From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38049) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VR2Hk-0002VB-3N for qemu-devel@nongnu.org; Tue, 01 Oct 2013 11:54:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VR2Hf-0003oJ-7c for qemu-devel@nongnu.org; Tue, 01 Oct 2013 11:54:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:10692) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VR2He-0003nw-W5 for qemu-devel@nongnu.org; Tue, 01 Oct 2013 11:54:47 -0400 Message-ID: <524AF040.9040309@redhat.com> Date: Tue, 01 Oct 2013 09:54:40 -0600 From: Eric Blake MIME-Version: 1.0 References: <1380633619-12213-1-git-send-email-kwolf@redhat.com> <524AED13.9030000@redhat.com> <20131001155032.GE3143@dhcp-200-207.str.redhat.com> In-Reply-To: <20131001155032.GE3143@dhcp-200-207.str.redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Mhv94sep7BCB1oks0SG1gDNR4r3lAfWSx" Subject: Re: [Qemu-devel] [PATCH v2 00/17] blockdev-add QMP command List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: benoit.canet@irqsave.net, armbru@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com, stefanha@redhat.com, xiawenc@linux.vnet.ibm.com This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --Mhv94sep7BCB1oks0SG1gDNR4r3lAfWSx Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 10/01/2013 09:50 AM, Kevin Wolf wrote: > Am 01.10.2013 um 17:41 hat Eric Blake geschrieben: >> On 10/01/2013 07:20 AM, Kevin Wolf wrote: >>> This series adds a blockdev-add QMP command and a row of cleanup patc= hes to >>> separate legacy -drive/drive_add behaviour from blockdev_init() to th= e wrapper >>> function drive_init(). >>> >>> v2: >>> >>> - Removed I/O throttling and copy-on-read options from the schema: Bo= th are >>> candidates for becoming block filters instead. For the time being, = you can >>> use the existing QMP commands in order to enable I/O throttling on = a device >>> created with blockdev-add in a second step. >> >> Tolerable as a stop-gap; but doesn't that mean that there is a window >> where throttling is not active? Anything that can restrict block >> operations must ultimately be specified atomically up front to avoid a= >> non-deterministic burst during the race window. But in the interest o= f >> incremental improvements, I can live with the approach used here, whil= e >> still waiting for throttling to be implemented as a true filter device= =2E >=20 > Immediately after blockdev-add, the block device is still completely > unused. You can set the throttling options before you do the > corresponding device-add or block job command or whatever you're > planning to do with the device. Ah. So there's no race window after all. Good to know. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --Mhv94sep7BCB1oks0SG1gDNR4r3lAfWSx Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJSSvBAAAoJEKeha0olJ0NqIdEH/iUgs8Ioy+38ES+YZx3nBFly o1rH15ktFMu6/0PKxPbfb/5nGtr/HtfBBL/SNuEx07chQYCUR78q8PGFUlwai1aC 7ojDbhewzGFB39DKa3WYhmWrtu5PPvgZBcPM/F1p/GER9on1mLHcF57M/VlFT4Lw mwfJZDbsKV8Ml/vsy+UCaR9bRNuDvFbgylh2Lc6UkQSbIbZj8cPmW1r0LKw7ul2+ PIYxDeC8kT6jfUGU4/zeG1yPoBVZO54cKnoD+AEAL7NKGL13YtYoCC7n1qm9Ta5g nD4w3e8z0EdukDkEPXogIw6GLlMz2QJxeKMcYDyAiLkchPOvQ5i6bg6bUlMs31U= =oetz -----END PGP SIGNATURE----- --Mhv94sep7BCB1oks0SG1gDNR4r3lAfWSx--