From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38948) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WhnCt-0003h0-Gf for qemu-devel@nongnu.org; Tue, 06 May 2014 17:47:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WhnCo-0000Yz-JG for qemu-devel@nongnu.org; Tue, 06 May 2014 17:47:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:10390) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WhnCo-0000Ym-BB for qemu-devel@nongnu.org; Tue, 06 May 2014 17:47:18 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s46LlGYN000529 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 6 May 2014 17:47:16 -0400 Message-ID: <53695863.9080009@redhat.com> Date: Tue, 06 May 2014 15:47:15 -0600 From: Eric Blake MIME-Version: 1.0 References: <1399402854-24559-1-git-send-email-mreitz@redhat.com> <536951A9.1070200@redhat.com> In-Reply-To: <536951A9.1070200@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="nA8xB91DuB1SG6vsmgJnnpj4xqtvnMScw" Subject: Re: [Qemu-devel] [PATCH v2] block/raw-posix: Try both FIEMAP and SEEK_HOLE List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Max Reitz , qemu-devel@nongnu.org Cc: Kevin Wolf , Stefan Hajnoczi This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --nA8xB91DuB1SG6vsmgJnnpj4xqtvnMScw Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 05/06/2014 03:18 PM, Eric Blake wrote: > ...if you are on a file system where SEEK_HOLE triggers the kernel > fallback of "entire file is allocated", but where FIEMAP is wired up fo= r > that file system, would it make sense to have try_seek_hole return -1 i= n > situations where lseek(s->fd, 0, SEEK_HOLE) returns the end of the file= ? > Even more, should skip_seek_hole be a tri-state? On the other hand, such systems are getting vanishingly rare as people upgrade to newer kernels. Do we care about catering to them, or is it fair game to just tell people to upgrade if they want performance? --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --nA8xB91DuB1SG6vsmgJnnpj4xqtvnMScw 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 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJTaVhjAAoJEKeha0olJ0Nq1BsH/08mjpb72yuHNxoOP1L7BlZM 1hpH6EzAgvZfKU61uj0nxm/MgAo4bhe/Bi7FC5jwOGdkEEPS1aYfAOfDhj75ry5f 1u74G2XNSGW8F2DG8Fk3Bbdowfn4cnYiBCi7bjKL2CyL5RQtMRl59fllnoKegVd8 w5QQfG0OuLfGQzTmTWYRLarjmf/s3TD+JlY9dPz6r5A9oKxHvsmMv8AXZf3Fntqf bmdbaXZVFuCo9cYYgQpN+ESam/fCPG+LFbC0G3TMvNQdv4IQ4jPCwDR5cSGA7kFj 0waVBRVVu1g5VlhmMvk3leZdfi0fQgDOZIPK7tl7EzajsJPKlHJ0LCYm1aqg62A= =xXhx -----END PGP SIGNATURE----- --nA8xB91DuB1SG6vsmgJnnpj4xqtvnMScw--