Date: Mon, 6 May 2013 22:29:52 +0200 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r250027 - head/sys/kern Message-ID: <20130506202951.GB1390@garage.freebsd.pl> In-Reply-To: <20130506200530.GD3047@kib.kiev.ua> References: <201304281912.r3SJC9bL030636@svn.freebsd.org> <20130506181610.GA1390@garage.freebsd.pl> <20130506200530.GD3047@kib.kiev.ua>
next in thread | previous in thread | raw e-mail | index | archive | help
--VrqPEDrXMn8OVzN4 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, May 06, 2013 at 11:05:30PM +0300, Konstantin Belousov wrote: > On Mon, May 06, 2013 at 08:16:11PM +0200, Pawel Jakub Dawidek wrote: > > On Sun, Apr 28, 2013 at 07:12:09PM +0000, Konstantin Belousov wrote: > > > Author: kib > > > Date: Sun Apr 28 19:12:09 2013 > > > New Revision: 250027 > > > URL: http://svnweb.freebsd.org/changeset/base/250027 > > >=20 > > > Log: > > > Eliminate the layering violation in the kern_sendfile(). When quer= ing > > > the file size, use VOP_GETATTR() instead of accessing vnode vm_obje= ct > > > un_pager.vnp.vnp_size. > >=20 > > Doesn't it add extra I/O to query file system about file's attributes? > > If it does, does it matter here? >=20 > It should not, typically. >=20 > E.g. UFS always keeps the unpacked inode in memory for any non-reclaimed > vnode. For NFS, vnode usually caches the attributes. I remember criticism on security.bsd.hardlink_check_[ug]id, because it added extra VOP_GETATTR() to the code path of link(2), which could hurt performance. sendfile(2) is different, as the file is open, so it should be fine indeed. --=20 Pawel Jakub Dawidek http://www.wheelsystems.com FreeBSD committer http://www.FreeBSD.org Am I Evil? Yes, I Am! http://mobter.com --VrqPEDrXMn8OVzN4 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEARECAAYFAlGIEr8ACgkQForvXbEpPzS9nwCeK3lE99kxonIFc6SSqdscihzt pewAn1BiuTD3qvSJIN6feHxXwEzvDsyb =tdEP -----END PGP SIGNATURE----- --VrqPEDrXMn8OVzN4--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20130506202951.GB1390>