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(-)
--
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