From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: Re: [PATCH net-next-2.6] e1000: save skb counts in TX to avoid cache misses Date: Thu, 25 Aug 2011 20:52:39 -0700 Message-ID: <1314330760.2097.39.camel@jtkirshe-mobl> References: <20110826003923.4083.24862.email-sent-by-dnelson@localhost6.localdomain6> Reply-To: jeffrey.t.kirsher@intel.com Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-KIw9PJRNwYOGE2z7jpUZ" Cc: "netdev@vger.kernel.org" , Andy Gospodarek To: Dean Nelson Return-path: Received: from mga02.intel.com ([134.134.136.20]:27563 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752059Ab1HZDwk (ORCPT ); Thu, 25 Aug 2011 23:52:40 -0400 In-Reply-To: <20110826003923.4083.24862.email-sent-by-dnelson@localhost6.localdomain6> Sender: netdev-owner@vger.kernel.org List-ID: --=-KIw9PJRNwYOGE2z7jpUZ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2011-08-25 at 17:39 -0700, Dean Nelson wrote: > Virtual Machines with emulated e1000 network adapter running on > Parallels' > server were seeing kernel panics due to the e1000 driver dereferencing > an > unexpected NULL pointer retrieved from buffer_info->skb. >=20 > The problem has been addressed for the e1000e driver, but not for the > e1000. > Since the two drivers share similar code in the affected area, a port > of the > following e1000e driver commit solves the issue for the e1000 driver: >=20 > commit 9ed318d546a29d7a591dbe648fd1a2efe3be1180 > Author: Tom Herbert > Date: Wed May 5 14:02:27 2010 +0000 >=20 > e1000e: save skb counts in TX to avoid cache misses >=20 > In e1000_tx_map, precompute number of segements and bytecounts > which > are derived from fields in skb; these are stored in buffer_info. > When > cleaning tx in e1000_clean_tx_irq use the values in the associated > buffer_info for statistics counting, this eliminates cache misses > on skb fields. >=20 >=20 > Signed-off-by: Dean Nelson =20 Acked-by: Jeff Kirsher Looks fine. --=-KIw9PJRNwYOGE2z7jpUZ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQEcBAABAgAGBQJOVxiHAAoJECTsCADr/EWUgRgH/3ZFTc0XQ+6zc9VPT/S2TAWX /M0KyWMv5QiOj1+Ror80nBIJT6DpAiNqMuXClQb6c2aTE/CRswA/ajw27eNyoDbN dX+gwfUsaIYVu/2KVoatKP7P5wqcJCDBDvjC9togf8CAGYD9v2TABQLUd/KR9mds U45QVIIp/MSN6+jGhLSf+3Q1FggjE78xhpc3UiTR1kxjbpcCdIbdHFO+13EbioeE 8yHq/pTYTBkwXu1FsWKEzUeo/2482wqaP0JAQmoBcLOoIxI9htIHdiwPTMy9i1G4 iJXc4MGA0Kki1cUYEFcNzNfk/jCXGK4rJdOQfMy0SqczGnwj1qjVODea01IJTnA= =EQgU -----END PGP SIGNATURE----- --=-KIw9PJRNwYOGE2z7jpUZ--