From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: [PATCH v7 15/17] vmx: VT-d posted-interrupt core logic handling Date: Mon, 21 Sep 2015 15:31:44 +0200 Message-ID: <1442842304.2691.67.camel@citrix.com> References: <55FFCB67.3050900@citrix.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============2113092089446250582==" Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "Wu, Feng" , George Dunlap Cc: "Tian, Kevin" , Keir Fraser , George Dunlap , Andrew Cooper , "xen-devel@lists.xen.org" , Jan Beulich List-Id: xen-devel@lists.xenproject.org --===============2113092089446250582== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-KKG0eV5VctPXjjE+cNHM" --=-KKG0eV5VctPXjjE+cNHM Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2015-09-21 at 11:59 +0000, Wu, Feng wrote: >=20 > > -----Original Message----- > > From: George Dunlap [mailto:george.dunlap@citrix.com] > > > I think the handling for lazy context switch is not only for the > > > blocking case, > > > we still need to do something for lazy context switch even we > > > handled the > > > blocking case in vcpu_block(), such as, > > > 1. For non-idle -> idle > > > - set 'SN' > >=20 > > If we set SN in vcpu_block(), then we don't need to set it on > > context > > switch -- =E6=98=AF=E4=B8=8D=E6=98=AF=EF=BC=9F >=20 > For preemption case (not blocking case) , we still need to clear/set > SN, and > this has no business with vcpu_block()/vcpu_wake(), right? Do I miss > something > here? BTW, you Chinese is good! :) >=20 Well, sure, preemptions are fine being dealt with during context switches. AFAICR, Geoge was suggesting investigating the possibility of doing that within the already existing arch specific part of the context switch itself. Have you checked whether that would be possible? If yes, it really would be great, IMO. Note that, in case of preemptions, we are switching from a non-idle vcpu to another, non-idle, vcpu, so lazy context switching to the idle vcpu should not have much to do with this case... Was this something you were saying something/asking about above? (seems so, but I can't be sure, so I thought I better ask :-) ). Regards, Dario --=20 <> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) --=-KKG0eV5VctPXjjE+cNHM 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 v1 iEUEABECAAYFAlYABsAACgkQk4XaBE3IOsTXYQCfVOc23nkq2qZNNcswhfeVUehB bHcAlRtXbXPTLSq1DYJ6GO7V5HWak7g= =xq8V -----END PGP SIGNATURE----- --=-KKG0eV5VctPXjjE+cNHM-- --===============2113092089446250582== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel --===============2113092089446250582==--