From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MVgUn-0007sx-Fr for qemu-devel@nongnu.org; Tue, 28 Jul 2009 02:49:09 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MVgUi-0007s7-5I for qemu-devel@nongnu.org; Tue, 28 Jul 2009 02:49:08 -0400 Received: from [199.232.76.173] (port=54022 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MVgUi-0007s4-0G for qemu-devel@nongnu.org; Tue, 28 Jul 2009 02:49:04 -0400 Received: from mx20.gnu.org ([199.232.41.8]:20615) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MVgUh-0008SC-DR for qemu-devel@nongnu.org; Tue, 28 Jul 2009 02:49:03 -0400 Received: from fmmailgate02.web.de ([217.72.192.227]) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MVgUg-0001xS-6l for qemu-devel@nongnu.org; Tue, 28 Jul 2009 02:49:02 -0400 Message-ID: <4A6E9F51.5050109@web.de> Date: Tue, 28 Jul 2009 08:48:49 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <1248468005-13907-1-git-send-email-glommer@redhat.com> <4A6AD034.4090802@web.de> <20090728010807.GR4776@poweredge.glommer> In-Reply-To: <20090728010807.GR4776@poweredge.glommer> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig0EAAFDDE5E42640274ACA700" Sender: jan.kiszka@web.de Subject: [Qemu-devel] Re: [PATCH] RFC: use logging count for individual regions List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Glauber Costa Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org, avi@redhat.com This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig0EAAFDDE5E42640274ACA700 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Glauber Costa wrote: > On Sat, Jul 25, 2009 at 11:28:20AM +0200, Jan Kiszka wrote: >> Glauber Costa wrote: >>> qemu-kvm use this scheme of logging count of individual regions, >>> which is, IMHO, more flexible which the one we have right now. >>> I'm proposing we use it. >>> >>> Anthony, please don't apply this patch yet, as I would want it >>> to receive proper testing, and FYI, current migration broken ;( >>> - and I don't really have time to go debug it now. >>> >>> Jan: Please let me know what you think of it. >> No principle concerns. But before looking into details: what additiona= l >> use cases will it cover (maybe some example from qemu-kvm), or what >> existing code can it help to simplify? >=20 > Maybe avi can provide more input here, but to the very least, I believe= this > approach is more proven, since it lived in qemu-kvm for a while now. Al= though more > cumbersome, the bits in avi's tree usually work better for kvm-related = stuff. As qemu-kvm uses different code here and has different instrumentation in the devices, it's a bit tricky to asses what it buys upstream. I'm not against the counting, but I would like to see proper reasoning in the changelog. >=20 > I don't see a particular code path it simplifies, but I believe it can = help us finding > bugs that will manifest in the form of an unbalanced count. It will als= o work if we ever > happen to have two entities manipulating dirty bits in the VGA region, = like if we some day > implement dual head or something (although one might arguee that we sho= uld change it when > the time comes...) >=20 > Btw, a side note: in your current scheme, what we do when migration fai= l? Do we keep migration_log > up ? I can't find any place in the code where we put it down Good question. From a first glance I would say the logging continues... What does qemu-kvm do on this? Can't find a cleanup there either. Jan --------------enig0EAAFDDE5E42640274ACA700 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iEYEARECAAYFAkpun1oACgkQniDOoMHTA+kdFACfc4X3JPpiyJtpVGUX+J93f3H0 GkEAn3hG1OBzuNLkDDcHPwaR4GYBqzFt =eq7R -----END PGP SIGNATURE----- --------------enig0EAAFDDE5E42640274ACA700--