From: Michael S. Tsirkin Date: Thu, 12 Apr 2007 15:10:25 +0000 (+0300) Subject: IB/mthca: Work around kernel QP starvation X-Git-Tag: v2.6.22-rc1~824^2~15 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9ba6d5529dd919b442eedf5bef1dd28aca2ee9fe;p=linux-2.6 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: Michael S. Tsirkin Signed-off-by: Roland Dreier --- diff --git a/drivers/infiniband/hw/mthca/mthca_qp.c b/drivers/infiniband/hw/mthca/mthca_qp.c index 8fe6fee7a9..fee60c852d 100644 --- a/drivers/infiniband/hw/mthca/mthca_qp.c +++ b/drivers/infiniband/hw/mthca/mthca_qp.c @@ -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);