid = local_domid;
> >
> > +            ret = xc_domain_set_llc_colors(ctx->xch, local_domid,
> > +                                           b_info->llc_colors,
> > +                                           b_info->num_llc_colors);
> > +            if (ret < 0 && errno != EOPNOTSUPP) {
>
> Wait, this additional check on EOPNOTSUPP, does that mean we ignore
> "llc_colors" configure by the admin of the VM if the system doesn't
> support it? Shouldn't we also report an error in this case? At least if
> `num_llc_colors > 0`.

You're right. The problem was that I didn't want to log because coloring is a
very niche feature and I need to indiscriminately try to color a domain. Doing
that only when `num_llc_colors > 0` is fine though.

Thanks.

> Thanks,
>
> --
> Anthony PERARD