From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dario Faggioli <dario.faggioli@citrix.com>
Subject: Re: [PATCH 16/16] xen: sched: implement vcpu hard
 affinity in Credit2
Date: Tue, 5 Apr 2016 18:50:23 +0200
Message-ID: <1459875023.3166.59.camel@citrix.com>
References: <20160318185524.8117.74837.stgit@Solace.station>
 <20160318190612.8117.79354.stgit@Solace.station>
 <CAFLBxZbfDm9ZDm5oADMvEhJrsmTJqkSoF4pykLVarVhD9pjp8w@mail.gmail.com>
Mime-Version: 1.0
Content-Type: multipart/mixed; boundary="===============0874536133666767091=="
Return-path: <xen-devel-bounces@lists.xen.org>
Received: from mail6.bemta3.messagelabs.com ([195.245.230.39])
 by lists.xenproject.org with esmtp (Exim 4.84_2)
 (envelope-from <prvs=896cd44d4=dario.faggioli@citrix.com>)
 id 1anUDx-00077m-0J
 for xen-devel@lists.xenproject.org; Tue, 05 Apr 2016 16:53:05 +0000
In-Reply-To: <CAFLBxZbfDm9ZDm5oADMvEhJrsmTJqkSoF4pykLVarVhD9pjp8w@mail.gmail.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
 <mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
 <mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Errors-To: xen-devel-bounces@lists.xen.org
Sender: "Xen-devel" <xen-devel-bounces@lists.xen.org>
To: George Dunlap <dunlapg@umich.edu>
Cc: xen-devel <xen-devel@lists.xenproject.org>, Justin Weaver <jtweaver@hawaii.edu>
List-Id: xen-devel@lists.xenproject.org

--===============0874536133666767091==
Content-Type: multipart/signed; micalg=pgp-sha1;
	protocol="application/pgp-signature"; boundary="=-4SjzPVuQVQYn675cx6B1"

--=-4SjzPVuQVQYn675cx6B1
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Thu, 2016-03-24 at 15:42 +0000, George Dunlap wrote:
> On Fri, Mar 18, 2016 at 7:06 PM, Dario Faggioli
> <dario.faggioli@citrix.com> wrote:
> >=20
> > From: Justin Weaver <jtweaver@hawaii.edu>
> >=C2=A0
> > Signed-off-by: Justin Weaver <jtweaver@hawaii.edu>
> > Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
> Just checking, are the main changes between this patch and the v4
> that
> Justin posted:
>=20
> 1) Moving the "scratch_mask" to a different patch
> 2) The code-cleanups you listed?
>=20
Yes, indeed! Sorry for not pointing that out more clearly (e.g., in the
cover letter).

> One rather tangential question...

> > --- a/xen/common/sched_credit2.c
> > +++ b/xen/common/sched_credit2.c
> > @@ -560,8 +590,9 @@ runq_tickle(const struct scheduler *ops,
> > unsigned int cpu, struct csched2_vcpu *
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0goto tickle;
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0}
> >=20
> > -=C2=A0=C2=A0=C2=A0=C2=A0/* Get a mask of idle, but not tickled */
> > +=C2=A0=C2=A0=C2=A0=C2=A0/* Get a mask of idle, but not tickled, that n=
ew is allowed to
> > run on. */
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0cpumask_andnot(&mask, &rqd->idle, &rqd->t=
ickled);
> > +=C2=A0=C2=A0=C2=A0=C2=A0cpumask_and(&mask, &mask, new->vcpu->cpu_hard_=
affinity);
> It looks like this uses a cpumask_t on the stack -- can we use
> scratch_mask here, or is there some reason we need to use the local
> variable?
>=20
> But that's really something to either add to the previous patch, or
> to
> do in yet a different patch.
>=20
It's because that cpumask stack variable is there already, and the
primary purpose of the scratch mask is to avoid _adding_more_ of them.
This is how it has been introduced and used so far in Credit1 and RTDS.

That said, I do agree it can well be used to get rid of some of the
already existing stack variable, but, as you suggest yourself, I'm
thinking about doing this in another patch.

> Acked-by: George Dunlap <george.dunlap@citrix.com>
>
Thanks and Regards,
Dario
--=20
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


--=-4SjzPVuQVQYn675cx6B1
Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: This is a digitally signed message part
Content-Transfer-Encoding: 7bit

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2

iEYEABECAAYFAlcD7M8ACgkQk4XaBE3IOsScPgCfRr/D8teeZObPkuAGQFTTmKyH
pPgAn0YYt4MokGDZWZOyXoupfPd0C08L
=H9Ad
-----END PGP SIGNATURE-----

--=-4SjzPVuQVQYn675cx6B1--


--===============0874536133666767091==
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: base64
Content-Disposition: inline

X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KWGVuLWRldmVs
IG1haWxpbmcgbGlzdApYZW4tZGV2ZWxAbGlzdHMueGVuLm9yZwpodHRwOi8vbGlzdHMueGVuLm9y
Zy94ZW4tZGV2ZWwK

--===============0874536133666767091==--