From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37975) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1buKMc-00072I-Fs for qemu-devel@nongnu.org; Wed, 12 Oct 2016 10:18:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1buKMY-0002ZJ-7S for qemu-devel@nongnu.org; Wed, 12 Oct 2016 10:18:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57668) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1buKMX-0002Z5-UU for qemu-devel@nongnu.org; Wed, 12 Oct 2016 10:18:30 -0400 References: <20161012140442.GB15590@stefanha-x1.localdomain> From: Eric Blake Message-ID: Date: Wed, 12 Oct 2016 09:18:28 -0500 MIME-Version: 1.0 In-Reply-To: <20161012140442.GB15590@stefanha-x1.localdomain> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="vf4bSvl6QT3w5kCb2RrX4oF7BI10sEFir" Subject: Re: [Qemu-devel] Async savevm using userfaultfd(2) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi , qemu-devel@nongnu.org Cc: Andrea Arcangeli , "Denis V. Lunev" , jsnow@redhat.com, "Dr. David Alan Gilbert" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --vf4bSvl6QT3w5kCb2RrX4oF7BI10sEFir From: Eric Blake To: Stefan Hajnoczi , qemu-devel@nongnu.org Cc: Andrea Arcangeli , "Denis V. Lunev" , jsnow@redhat.com, "Dr. David Alan Gilbert" Message-ID: Subject: Re: [Qemu-devel] Async savevm using userfaultfd(2) References: <20161012140442.GB15590@stefanha-x1.localdomain> In-Reply-To: <20161012140442.GB15590@stefanha-x1.localdomain> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 10/12/2016 09:04 AM, Stefan Hajnoczi wrote: > John and I recently discussed asynchronous savevm and I wanted to post > the ideas so they aren't forgotten. (We're not actively working on thi= s > feature.) >=20 > Asynchronous savevm has the same effect as the 'savevm' monitor command= : > it saves RAM, device state, and a snapshot of all disks at the point in= > time the command was issued. >=20 Interesting idea. I suspect this would have benefits over using fork()'s copy-on-write semantics, even if we could come up with a way to safely fork where the child permits no state modification, but merely starts scraping off the memory state of the guest at the time of the fork. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --vf4bSvl6QT3w5kCb2RrX4oF7BI10sEFir 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 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJX/kY0AAoJEKeha0olJ0Nq4lAH+wY6DY/nbVZBl1Y3WvxgDZDd uXhd3pkxskRRPRZOEiiehvUKxnvFULEDMgFP5TFQW8k0QjgDMEQQPVzxiY9wYhaT lz0hQHgT8KxUXcR0D9k35jOWlb+MpL9JtntdiTWYrwDaWhxfdYcNv431VQYlX8d1 2OO6CtUN3qTwyD/G93pSCN7JZU+6UWZ8in6RgCezWJFY8SEwUpXQN0BBwRczOo1L z6maFf/ah4vhh0N/ysQZ2g04I5/+CSco99Vupgraxfd9i7rRO6rsWkqE9S6UWXgT K00JygYJzfyl6Aac1nmzHW28kH7V3dsU23LjQ0cRGoXAoWKOPDDxbfBxw8+oW3w= =c3tW -----END PGP SIGNATURE----- --vf4bSvl6QT3w5kCb2RrX4oF7BI10sEFir--