Date: Sun, 03 Jul 2005 01:07:13 -0000 From: Ruslan Ermilov <ru@freebsd.org> To: Sam Leffler <sam@errno.com> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/net if_ethersubr.c Message-ID: <20050214195558.GD69635@ip.net.ua> In-Reply-To: <4210F849.8060005@errno.com> References: <200502140829.j1E8TgDs086634@repoman.freebsd.org> <4210D210.3080700@errno.com> <20050214181431.GA69635@ip.net.ua> <4210F849.8060005@errno.com>
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--ZJcv+A0YCCLh2VIg Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Feb 14, 2005 at 11:13:13AM -0800, Sam Leffler wrote: > >>This also has the potential to noticeably=20 > >>affect performance so I think a better solution is needed. > > > >Here are my thoughts. On a typical input path, there will be > >either one or zero mtags, one if driver provided us with the > >VLAN mtag, so effectively we replaced "ifp->if_nvlans" with > >"m_tag_first(m) !=3D NULL", and this doesn't look like a huge > >performance downgrade to me, if at all. >=20 > The intent was/is that if_nvlans be the definitive check for whether or= =20 > not one should inspect the tag chain for vlan tags. This effectively=20 > renders that assumption invalid. I think it would better to discard=20 > these frames in the driver rather than allocate a tag, pass it up, then= =20 > discard it in ether_demux. I think you could encapsulate the check in=20 > VLAN_INPUT_TAG. >=20 I said this before: vlan(4) is not the only consumer of VLAN frames in FreeBSD. VLAN frames are also accepted by ng_vlan(4), so using the vlan(4)-specific if_nvlans to decide whether we should accept VLAN frames (in the driver) just isn't appropriate. Cheers, --=20 Ruslan Ermilov ru@FreeBSD.org FreeBSD committer --ZJcv+A0YCCLh2VIg Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) iD8DBQFCEQJOqRfpzJluFF4RArqWAJ4nebCnnEqH9bY70nRcsIHBccSpygCcCgy6 iFW2jaRYMsBIImp9B4KQk0s= =8o75 -----END PGP SIGNATURE----- --ZJcv+A0YCCLh2VIg--
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