On Wed, May 26, 2021 at 04:49:06PM -0300, Jason Gunthorpe wrote:

On Thu, May 20, 2021 at 01:13:36PM +0300, Leon Romanovsky wrote:

quoted

From: Avihai Horon <redacted>

Relaxed Ordering is enabled by default for kernel ULPs, and is set
during MKey creation, yet it cannot be modified by them afterwards.

Allow modifying Relaxed Ordering via fast registration work request.
This is done by setting the relevant flags in the MKey context mask and
the Relaxed Ordering flags in the MKey context itself.

Only ConnectX-7 supports modifying Relaxed Ordering via fast
registration, and HCA capabilities indicate it. These capabilities are
checked, and if a fast registration work request tries to modify Relaxed
Ordering and the capabilities are not present, the work request will fail.

quoted

@@ -762,23 +786,33 @@ static void set_sig_mkey_segment(struct mlx5_mkey_seg *seg,
 	seg->len = cpu_to_be64(length);
 	seg->xlt_oct_size = cpu_to_be32(get_xlt_octo(size));
 	seg->bsfs_octo_size = cpu_to_be32(MLX5_MKEY_BSF_OCTO_SIZE);
+
+	if (!(access_flags & IB_ACCESS_DISABLE_RELAXED_ORDERING)) {
+		MLX5_SET(mkc, seg, relaxed_ordering_write,
+			 MLX5_CAP_GEN(dev->mdev, relaxed_ordering_write_umr));
+		MLX5_SET(mkc, seg, relaxed_ordering_read,
+			 MLX5_CAP_GEN(dev->mdev, relaxed_ordering_read_umr));
+	}
 }

I don't quite get this patch

This is premature optimization. We don't really need it.

Thanks