From: Dag Moxnes <dag.moxnes@oracle.com>
Date: Wed, 30 Oct 2019 13:44:00 +0100
Subject: RDMA/cma: Use ACK timeout for RoCE packetLifeTime
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Patch-mainline: v5.5-rc1
Git-commit: e1ee1e62bec4a8968355517ea11b2a06b7364408
References: jsc#SLE-8449
The cma is currently using a hard-coded value, CMA_IBOE_PACKET_LIFETIME,
for the PacketLifeTime, as it can not be determined from the network.
This value might not be optimal for all networks.
The cma module supports the function rdma_set_ack_timeout to set the ACK
timeout for a QP associated with a connection. As per IBTA 12.7.34 local
ACK timeout = (2 * PacketLifeTime + Local CA’s ACK delay). Assuming a
negligible local ACK delay, we can use PacketLifeTime = local ACK
timeout/2 as a reasonable approximation for RoCE networks.
Link: https://lore.kernel.org/r/1572439440-17416-1-git-send-email-dag.moxnes@oracle.com
Signed-off-by: Dag Moxnes <dag.moxnes@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/infiniband/core/cma.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -2504,7 +2504,9 @@ EXPORT_SYMBOL(rdma_set_service_type);
* This function should be called before rdma_connect() on active side,
* and on passive side before rdma_accept(). It is applicable to primary
* path only. The timeout will affect the local side of the QP, it is not
- * negotiated with remote side and zero disables the timer.
+ * negotiated with remote side and zero disables the timer. In case it is
+ * set before rdma_resolve_route, the value will also be used to determine
+ * PacketLifeTime for RoCE.
*
* Return: 0 for success
*/
@@ -2913,7 +2915,16 @@ static int cma_resolve_iboe_route(struct
route->path_rec->rate = iboe_get_rate(ndev);
dev_put(ndev);
route->path_rec->packet_life_time_selector = IB_SA_EQ;
- route->path_rec->packet_life_time = CMA_IBOE_PACKET_LIFETIME;
+ /* In case ACK timeout is set, use this value to calculate
+ * PacketLifeTime. As per IBTA 12.7.34,
+ * local ACK timeout = (2 * PacketLifeTime + Local CA’s ACK delay).
+ * Assuming a negligible local ACK delay, we can use
+ * PacketLifeTime = local ACK timeout/2
+ * as a reasonable approximation for RoCE networks.
+ */
+ route->path_rec->packet_life_time = id_priv->timeout_set ?
+ id_priv->timeout - 1 : CMA_IBOE_PACKET_LIFETIME;
+
if (!route->path_rec->mtu) {
ret = -EINVAL;
goto err2;