From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: Re: [PATCH 3/3] fm10k/igb/ixgbe: Use load_acquire on Rx descriptor Date: Fri, 14 Nov 2014 09:25:19 -0800 Message-ID: <1415985919.2454.50.camel@jtkirshe-mobl> References: <20141113191250.12579.19694.stgit@ahduyck-server> <20141113192746.12579.91054.stgit@ahduyck-server> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-tkmFPNkhUJCew2m+hnBt" Cc: linux-arch@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, mikey@neuling.org, tony.luck@intel.com, mathieu.desnoyers@polymtl.ca, donald.c.skidmore@intel.com, peterz@infradead.org, benh@kernel.crashing.org, heiko.carstens@de.ibm.com, oleg@redhat.com, will.deacon@arm.com, davem@davemloft.net, michael@ellerman.id.au, matthew.vick@intel.com, nic_swsd@realtek.com, geert@linux-m68k.org, fweisbec@gmail.com, schwidefsky@de.ibm.com, linux@arm.linux.org.uk, paulmck@linux.vnet.ibm.com, torvalds@linux-foundation.org, mingo@kernel.org To: Alexander Duyck Return-path: In-Reply-To: <20141113192746.12579.91054.stgit@ahduyck-server> Sender: linux-arch-owner@vger.kernel.org List-Id: netdev.vger.kernel.org --=-tkmFPNkhUJCew2m+hnBt Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2014-11-13 at 11:27 -0800, Alexander Duyck wrote: > This change makes it so that load_acquire is used when reading the Rx > descriptor. The advantage of load_acquire is that it allows for a > much > lower cost barrier on x86, ia64, powerpc, arm64, and s390 > architectures > than a traditional memory barrier when dealing with reads that only > have > to synchronize to system memory. >=20 > In addition I have updated the code so that it just checks to see if > any > bits have been set instead of just the DD bit since the DD bit will > always > be set as a part of a descriptor write-back so we just need to check > for a > non-zero value being present at that memory location rather than just > checking for any specific bit. This allows the code itself to appear > much > cleaner and allows the compiler more room to optimize. >=20 > Cc: Jeff Kirsher > Cc: Matthew Vick > Cc: Don Skidmore > Signed-off-by: Alexander Duyck > --- > drivers/net/ethernet/intel/fm10k/fm10k_main.c | 8 +++----- > drivers/net/ethernet/intel/igb/igb_main.c | 8 +++----- > drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 11 ++++------- > 3 files changed, 10 insertions(+), 17 deletions(-) Based on the discussion on patch 01 of the series, it appears changes are coming to the series, so I won't be picking up this patch. I will wait for Alex to re-spin the series with the suggested changes. --=-tkmFPNkhUJCew2m+hnBt 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 v2 iQIcBAABCgAGBQJUZjr/AAoJEOVv75VaS+3O7EoP/jPOeNPsC6iYfhdffYVIuRSd 02LHiX6nVaiQ5b7MRq39BhaFyeqUne5Kdmj44xpKr9SBjFLcl93XE2llV3DzwvZ2 W9iQgSEliV+ZpCTuhPTGP34nx2chUH9UMLc5vxUlNjEaoInq8CCg0HYyHtV8I1tV pxbx3sQbH/kAsiXZ2gn4cN0VwAWAmjzViaE20mBLXK73ulzUbyZ2LLFiSgo7Op3m N/B9PmdfZnhafJRy3xOAz/GPPVhJKkgzxfme6QQbtTI2lGFYZFUcg3R5WPJ8T43/ IDxnyw27IgKRR/EbZNbRr76hl8FzuhgAHZkkMy4EkTfAwMlrYrQ/LsXsMMwirR3/ ZHeQ11DB/JMZIB78G9GlNXmbT1s6daKExcuaTigJcWxeVNkQDEPHbA/0x+J8TSgs WWH3qgSGJ2MolizljOWywF/phP2Mg9PFAmwpHBZO1mML9hxuleral4h9r/jou4kv kn27OYUK7YwI/D6yo8PhaboMlkPwx/fISzdjFfMn5hs4EtOVP2c/5qgH8iFwJFOi H2JPu1b3OBoiLcUXMPV7g4DV2w1ePzFsLjMNgQwLybehZow9mgJR2Rnroc2HPXQO lcYz9fATkKlJ95f2z9Nsgm7k2Nb73PgZkINxkG05Gcb43HMLRz6OdYyHJP+SLEvp kwLli3RkROPoYBay0zM1 =QB5M -----END PGP SIGNATURE----- --=-tkmFPNkhUJCew2m+hnBt--