Messages in this thread | | | Subject | Re: [PATCH v5 4/4] fm10k/igb/ixgbe: Use dma_rmb on Rx descriptor reads | From | Jeff Kirsher <> | Date | Tue, 18 Nov 2014 17:28:48 -0800 |
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On Tue, 2014-11-18 at 17:24 -0800, Alexander Duyck wrote: > This change makes it so that dma_rmb is used when reading the Rx > descriptor. The advantage of dma_rmb is that it allows for a much > lower cost barrier on x86, powerpc, arm, and arm64 architectures than > a > traditional memory barrier when dealing with reads that only have to > synchronize to coherent memory. > > 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. > > Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com> > Cc: Matthew Vick <matthew.vick@intel.com> > Cc: Don Skidmore <donald.c.skidmore@intel.com> > Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com> > --- > drivers/net/ethernet/intel/fm10k/fm10k_main.c | 6 +++--- > drivers/net/ethernet/intel/igb/igb_main.c | 6 +++--- > drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 9 ++++----- > 3 files changed, 10 insertions(+), 11 deletions(-)
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> [unhandled content-type:application/pgp-signature] | |