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Commit 9ba6d552 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by Roland Dreier
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IB/mthca: Work around kernel QP starvation 



With mthca, RC QPs can starve each other and even UD QPs on the same
hardware schedule queue.  As a result, userspace MPI can starve
e.g. IPoIB traffic, with netdev watchdog warnings getting printed out,
and TCP connections getting stuck or failing.

Reduce the chance of this happening by using three separate hardware
schedule queues: one for userspace RC QPs, one for kernel RC QPs, and
one for all other QPs.

Signed-off-by: default avatarMichael S. Tsirkin <mst@dev.mellanox.co.il>
Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent c3af664a

drivers/infiniband/hw/mthca/mthca_qp.c

+13 −0
Original line number Diff line number Diff line
@@ -701,6 +701,19 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask, 
		qp_param->opt_param_mask |= cpu_to_be32(MTHCA_QP_OPTPAR_PRIMARY_ADDR_PATH);

	}



	if (ibqp->qp_type == IB_QPT_RC &&

	    cur_state == IB_QPS_INIT && new_state == IB_QPS_RTR) {

		u8 sched_queue = ibqp->uobject ? 0x2 : 0x1;



		if (mthca_is_memfree(dev))

			qp_context->rlkey_arbel_sched_queue |= sched_queue;

		else

			qp_context->tavor_sched_queue |= cpu_to_be32(sched_queue);



		qp_param->opt_param_mask |=

			cpu_to_be32(MTHCA_QP_OPTPAR_SCHED_QUEUE);

	}



	if (attr_mask & IB_QP_TIMEOUT) {

		qp_context->pri_path.ackto = attr->timeout << 3;

		qp_param->opt_param_mask |= cpu_to_be32(MTHCA_QP_OPTPAR_ACK_TIMEOUT);