The following series implements adds blk-mq support to the pmem block driver and also adds infrastructure code to ioatdma and dmaengine in order to support copying to and from scatterlist in order to process block requests provided by blk-mq. The usage of DMA engines available on certain platforms allow us to drastically reduce CPU utilization and at the same time maintain performance that is good enough. Experimentations have been done on DRAM backed pmem block device that showed the utilization of DMA engine is beneficial. User can revert back to original behavior by providing queue_mode=0 to the nd_pmem kernel module if desired.
--- Dave Jiang (5): dmaengine: ioatdma: revert 7618d035 to allow sharing of DMA channels dmaengine: ioatdma: dma_prep_memcpy_to/from_sg support dmaengine: add SG support to dmaengine_unmap libnvdimm: Adding blk-mq support to the pmem driver libnvdimm: add DMA support for pmem blk-mq drivers/dma/dmaengine.c | 45 +++++- drivers/dma/ioat/dma.h | 8 + drivers/dma/ioat/init.c | 6 - drivers/dma/ioat/prep.c | 105 ++++++++++++++ drivers/nvdimm/pmem.c | 340 ++++++++++++++++++++++++++++++++++++++++++--- drivers/nvdimm/pmem.h | 3 include/linux/dmaengine.h | 14 ++ 7 files changed, 488 insertions(+), 33 deletions(-) -- _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm