Messages in this thread Patch in this message | | | From | Ben Hutchings <> | Date | Sun, 07 Apr 2013 23:45:42 +0100 | Subject | [26/74] IPoIB: Fix send lockup due to missed TX completion |
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3.2.43-rc1 review patch. If anyone has any objections, please let me know.
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From: Mike Marciniszyn <mike.marciniszyn@intel.com>
commit 1ee9e2aa7b31427303466776f455d43e5e3c9275 upstream.
Commit f0dc117abdfa ("IPoIB: Fix TX queue lockup with mixed UD/CM traffic") attempts to solve an issue where unprocessed UD send completions can deadlock the netdev.
The patch doesn't fully resolve the issue because if more than half the tx_outstanding's were UD and all of the destinations are RC reachable, arming the CQ doesn't solve the issue.
This patch uses the IB_CQ_REPORT_MISSED_EVENTS on the ib_req_notify_cq(). If the rc is above 0, the UD send cq completion callback is called directly to re-arm the send completion timer.
This issue is seen in very large parallel filesystem deployments and the patch has been shown to correct the issue.
Reviewed-by: Dean Luick <dean.luick@intel.com> Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/infiniband/ulp/ipoib/ipoib_cm.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c @@ -755,9 +755,13 @@ void ipoib_cm_send(struct net_device *de if (++priv->tx_outstanding == ipoib_sendq_size) { ipoib_dbg(priv, "TX ring 0x%x full, stopping kernel net queue\n", tx->qp->qp_num); - if (ib_req_notify_cq(priv->send_cq, IB_CQ_NEXT_COMP)) - ipoib_warn(priv, "request notify on send CQ failed\n"); netif_stop_queue(dev); + rc = ib_req_notify_cq(priv->send_cq, + IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS); + if (rc < 0) + ipoib_warn(priv, "request notify on send CQ failed\n"); + else if (rc) + ipoib_send_comp_handler(priv->send_cq, dev); } } }
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