diff options
author | Jason Gunthorpe <jgg@mellanox.com> | 2019-10-22 20:27:25 +0300 |
---|---|---|
committer | Jason Gunthorpe <jgg@mellanox.com> | 2019-10-22 20:27:25 +0300 |
commit | a2aca4d7f0f8ab98ba1e0db484576fc827568689 (patch) | |
tree | 12258cf10d134588e741bf224f1b439de7af80af /drivers/infiniband/core | |
parent | cf049bb31f7101d9672eaf97ade4fdd5171ddf26 (diff) | |
parent | 366090564b812453f531051129b82b63dad8f38b (diff) | |
download | linux-a2aca4d7f0f8ab98ba1e0db484576fc827568689.tar.xz |
Merge branch 'mlx5-rd-sgl' into rdma.git for-next
From Yamin Friedman:
====================
This series from Yamin implements long standing "TODO" existed in rw.c. It
allows the driver to specify a cut-over point where it is faster to build
a lkey MR rather than do a large SGL for RDMA READ operations.
mlx5 HW gets a notable performane boost by switching to MRs.
====================
Based on the mlx5-next branch from
git://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux for
dependencies
* branch 'mlx5-rd-sgl': (3 commits)
RDMA/mlx5: Add capability for max sge to get optimized performance
RDMA/rw: Support threshold for registration vs scattering to local pages
net/mlx5: Expose optimal performance scatter entries capability
Diffstat (limited to 'drivers/infiniband/core')
-rw-r--r-- | drivers/infiniband/core/rw.c | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/drivers/infiniband/core/rw.c b/drivers/infiniband/core/rw.c index 5337393d4dfe..4fad732f9b3c 100644 --- a/drivers/infiniband/core/rw.c +++ b/drivers/infiniband/core/rw.c @@ -20,14 +20,17 @@ module_param_named(force_mr, rdma_rw_force_mr, bool, 0); MODULE_PARM_DESC(force_mr, "Force usage of MRs for RDMA READ/WRITE operations"); /* - * Check if the device might use memory registration. This is currently only - * true for iWarp devices. In the future we can hopefully fine tune this based - * on HCA driver input. + * Report whether memory registration should be used. Memory registration must + * be used for iWarp devices because of iWARP-specific limitations. Memory + * registration is also enabled if registering memory might yield better + * performance than using multiple SGE entries, see rdma_rw_io_needs_mr() */ static inline bool rdma_rw_can_use_mr(struct ib_device *dev, u8 port_num) { if (rdma_protocol_iwarp(dev, port_num)) return true; + if (dev->attrs.max_sgl_rd) + return true; if (unlikely(rdma_rw_force_mr)) return true; return false; @@ -35,17 +38,19 @@ static inline bool rdma_rw_can_use_mr(struct ib_device *dev, u8 port_num) /* * Check if the device will use memory registration for this RW operation. - * We currently always use memory registrations for iWarp RDMA READs, and - * have a debug option to force usage of MRs. - * - * XXX: In the future we can hopefully fine tune this based on HCA driver - * input. + * For RDMA READs we must use MRs on iWarp and can optionally use them as an + * optimization otherwise. Additionally we have a debug option to force usage + * of MRs to help testing this code path. */ static inline bool rdma_rw_io_needs_mr(struct ib_device *dev, u8 port_num, enum dma_data_direction dir, int dma_nents) { - if (rdma_protocol_iwarp(dev, port_num) && dir == DMA_FROM_DEVICE) - return true; + if (dir == DMA_FROM_DEVICE) { + if (rdma_protocol_iwarp(dev, port_num)) + return true; + if (dev->attrs.max_sgl_rd && dma_nents > dev->attrs.max_sgl_rd) + return true; + } if (unlikely(rdma_rw_force_mr)) return true; return false; |