Subject: [PATCH mlx5-next 10/10] net/rds: Use prefetch for On-Demand-Paging MR

From: Leon Romanovsky <[email-masked]>
Date: Wed, 15 Jan 2020 14:43:40 +0200

From: Hans Westgaard Ry <[email-masked]>

Try prefetching pages when using On-Demand-Paging MR using
ib_advise_mr.

Signed-off-by: Hans Westgaard Ry <[email-masked]>
Signed-off-by: Leon Romanovsky <[email-masked]>
---
 net/rds/ib_rdma.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/net/rds/ib_rdma.c b/net/rds/ib_rdma.c
index 5a02b313ec50..5268a76e5db7 100644
--- a/net/rds/ib_rdma.c
+++ b/net/rds/ib_rdma.c
@@ -574,6 +574,7 @@ void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
 			(IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_READ |
 			 IB_ACCESS_REMOTE_WRITE | IB_ACCESS_REMOTE_ATOMIC |
 			 IB_ACCESS_ON_DEMAND);
+		struct ib_sge sge = {};
 		struct ib_mr *ib_mr;

 		if (!rds_ibdev->odp_capable) {
@@ -601,6 +602,14 @@ void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
 		}
 		ibmr->u.mr = ib_mr;
 		ibmr->odp = 1;
+
+		sge.addr = virt_addr;
+		sge.length = length;
+		sge.lkey = ib_mr->lkey;
+
+		ib_advise_mr(rds_ibdev->pd,
+			     IB_UVERBS_ADVISE_MR_ADVICE_PREFETCH_WRITE,
+			     IB_UVERBS_ADVISE_MR_FLAG_FLUSH, &sge, 1);
 		return ibmr;
 	}

--
2.20.1