Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) client-ip=2620:137:e000::3:7;
MIME-Version: 1.0
References: <20231201214737.104444-1-tony.luck@intel.com> <20231207195613.153980-1-tony.luck@intel.com>
 <20231207195613.153980-2-tony.luck@intel.com> <CALPaoCji1yzfkA=tms3LhYMvRB+wSJQM3qzPKrHNEa7a+KduTA@mail.gmail.com>
 <ZXORTTIUKWXOsd9p@agluck-desk3>
In-Reply-To: <ZXORTTIUKWXOsd9p@agluck-desk3>
From:   Peter Newman <peternewman@google.com>
Date:   Fri, 8 Dec 2023 14:09:52 -0800
Message-ID: <CALPaoCj_OvMzD8W9+jEORewwDquM6F-sOW32Ngcy+Gm6A1+OcQ@mail.gmail.com>
Subject: Re: [PATCH v6 1/3] x86/resctrl: Add mount option "mba_MBps_event"
To:     Tony Luck <tony.luck@intel.com>
Cc:     Fenghua Yu <fenghua.yu@intel.com>,
        Reinette Chatre <reinette.chatre@intel.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Shuah Khan <skhan@linuxfoundation.org>, x86@kernel.org,
        Shaopeng Tan <tan.shaopeng@fujitsu.com>,
        James Morse <james.morse@arm.com>,
        Jamie Iles <quic_jiles@quicinc.com>,
        Babu Moger <babu.moger@amd.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
        patches@lists.linux.dev
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Fri, Dec 8, 2023 at 1:57=E2=80=AFPM Tony Luck <tony.luck@intel.com> wrot=
e:
>
> On Fri, Dec 08, 2023 at 10:17:08AM -0800, Peter Newman wrote:
> > Hi Tony,
> >
> > On Thu, Dec 7, 2023 at 11:56=E2=80=AFAM Tony Luck <tony.luck@intel.com>=
 wrote:
> > > @@ -2715,7 +2723,25 @@ static int rdt_parse_param(struct fs_context *=
fc, struct fs_parameter *param)
> > >         case Opt_mba_mbps:
> > >                 if (!supports_mba_mbps())
> > >                         return -EINVAL;
> > > -               ctx->enable_mba_mbps =3D true;
> > > +               if (is_mbm_local_enabled())
> > > +                       ctx->enable_mba_mbps_local =3D true;
> > > +               else
> > > +                       return -EINVAL;
> > > +               return 0;
> > > +       case Opt_mba_mbps_event:
> > > +               if (!supports_mba_mbps())
> > > +                       return -EINVAL;
> > > +               if (!strcmp("mbm_local_bytes", param->string)) {
> > > +                       if (!is_mbm_local_enabled())
> > > +                               return -EINVAL;
> > > +                       ctx->enable_mba_mbps_local =3D true;
> > > +               } else if (!strcmp("mbm_total_bytes", param->string))=
 {
> > > +                       if (!is_mbm_total_enabled())
> > > +                               return -EINVAL;
> > > +                       ctx->enable_mba_mbps_total =3D true;
> > > +               } else {
> > > +                       return -EINVAL;
> >
> > It looks like if I pass
> > "mba_MBps_event=3Dmbm_total_bytes,mba_MBps_event=3Dmbm_local_bytes" I c=
an
> > set both flags true.
>
> That's going to be confusing. I'll add code to stop the user from
> passing both options.

Also kind of confusing, after reading the second patch, I realized
"mba_MBps_event=3Dmbm_total_bytes,mba_MBps" also results in both being
set. If you're able to fail the mount operation if both flags somehow
get set, that would address this one too.

-Peter