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IB/core: add max_send_sge and max_recv_sge attributes

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This patch replaces the ib_device_attr.max_sge with max_send_sge and
max_recv_sge. It allows ulps to take advantage of devices that have very
different send and recv sge depths.  For example cxgb4 has a max_recv_sge
of 4, yet a max_send_sge of 16.  Splitting out these attributes allows
much more efficient use of the SQ for cxgb4 with ulps that use the RDMA_RW
API. Consider a large RDMA WRITE that has 16 scattergather entries.
With max_sge of 4, the ulp would send 4 WRITE WRs, but with max_sge of
16, it can be done with 1 WRITE WR.

Acked-by: Sagi Grimberg <sagi@grimberg.me>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Selvin Xavier <selvin.xavier@broadcom.com>
Acked-by: Shiraz Saleem <shiraz.saleem@intel.com>
Acked-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Steve Wise
2018-06-18 08:05:26 -07:00
committed by Jason Gunthorpe
parent b90575ce7b
commit 33023fb85a
28 changed files with 65 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
net/rds/ib.c
View File

@ -143,7 +143,7 @@ static void rds_ib_add_one(struct ib_device *device)
INIT_WORK(&rds_ibdev->free_work, rds_ib_dev_free);
rds_ibdev->max_wrs = device->attrs.max_qp_wr;
rds_ibdev->max_sge = min(device->attrs.max_sge, RDS_IB_MAX_SGE);
rds_ibdev->max_sge = min(device->attrs.max_send_sge, RDS_IB_MAX_SGE);
has_fr = (device->attrs.device_cap_flags &
IB_DEVICE_MEM_MGT_EXTENSIONS);

2
net/sunrpc/xprtrdma/svc_rdma_transport.c
View File

@ -476,7 +476,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
/* Qualify the transport resource defaults with the
* capabilities of this particular device */
newxprt->sc_max_send_sges = dev->attrs.max_sge;
newxprt->sc_max_send_sges = dev->attrs.max_send_sge;
/* transport hdr, head iovec, one page list entry, tail iovec */
if (newxprt->sc_max_send_sges < 4) {
pr_err("svcrdma: too few Send SGEs available (%d)\n",

2
net/sunrpc/xprtrdma/verbs.c
View File

@ -508,7 +508,7 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
unsigned int max_sge;
int rc;
max_sge = min_t(unsigned int, ia->ri_device->attrs.max_sge,
max_sge = min_t(unsigned int, ia->ri_device->attrs.max_send_sge,
RPCRDMA_MAX_SEND_SGES);
if (max_sge < RPCRDMA_MIN_SEND_SGES) {
pr_warn("rpcrdma: HCA provides only %d send SGEs\n", max_sge);