On 11/25/2014 12:35 PM, Alexander Duyck wrote: > These patches introduce two new primitives for synchronizing cache coherent > memory writes and reads. These two new primitives are: > > dma_rmb() > dma_wmb() > > The first patch cleans up some unnecessary overhead related to the > definition of read_barrier_depends, smp_read_barrier_depends, and comments > related to the barrier. > > The second patch adds the primitives for the applicable architectures and > asm-generic. > > The third patch adds the barriers to r8169 which turns out to be a good > example of where the new barriers might be useful as they have full > rmb()/wmb() barriers ordering accesses to the descriptors and the DescOwn > bit. > > The fourth patch adds support for coherent_rmb() to the Intel fm10k, igb, > and ixgbe drivers. Testing with the ixgbe driver has shown a processing > time reduction of at least 7ns per 64B frame on a Core i7-4930K. > > This patch series is essentially the v7 for: > v4-6: Add lightweight memory barriers for coherent memory access > v3: Add lightweight memory barriers fast_rmb() and fast_wmb() > v2: Introduce load_acquire() and store_release() > v1: Introduce read_acquire() > > The key changes in this patch series versus the earlier patches are: > v7: > - Dropped test/debug patch that was accidentally slipped in > v6: > - Replaced "memory based device I/O" with "consistent memory" in > docs > - Added reference to DMA-API.txt to explain consistent memory > v5: > - Renamed barriers dma_rmb and dma_wmb > - Undid smp_wmb changes in x86 and PowerPC > - Defined smp_rmb as __lwsync for SMP case on PowerPC > v4: > - Renamed barriers coherent_rmb and coherent_wmb > - Added smp_lwsync for use in smp_load_acquire/smp_store_release > v3: > - Moved away from acquire()/store() and instead focused on barriers > - Added cleanup of read_barrier_depends > - Added change in r8169 to fix cur_tx/DescOwn ordering > - Simplified changes to just replacing/moving barriers in r8169 > - Added update to documentation with code example > v2: > - Renamed read_acquire() to be consistent with smp_load_acquire() > - Changed barrier used to be consistent with smp_load_acquire() > - Updated PowerPC code to use __lwsync based on IBM article > - Added store_release() as this is a viable use case for drivers > - Added r8169 patch which is able to fully use primitives > - Added fm10k/igb/ixgbe patch which is able to test performance > > --- > > Alexander Duyck (4): > arch: Cleanup read_barrier_depends() and comments > arch: Add lightweight memory barriers dma_rmb() and dma_wmb() > r8169: Use dma_rmb() and dma_wmb() for DescOwn checks > fm10k/igb/ixgbe: Use dma_rmb on Rx descriptor reads > > > Documentation/memory-barriers.txt | 42 +++++++++++++++ > arch/alpha/include/asm/barrier.h | 51 ++++++++++++++++++ > arch/arm/include/asm/barrier.h | 4 + > arch/arm64/include/asm/barrier.h | 3 + > arch/blackfin/include/asm/barrier.h | 51 ++++++++++++++++++ > arch/ia64/include/asm/barrier.h | 25 ++++----- > arch/metag/include/asm/barrier.h | 19 ++++--- > arch/mips/include/asm/barrier.h | 61 ++-------------------- > arch/powerpc/include/asm/barrier.h | 19 ++++--- > arch/s390/include/asm/barrier.h | 7 ++- > arch/sparc/include/asm/barrier_64.h | 7 ++- > arch/x86/include/asm/barrier.h | 70 ++++--------------------- > arch/x86/um/asm/barrier.h | 20 ++++--- > 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 +-- > drivers/net/ethernet/realtek/r8169.c | 29 ++++++++-- > include/asm-generic/barrier.h | 8 +++ > 18 files changed, 258 insertions(+), 179 deletions(-) > > -- It occurs to me that I never got a sign off from any of the maintainers on getting this pulled in. Since the merge window is open I was wondering which tree I should make sure these patches apply to and who will be the one to pull them in? Since I was modifying network drivers should I resubmit them for netdev, or should I submit them for asm-generic or some other tree? - Alex -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
